external/ibm-public/postfix/dist/src/postlock/postlock.c

   1 /*      $NetBSD$        */
   2
   3 /*++
   4 /* NAME
   5 /*      postlock 1
   6 /* SUMMARY
   7 /*      lock mail folder and execute command
   8 /* SYNOPSIS
   9 /* .fi
  10 /*      \fBpostlock\fR [\fB-c \fIconfig_dir\fB] [\fB-l \fIlock_style\fB]
  11 /*              [\fB-v\fR] \fIfile command...\fR
  12 /* DESCRIPTION
  13 /*      The \fBpostlock\fR(1) command locks \fIfile\fR for exclusive
  14 /*      access, and executes \fIcommand\fR. The locking method is
  15 /*      compatible with the Postfix UNIX-style local delivery agent.
  16 /*
  17 /*      Options:
  18 /* .IP "\fB-c \fIconfig_dir\fR"
  19 /*      Read the \fBmain.cf\fR configuration file in the named directory
  20 /*      instead of the default configuration directory.
  21 /* .IP "\fB-l \fIlock_style\fR"
  22 /*      Override the locking method specified via the
  23 /*      \fBmailbox_delivery_lock\fR configuration parameter (see below).
  24 /* .IP \fB-v\fR
  25 /*      Enable verbose logging for debugging purposes. Multiple \fB-v\fR
  26 /*      options make the software increasingly verbose.
  27 /* .PP
  28 /*      Arguments:
  29 /* .IP \fIfile\fR
  30 /*      A mailbox file. The user should have read/write permission.
  31 /* .IP \fIcommand...\fR
  32 /*      The command to execute while \fIfile\fR is locked for exclusive
  33 /*      access.  The command is executed directly, i.e. without
  34 /*      interpretation by a shell command interpreter.
  35 /* DIAGNOSTICS
  36 /*      The result status is 75 (EX_TEMPFAIL) when \fBpostlock\fR(1)
  37 /*      could not perform the requested operation.  Otherwise, the
  38 /*      exit status is the exit status from the command.
  39 /* BUGS
  40 /*      With remote file systems, the ability to acquire a lock does not
  41 /*      necessarily eliminate access conflicts. Avoid file access by
  42 /*      processes running on different machines.
  43 /* ENVIRONMENT
  44 /* .ad
  45 /* .fi
  46 /* .IP \fBMAIL_CONFIG\fR
  47 /*      Directory with Postfix configuration files.
  48 /* .IP \fBMAIL_VERBOSE\fR
  49 /*      Enable verbose logging for debugging purposes.
  50 /* CONFIGURATION PARAMETERS
  51 /* .ad
  52 /* .fi
  53 /*      The following \fBmain.cf\fR parameters are especially relevant to
  54 /*      this program.
  55 /*      The text below provides only a parameter summary. See
  56 /*      \fBpostconf\fR(5) for more details including examples.
  57 /* LOCKING CONTROLS
  58 /* .ad
  59 /* .fi
  60 /* .IP "\fBdeliver_lock_attempts (20)\fR"
  61 /*      The maximal number of attempts to acquire an exclusive lock on a
  62 /*      mailbox file or \fBbounce\fR(8) logfile.
  63 /* .IP "\fBdeliver_lock_delay (1s)\fR"
  64 /*      The time between attempts to acquire an exclusive lock on a mailbox
  65 /*      file or \fBbounce\fR(8) logfile.
  66 /* .IP "\fBstale_lock_time (500s)\fR"
  67 /*      The time after which a stale exclusive mailbox lockfile is removed.
  68 /* .IP "\fBmailbox_delivery_lock (see 'postconf -d' output)\fR"
  69 /*      How to lock a UNIX-style \fBlocal\fR(8) mailbox before attempting delivery.
  70 /* RESOURCE AND RATE CONTROLS
  71 /* .ad
  72 /* .fi
  73 /* .IP "\fBfork_attempts (5)\fR"
  74 /*      The maximal number of attempts to fork() a child process.
  75 /* .IP "\fBfork_delay (1s)\fR"
  76 /*      The delay between attempts to fork() a child process.
  77 /* MISCELLANEOUS CONTROLS
  78 /* .ad
  79 /* .fi
  80 /* .IP "\fBconfig_directory (see 'postconf -d' output)\fR"
  81 /*      The default location of the Postfix main.cf and master.cf
  82 /*      configuration files.
  83 /* SEE ALSO
  84 /*      postconf(5), configuration parameters
  85 /* LICENSE
  86 /* .ad
  87 /* .fi
  88 /*      The Secure Mailer license must be distributed with this software.
