Linuxプロセスのトラブルシューティングとデバッグのための10のstraceコマンド


ある[ strace は、LinuxなどのUnixライクなオペレーティングシステムでプログラムをデバッグおよびトラブルシューティングするための強力なコマンドラインツールです。プロセスによって行われたすべてのシステムコールとプロセスによって受信されたシグナルを取得して記録します。

各システムコールの名前とその引数をかっこで囲み、その戻り値を標準エラーに表示します。オプションでファイルにリダイレクトすることもできます。

この記事では、Linuxシステムにおけるプログラムとプロセスのトラブルシューティングとデバッグのための10のstraceコマンド例を説明します。

LinuxにStrace Process Monitoring Toolをインストールする方法

Linuxシステムに strace がプレインストールされていない場合は、ディストリビューションに合わせて以下の適切なコマンドを実行してインストールします。

$ sudo apt install strace	#Debian/Ubuntu 
# yum install strace		#RHEL/CentOS
# dnf install strace		#Fedora 22+

プログラムがクラッシュしたり予期しない方法で動作したりする場合は、システムコールを調べて、実行中に正確に起こったことの手掛かりを得ることができます。後で見るように、システムコールはプロセス管理に関するもの、ファイルを引数とするもの、ネットワーキング、メモリマッピング、シグナル、IPC、そしてファイルディスクリプタ関連のシステムコールなど、さまざまなイベントに分類できます。

プログラム/コマンドをstraceで実行するか、以下の例のように -p オプションを使用してPIDを渡すことができます。

1. Linuxコマンドシステムコールのトレース

このように strace を付けてコマンドを実行することができます。ここでは、dfコマンドによって行われたすべてのシステムコールをトレースしています。

$ strace df -h

execve("/bin/df", ["df", "-h"], [/* 50 vars */]) = 0
brk(NULL)                               = 0x136e000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f82f78fd000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f82f78d8000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "7ELF
$ strace df -h
execve("/bin/df", ["df", "-h"], [/* 50 vars */]) = 0
brk(NULL)                               = 0x136e000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f82f78fd000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f82f78d8000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f82f7310000
...
$ strace df -h
execve("/bin/df", ["df", "-h"], [/* 50 vars */]) = 0
brk(NULL)                               = 0x136e000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f82f78fd000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f82f78d8000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f82f7310000
...
$ strace df -h
execve("/bin/df", ["df", "-h"], [/* 50 vars */]) = 0
brk(NULL)                               = 0x136e000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f82f78fd000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f82f78d8000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f82f7310000
...
$ strace df -h
execve("/bin/df", ["df", "-h"], [/* 50 vars */]) = 0
brk(NULL)                               = 0x136e000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f82f78fd000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f82f78d8000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f82f7310000
...
$ strace df -h
execve("/bin/df", ["df", "-h"], [/* 50 vars */]) = 0
brk(NULL)                               = 0x136e000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f82f78fd000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f82f78d8000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f82f7310000
...
$ strace df -h
execve("/bin/df", ["df", "-h"], [/* 50 vars */]) = 0
brk(NULL)                               = 0x136e000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f82f78fd000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f82f78d8000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f82f7310000
...
$ strace df -h
execve("/bin/df", ["df", "-h"], [/* 50 vars */]) = 0
brk(NULL)                               = 0x136e000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f82f78fd000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f82f78d8000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f82f7310000
...
$ strace df -h
execve("/bin/df", ["df", "-h"], [/* 50 vars */]) = 0
brk(NULL)                               = 0x136e000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f82f78fd000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f82f78d8000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f82f7310000
...
$ strace df -h
execve("/bin/df", ["df", "-h"], [/* 50 vars */]) = 0
brk(NULL)                               = 0x136e000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f82f78fd000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f82f78d8000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f82f7310000
...
$ strace df -h
execve("/bin/df", ["df", "-h"], [/* 50 vars */]) = 0
brk(NULL)                               = 0x136e000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f82f78fd000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f82f78d8000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f82f7310000
...
$ strace df -h
execve("/bin/df", ["df", "-h"], [/* 50 vars */]) = 0
brk(NULL)                               = 0x136e000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f82f78fd000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f82f78d8000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f82f7310000
...
$ strace df -h
execve("/bin/df", ["df", "-h"], [/* 50 vars */]) = 0
brk(NULL)                               = 0x136e000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f82f78fd000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f82f78d8000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f82f7310000
...
$ strace df -h
execve("/bin/df", ["df", "-h"], [/* 50 vars */]) = 0
brk(NULL)                               = 0x136e000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f82f78fd000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f82f78d8000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f82f7310000
...
$ strace df -h
execve("/bin/df", ["df", "-h"], [/* 50 vars */]) = 0
brk(NULL)                               = 0x136e000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f82f78fd000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f82f78d8000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f82f7310000
...
$ strace df -h
execve("/bin/df", ["df", "-h"], [/* 50 vars */]) = 0
brk(NULL)                               = 0x136e000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f82f78fd000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f82f78d8000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f82f7310000
...
$ strace df -h
execve("/bin/df", ["df", "-h"], [/* 50 vars */]) = 0
brk(NULL)                               = 0x136e000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f82f78fd000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f82f78d8000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f82f7310000
...
$ strace df -h
execve("/bin/df", ["df", "-h"], [/* 50 vars */]) = 0
brk(NULL)                               = 0x136e000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f82f78fd000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f82f78d8000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f82f7310000
...
$ strace df -h
execve("/bin/df", ["df", "-h"], [/* 50 vars */]) = 0
brk(NULL)                               = 0x136e000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f82f78fd000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f82f78d8000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f82f7310000
...

