1 /*
2 * logsave.c --- A program which saves the output of a program until
3 * /var/log is mounted.
4 *
5 * Copyright (C) 2003 Theodore Ts'o.
6 *
7 * %Begin-Header%
8 * This file may be redistributed under the terms of the GNU Public
9 * License.
10 * %End-Header%
11 */
12
13 #define _XOPEN_SOURCE 600 /* for inclusion of sa_handler in Solaris */
14
15 #include "config.h"
16 #include <stdio.h>
17 #include <stdlib.h>
18 #include <unistd.h>
19 #include <string.h>
20 #include <sys/types.h>
21 #include <sys/wait.h>
22 #include <fcntl.h>
23 #include <time.h>
24 #include <errno.h>
25 #ifdef HAVE_SIGNAL_H
26 #include <signal.h>
27 #endif
28 #ifdef HAVE_GETOPT_H
29 #include <getopt.h>
30 #else
31 extern char *optarg;
32 extern int optind;
33 #endif
34
35 static int outfd = -1;
36 static int outbufsize = 0;
37 static void *outbuf = 0;
38 static int verbose = 0;
39 static int do_skip = 0;
40 static int skip_mode = 0;
41 static pid_t child_pid = -1;
42
usage(char * progname)43 static void usage(char *progname)
44 {
45 printf("Usage: %s [-asv] logfile program\n", progname);
46 exit(1);
47 }
48
49 #define SEND_LOG 0x01
50 #define SEND_CONSOLE 0x02
51 #define SEND_BOTH 0x03
52
53 /*
54 * Helper function that does the right thing if write returns a
55 * partial write, or an EAGAIN/EINTR error.
56 */
write_all(int fd,const char * buf,size_t count)57 static int write_all(int fd, const char *buf, size_t count)
58 {
59 ssize_t ret;
60 int c = 0;
61
62 while (count > 0) {
63 ret = write(fd, buf, count);
64 if (ret < 0) {
65 if ((errno == EAGAIN) || (errno == EINTR))
66 continue;
67 return -1;
68 }
69 count -= ret;
70 buf += ret;
71 c += ret;
72 }
73 return c;
74 }
75
send_output(const char * buffer,int c,int flag)76 static void send_output(const char *buffer, int c, int flag)
77 {
78 const char *cp;
79 char *n;
80 int cnt, d, del;
81
82 if (c == 0)
83 c = strlen(buffer);
84
85 if (flag & SEND_CONSOLE) {
86 cnt = c;
87 cp = buffer;
88 while (cnt) {
89 del = 0;
90 for (d=0; d < cnt; d++) {
91 if (skip_mode &&
92 (cp[d] == '\001' || cp[d] == '\002')) {
93 del = 1;
94 break;
95 }
96 }
97 write_all(1, cp, d);
98 if (del)
99 d++;
100 cnt -= d;
101 cp += d;
102 }
103 }
104 if (!(flag & SEND_LOG))
105 return;
106 if (outfd > 0)
107 write_all(outfd, buffer, c);
108 else {
109 n = realloc(outbuf, outbufsize + c);
110 if (n) {
111 outbuf = n;
112 memcpy(((char *)outbuf)+outbufsize, buffer, c);
113 outbufsize += c;
114 }
115 }
116 }
117
do_read(int fd)118 static int do_read(int fd)
119 {
120 int c;
121 char buffer[4096], *cp, *sep;
122
123 c = read(fd, buffer, sizeof(buffer)-1);
124 if (c <= 0)
125 return c;
126 if (do_skip) {
127 send_output(buffer, c, SEND_CONSOLE);
128 buffer[c] = 0;
129 cp = buffer;
130 while (*cp) {
131 if (skip_mode) {
132 cp = strchr(cp, '\002');
133 if (!cp)
134 return 0;
135 cp++;
136 skip_mode = 0;
137 continue;
138 }
139 sep = strchr(cp, '\001');
140 if (sep)
141 *sep = 0;
142 send_output(cp, 0, SEND_LOG);
143 if (sep) {
144 cp = sep + 1;
145 skip_mode = 1;
146 } else
147 break;
148 }
149 } else
150 send_output(buffer, c, SEND_BOTH);
151 return c;
152 }
153
signal_term(int sig)154 static void signal_term(int sig)
155 {
156 if (child_pid > 0)
157 kill(child_pid, sig);
158 }
159
run_program(char ** argv)160 static int run_program(char **argv)
161 {
162 int fds[2];
163 int status, rc, pid;
164 char buffer[80];
165 #ifdef HAVE_SIGNAL_H
166 struct sigaction sa;
167 #endif
168
169 if (pipe(fds) < 0) {
