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-rw-r--r--include/usage.h2
-rw-r--r--libbb/find_pid_by_name.c29
-rw-r--r--procps/pidof.c33
3 files changed, 44 insertions, 20 deletions
diff --git a/include/usage.h b/include/usage.h
index 2baa495..6d02c8b 100644
--- a/include/usage.h
+++ b/include/usage.h
@@ -2544,7 +2544,7 @@
USE_FEATURE_PIDOF_SINGLE( \
"\n -s Display only a single PID") \
USE_FEATURE_PIDOF_OMIT( \
- "\n -o Omit given pid") \
+ "\n -o PID Omit given pid") \
USE_FEATURE_PIDOF_OMIT( \
"\n Use %PPID to omit the parent pid of pidof itself")
#define pidof_example_usage \
diff --git a/libbb/find_pid_by_name.c b/libbb/find_pid_by_name.c
index e986169..13ccb54 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
diff --git a/procps/pidof.c b/procps/pidof.c
index 3541aee..01e587c 100644
--- a/procps/pidof.c
+++ b/procps/pidof.c
@@ -20,9 +20,9 @@ int pidof_main(int argc, char **argv);
int pidof_main(int argc, char **argv)
{
unsigned first = 1;
- unsigned fail = 1;
unsigned opt;
#if ENABLE_FEATURE_PIDOF_OMIT
+ char ppid_str[sizeof(int)*3 + 1];
llist_t *omits = NULL; /* list of pids to omit */
opt_complementary = "o::";
#endif
@@ -35,14 +35,12 @@ int pidof_main(int argc, char **argv)
#if ENABLE_FEATURE_PIDOF_OMIT
/* fill omit list. */
{
- char getppid_str[sizeof(int)*3 + 1];
- llist_t * omits_p = omits;
+ llist_t *omits_p = omits;
while (omits_p) {
/* are we asked to exclude the parent's process ID? */
- if (!strncmp(omits_p->data, "%PPID", 5)) {
- llist_pop(&omits_p);
- snprintf(getppid_str, sizeof(getppid_str), "%u", (unsigned)getppid());
- llist_add_to(&omits_p, getppid_str);
+ if (strcmp(omits_p->data, "%PPID") == 0) {
+ sprintf(ppid_str, "%u", (unsigned)getppid());
+ omits_p->data = ppid_str;
}
omits_p = omits_p->link;
}
@@ -56,27 +54,24 @@ int pidof_main(int argc, char **argv)
/* reverse the pidlist like GNU pidof does. */
pidList = pidlist_reverse(find_pid_by_name(argv[optind]));
for (pl = pidList; *pl; pl++) {
- SKIP_FEATURE_PIDOF_OMIT(const) unsigned omitted = 0;
#if ENABLE_FEATURE_PIDOF_OMIT
if (opt & OPT_OMIT) {
llist_t *omits_p = omits;
while (omits_p) {
if (xatoul(omits_p->data) == *pl) {
- omitted = 1;
- break;
- } else
- omits_p = omits_p->link;
+ goto omitting;
+ }
+ omits_p = omits_p->link;
}
}
#endif
- if (!omitted) {
- printf(" %u" + first, (unsigned)*pl);
- first = 0;
- }
- fail = (!ENABLE_FEATURE_PIDOF_OMIT && omitted);
-
+ printf(" %u" + first, (unsigned)*pl);
+ first = 0;
if (ENABLE_FEATURE_PIDOF_SINGLE && (opt & OPT_SINGLE))
break;
+#if ENABLE_FEATURE_PIDOF_OMIT
+ omitting: ;
+#endif
}
free(pidList);
optind++;
@@ -87,5 +82,5 @@ int pidof_main(int argc, char **argv)
if (ENABLE_FEATURE_CLEAN_UP)
llist_free(omits, NULL);
#endif
- return fail ? EXIT_FAILURE : EXIT_SUCCESS;
+ return first; /* 1 (failure) - no processes found */
}