上記の出力から、たとえば df command によって行われたさまざまなタイプのシステムコールを見ることができます。

open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3

どこで:

  • open – is the type of system call
  • (“/etc/ld.so.cache”, O_RDONLY|O_CLOEXEC) – system call argument
  • 3 – system call return value

下記はwriteシステムコールを示す出力例です。これは画面に df command の出力を表示します。

mmap(NULL, 26258, PROT_READ, MAP_SHARED, 3, 0) = 0x7f82f78f5000
close(3)                                = 0
fstat(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 1), ...}) = 0
write(1, "Filesystem      Size  Used Avail"..., 49Filesystem      Size  Used Avail Use% Mounted on
) = 49
write(1, "udev            3.9G     0  3.9G"..., 43udev            3.9G     0  3.9G   0% /dev
) = 43
write(1, "tmpfs           788M  9.6M  779M"..., 43tmpfs           788M  9.6M  779M   2% /run
) = 43
write(1, "/dev/sda10      324G  252G   56G"..., 40/dev/sda10      324G  252G   56G  82% /
) = 40
write(1, "tmpfs           3.9G  104M  3.8G"..., 47tmpfs           3.9G  104M  3.8G   3% /dev/shm
) = 47
write(1, "tmpfs           5.0M  4.0K  5.0M"..., 48tmpfs           5.0M  4.0K  5.0M   1% /run/lock
) = 48
write(1, "tmpfs           3.9G     0  3.9G"..., 53tmpfs           3.9G     0  3.9G   0% /sys/fs/cgroup
) = 53
write(1, "cgmfs           100K     0  100K"..., 56cgmfs           100K     0  100K   0% /run/cgmanager/fs
) = 56
write(1, "tmpfs           788M   36K  788M"..., 53tmpfs           788M   36K  788M   1% /run/user/1000
) = 53
close(1)                                = 0
close(2)                                = 0
exit_group(0)                           = ?
+++ exited with 0 +++

2. LinuxプロセスPIDのトレース

プロセスがすでに実行されている場合は、次のように PID を渡すだけで追跡できます。これにより、プロセスによって実行されているシステムコールを示す出力が画面に表示されます。終了するには、 [Ctrl + C] を押します。

