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