Diff of /tags/mkinitrd-6_1_12/busybox/libbb/find_pid_by_name.c

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	revision 532 by niro, Sat Sep 1 22:45:15 2007 UTC	revision 816 by niro, Fri Apr 24 18:33:46 2009 UTC
#	Line 9	Line 9
9
10	#include "libbb.h"	#include "libbb.h"
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
41		static int comm_match(procps_status_t *p, const char *procName)
42		{
43		int argv1idx;
44
45		/* comm does not match */
46		if (strncmp(p->comm, procName, 15) != 0)
47		return 0;
48
49		/* in Linux, if comm is 15 chars, it may be a truncated */
50		if (p->comm[14] == '\0') /* comm is not truncated - match */
51		return 1;
52
53		/* comm is truncated, but first 15 chars match.
54		* This can be crazily_long_script_name.sh!
55		* The telltale sign is basename(argv[1]) == procName. */
56
57		if (!p->argv0)
58		return 0;
59
60		argv1idx = strlen(p->argv0) + 1;
61		if (argv1idx >= p->argv_len)
62		return 0;
63
64		if (strcmp(bb_basename(p->argv0 + argv1idx), procName) != 0)
65		return 0;
66
67		return 1;
68		}
69
70	/* find_pid_by_name()	/* find_pid_by_name()
71	*	*
72	*  Modified by Vladimir Oleynik for use with libbb/procps.c	*  Modified by Vladimir Oleynik for use with libbb/procps.c
#	Line 19	Line 77
77	*  Returns a list of all matching PIDs	*  Returns a list of all matching PIDs
78	*  It is the caller's duty to free the returned pidlist.	*  It is the caller's duty to free the returned pidlist.
79	*/	*/
80	pid_t* find_pid_by_name(const char* procName)	pid_t* FAST_FUNC find_pid_by_name(const char *procName)
81	{	{
82	pid_t* pidList;	pid_t* pidList;
83	int i = 0;	int i = 0;
84	procps_status_t* p = NULL;	procps_status_t* p = NULL;
85
86	pidList = xmalloc(sizeof(*pidList));	pidList = xzalloc(sizeof(*pidList));
87	while ((p = procps_scan(p, PSSCAN_PID|PSSCAN_COMM))) {	while ((p = procps_scan(p, PSSCAN_PID|PSSCAN_COMM|PSSCAN_ARGVN))) {
88	if (strncmp(p->comm, procName, sizeof(p->comm)-1) == 0) {	if (comm_match(p, procName)
89	pidList = xrealloc(pidList, sizeof(*pidList) * (i+2));	/* or we require argv0 to match (essential for matching reexeced /proc/self/exe)*/
90		|| (p->argv0 && strcmp(bb_basename(p->argv0), procName) == 0)
91		/* TODO: we can also try /proc/NUM/exe link, do we want that? */
92		) {
93		pidList = xrealloc_vector(pidList, 2, i);
94	pidList[i++] = p->pid;	pidList[i++] = p->pid;
95	}	}
96	}	}
#	Line 37  pid_t* find_pid_by_name(const char* proc	Line 99  pid_t* find_pid_by_name(const char* proc
99	return pidList;	return pidList;
100	}	}
101
102	pid_t *pidlist_reverse(pid_t *pidList)	pid_t* FAST_FUNC pidlist_reverse(pid_t *pidList)
103	{	{
104	int i = 0;	int i = 0;
105	while (pidList[i])	while (pidList[i])

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