$ sudo strace -p 3569

strace: Process 3569 attached
restart_syscall(<... resuming interrupted poll ...>) = 1
recvmsg(4, {msg_name(0)=NULL, msg_iov(1)=[{"U0!70
$ sudo strace -p 3569
strace: Process 3569 attached
restart_syscall(<... resuming interrupted poll ...>) = 1
recvmsg(4, {msg_name(0)=NULL, msg_iov(1)=[{"U\2\24\300!\247\330\0\3\24\4\0\20\0\0\0\0\0\0\24\24\24\24\24\0\0\3\37%\2\0\0", 4096}], msg_controllen=0, msg_flags=0}, 0) = 32
recvmsg(4, 0x7ffee4dbf870, 0)           = -1 EAGAIN (Resource temporarily unavailable)
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, -1) = 1 ([{fd=31, revents=POLLIN}])
read(31, "\372", 1)                     = 1
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, 0) = 1 ([{fd=31, revents=POLLIN}])
read(31, "\372", 1)                     = 1
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, 0) = 0 (Timeout)
mprotect(0x207faa20000, 8192, PROT_READ|PROT_WRITE) = 0
mprotect(0x207faa20000, 8192, PROT_READ|PROT_EXEC) = 0
mprotect(0x207faa21000, 4096, PROT_READ|PROT_WRITE) = 0
mprotect(0x207faa21000, 4096, PROT_READ|PROT_EXEC) = 0
...
$ sudo strace -p 3569
strace: Process 3569 attached
restart_syscall(<... resuming interrupted poll ...>) = 1
recvmsg(4, {msg_name(0)=NULL, msg_iov(1)=[{"U\2\24\300!\247\330\0\3\24\4\0\20\0\0\0\0\0\0\24\24\24\24\24\0\0\3\37%\2\0\0", 4096}], msg_controllen=0, msg_flags=0}, 0) = 32
recvmsg(4, 0x7ffee4dbf870, 0)           = -1 EAGAIN (Resource temporarily unavailable)
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, -1) = 1 ([{fd=31, revents=POLLIN}])
read(31, "\372", 1)                     = 1
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, 0) = 1 ([{fd=31, revents=POLLIN}])
read(31, "\372", 1)                     = 1
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, 0) = 0 (Timeout)
mprotect(0x207faa20000, 8192, PROT_READ|PROT_WRITE) = 0
mprotect(0x207faa20000, 8192, PROT_READ|PROT_EXEC) = 0
mprotect(0x207faa21000, 4096, PROT_READ|PROT_WRITE) = 0
mprotect(0x207faa21000, 4096, PROT_READ|PROT_EXEC) = 0
...
$ sudo strace -p 3569
strace: Process 3569 attached
restart_syscall(<... resuming interrupted poll ...>) = 1
recvmsg(4, {msg_name(0)=NULL, msg_iov(1)=[{"U\2\24\300!\247\330\0\3\24\4\0\20\0\0\0\0\0\0\24\24\24\24\24\0\0\3\37%\2\0\0", 4096}], msg_controllen=0, msg_flags=0}, 0) = 32
recvmsg(4, 0x7ffee4dbf870, 0)           = -1 EAGAIN (Resource temporarily unavailable)
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, -1) = 1 ([{fd=31, revents=POLLIN}])
read(31, "\372", 1)                     = 1
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, 0) = 1 ([{fd=31, revents=POLLIN}])
read(31, "\372", 1)                     = 1
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, 0) = 0 (Timeout)
mprotect(0x207faa20000, 8192, PROT_READ|PROT_WRITE) = 0
mprotect(0x207faa20000, 8192, PROT_READ|PROT_EXEC) = 0
mprotect(0x207faa21000, 4096, PROT_READ|PROT_WRITE) = 0
mprotect(0x207faa21000, 4096, PROT_READ|PROT_EXEC) = 0
...
$ sudo strace -p 3569
strace: Process 3569 attached
restart_syscall(<... resuming interrupted poll ...>) = 1
recvmsg(4, {msg_name(0)=NULL, msg_iov(1)=[{"U\2\24\300!\247\330\0\3\24\4\0\20\0\0\0\0\0\0\24\24\24\24\24\0\0\3\37%\2\0\0", 4096}], msg_controllen=0, msg_flags=0}, 0) = 32
recvmsg(4, 0x7ffee4dbf870, 0)           = -1 EAGAIN (Resource temporarily unavailable)
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, -1) = 1 ([{fd=31, revents=POLLIN}])
read(31, "\372", 1)                     = 1
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, 0) = 1 ([{fd=31, revents=POLLIN}])
read(31, "\372", 1)                     = 1
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, 0) = 0 (Timeout)
mprotect(0x207faa20000, 8192, PROT_READ|PROT_WRITE) = 0
mprotect(0x207faa20000, 8192, PROT_READ|PROT_EXEC) = 0
mprotect(0x207faa21000, 4096, PROT_READ|PROT_WRITE) = 0
mprotect(0x207faa21000, 4096, PROT_READ|PROT_EXEC) = 0
...
$ sudo strace -p 3569
strace: Process 3569 attached
restart_syscall(<... resuming interrupted poll ...>) = 1
recvmsg(4, {msg_name(0)=NULL, msg_iov(1)=[{"U\2\24\300!\247\330\0\3\24\4\0\20\0\0\0\0\0\0\24\24\24\24\24\0\0\3\37%\2\0\0", 4096}], msg_controllen=0, msg_flags=0}, 0) = 32
recvmsg(4, 0x7ffee4dbf870, 0)           = -1 EAGAIN (Resource temporarily unavailable)
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, -1) = 1 ([{fd=31, revents=POLLIN}])
read(31, "\372", 1)                     = 1
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, 0) = 1 ([{fd=31, revents=POLLIN}])
read(31, "\372", 1)                     = 1
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, 0) = 0 (Timeout)
mprotect(0x207faa20000, 8192, PROT_READ|PROT_WRITE) = 0
mprotect(0x207faa20000, 8192, PROT_READ|PROT_EXEC) = 0
mprotect(0x207faa21000, 4096, PROT_READ|PROT_WRITE) = 0
mprotect(0x207faa21000, 4096, PROT_READ|PROT_EXEC) = 0
...
$ sudo strace -p 3569
strace: Process 3569 attached
restart_syscall(<... resuming interrupted poll ...>) = 1
recvmsg(4, {msg_name(0)=NULL, msg_iov(1)=[{"U\2\24\300!\247\330\0\3\24\4\0\20\0\0\0\0\0\0\24\24\24\24\24\0\0\3\37%\2\0\0", 4096}], msg_controllen=0, msg_flags=0}, 0) = 32
recvmsg(4, 0x7ffee4dbf870, 0)           = -1 EAGAIN (Resource temporarily unavailable)
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, -1) = 1 ([{fd=31, revents=POLLIN}])
read(31, "\372", 1)                     = 1
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, 0) = 1 ([{fd=31, revents=POLLIN}])
read(31, "\372", 1)                     = 1
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, 0) = 0 (Timeout)
mprotect(0x207faa20000, 8192, PROT_READ|PROT_WRITE) = 0
mprotect(0x207faa20000, 8192, PROT_READ|PROT_EXEC) = 0
mprotect(0x207faa21000, 4096, PROT_READ|PROT_WRITE) = 0
mprotect(0x207faa21000, 4096, PROT_READ|PROT_EXEC) = 0
