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                          * we base off the time the job was scheduled/started waiting, not the time it finished
 157                          */
 158                         /*
 159                         line->cl_NotUntil = time(NULL) + line->cl_Delay;        // to base off time finished
 160                         line->cl_NotUntil += line->cl_Delay;    // already applied
 161                          */
 162                 } else {
 163                         /* process finished without returning EAGAIN (it may have returned some other error)
 164                          * mark as having run and update timestamp
 165                          */
 166                         FILE *fi;
 167                         char buf[64];
 168                         int succeeded = 0;
 169                         /*
 170                          * we base off the time the job was scheduled/started waiting, not the time it finished
 171                          */
 172                         /*
 173                         line->cl_LastRan = time(NULL);  // to base off time finished
 174                         */
 175                         line->cl_LastRan = line->cl_NotUntil - line->cl_Delay;
 176                         if ((fi = fopen(line->cl_Timestamp, "w")) != NULL) {
 177                                 if (strftime(buf, sizeof(buf), TIMESTAMP_FMT, localtime(&line->cl_LastRan)))
 178                                         if (fputs(buf, fi) >= 0)
 179                                                 succeeded = 1;
 180                                 fclose(fi);
 181                         }
 182                         if (!succeeded)
 183                                 logn(LOG_WARNING, "unable to write timestamp to %s (user %s %s)\n", line->cl_Timestamp, file->cf_UserName, line->cl_Description);
 184                         line->cl_NotUntil = line->cl_LastRan;
 185                         line->cl_NotUntil += (line->cl_Freq > 0) ? line->cl_Freq : line->cl_Delay;
 186                 }
 187         }
 188
 189         if (exit_status != EAGAIN) {
 190                 /*
 191                  * notify any waiters
 192                  */
 193                 notif = line->cl_Notifs;
 194                 while (notif) {
 195                         if (notif->cn_Waiter) {
 196                                 notif->cn_Waiter->cw_Flag = exit_status;
 197                         }
 198                         notif = notif->cn_Next;
 199                 }
 200
 201                 if (exit_status) {
 202                         /*
 203                          * log non-zero exit_status
 204                          */
 205                         logn(LOG_INFO, "exit status %d from %s %s\n",
 206                                         exit_status,
 207                                         file->cf_UserName,
 208                                         line->cl_Description
 209                                 );
 210
 211                         }
 212         }
 213
 214         snprintf(mailFile, sizeof(mailFile), TempFileFmt,
 215                         file->cf_UserName, line->cl_Pid);
 216
 217         line->cl_Pid = 0;
 218
 219         if (line->cl_MailFlag != 1)
 220         /*
 221          * End of job and no mail file
 222          */
 223                 return;
 224
 225         line->cl_MailFlag = 0;
 226
 227         /*
 228          * Check mail file. If size has increased and
 229          * the file is still valid, we sendmail it.
 230          */
 231
 232         mailFd = open(mailFile, O_RDONLY);
 233         remove(mailFile);
 234         if (mailFd < 0) {
 235                 return;
 236         }
 237
 238         if (fstat(mailFd, &sbuf) < 0 ||
 239                         sbuf.st_uid != DaemonUid ||
 240                         sbuf.st_nlink != 0 ||
 241                         sbuf.st_size == line->cl_MailPos ||
 242                         !S_ISREG(sbuf.st_mode)
 243            ) {
 244                 close(mailFd);
 245                 return;
 246         }
 247
 248         if ((line->cl_Pid = fork()) == 0) {
 249                 /*
 250                  * CHILD, FORK OK
 251                  */
 252
 253                 /*
 254                  * change user id - no way in hell security can be compromised
 255                  * by the mailing and we already verified the mail file.
 256                  */
 257
 258                 if (ChangeUser(file->cf_UserName, 1) < 0) {
 259                         logn(LOG_ERR, "ChangeUser %s failed; unable to send mail\n",
 260                                         file->cf_UserName
 261                                         );
 262                         exit(0);
 263                 }
 264
 265                 /* create close-on-exec log descriptor in case exec fails */
 266                 dup2(2, 8);
 267                 fcntl(8, F_SETFD, 1);
 268                 fclose(stderr);
 269
 270                 /*
 271                  * run sendmail with mail file as standard input, only if
 272                  * mail file exists!
 273                  */
 274
 275                 dup2(mailFd, 0);
 276                 dup2(1, 2);
 277                 close(mailFd);
 278
 279                 if (!SendMail) {
 280                         logfd(LOG_INFO, 8, "mailing cron output for user %s %s\n",
 281                                         file->cf_UserName,
 282                                         line->cl_Description
 283                                  );
 284                         execl(SENDMAIL, SENDMAIL, SENDMAIL_ARGS, NULL, NULL);
 285                 } else
 286                         execl(SendMail, SendMail, NULL, NULL);
 287
 288                         logfd(LOG_WARNING, 8, "unable to exec %s %s: cron output for user %s %s to /dev/null\n",
 289                                         SendMail,
 290                                         SENDMAIL_ARGS,
 291                                         file->cf_UserName,
 292                                         line->cl_Description
 293                                    );
 294                 exit(0);
 295         } else if (line->cl_Pid < 0) {
 296                 /*
 297                  * PARENT, FORK FAILED
 298                  */
 299                 logn(LOG_ERR, "unable to fork: cron output for user %s %s to /dev/null\n",
 300                                 file->cf_UserName,
 301                                 line->cl_Description
 302                         );
 303         } else {
 304                 /*
 305                  * PARENT, FORK OK
 306                  */
 307         }
 308         line->cl_Pid = 0;
 309         close(mailFd);
 310 }
 311