job.c

   1
   2 /*
   3  * JOB.C
   4  *
   5  * Copyright 1994 Matthew Dillon (dillon@apollo.backplane.com)
   6  * Copyright 2009 James Pryor <profjim@jimpryor.net>
   7  * May be distributed under the GNU General Public License
   8  */
   9
  10 #include "defs.h"
  11
  12 Prototype void RunJob(CronFile *file, CronLine *line);
  13 Prototype void EndJob(CronFile *file, CronLine *line, int exit_status);
  14 Prototype const char *SendMail;
  15
  16 void
  17 RunJob(CronFile *file, CronLine *line)
  18 {
  19         char mailFile[128];
  20         int mailFd;
  21         const char *value = Mailto;
  22
  23         line->cl_Pid = 0;
  24         line->cl_MailFlag = 0;
  25
  26         /*
  27          * open mail file - owner root so nobody can screw with it.
  28          */
  29
  30         snprintf(mailFile, sizeof(mailFile), TempFileFmt,
  31                         file->cf_UserName, (int)getpid());
  32         mailFd = open(mailFile, O_CREAT|O_TRUNC|O_WRONLY|O_EXCL|O_APPEND, 0600);
  33
  34         if (mailFd >= 0) {
  35                 line->cl_MailFlag = 1;
  36                 if (!value)
  37                         value = file->cf_UserName;
  38                 fdprintf(mailFd, "To: %s\nSubject: cron for user %s %s\n\n",
  39                                 value,
  40                                 file->cf_UserName,
  41                                 line->cl_Description
  42                                 );
  43                 line->cl_MailPos = lseek(mailFd, 0, 1);
  44         }
  45         /* else we issue warning later */
  46
  47         /*
  48          * Fork as the user in question and run program
  49          */
  50
  51         if ((line->cl_Pid = fork()) == 0) {
  52                 /*
  53                  * CHILD, FORK OK
  54                  */
  55
  56                 /*
  57                  * Change running state to the user in question
  58                  */
  59
  60                 if (ChangeUser(file->cf_UserName, 1) < 0) {
  61                         logn(LOG_ERR, "ChangeUser failed (user %s %s)\n",
  62                                         file->cf_UserName,
  63                                         line->cl_Description
  64                                         );
  65                         exit(0);
  66                 }
  67
  68                 if (DebugOpt)
  69                         logn(LOG_DEBUG, "child running: %s\n", line->cl_Description);
  70
  71         /* Setup close-on-exec descriptor in case exec fails */
  72         dup2(2, 8);
  73         fcntl(8, F_SETFD, 1);
  74         fclose(stderr);
  75
  76         /* stdin is already /dev/null, setup stdout and stderr */
  77
  78                 if (mailFd >= 0) {
  79                         dup2(mailFd, 1);
  80                         dup2(mailFd, 2);
  81                         close(mailFd);
  82                 } else {
  83                         logfd(LOG_WARNING, 8, "unable to create mail file %s: cron output for user %s %s to /dev/null\n",
  84                                         mailFile,
  85                                         file->cf_UserName,
  86                                         line->cl_Description
  87                                    );
  88                 }
  89                 execl("/bin/sh", "/bin/sh", "-c", line->cl_Shell, NULL, NULL);
  90                 logfd(LOG_ERR, 8, "unable to exec (user %s cmd /bin/sh -c %s)\n",
  91                                 file->cf_UserName,
  92                                 line->cl_Shell
  93                            );
  94                 /* we also write error to the mailed cron output */
  95                 fdprintf(1, "unable to exec: /bin/sh -c %s\n", line->cl_Shell);
  96                 exit(0);
  97         } else if (line->cl_Pid < 0) {
  98                 /*
  99                  * PARENT, FORK FAILED
 100                  */
 101                 logn(LOG_ERR, "unable to fork (user %s %s)\n",
 102                                 file->cf_UserName,
 103                                 line->cl_Description
 104                                 );
 105                 line->cl_Pid = 0;
 106                 remove(mailFile);
 107         } else {
 108                 /*
 109                  * PARENT, FORK SUCCESS
 110                  *
 111                  * rename mail-file based on pid of child process
 112                  */
 113                 char mailFile2[128];
 114
 115                 snprintf(mailFile2, sizeof(mailFile2), TempFileFmt,
 116                                 file->cf_UserName, line->cl_Pid);
 117                 rename(mailFile, mailFile2);
 118         }
 119
 120         /*
 121          * Close the mail file descriptor.. we can't just leave it open in
 122          * a structure, closing it later, because we might run out of descriptors
 123          */
 124
 125         if (mailFd >= 0)
 126                 close(mailFd);
 127 }
 128
 129 /*
 130  * EndJob - called when job terminates and when mail terminates
 131  */
 132
 133 void
 134 EndJob(CronFile *file, CronLine *line, int exit_status)
 135 {
 136         int mailFd;
 137         char mailFile[128];
 138         struct stat sbuf;
 139         struct  CronNotifier *notif;
 140
 141         if (line->cl_Pid <= 0) {
 142                 /*
 143                  * No job
 144                  */
 145                 line->cl_Pid = 0;
 146                 return;
 147         }
 148
 149
 150         /*
 151          * check return status?
