xref: /illumos-gate/usr/src/cmd/ptools/preap/preap.c (revision 8aafd47d0dbabbca4365c9565fbe0e051e7346dd)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2003 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #include <stdio.h>
28 #include <stdlib.h>
29 #include <unistd.h>
30 #include <fcntl.h>
31 #include <ctype.h>
32 #include <string.h>
33 #include <signal.h>
34 #include <errno.h>
35 #include <sys/types.h>
36 #include <sys/wait.h>
37 #include <libproc.h>
38 
39 #define	NOREAP_TIME 60		/* wait 60 seconds before allow a reap */
40 
41 static volatile int interrupt;
42 static int Fflag;
43 static char *command;
44 
45 static void
46 intr(int sig)
47 {
48 	interrupt = sig;
49 }
50 
51 static int
52 open_usage(pid_t pid, int *perr)
53 {
54 	char path[64];
55 	struct stat64 st;
56 	int fd;
57 
58 	(void) snprintf(path, sizeof (path), "/proc/%d/usage", (int)pid);
59 
60 	/*
61 	 * Attempt to open the usage file, and return the fd if we can
62 	 * confirm this is a regular file provided by /proc.
63 	 */
64 	if ((fd = open64(path, O_RDONLY)) >= 0) {
65 		if (fstat64(fd, &st) != 0 || !S_ISREG(st.st_mode) ||
66 		    strcmp(st.st_fstype, "proc") != 0) {
67 			(void) close(fd);
68 			fd = -1;
69 		}
70 	} else if (errno == EACCES || errno == EPERM)
71 		*perr = G_PERM;
72 
73 	return (fd);
74 }
75 
76 static int
77 proc_usage(pid_t pid, prusage_t *pup, int *perr)
78 {
79 	int fd;
80 
81 	*perr = G_NOPROC;
82 
83 	if ((fd = open_usage(pid, perr)) != -1) {
84 		if (read(fd, pup, sizeof (prusage_t)) == sizeof (prusage_t)) {
85 			*perr = 0;
86 			(void) close(fd);
87 			return (0);
88 		}
89 
90 		/*
91 		 * If the read failed, the process may have gone away.
92 		 */
93 		(void) close(fd);
94 	}
95 	return (-1);
96 }
97 
98 /*
99  * Force the parent process (ppid) to wait for its child process (pid).
100  */
101 static int
102 reap(char *arg, pid_t *reap_pid, int *exit_status)
103 {
104 	struct ps_prochandle *Pr;
105 	siginfo_t siginfo;
106 	psinfo_t psinfo;
107 	prusage_t usage;
108 	pid_t pid, ppid;
109 	time_t elapsed;
110 	int gret;
111 
112 	/*
113 	 * get the specified pid and the psinfo struct
114 	 */
115 	if ((pid = proc_arg_psinfo(arg, PR_ARG_PIDS, &psinfo, &gret)) == -1) {
116 		(void) fprintf(stderr, "%s: cannot examine %s: %s\n",
117 		    command, arg, Pgrab_error(gret));
118 		return (1);
119 	}
120 
121 	if (psinfo.pr_nlwp != 0) {
122 		(void) fprintf(stderr, "%s: process not defunct: %d\n",
123 		    command, (int)pid);
124 		return (1);
125 	}
126 
127 	*exit_status = psinfo.pr_wstat;
128 	*reap_pid = psinfo.pr_pid;
129 	ppid = psinfo.pr_ppid;
130 
131 	if (ppid == 1) {
132 		(void) fprintf(stderr, "%s: Failed to reap %d: the only "
133 		    "non-defunct ancestor is 'init'\n", command,
134 		    (int)pid);
135 		return (1);
136 	}
137 
138 	if (proc_usage(pid, &usage, &gret) == 0) {
139 		elapsed = usage.pr_tstamp.tv_sec - usage.pr_term.tv_sec;
140 	} else {
141 		(void) fprintf(stderr, "%s: cannot examine %d: %s\n",
142 		    command, (int)pid, Pgrab_error(gret));
143 		return (1);
144 	}
145 
146 	if ((Fflag == 0) && (elapsed < NOREAP_TIME)) {
147 		(void) fprintf(stderr, "%s: unsafe to reap %d; it has been "
148 		    "defunct less than %d seconds\n", command, (int)pid,
149 		    NOREAP_TIME);
150 		return (1);
151 	}
152 
153 	if ((Pr = Pgrab(ppid, Fflag | PGRAB_NOSTOP, &gret)) == NULL) {
154 		(void) fprintf(stderr, "%s: cannot examine %d: %s\n", command,
155 		    (int)ppid, Pgrab_error(gret));
156 		return (1);
157 	}
158 
159 	if ((Fflag == 0) && (Pstate(Pr) == PS_STOP)) {
160 		Prelease(Pr, 0);
161 		(void) fprintf(stderr, "%s: unsafe to reap %d; parent is "
162 		    "stopped and may reap status upon restart\n", command,
163 		    (int)pid);
164 		return (1);
165 	}
166 
167 	/*
168 	 * Pstop() will fail if the process to be stopped has become a zombie.