...
$ sudo strace -p 3569
strace: Process 3569 attached
restart_syscall(<... resuming interrupted poll ...>) = 1
recvmsg(4, {msg_name(0)=NULL, msg_iov(1)=[{"U\2\24\300!\247\330\0\3\24\4\0\20\0\0\0\0\0\0\24\24\24\24\24\0\0\3\37%\2\0\0", 4096}], msg_controllen=0, msg_flags=0}, 0) = 32
recvmsg(4, 0x7ffee4dbf870, 0)           = -1 EAGAIN (Resource temporarily unavailable)
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, -1) = 1 ([{fd=31, revents=POLLIN}])
read(31, "\372", 1)                     = 1
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, 0) = 1 ([{fd=31, revents=POLLIN}])
read(31, "\372", 1)                     = 1
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, 0) = 0 (Timeout)
mprotect(0x207faa20000, 8192, PROT_READ|PROT_WRITE) = 0
mprotect(0x207faa20000, 8192, PROT_READ|PROT_EXEC) = 0
mprotect(0x207faa21000, 4096, PROT_READ|PROT_WRITE) = 0
mprotect(0x207faa21000, 4096, PROT_READ|PROT_EXEC) = 0
...
$ sudo strace -p 3569
strace: Process 3569 attached
restart_syscall(<... resuming interrupted poll ...>) = 1
recvmsg(4, {msg_name(0)=NULL, msg_iov(1)=[{"U\2\24\300!\247\330\0\3\24\4\0\20\0\0\0\0\0\0\24\24\24\24\24\0\0\3\37%\2\0\0", 4096}], msg_controllen=0, msg_flags=0}, 0) = 32
recvmsg(4, 0x7ffee4dbf870, 0)           = -1 EAGAIN (Resource temporarily unavailable)
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, -1) = 1 ([{fd=31, revents=POLLIN}])
read(31, "\372", 1)                     = 1
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, 0) = 1 ([{fd=31, revents=POLLIN}])
read(31, "\372", 1)                     = 1
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, 0) = 0 (Timeout)
mprotect(0x207faa20000, 8192, PROT_READ|PROT_WRITE) = 0
mprotect(0x207faa20000, 8192, PROT_READ|PROT_EXEC) = 0
mprotect(0x207faa21000, 4096, PROT_READ|PROT_WRITE) = 0
mprotect(0x207faa21000, 4096, PROT_READ|PROT_EXEC) = 0
...
$ sudo strace -p 3569
strace: Process 3569 attached
restart_syscall(<... resuming interrupted poll ...>) = 1
recvmsg(4, {msg_name(0)=NULL, msg_iov(1)=[{"U\2\24\300!\247\330\0\3\24\4\0\20\0\0\0\0\0\0\24\24\24\24\24\0\0\3\37%\2\0\0", 4096}], msg_controllen=0, msg_flags=0}, 0) = 32
recvmsg(4, 0x7ffee4dbf870, 0)           = -1 EAGAIN (Resource temporarily unavailable)
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, -1) = 1 ([{fd=31, revents=POLLIN}])
read(31, "\372", 1)                     = 1
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, 0) = 1 ([{fd=31, revents=POLLIN}])
read(31, "\372", 1)                     = 1
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, 0) = 0 (Timeout)
mprotect(0x207faa20000, 8192, PROT_READ|PROT_WRITE) = 0
mprotect(0x207faa20000, 8192, PROT_READ|PROT_EXEC) = 0
mprotect(0x207faa21000, 4096, PROT_READ|PROT_WRITE) = 0
mprotect(0x207faa21000, 4096, PROT_READ|PROT_EXEC) = 0
...
$ sudo strace -p 3569
strace: Process 3569 attached
restart_syscall(<... resuming interrupted poll ...>) = 1
recvmsg(4, {msg_name(0)=NULL, msg_iov(1)=[{"U\2\24\300!\247\330\0\3\24\4\0\20\0\0\0\0\0\0\24\24\24\24\24\0\0\3\37%\2\0\0", 4096}], msg_controllen=0, msg_flags=0}, 0) = 32
recvmsg(4, 0x7ffee4dbf870, 0)           = -1 EAGAIN (Resource temporarily unavailable)
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, -1) = 1 ([{fd=31, revents=POLLIN}])
read(31, "\372", 1)                     = 1
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, 0) = 1 ([{fd=31, revents=POLLIN}])
read(31, "\372", 1)                     = 1
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, 0) = 0 (Timeout)
mprotect(0x207faa20000, 8192, PROT_READ|PROT_WRITE) = 0
mprotect(0x207faa20000, 8192, PROT_READ|PROT_EXEC) = 0
mprotect(0x207faa21000, 4096, PROT_READ|PROT_WRITE) = 0
mprotect(0x207faa21000, 4096, PROT_READ|PROT_EXEC) = 0
...
$ sudo strace -p 3569
strace: Process 3569 attached
restart_syscall(<... resuming interrupted poll ...>) = 1
recvmsg(4, {msg_name(0)=NULL, msg_iov(1)=[{"U\2\24\300!\247\330\0\3\24\4\0\20\0\0\0\0\0\0\24\24\24\24\24\0\0\3\37%\2\0\0", 4096}], msg_controllen=0, msg_flags=0}, 0) = 32
recvmsg(4, 0x7ffee4dbf870, 0)           = -1 EAGAIN (Resource temporarily unavailable)
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, -1) = 1 ([{fd=31, revents=POLLIN}])
read(31, "\372", 1)                     = 1
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, 0) = 1 ([{fd=31, revents=POLLIN}])
read(31, "\372", 1)                     = 1
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, 0) = 0 (Timeout)
mprotect(0x207faa20000, 8192, PROT_READ|PROT_WRITE) = 0
mprotect(0x207faa20000, 8192, PROT_READ|PROT_EXEC) = 0
mprotect(0x207faa21000, 4096, PROT_READ|PROT_WRITE) = 0
mprotect(0x207faa21000, 4096, PROT_READ|PROT_EXEC) = 0
...
$ sudo strace -p 3569
strace: Process 3569 attached
restart_syscall(<... resuming interrupted poll ...>) = 1
recvmsg(4, {msg_name(0)=NULL, msg_iov(1)=[{"U\2\24\300!\247\330\0\3\24\4\0\20\0\0\0\0\0\0\24\24\24\24\24\0\0\3\37%\2\0\0", 4096}], msg_controllen=0, msg_flags=0}, 0) = 32
recvmsg(4, 0x7ffee4dbf870, 0)           = -1 EAGAIN (Resource temporarily unavailable)
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, -1) = 1 ([{fd=31, revents=POLLIN}])
read(31, "\372", 1)                     = 1
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, 0) = 1 ([{fd=31, revents=POLLIN}])
read(31, "\372", 1)                     = 1
recvmsg(4, 0x7ffee4dbf850, 0)           = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=10, events=POLLIN}, {fd=30, events=POLLIN}, {fd=31, events=POLLIN}], 6, 0) = 0 (Timeout)
mprotect(0x207faa20000, 8192, PROT_READ|PROT_WRITE) = 0
mprotect(0x207faa20000, 8192, PROT_READ|PROT_EXEC) = 0
mprotect(0x207faa21000, 4096, PROT_READ|PROT_WRITE) = 0
mprotect(0x207faa21000, 4096, PROT_READ|PROT_EXEC) = 0
...

