TLPI memo 3
2.15 疑似端末
自分の端末はw
ででてきた、TTY
でわかる
vagrant@precise64:~$ w 12:53:33 up 0 min, 1 user, load average: 0.00, 0.00, 0.00 USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT vagrant pts/0 10.0.2.2 12:53 0.00s 0.20s 0.00s w vagrant@precise64:~$ vagrant@precise64:~$ ls -la /dev/pts/0 crw--w---- 1 vagrant tty 136, 0 Jan 19 12:53 /dev/pts/0
3.1 システムコール
strace
にコマンドを渡すと実行されるシステムコールがドバドバ出る
strace ls .
こんなかんじで
execve("/bin/ls", ["ls", "."], [/* 18 vars */]) = 0 brk(0) = 0x10b8000 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) = 0x7f723661d000 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=18510, ...}) = 0 mmap(NULL, 18510, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f7236618000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
標準関数(関数)とは
glibcに含まれるもの