169 	 * This means that we can say with certainty that the child of this
170 	 * process has not changed parents (i.e. been reparented to init) once
171 	 * the Pstop() succeeds.
172 	 */
173 	if (Pstop(Pr, 1000) != 0) {
174 		Prelease(Pr, 0);
175 		(void) fprintf(stderr, "%s: failed to stop %d: %s", command,
176 		    (int)ppid, strerror(errno));
177 		return (1);
178 	}
179 
180 	if (pr_waitid(Pr, P_PID, pid, &siginfo, WEXITED|WNOHANG) != 0) {
181 		Prelease(Pr, 0);
182 		(void) fprintf(stderr, "%s: waitid() in process %d failed: %s",
183 		    command, (int)ppid, strerror(errno));
184 		return (1);
185 	}
186 
187 	Prelease(Pr, 0);
188 	return (0);
189 }
190 
191 static void
192 print_exit_status(pid_t pid, int wstat)
193 {
194 	(void) printf("%d: ", (int)pid);
195 	if (WIFSIGNALED(wstat)) {
196 		char buf[SIG2STR_MAX];
197 		int sig = WTERMSIG(wstat);
198 
199 		if (sig2str(sig, buf) == 0)
200 			(void) printf("killed by signal %s", buf);
201 		else
202 			(void) printf("killed by signal %d", sig);
203 
204 		if (WCOREDUMP(wstat))
205 			(void) printf(" (core dumped)");
206 	} else {
207 		(void) printf("exited with status %d", WEXITSTATUS(wstat));
208 	}
209 	(void) printf("\n");
210 }
211 
212 int
213 main(int argc, char *argv[])
214 {
215 	int retc = 0;
216 	int opt;
217 	int errflg = 0;
218 
219 	if ((command = strrchr(argv[0], '/')) != NULL)
220 		command++;
221 	else
222 		command = argv[0];
223 
224 	while ((opt = getopt(argc, argv, "F")) != EOF) {
225 		switch (opt) {
226 		case 'F':		/* force grabbing (no O_EXCL) */
227 			Fflag = PGRAB_FORCE;
228 			break;
229 		default:
230 			errflg = 1;
231 			break;
232 		}
233 	}
234 
235 	argc -= optind;
236 	argv += optind;
237 
238 	if (errflg || argc <= 0) {
239 		(void) fprintf(stderr, "usage:  %s pid ...\n", command);
240 		(void) fprintf(stderr, "  (Reap a defunct process by forcing "
241 		    "its parent to wait(2) for it)\n");
242 		exit(2);
243 	}
244 
245 	/* catch signals from terminal */
246 	if (sigset(SIGHUP, SIG_IGN) == SIG_DFL)
247 		(void) sigset(SIGHUP, intr);
248 	if (sigset(SIGINT, SIG_IGN) == SIG_DFL)
249 		(void) sigset(SIGINT, intr);
250 	if (sigset(SIGPIPE, SIG_IGN) == SIG_DFL)
251 		(void) sigset(SIGPIPE, intr);
252 	if (sigset(SIGQUIT, SIG_IGN) == SIG_DFL)
253 		(void) sigset(SIGQUIT, intr);
254 	(void) sigset(SIGTERM, intr);
255 
256 	while (--argc >= 0 && !interrupt) {
257 		pid_t pid;
258 		int wstat, r;
259 
260 		retc += r = reap(*argv++, &pid, &wstat);
261 
262 		if (r == 0)
263 			print_exit_status(pid, wstat);
264 	}
265 
266 	if (interrupt && retc == 0)
267 		retc++;
268 	return (retc == 0 ? 0 : 1);
269 }
270