 152          */
 153         if (line->cl_Delay > 0) {
 154                 if (exit_status == EAGAIN) {
 155                         /* returned EAGAIN, wait cl_Delay then retry */
 156                         /*
 157                         line->cl_NotUntil = time(NULL) + line->cl_Delay;
 158                          */
 159                         line->cl_NotUntil += line->cl_Delay; // we base off the time the job was scheduled/started waiting, not the time it finished
 160                 } else {
 161                         /* process finished without returning EAGAIN (it may have returned some other error)
 162                          * mark as having run and update timestamp
 163                          */
 164                         FILE *fi;
 165                         char buf[64];
 166                         /*
 167                         line->cl_LastRan = time(NULL);
 168                          */
 169                         line->cl_LastRan = line->cl_NotUntil; // we base off the time the job was scheduled/started waiting, not the time it finished
 170                         if ((fi = fopen(line->cl_Timestamp, "w")) != NULL) {
 171                                 if (strftime(buf, sizeof(buf), TIMESTAMP_FMT, localtime(&line->cl_LastRan))) {
 172                                         fputs(buf, fi);
 173                                 } else
 174                                         logn(LOG_NOTICE, "unable to format timestamp (user %s %s)\n", file->cf_UserName, line->cl_Description);
 175                                 fclose(fi);
 176                         } else {
 177                                 logn(LOG_NOTICE, "unable to write timestamp to %s (user %s %s)\n", line->cl_Timestamp, file->cf_UserName, line->cl_Description);
 178                         }
 179                         line->cl_NotUntil = line->cl_LastRan;
 180                         line->cl_NotUntil += (line->cl_Freq > 0) ? line->cl_Freq : line->cl_Delay;
 181                 }
 182         }
 183
 184         if (exit_status != EAGAIN) {
 185                 /*
 186                  * notify any waiters
 187                  */
 188                 notif = line->cl_Notifs;
 189                 while (notif) {
 190                         if (notif->cn_Waiter) {
 191                                 notif->cn_Waiter->cw_Flag = exit_status;
 192                         }
 193                         notif = notif->cn_Next;
 194                 }
 195
 196                 if (exit_status) {
 197                         /*
 198                          * log non-zero exit_status
 199                          */
 200                         logn(LOG_INFO, "exit status %d from %s %s\n",
 201                                         exit_status,
 202                                         file->cf_UserName,
 203                                         line->cl_Description
 204                                 );
 205
 206                         }
 207         }
 208
 209         snprintf(mailFile, sizeof(mailFile), TempFileFmt,
 210                         file->cf_UserName, line->cl_Pid);
 211
 212         line->cl_Pid = 0;
 213
 214         if (line->cl_MailFlag != 1)
 215         /*
 216          * End of job and no mail file
 217          */
 218                 return;
 219
 220         line->cl_MailFlag = 0;
 221
 222         /*
 223          * Check mail file. If size has increased and
 224          * the file is still valid, we sendmail it.
 225          */
 226
 227         mailFd = open(mailFile, O_RDONLY);
 228         remove(mailFile);
 229         if (mailFd < 0) {
 230                 return;
 231         }
 232
 233         if (fstat(mailFd, &sbuf) < 0 ||
 234                         sbuf.st_uid != DaemonUid ||
 235                         sbuf.st_nlink != 0 ||
 236                         sbuf.st_size == line->cl_MailPos ||
 237                         !S_ISREG(sbuf.st_mode)
 238            ) {
 239                 close(mailFd);
 240                 return;
 241         }
 242
 243         if ((line->cl_Pid = fork()) == 0) {
 244                 /*
 245                  * CHILD, FORK OK
 246                  */
 247
 248                 /*
 249                  * change user id - no way in hell security can be compromised
 250                  * by the mailing and we already verified the mail file.
 251                  */
 252
 253                 if (ChangeUser(file->cf_UserName, 1) < 0) {
 254                         logn(LOG_ERR, "ChangeUser %s failed; unable to send mail\n",
 255                                         file->cf_UserName
 256                                         );
 257                         exit(0);
 258                 }
 259
 260                 /* create close-on-exec log descriptor in case exec fails */
 261                 dup2(2, 8);
 262                 fcntl(8, F_SETFD, 1);
 263                 fclose(stderr);
 264
 265                 /*
 266                  * run sendmail with mail file as standard input, only if
 267                  * mail file exists!
 268                  */
 269
 270                 dup2(mailFd, 0);
 271                 dup2(1, 2);
 272                 close(mailFd);
 273
 274                 if (!SendMail) {
 275                         logfd(LOG_INFO, 8, "mailing cron output for user %s %s\n",
 276                                         file->cf_UserName,
 277                                         line->cl_Description
 278                                  );
 279                         execl(SENDMAIL, SENDMAIL, SENDMAIL_ARGS, NULL, NULL);
 280                 } else
 281                         execl(SendMail, SendMail, NULL, NULL);
 282
 283                         logfd(LOG_WARNING, 8, "unable to exec %s %s: cron output for user %s %s to /dev/null\n",
 284                                         SendMail,
 285                                         SENDMAIL_ARGS,
 286                                         file->cf_UserName,
 287                                         line->cl_Description
 288                                    );
 289                 exit(0);
 290         } else if (line->cl_Pid < 0) {
 291                 /*
 292                  * PARENT, FORK FAILED
 293                  */
 294                 logn(LOG_ERR, "unable to fork: cron output for user %s %s to /dev/null\n",
 295                                 file->cf_UserName,
 296                                 line->cl_Description
 297                         );
 298         } else {
 299                 /*
 300                  * PARENT, FORK OK
 301                  */
 302         }
 303         line->cl_Pid = 0;
 304         close(mailFd);
 305 }
 306