3. Linuxプロセスの概要を入手する

次のように、 -c フラグを使用して、各システムコールの合計時間、通話、およびエラーのレポートを生成できます。

$ sudo strace -c -p 3569

strace: Process 3569 attached

^Cstrace: Process 3569 detached
% time     seconds  usecs/call     calls    errors syscall
------ ----------- ----------- --------- --------- ----------------
 99.73    0.016000           8      1971           poll
  0.16    0.000025           0       509        75 futex
  0.06    0.000010           0      1985      1966 recvmsg
  0.06    0.000009           0      2336           mprotect
  0.00    0.000000           0       478           read
  0.00    0.000000           0        13           write
  0.00    0.000000           0        29           mmap
  0.00    0.000000           0         9           munmap
  0.00    0.000000           0        18           writev
  0.00    0.000000           0       351           madvise
  0.00    0.000000           0         1           restart_syscall
------ ----------- ----------- --------- --------- ----------------
100.00    0.016044                  7700      2041 total

4.システムコール中の印刷指示ポインタ

-i オプションは、プログラムによって行われた各システムコールの時点での命令ポインタを表示します。

$ sudo strace -i df -h

[00007f0d7534c777] execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
[00007faf9cafa4b9] brk(NULL)            = 0x12f0000
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb47a] mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7faf9cd03000
[00007faf9cafb387] access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7faf9ccde000
[00007faf9cafb427] close(3)             = 0
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb347] read(3, "7ELF
$ sudo strace -i df -h
[00007f0d7534c777] execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
[00007faf9cafa4b9] brk(NULL)            = 0x12f0000
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb47a] mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7faf9cd03000
[00007faf9cafb387] access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7faf9ccde000
[00007faf9cafb427] close(3)             = 0
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb347] read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7faf9c716000
[00007faf9cafb517] mprotect(0x7faf9c8d6000, 2097152, PROT_NONE) = 0
...
$ sudo strace -i df -h
[00007f0d7534c777] execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
[00007faf9cafa4b9] brk(NULL)            = 0x12f0000
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb47a] mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7faf9cd03000
[00007faf9cafb387] access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7faf9ccde000
[00007faf9cafb427] close(3)             = 0
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb347] read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7faf9c716000
[00007faf9cafb517] mprotect(0x7faf9c8d6000, 2097152, PROT_NONE) = 0
...
$ sudo strace -i df -h
[00007f0d7534c777] execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
[00007faf9cafa4b9] brk(NULL)            = 0x12f0000
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb47a] mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7faf9cd03000
[00007faf9cafb387] access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7faf9ccde000
[00007faf9cafb427] close(3)             = 0
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb347] read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7faf9c716000
[00007faf9cafb517] mprotect(0x7faf9c8d6000, 2097152, PROT_NONE) = 0
...
$ sudo strace -i df -h
[00007f0d7534c777] execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
[00007faf9cafa4b9] brk(NULL)            = 0x12f0000
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb47a] mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7faf9cd03000
[00007faf9cafb387] access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7faf9ccde000
[00007faf9cafb427] close(3)             = 0
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb347] read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7faf9c716000
[00007faf9cafb517] mprotect(0x7faf9c8d6000, 2097152, PROT_NONE) = 0
...
$ sudo strace -i df -h
[00007f0d7534c777] execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
[00007faf9cafa4b9] brk(NULL)            = 0x12f0000
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb47a] mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7faf9cd03000
[00007faf9cafb387] access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7faf9ccde000
[00007faf9cafb427] close(3)             = 0
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb347] read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7faf9c716000
[00007faf9cafb517] mprotect(0x7faf9c8d6000, 2097152, PROT_NONE) = 0
...
$ sudo strace -i df -h
[00007f0d7534c777] execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
[00007faf9cafa4b9] brk(NULL)            = 0x12f0000
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb47a] mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7faf9cd03000
[00007faf9cafb387] access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7faf9ccde000
[00007faf9cafb427] close(3)             = 0
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb347] read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7faf9c716000
[00007faf9cafb517] mprotect(0x7faf9c8d6000, 2097152, PROT_NONE) = 0
...
$ sudo strace -i df -h
[00007f0d7534c777] execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
[00007faf9cafa4b9] brk(NULL)            = 0x12f0000
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb47a] mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7faf9cd03000
[00007faf9cafb387] access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7faf9ccde000
[00007faf9cafb427] close(3)             = 0
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb347] read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7faf9c716000
[00007faf9cafb517] mprotect(0x7faf9c8d6000, 2097152, PROT_NONE) = 0
...
$ sudo strace -i df -h
[00007f0d7534c777] execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
[00007faf9cafa4b9] brk(NULL)            = 0x12f0000
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb47a] mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7faf9cd03000
[00007faf9cafb387] access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7faf9ccde000
[00007faf9cafb427] close(3)             = 0
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb347] read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7faf9c716000
[00007faf9cafb517] mprotect(0x7faf9c8d6000, 2097152, PROT_NONE) = 0
...
$ sudo strace -i df -h
[00007f0d7534c777] execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
[00007faf9cafa4b9] brk(NULL)            = 0x12f0000
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb47a] mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7faf9cd03000
[00007faf9cafb387] access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7faf9ccde000
[00007faf9cafb427] close(3)             = 0
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb347] read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7faf9c716000
[00007faf9cafb517] mprotect(0x7faf9c8d6000, 2097152, PROT_NONE) = 0
...
$ sudo strace -i df -h
[00007f0d7534c777] execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
[00007faf9cafa4b9] brk(NULL)            = 0x12f0000
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb47a] mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7faf9cd03000
[00007faf9cafb387] access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7faf9ccde000
[00007faf9cafb427] close(3)             = 0
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb347] read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7faf9c716000
[00007faf9cafb517] mprotect(0x7faf9c8d6000, 2097152, PROT_NONE) = 0
...
$ sudo strace -i df -h
[00007f0d7534c777] execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
[00007faf9cafa4b9] brk(NULL)            = 0x12f0000
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb47a] mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7faf9cd03000
[00007faf9cafb387] access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7faf9ccde000
[00007faf9cafb427] close(3)             = 0
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb347] read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7faf9c716000
[00007faf9cafb517] mprotect(0x7faf9c8d6000, 2097152, PROT_NONE) = 0
...
$ sudo strace -i df -h
[00007f0d7534c777] execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
[00007faf9cafa4b9] brk(NULL)            = 0x12f0000
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb47a] mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7faf9cd03000
[00007faf9cafb387] access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7faf9ccde000
[00007faf9cafb427] close(3)             = 0
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb347] read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7faf9c716000
[00007faf9cafb517] mprotect(0x7faf9c8d6000, 2097152, PROT_NONE) = 0
...
$ sudo strace -i df -h
[00007f0d7534c777] execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
[00007faf9cafa4b9] brk(NULL)            = 0x12f0000
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb47a] mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7faf9cd03000
[00007faf9cafb387] access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7faf9ccde000
[00007faf9cafb427] close(3)             = 0
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb347] read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7faf9c716000
[00007faf9cafb517] mprotect(0x7faf9c8d6000, 2097152, PROT_NONE) = 0
...
$ sudo strace -i df -h
[00007f0d7534c777] execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
[00007faf9cafa4b9] brk(NULL)            = 0x12f0000
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb47a] mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7faf9cd03000
[00007faf9cafb387] access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7faf9ccde000
[00007faf9cafb427] close(3)             = 0
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb347] read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7faf9c716000
[00007faf9cafb517] mprotect(0x7faf9c8d6000, 2097152, PROT_NONE) = 0
...
$ sudo strace -i df -h
[00007f0d7534c777] execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
[00007faf9cafa4b9] brk(NULL)            = 0x12f0000
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb47a] mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7faf9cd03000
[00007faf9cafb387] access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7faf9ccde000
[00007faf9cafb427] close(3)             = 0
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb347] read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7faf9c716000
[00007faf9cafb517] mprotect(0x7faf9c8d6000, 2097152, PROT_NONE) = 0
...
$ sudo strace -i df -h
[00007f0d7534c777] execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
[00007faf9cafa4b9] brk(NULL)            = 0x12f0000
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb47a] mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7faf9cd03000
[00007faf9cafb387] access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7faf9ccde000
[00007faf9cafb427] close(3)             = 0
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb347] read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7faf9c716000
[00007faf9cafb517] mprotect(0x7faf9c8d6000, 2097152, PROT_NONE) = 0
...
$ sudo strace -i df -h
[00007f0d7534c777] execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
[00007faf9cafa4b9] brk(NULL)            = 0x12f0000
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb47a] mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7faf9cd03000
[00007faf9cafb387] access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7faf9ccde000
[00007faf9cafb427] close(3)             = 0
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb347] read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7faf9c716000
[00007faf9cafb517] mprotect(0x7faf9c8d6000, 2097152, PROT_NONE) = 0
...
$ sudo strace -i df -h
[00007f0d7534c777] execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
[00007faf9cafa4b9] brk(NULL)            = 0x12f0000
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb47a] mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7faf9cd03000
[00007faf9cafb387] access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7faf9ccde000
[00007faf9cafb427] close(3)             = 0
[00007faf9cafb387] access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
[00007faf9cafb327] open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
[00007faf9cafb347] read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
[00007faf9cafb2b4] fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
[00007faf9cafb47a] mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7faf9c716000
[00007faf9cafb517] mprotect(0x7faf9c8d6000, 2097152, PROT_NONE) = 0
...

