diff options
Diffstat (limited to 'libbb')
| -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 @@ #include "libbb.h" +/* +In Linux we have three ways to determine "process name": +1. /proc/PID/stat has "...(name)...", among other things. It's so-called "comm" field. +2. /proc/PID/cmdline's first NUL-terminated string. It's argv[0] from exec syscall. +3. /proc/PID/exe symlink. Points to the running executable file. + +kernel threads: + comm: thread name + cmdline: empty + exe: <readlink fails> + +executable + comm: first 15 chars of base name + (if executable is a symlink, then first 15 chars of symlink name are used) + cmdline: argv[0] from exec syscall + exe: points to executable (resolves symlink, unlike comm) + +script (an executable with #!/path/to/interpreter): + comm: first 15 chars of script's base name (symlinks are not resolved) + cmdline: /path/to/interpreter (symlinks are not resolved) + (script name is in argv[1], args are pushed into argv[2] etc) + exe: points to interpreter's executable (symlinks are resolved) + +If FEATURE_PREFER_APPLETS=y (and more so if FEATURE_SH_STANDALONE=y), +some commands started from busybox shell, xargs or find are started by +execXXX("/proc/self/exe", applet_name, params....) +and therefore comm field contains "exe". +*/ + /* find_pid_by_name() * * Modified by Vladimir Oleynik for use with libbb/procps.c |