src/afsweb/apache_afs_weblog.c

   1 /*
   2  * Copyright 2000, International Business Machines Corporation and others.
   3  * All Rights Reserved.
   4  *
   5  * This software has been released under the terms of the IBM Public
   6  * License.  For details, see the LICENSE file in the top-level source
   7  * directory or online at http://www.openafs.org/dl/license10.html
   8  */
   9
  10 /* the wrapper nanny process around weblog that would restart it in case it
  11  * failed and hopefully log the error somewhere! The need for this nanny
  12  * process arises because the pipe descriptors need to be maintained. The
  13  * process catches SIGTERM and kills the weblog process and exits.
  14  * The following line needs to precede the kill -TERM line for httpd.pid
  15  * in the stopd script to stop the server
  16           kill -TERM `<cat /local/stronghold/apache/logs/httpd.pid>.afs`
  17  * or whatever the pid file
  18  */
  19
  20 #include <afs/stds.h>
  21
  22 #include <stdio.h>
  23 #include <sys/types.h>
  24 #include <sys/wait.h>
  25 #include <signal.h>
  26 #include <fcntl.h>
  27
  28 #include "weblog_errors.h"
  29 #include "AFS_component_version_number.c"
  30
  31 #define WEBLOG_BIN "weblog"
  32
  33 /* TODO - set restart_attempts to 0 if not within certain time period */
  34 #define MAX_RESTARTS        3   /* after this many restarts just die */
  35 static int restart_attempts = 0;
  36
  37 int error_fd;                   /* error file descriptor */
  38
  39 void
  40 sig_term()
  41 {
  42 #ifdef AIX
  43     pid_t pgrp = getpgrp();
  44 #else
  45     pid_t pgrp = getpgrp(0);
  46 #endif
  47     int n;
  48
  49 #ifdef DEBUG
  50     write(2, "weblog_starter: caught SIGTERM, shutting down", 43);
  51 #endif
  52
  53     log_error("weblog_starter: caught SIGTERM, shutting down");
  54
  55     if (pgrp == (pid_t) - 1) {
  56         log_error("getpgrp failed - kill weblog manually");
  57         write(2, "getpgrp failed - kill weblog manually", 38);
  58         exit(1);
  59     }
  60     kill(-pgrp, SIGKILL);
  61     exit(1);
  62 }
  63
  64 /* strip out this binary and replace it with the weblog binary's name */
  65 getpath(char *this, char *path)
  66 {
  67     char *temp = &this[0];
  68     int len = strlen(this);
  69     int pos = 0, i = 0, j = 0;
  70     char bin_name[] = WEBLOG_BIN;
  71     int len1 = strlen(bin_name);
  72
  73     strcpy(path, this);
  74     temp += (len);
  75     pos = len;
  76     while (*temp != '/') {
  77         temp--;
  78         pos--;
  79     }
  80     for (i = (pos + 1); i < len; i++, j++) {
  81         path[i] = bin_name[j];
  82         if (j >= len1)
  83             break;
  84     }
  85 }
  86
  87 char *
  88 get_time()
  89 {
  90     time_t t;
  91     char *time_string;
  92
  93     t = time(NULL);
  94     time_string = (char *)ctime(&t);
  95     time_string[strlen(time_string) - 1] = '\0';
  96     return (time_string);
  97 }
  98
  99 log_error(char *msg)
 100 {
 101     char err_msg[1024];
 102
 103     sprintf(err_msg, "[%s] weblog:%s\n", get_time(), msg);
 104     write(error_fd, (void *)err_msg, strlen(err_msg));
 105 }
 106
 107
 108 int
 109 main(int argc, char **argv)
 110 {
 111     pid_t weblog_pid;
 112     int stat = -1;
 113     int exitstatus = 0;
 114     char rn[] = "weblog_starter";
 115     char path[1024];
 116     char error_fname[1024];
 117
 118     struct sigaction sa;
 119
 120     memset(&sa, 0, sizeof sa);
 121     sa.sa_handler = (void (*)())sig_term;
 122     if (sigaction(SIGTERM, &sa, NULL) < 0) {
 123         perror("sigaction(SIGTERM)");
 124     }
 125
 126     getpath(argv[1], path);
 127     strcpy(error_fname, argv[2]);
 128
 129     error_fd = open(error_fname, O_WRONLY | O_APPEND | O_CREAT);
 130     if (error_fd < 0) {
 131         fprintf(stderr, "%s:Error opening log file:%s\nExiting\n", rn,
 132                 error_fname);
 133         perror("open");
 134         exit(-1);
 135     }
 136
 137     log_error("weblog_starter resuming normal operation");
 138
 139     while (restart_attempts < MAX_RESTARTS) {
 140         /* fork the weblog process and wait till it exits */