5.各トレース出力行に時刻を表示する

-t フラグを渡して、トレース出力の各行の時刻を印刷することもできます。

$ sudo strace -t df -h

15:19:25 execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
15:19:25 brk(NULL)                      = 0x234c000
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8c7f1d9000
15:19:25 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
15:19:25 fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
15:19:25 mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f8c7f1b4000
15:19:25 close(3)                       = 0
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
15:19:25 read(3, "7ELF
$ sudo strace -t df -h
15:19:25 execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
15:19:25 brk(NULL)                      = 0x234c000
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8c7f1d9000
15:19:25 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
15:19:25 fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
15:19:25 mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f8c7f1b4000
15:19:25 close(3)                       = 0
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
15:19:25 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
15:19:25 fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
15:19:25 mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f8c7ebec000
15:19:25 mprotect(0x7f8c7edac000, 2097152, PROT_NONE) = 0
...
$ sudo strace -t df -h
15:19:25 execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
15:19:25 brk(NULL)                      = 0x234c000
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8c7f1d9000
15:19:25 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
15:19:25 fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
15:19:25 mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f8c7f1b4000
15:19:25 close(3)                       = 0
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
15:19:25 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
15:19:25 fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
15:19:25 mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f8c7ebec000
15:19:25 mprotect(0x7f8c7edac000, 2097152, PROT_NONE) = 0
...
$ sudo strace -t df -h
15:19:25 execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
15:19:25 brk(NULL)                      = 0x234c000
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8c7f1d9000
15:19:25 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
15:19:25 fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
15:19:25 mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f8c7f1b4000
15:19:25 close(3)                       = 0
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
15:19:25 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
15:19:25 fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
15:19:25 mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f8c7ebec000
15:19:25 mprotect(0x7f8c7edac000, 2097152, PROT_NONE) = 0
...
$ sudo strace -t df -h
15:19:25 execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
15:19:25 brk(NULL)                      = 0x234c000
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8c7f1d9000
15:19:25 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
15:19:25 fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
15:19:25 mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f8c7f1b4000
15:19:25 close(3)                       = 0
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
15:19:25 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
15:19:25 fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
15:19:25 mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f8c7ebec000
15:19:25 mprotect(0x7f8c7edac000, 2097152, PROT_NONE) = 0
...
$ sudo strace -t df -h
15:19:25 execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
15:19:25 brk(NULL)                      = 0x234c000
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8c7f1d9000
15:19:25 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
15:19:25 fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
15:19:25 mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f8c7f1b4000
15:19:25 close(3)                       = 0
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
15:19:25 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
15:19:25 fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
15:19:25 mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f8c7ebec000
15:19:25 mprotect(0x7f8c7edac000, 2097152, PROT_NONE) = 0
...
$ sudo strace -t df -h
15:19:25 execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
15:19:25 brk(NULL)                      = 0x234c000
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8c7f1d9000
15:19:25 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
15:19:25 fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
15:19:25 mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f8c7f1b4000
15:19:25 close(3)                       = 0
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
15:19:25 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
15:19:25 fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
15:19:25 mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f8c7ebec000
15:19:25 mprotect(0x7f8c7edac000, 2097152, PROT_NONE) = 0
...
$ sudo strace -t df -h
15:19:25 execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
15:19:25 brk(NULL)                      = 0x234c000
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8c7f1d9000
15:19:25 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
15:19:25 fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
15:19:25 mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f8c7f1b4000
15:19:25 close(3)                       = 0
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
15:19:25 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
15:19:25 fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
15:19:25 mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f8c7ebec000
15:19:25 mprotect(0x7f8c7edac000, 2097152, PROT_NONE) = 0
...
$ sudo strace -t df -h
15:19:25 execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
15:19:25 brk(NULL)                      = 0x234c000
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8c7f1d9000
15:19:25 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
15:19:25 fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
15:19:25 mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f8c7f1b4000
15:19:25 close(3)                       = 0
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
15:19:25 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
15:19:25 fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
15:19:25 mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f8c7ebec000
15:19:25 mprotect(0x7f8c7edac000, 2097152, PROT_NONE) = 0
...
$ sudo strace -t df -h
15:19:25 execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
15:19:25 brk(NULL)                      = 0x234c000
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8c7f1d9000
15:19:25 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
15:19:25 fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
15:19:25 mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f8c7f1b4000
15:19:25 close(3)                       = 0
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
15:19:25 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
15:19:25 fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
15:19:25 mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f8c7ebec000
15:19:25 mprotect(0x7f8c7edac000, 2097152, PROT_NONE) = 0
...
$ sudo strace -t df -h
15:19:25 execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
15:19:25 brk(NULL)                      = 0x234c000
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8c7f1d9000