170 perror("pipe");
171 exit(1);
172 }
173
174 #ifdef HAVE_SIGNAL_H
175 memset(&sa, 0, sizeof(struct sigaction));
176 sa.sa_handler = signal_term;
177 sigaction(SIGINT, &sa, 0);
178 sigaction(SIGTERM, &sa, 0);
179 #ifdef SA_RESTART
180 sa.sa_flags = SA_RESTART;
181 #endif
182 #endif
183
184 pid = fork();
185 if (pid < 0) {
186 perror("vfork");
187 exit(1);
188 }
189 if (pid == 0) {
190 dup2(fds[1],1); /* fds[1] replaces stdout */
191 dup2(fds[1],2); /* fds[1] replaces stderr */
192 close(fds[0]); /* don't need this here */
193 close(fds[1]);
194
195 execvp(argv[0], argv);
196 perror(argv[0]);
197 exit(1);
198 }
199 child_pid = pid;
200 close(fds[1]);
201
202 while (!(waitpid(pid, &status, WNOHANG ))) {
203 do_read(fds[0]);
204 }
205 child_pid = -1;
206 do_read(fds[0]);
207 close(fds[0]);
208
209 if ( WIFEXITED(status) ) {
210 rc = WEXITSTATUS(status);
211 if (rc) {
212 send_output(argv[0], 0, SEND_BOTH);
213 sprintf(buffer, " exited with status code %d\n", rc);
214 send_output(buffer, 0, SEND_BOTH);
215 }
216 } else {
217 if (WIFSIGNALED(status)) {
218 send_output(argv[0], 0, SEND_BOTH);
219 sprintf(buffer, "died with signal %d\n",
220 WTERMSIG(status));
221 send_output(buffer, 0, SEND_BOTH);
222 return 1;
223 }
224 rc = 0;
225 }
226 return rc;
227 }
228
copy_from_stdin(void)229 static int copy_from_stdin(void)
230 {
231 int c, bad_read = 0;
232
233 while (1) {
234 c = do_read(0);
235 if ((c == 0 ) ||
236 ((c < 0) && ((errno == EAGAIN) || (errno == EINTR)))) {
237 if (bad_read++ > 3)
238 break;
239 continue;
240 }
241 if (c < 0) {
242 perror("read");
243 exit(1);
244 }
245 bad_read = 0;
246 }
247 return 0;
248 }
249
250
251
main(int argc,char ** argv)252 int main(int argc, char **argv)
253 {
254 int c, pid, rc;
255 char *outfn, **cpp;
256 int openflags = O_CREAT|O_WRONLY|O_TRUNC;
257 int send_flag = SEND_LOG;
258 int do_stdin;
259 time_t t;
260
261 while ((c = getopt(argc, argv, "+asv")) != EOF) {
262 switch (c) {
263 case 'a':
264 openflags &= ~O_TRUNC;
265 openflags |= O_APPEND;
266 break;
267 case 's':
268 do_skip = 1;
269 break;
270 case 'v':
271 verbose++;
272 send_flag |= SEND_CONSOLE;
273 break;
274 }
275 }
276 if (optind == argc || optind+1 == argc)
277 usage(argv[0]);
278 outfn = argv[optind];
279 optind++;
280 argv += optind;
281 argc -= optind;
282
283 outfd = open(outfn, openflags, 0644);
284 do_stdin = !strcmp(argv[0], "-");
285
286 send_output("Log of ", 0, send_flag);
287 if (do_stdin)
288 send_output("stdin", 0, send_flag);
289 else {
290 for (cpp = argv; *cpp; cpp++) {
291 send_output(*cpp, 0, send_flag);
292 send_output(" ", 0, send_flag);
293 }
294 }
295 send_output("\n", 0, send_flag);
296 t = time(0);
297 send_output(ctime(&t), 0, send_flag);
298 send_output("\n", 0, send_flag);
299
300 if (do_stdin)
301 rc = copy_from_stdin();
302 else
303 rc = run_program(argv);
304
305 send_output("\n", 0, send_flag);
306 t = time(0);
307 send_output(ctime(&t), 0, send_flag);
308 send_output("----------------\n", 0, send_flag);
309
310 if (outbuf) {
311 pid = fork();
312 if (pid < 0) {
313 perror("fork");
314 exit(1);
315 }
316 if (pid) {
317 if (verbose)
318 printf("Backgrounding to save %s later\n",
319 outfn);
320 exit(rc);
321 }
322 setsid(); /* To avoid getting killed by init */
323 while (outfd < 0) {
324 outfd = open(outfn, openflags, 0644);
325 sleep(1);
326 }
327 write_all(outfd, outbuf, outbufsize);
328 free(outbuf);
329 }
330 if (outfd >= 0)
331 close(outfd);
332
333 exit(rc);
334 }
335