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 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 EGAIN/EINTR error. 56 */ 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 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 } 117 118 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 } 153 154 static void signal_term(int sig) 155 { 156 if (child_pid > 0) 157 kill(child_pid, sig); 158 } 159 160 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 } 228 229 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 } 249 250 251 252 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