15:19:25 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
15:19:25 fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
15:19:25 mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f8c7f1b4000
15:19:25 close(3)                       = 0
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
15:19:25 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
15:19:25 fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
15:19:25 mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f8c7ebec000
15:19:25 mprotect(0x7f8c7edac000, 2097152, PROT_NONE) = 0
...
$ sudo strace -t df -h
15:19:25 execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
15:19:25 brk(NULL)                      = 0x234c000
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8c7f1d9000
15:19:25 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
15:19:25 fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
15:19:25 mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f8c7f1b4000
15:19:25 close(3)                       = 0
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
15:19:25 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
15:19:25 fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
15:19:25 mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f8c7ebec000
15:19:25 mprotect(0x7f8c7edac000, 2097152, PROT_NONE) = 0
...
$ sudo strace -t df -h
15:19:25 execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
15:19:25 brk(NULL)                      = 0x234c000
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8c7f1d9000
15:19:25 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
15:19:25 fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
15:19:25 mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f8c7f1b4000
15:19:25 close(3)                       = 0
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
15:19:25 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
15:19:25 fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
15:19:25 mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f8c7ebec000
15:19:25 mprotect(0x7f8c7edac000, 2097152, PROT_NONE) = 0
...
$ sudo strace -t df -h
15:19:25 execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
15:19:25 brk(NULL)                      = 0x234c000
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8c7f1d9000
15:19:25 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
15:19:25 fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
15:19:25 mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f8c7f1b4000
15:19:25 close(3)                       = 0
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
15:19:25 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
15:19:25 fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
15:19:25 mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f8c7ebec000
15:19:25 mprotect(0x7f8c7edac000, 2097152, PROT_NONE) = 0
...
$ sudo strace -t df -h
15:19:25 execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
15:19:25 brk(NULL)                      = 0x234c000
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8c7f1d9000
15:19:25 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
15:19:25 fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
15:19:25 mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f8c7f1b4000
15:19:25 close(3)                       = 0
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
15:19:25 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
15:19:25 fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
15:19:25 mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f8c7ebec000
15:19:25 mprotect(0x7f8c7edac000, 2097152, PROT_NONE) = 0
...
$ sudo strace -t df -h
15:19:25 execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
15:19:25 brk(NULL)                      = 0x234c000
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8c7f1d9000
15:19:25 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
15:19:25 fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
15:19:25 mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f8c7f1b4000
15:19:25 close(3)                       = 0
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
15:19:25 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
15:19:25 fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
15:19:25 mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f8c7ebec000
15:19:25 mprotect(0x7f8c7edac000, 2097152, PROT_NONE) = 0
...
$ sudo strace -t df -h
15:19:25 execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
15:19:25 brk(NULL)                      = 0x234c000
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8c7f1d9000
15:19:25 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
15:19:25 fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
15:19:25 mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f8c7f1b4000
15:19:25 close(3)                       = 0
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
15:19:25 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
15:19:25 fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
15:19:25 mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f8c7ebec000
15:19:25 mprotect(0x7f8c7edac000, 2097152, PROT_NONE) = 0
...
$ sudo strace -t df -h
15:19:25 execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
15:19:25 brk(NULL)                      = 0x234c000
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8c7f1d9000
15:19:25 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
15:19:25 fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
15:19:25 mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f8c7f1b4000
15:19:25 close(3)                       = 0
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
15:19:25 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
15:19:25 fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
15:19:25 mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f8c7ebec000
15:19:25 mprotect(0x7f8c7edac000, 2097152, PROT_NONE) = 0
...
$ sudo strace -t df -h
15:19:25 execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
15:19:25 brk(NULL)                      = 0x234c000
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8c7f1d9000
15:19:25 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
15:19:25 fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0
15:19:25 mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f8c7f1b4000
15:19:25 close(3)                       = 0
15:19:25 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
15:19:25 open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
15:19:25 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
15:19:25 fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
15:19:25 mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f8c7ebec000
15:19:25 mprotect(0x7f8c7edac000, 2097152, PROT_NONE) = 0
...

6.システムコールにかかったコマンド時間を印刷する

プログラムによって行われた各システムコールの開始と終了の時間差を表示するには、 -T オプションを使用します。

$ sudo strace -T df -h

execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0 <0.000287>
brk(NULL)                               = 0xeca000 <0.000035>
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory) <0.000028>
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f9aff2b1000 <0.000020>
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory) <0.000019>
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3 <0.000022>
fstat(3, {st_mode=S_IFREG|0644, st_size=147662, ...}) = 0 <0.000015>
mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f9aff28c000 <0.000019>
close(3)                                = 0 <0.000014>
...

7.特定のシステムコールだけをトレースする

以下のコマンドでは、 trace = write は修飾表現として知られています。 trace は修飾子です(その他にはsignal、abbrev、verbose、raw、read、writeが含まれます)。 。ここで、 write は修飾子の値です。