 141         if ((weblog_pid = fork()) < 0) {
 142             log_error("Could not fork process");
 143 #ifdef DEBUG
 144             perror("apache_afs_weblog:Could not fork process");
 145 #endif
 146             exit(-1);
 147         }
 148         switch (weblog_pid) {
 149         case 0:
 150             /* the child process - in this case weblog */
 151             execlp(path, "weblog", argv[3], argv[4], argv[5], argv[6], NULL);
 152 #ifdef DEBUG
 153             perror("apache_afs_weblog:Could not execute weblog");
 154 #endif
 155             exit(RESTARTERROR);
 156
 157         default:
 158             /* parent: just wait for the child */
 159             weblog_pid = waitpid((pid_t) - 1, &stat, 0);
 160
 161             if (weblog_pid == -1) {
 162 #ifdef DEBUG
 163                 perror("apache_Afs_weblog: wait error");
 164 #endif
 165                 log_error("wait error");
 166                 kill(getpid(), SIGTERM);
 167             }
 168
 169             if (WIFEXITED(stat)) {
 170                 exitstatus = WEXITSTATUS(stat);
 171                 switch (exitstatus) {
 172                 case 0:
 173 #ifdef DEBUG
 174                     fprintf(stderr, "%s:No error ... restarting\n", rn);
 175 #endif
 176                     break;
 177
 178                 case RESTART:
 179 #ifdef DEBUG
 180                     fprintf(stderr, "%s:%s...Exiting\n", rn, RESTARTMSG);
 181 #endif
 182                     log_error(RESTARTMSG);
 183                     exit(-1);
 184
 185                 case NULLARGS:
 186 #ifdef DEBUG
 187                     fprintf(stderr, "%s:%s...Exiting\n", rn, NULLARGSMSG);
 188                     log_error(NULLARGSMSG);
 189 #endif
 190                     exit(-1);
 191
 192                 case PIPESEND:
 193 #ifdef DEBUG
 194                     fprintf(stderr, "%s:%s...Restarting\n", rn, PIPESENDMSG);
 195 #endif
 196                     log_error(PIPESENDMSG);
 197                     break;
 198
 199                 case PIPEREAD:
 200 #ifdef DEBUG
 201                     fprintf(stderr, "%s:%s...Exiting\n", rn, PIPEREADMSG);
 202 #endif
 203                     log_error(PIPEREADMSG);
 204                     exit(-1);
 205
 206                 case PARSE:
 207 #ifdef DEBUG
 208                     fprintf(stderr, "%s:%s...Exiting\n", rn, PARSEMSG);
 209 #endif
 210                     log_error(PARSEMSG);
 211                     exit(-1);
 212
 213                 case KA:
 214 #ifdef DEBUG
 215                     fprintf(stderr, "%s:%s...Exiting\n", rn, KAMSG);
 216 #endif
 217                     log_error(KAMSG);
 218                     exit(-1);
 219
 220                 default:
 221 #ifdef DEBUG
 222                     fprintf(stderr, "%s:Unknown error...Exiting\n", rn);
 223 #endif
 224                     log_error("Unknown error");
 225                     exit(-1);
 226                 }               /* switch (exitstatus) */
 227             }
 228             /* if weblog exited */
 229             else {              /* weblog terminated abnormally */
 230                 if (WIFSIGNALED(stat)) {
 231 #ifdef DEBUG
 232                     fprintf(stderr,
 233                             "%s:The signal that terminated weblog:%d\n"
 234                             "Restarting weblog ...\n", rn, WTERMSIG(stat));
 235 #endif
 236                 }
 237 #ifndef AIX
 238                 else if (WCOREDUMP(stat)) {
 239 #ifdef DEBUG
 240                     fprintf(stderr, "%s: weblog dumped core" "Exiting ...\n",
 241                             rn);
 242 #endif
 243                     log_error("Core dump");
 244                     exit(-1);
 245                 }
 246 #endif
 247                 else {
 248 #ifdef DEBUG
 249                     fprintf(stderr,
 250                             "%s: weblog died under STRANGE circumstances..."
 251                             "restarting weblog\n", rn);
 252 #endif
 253                 }
 254             }
 255             break;
 256         }                       /* switch(weblog_pid) */
 257         restart_attempts++;
 258     }                           /* while */
 259 }