1/* vi: set sw=4 ts=4: */
2/*
3 * Mini kill/killall[5] implementation for busybox
4 *
5 * Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
6 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
7 *
8 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
9 */
10
11#include "libbb.h"
12
13/* Note: kill_main is directly called from shell in order to implement
14 * kill built-in. Shell substitutes job ids with process groups first.
15 *
16 * This brings some complications:
17 *
18 * + we can't use xfunc here
19 * + we can't use applet_name
20 * + we can't use bb_show_usage
21 * (Above doesn't apply for killall[5] cases)
22 *
23 * kill %n gets translated into kill ' -<process group>' by shell (note space!)
24 * This is needed to avoid collision with kill -9 ... syntax
25 */
26
27int kill_main(int argc, char **argv);
28int kill_main(int argc, char **argv)
29{
30	char *arg;
31	pid_t pid;
32	int signo = SIGTERM, errors = 0, quiet = 0;
33#if !ENABLE_KILLALL && !ENABLE_KILLALL5
34#define killall 0
35#define killall5 0
36#else
37/* How to determine who we are? find 3rd char from the end:
38 * kill, killall, killall5
39 *  ^i       ^a        ^l  - it's unique
40 * (checking from the start is complicated by /bin/kill... case) */
41	const char char3 = argv[0][strlen(argv[0]) - 3];
42#define killall (ENABLE_KILLALL && char3 == 'a')
43#define killall5 (ENABLE_KILLALL5 && char3 == 'l')
44#endif
45
46	/* Parse any options */
47	argc--;
48	arg = *++argv;
49
50	if (argc < 1 || arg[0] != '-') {
51		goto do_it_now;
52	}
53
54	/* The -l option, which prints out signal names.
55	 * Intended usage in shell:
56	 * echo "Died of SIG`kill -l $?`"
57	 * We try to mimic what kill from coreutils-6.8 does */
58	if (arg[1] == 'l' && arg[2] == '\0') {
59		if (argc == 1) {
60			/* Print the whole signal list */
61			for (signo = 1; signo < 32; signo++) {
62				const char *name = get_signame(signo);
63				if (!isdigit(name[0]))
64					puts(name);
65			}
66		} else { /* -l <sig list> */
67			while ((arg = *++argv)) {
68				if (isdigit(arg[0])) {
69					signo = bb_strtou(arg, NULL, 10);
70					if (errno) {
71						bb_error_msg("unknown signal '%s'", arg);
72						return EXIT_FAILURE;
73					}
74					/* Exitcodes >= 0x80 are to be treated
75					 * as "killed by signal (exitcode & 0x7f)" */
76					puts(get_signame(signo & 0x7f));
77					/* TODO: 'bad' signal# - coreutils says:
78					 * kill: 127: invalid signal
79					 * we just print "127" instead */
80				} else {
81					signo = get_signum(arg);
82					if (signo < 0) {
83						bb_error_msg("unknown signal '%s'", arg);
84						return EXIT_FAILURE;
85					}
86					printf("%d\n", signo);
87				}
88			}
89		}
90		/* If they specified -l, we are all done */
91		return EXIT_SUCCESS;
92	}
93
94	/* The -q quiet option */
95	if (killall && arg[1] == 'q' && arg[2] == '\0') {
96		quiet = 1;
97		arg = *++argv;
98		argc--;
99		if (argc < 1) bb_show_usage();
100		if (arg[0] != '-') goto do_it_now;
101	}
102
103	/* -SIG */
104	signo = get_signum(&arg[1]);
105	if (signo < 0) { /* || signo > MAX_SIGNUM ? */
106		bb_error_msg("bad signal name '%s'", &arg[1]);
107		return EXIT_FAILURE;
108	}
109	arg = *++argv;
110	argc--;
111
112do_it_now:
113
114	if (killall5) {
115		pid_t sid;
116		procps_status_t* p = NULL;
117
118		/* Now stop all processes */
119		kill(-1, SIGSTOP);
120		/* Find out our own session id */
121		pid = getpid();
122		sid = getsid(pid);
123		/* Now kill all processes except our session */
124		while ((p = procps_scan(p, PSSCAN_PID|PSSCAN_SID))) {
125			if (p->sid != sid && p->pid != pid && p->pid != 1)
126				kill(p->pid, signo);
127		}
128		/* And let them continue */
129		kill(-1, SIGCONT);
130		return 0;
131	}
132
133	/* Pid or name is required for kill/killall */
134	if (argc < 1) {
135		puts("You need to specify whom to kill");
136		return EXIT_FAILURE;
137	}
138
139	if (killall) {
140		/* Looks like they want to do a killall.  Do that */
141		pid = getpid();
142		while (arg) {
143			pid_t* pidList;
144
145			pidList = find_pid_by_name(arg);
146			if (*pidList == 0) {
147				errors++;
148				if (!quiet)
149					bb_error_msg("%s: no process killed", arg);
150			} else {
151				pid_t *pl;
152
153				for (pl = pidList; *pl; pl++) {
154					if (*pl == pid)
155						continue;
156					if (kill(*pl, signo) == 0)
157						continue;
158					errors++;
159					if (!quiet)
160						bb_perror_msg("cannot kill pid %u", (unsigned)*pl);
161				}
162			}
163			free(pidList);
164			arg = *++argv;
165		}
166		return errors;
167	}
168
169	/* Looks like they want to do a kill. Do that */
170	while (arg) {
171		/* Support shell 'space' trick */
172		if (arg[0] == ' ')
173			arg++;
174		pid = bb_strtoi(arg, NULL, 10);
175		if (errno) {
176			bb_error_msg("bad pid '%s'", arg);
177			errors++;
178		} else if (kill(pid, signo) != 0) {
179			bb_perror_msg("cannot kill pid %d", (int)pid);
180			errors++;
181		}
182		arg = *++argv;
183	}
184	return errors;
185}
186