次のコマンドは、実際には df 出力を標準出力に印刷するシステムコールを示しています。

$ sudo strace -e trace=write df -h

write(1, "Filesystem      Size  Used Avail"..., 49Filesystem      Size  Used Avail Use% Mounted on
) = 49
write(1, "udev            3.9G     0  3.9G"..., 43udev            3.9G     0  3.9G   0% /dev
) = 43
write(1, "tmpfs           788M  9.6M  779M"..., 43tmpfs           788M  9.6M  779M   2% /run
) = 43
write(1, "/dev/sda10      324G  252G   56G"..., 40/dev/sda10      324G  252G   56G  82% /
) = 40
write(1, "tmpfs           3.9G  104M  3.8G"..., 47tmpfs           3.9G  104M  3.8G   3% /dev/shm
) = 47
write(1, "tmpfs           5.0M  4.0K  5.0M"..., 48tmpfs           5.0M  4.0K  5.0M   1% /run/lock
) = 48
write(1, "tmpfs           3.9G     0  3.9G"..., 53tmpfs           3.9G     0  3.9G   0% /sys/fs/cgroup
) = 53
write(1, "cgmfs           100K     0  100K"..., 56cgmfs           100K     0  100K   0% /run/cgmanager/fs
) = 56
write(1, "tmpfs           788M   28K  788M"..., 53tmpfs           788M   28K  788M   1% /run/user/1000
) = 53
+++ exited with 0 +++

これは、トレース修飾子に関する追加のコマンドです。

$ sudo strace -e trace=open,close df -h
$ sudo strace -e trace=open,close,read,write df -h
$ sudo strace -e trace=all df -h	

8.特定の条件に基づいてシステムコールを追跡する

特定の種類のイベントに関連するシステムコールを追跡する方法を見てみましょう。このコマンドは、プロセス管理を含むすべてのシステムコールを追跡するために使用できます。

$ sudo strace -q -e trace=process df -h	

execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
arch_prctl(ARCH_SET_FS, 0x7fe2222ff700) = 0
Filesystem      Size  Used Avail Use% Mounted on
udev            3.9G     0  3.9G   0% /dev
tmpfs           788M  9.6M  779M   2% /run
/dev/sda10      324G  252G   56G  82% /
tmpfs           3.9G  104M  3.8G   3% /dev/shm
tmpfs           5.0M  4.0K  5.0M   1% /run/lock
tmpfs           3.9G     0  3.9G   0% /sys/fs/cgroup
cgmfs           100K     0  100K   0% /run/cgmanager/fs
tmpfs           788M   28K  788M   1% /run/user/1000
exit_group(0)                           = ?
+++ exited with 0 +++

次に、ファイル名を引数としてとるすべてのシステムコールをトレースするには、このコマンドを実行します。

$ sudo strace -q  -e trace=file df -h

execve("/bin/df", ["df", "-h"], [/* 17 vars */]) = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
open("/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3
open("/usr/share/locale/locale.alias", O_RDONLY|O_CLOEXEC) = 3
...

メモリマッピングを含むすべてのシステムコールをトレースするには、と入力します。

$ sudo strace -q -e trace=memory df -h	

brk(NULL)                               = 0x77a000
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fe8f4658000
mmap(NULL, 147662, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7fe8f4633000
mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fe8f406b000
mprotect(0x7fe8f422b000, 2097152, PROT_NONE) = 0
mmap(0x7fe8f442b000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1c0000) = 0x7fe8f442b000
mmap(0x7fe8f4431000, 14752, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7fe8f4431000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fe8f4632000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fe8f4631000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fe8f4630000
mprotect(0x7fe8f442b000, 16384, PROT_READ) = 0
mprotect(0x616000, 4096, PROT_READ)     = 0
mprotect(0x7fe8f465a000, 4096, PROT_READ) = 0
munmap(0x7fe8f4633000, 147662)          = 0
mmap(NULL, 2981280, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7fe8f3d93000
brk(NULL)                               = 0x77a000
brk(0x79b000)                           = 0x79b000
mmap(NULL, 619, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7fe8f4657000
mmap(NULL, 26258, PROT_READ, MAP_SHARED, 3, 0) = 0x7fe8f4650000
Filesystem      Size  Used Avail Use% Mounted on
udev            3.9G     0  3.9G   0% /dev
tmpfs           788M  9.6M  779M   2% /run
/dev/sda10      324G  252G   56G  82% /
tmpfs           3.9G  104M  3.8G   3% /dev/shm
tmpfs           5.0M  4.0K  5.0M   1% /run/lock
tmpfs           3.9G     0  3.9G   0% /sys/fs/cgroup
cgmfs           100K     0  100K   0% /run/cgmanager/fs
tmpfs           788M   28K  788M   1% /run/user/1000
+++ exited with 0 +++

あなたはすべてのネットワークをトレースし、関連するシステムコールを知らせることができます。

$ sudo strace -e trace=network df -h
$ sudo strace -e trace=signal df -h

9.トレース出力をファイルにリダイレクト

標準エラーに送信されたトレースメッセージをファイルに書き込むには、 -o オプションを使います。これは、以下に示すように、コマンド出力のみが画面に印刷されることを意味します。

$ sudo strace -o df_debug.txt df -h

Filesystem      Size  Used Avail Use% Mounted on
udev            3.9G     0  3.9G   0% /dev
tmpfs           788M  9.6M  779M   2% /run
/dev/sda10      324G  252G   56G  82% /
tmpfs           3.9G  104M  3.8G   3% /dev/shm
tmpfs           5.0M  4.0K  5.0M   1% /run/lock
tmpfs           3.9G     0  3.9G   0% /sys/fs/cgroup
cgmfs           100K     0  100K   0% /run/cgmanager/fs
tmpfs           788M   28K  788M   1% /run/user/1000

ファイルを調べるには、catコマンドを使用してください。

$ cat df_debug.txt 

10. Straceのデバッグ出力をいくつか表示する

straceツールのデバッグ情報を表示するには、 -d フラグを使用してください。

$ strace -d df -h

追加情報については、straceのmanページを参照してください。

$ man strace

これらの便利な関連記事も読んでください。

  1. 20 Command Line Tools to Monitor Linux Performance
  2. Sysdig – A Powerful System Monitoring and Troubleshooting Tool for Linux
  3. How to Trace Execution of Commands in Shell Script with Shell Tracing
  4. BCC – Dynamic Tracing Tools for Linux Performance Monitoring, Networking and More

結論として、 strace はプログラムの失敗の原因を診断するための優れたツールです。強力なデバッグとトラブルシューティングです。経験豊富なシステム管理者、プログラマー、ハッカーにとって実用的です。この記事に関する意見を共有するには、以下のフィードバックフォームを使用してください。