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| author | Denis Vlasenko <vda.linux@googlemail.com> | 2007-06-23 14:56:43 +0000 |
|---|---|---|
| committer | Denis Vlasenko <vda.linux@googlemail.com> | 2007-06-23 14:56:43 +0000 |
| commit | 198badafd82905c9a2e76eeacb7ce463d8518bda (patch) | |
| tree | fcb367654b5c6cafdca09ef189342fc7019095fc /libbb/find_pid_by_name.c | |
| parent | 118b81df76be0e372309d76196c8eedf19ac56cd (diff) | |
| download | busybox-w32-198badafd82905c9a2e76eeacb7ce463d8518bda.tar.gz busybox-w32-198badafd82905c9a2e76eeacb7ce463d8518bda.tar.bz2 busybox-w32-198badafd82905c9a2e76eeacb7ce463d8518bda.zip | |
pidof: size optimizations (-50 bytes)
Diffstat (limited to 'libbb/find_pid_by_name.c')
| -rw-r--r-- | libbb/find_pid_by_name.c | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/libbb/find_pid_by_name.c b/libbb/find_pid_by_name.c index e98616940..13ccb545d 100644 --- a/libbb/find_pid_by_name.c +++ b/libbb/find_pid_by_name.c | |||
| @@ -9,6 +9,35 @@ | |||
| 9 | 9 | ||
| 10 | #include "libbb.h" | 10 | #include "libbb.h" |
| 11 | 11 | ||
| 12 | /* | ||
| 13 | In Linux we have three ways to determine "process name": | ||
| 14 | 1. /proc/PID/stat has "...(name)...", among other things. It's so-called "comm" field. | ||
| 15 | 2. /proc/PID/cmdline's first NUL-terminated string. It's argv[0] from exec syscall. | ||
| 16 | 3. /proc/PID/exe symlink. Points to the running executable file. | ||
| 17 | |||
| 18 | kernel threads: | ||
| 19 | comm: thread name | ||
| 20 | cmdline: empty | ||
| 21 | exe: <readlink fails> | ||
| 22 | |||
| 23 | executable | ||
| 24 | comm: first 15 chars of base name | ||
| 25 | (if executable is a symlink, then first 15 chars of symlink name are used) | ||
| 26 | cmdline: argv[0] from exec syscall | ||
| 27 | exe: points to executable (resolves symlink, unlike comm) | ||
| 28 | |||
| 29 | script (an executable with #!/path/to/interpreter): | ||
| 30 | comm: first 15 chars of script's base name (symlinks are not resolved) | ||
| 31 | cmdline: /path/to/interpreter (symlinks are not resolved) | ||
| 32 | (script name is in argv[1], args are pushed into argv[2] etc) | ||
| 33 | exe: points to interpreter's executable (symlinks are resolved) | ||
| 34 | |||
| 35 | If FEATURE_PREFER_APPLETS=y (and more so if FEATURE_SH_STANDALONE=y), | ||
| 36 | some commands started from busybox shell, xargs or find are started by | ||
| 37 | execXXX("/proc/self/exe", applet_name, params....) | ||
| 38 | and therefore comm field contains "exe". | ||
| 39 | */ | ||
| 40 | |||
| 12 | /* find_pid_by_name() | 41 | /* find_pid_by_name() |
| 13 | * | 42 | * |
| 14 | * Modified by Vladimir Oleynik for use with libbb/procps.c | 43 | * Modified by Vladimir Oleynik for use with libbb/procps.c |