  89 /* AUTHOR(S)
  90 /*      Wietse Venema
  91 /*      IBM T.J. Watson Research
  92 /*      P.O. Box 704
  93 /*      Yorktown Heights, NY 10598, USA
  94 /*--*/
  95
  96 /* System library. */
  97
  98 #include <sys_defs.h>
  99 #include <sys/stat.h>
 100 #include <sys/wait.h>
 101 #include <stdlib.h>
 102 #include <unistd.h>
 103 #include <fcntl.h>
 104 #include <errno.h>
 105
 106 /* Utility library. */
 107
 108 #include <msg.h>
 109 #include <vstring.h>
 110 #include <vstream.h>
 111 #include <msg_vstream.h>
 112 #include <iostuff.h>
 113
 114 /* Global library. */
 115
 116 #include <mail_params.h>
 117 #include <mail_version.h>
 118 #include <dot_lockfile.h>
 119 #include <deliver_flock.h>
 120 #include <mail_conf.h>
 121 #include <sys_exits.h>
 122 #include <mbox_conf.h>
 123 #include <mbox_open.h>
 124 #include <dsn_util.h>
 125
 126 /* Application-specific. */
 127
 128 /* usage - explain */
 129
 130 static NORETURN usage(char *myname)
 131 {
 132     msg_fatal("usage: %s [-c config_dir] [-l lock_style] [-v] folder command...", myname);
 133 }
 134
 135 /* fatal_exit - all failures are deemed recoverable */
 136
 137 static void fatal_exit(void)
 138 {
 139     exit(EX_TEMPFAIL);
 140 }
 141
 142 MAIL_VERSION_STAMP_DECLARE;
 143
 144 /* main - go for it */
 145
 146 int     main(int argc, char **argv)
 147 {
 148     DSN_BUF *why;
 149     char   *folder;
 150     char  **command;
 151     int     ch;
 152     int     fd;
 153     struct stat st;
 154     int     count;
 155     WAIT_STATUS_T status;
 156     pid_t   pid;
 157     int     lock_mask;
 158     char   *lock_style = 0;
 159     MBOX   *mp;
 160
 161     /*
 162      * Fingerprint executables and core dumps.
 163      */
 164     MAIL_VERSION_STAMP_ALLOCATE;
 165
 166     /*
 167      * Be consistent with file permissions.
 168      */
 169     umask(022);
 170
 171     /*
 172      * To minimize confusion, make sure that the standard file descriptors
 173      * are open before opening anything else. XXX Work around for 44BSD where
 174      * fstat can return EBADF on an open file descriptor.
 175      */
 176     for (fd = 0; fd < 3; fd++)
 177         if (fstat(fd, &st) == -1
 178             && (close(fd), open("/dev/null", O_RDWR, 0)) != fd)
 179             msg_fatal("open /dev/null: %m");
 180
 181     /*
 182      * Process environment options as early as we can. We are not set-uid,
 183      * and we are supposed to be running in a controlled environment.
 184      */
 185     if (getenv(CONF_ENV_VERB))
 186         msg_verbose = 1;
 187
 188     /*
 189      * Set up logging and error handling. Intercept fatal exits so we can
 190      * return a distinguished exit status.
 191      */
 192     msg_vstream_init(argv[0], VSTREAM_ERR);
 193     msg_cleanup(fatal_exit);
 194
 195     /*
 196      * Parse JCL.
 197      */
 198     while ((ch = GETOPT(argc, argv, "c:l:v")) > 0) {
 199         switch (ch) {
 200         default:
 201             usage(argv[0]);
 202             break;
 203         case 'c':
 204             if (setenv(CONF_ENV_PATH, optarg, 1) < 0)
 205                 msg_fatal("out of memory");
 206             break;
 207         case 'l':
 208             lock_style = optarg;
 209             break;
 210         case 'v':
 211             msg_verbose++;
 212             break;
 213         }
 214     }
 215     if (optind + 2 > argc)
 216         usage(argv[0]);
 217     folder = argv[optind];
 218     command = argv + optind + 1;
 219
 220     /*
 221      * Read the config file. The command line lock style can override the
 222      * configured lock style.
 223      */
 224     mail_conf_read();
 225     lock_mask = mbox_lock_mask(lock_style ? lock_style :
 226                get_mail_conf_str(VAR_MAILBOX_LOCK, DEF_MAILBOX_LOCK, 1, 0));
 227
 228     /*
 229      * Lock the folder for exclusive access. Lose the lock upon exit. The
 230      * command is not supposed to disappear into the background.
 231      */
 232     why = dsb_create();
 233     if ((mp = mbox_open(folder, O_APPEND | O_WRONLY | O_CREAT,
 234                         S_IRUSR | S_IWUSR, (struct stat *) 0,
 235                         -1, -1, lock_mask, "5.2.0", why)) == 0)
 236         msg_fatal("open file %s: %s", folder, vstring_str(why->reason));
 237     dsb_free(why);
 238
 239     /*
 240      * Run the command. Remove the lock after completion.
 241      */
 242     for (count = 1; (pid = fork()) == -1; count++) {
 243         msg_warn("fork %s: %m", command[0]);
 244         if (count >= var_fork_tries) {
 245             mbox_release(mp);
 246             exit(EX_TEMPFAIL);
 247         }
 248         sleep(var_fork_delay);
 249     }
 250     switch (pid) {
 251     case 0:
 252         (void) msg_cleanup((MSG_CLEANUP_FN) 0);
 253         execvp(command[0], command);
 254         msg_fatal("execvp %s: %m", command[0]);
 255     default:
 256         if (waitpid(pid, &status, 0) < 0)
 257             msg_fatal("waitpid: %m");
 258         vstream_fclose(mp->fp);
 259         mbox_release(mp);
 260         exit(WIFEXITED(status) ? WEXITSTATUS(status) : 1);
 261     }
 262 }