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-rw-r--r--src/postlock/postlock.c277
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diff --git a/src/postlock/postlock.c b/src/postlock/postlock.c
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+/*++
+/* NAME
+/* postlock 1
+/* SUMMARY
+/* lock mail folder and execute command
+/* SYNOPSIS
+/* .fi
+/* \fBpostlock\fR [\fB-c \fIconfig_dir\fR] [\fB-l \fIlock_style\fR]
+/* [\fB-v\fR] \fIfile command...\fR
+/* DESCRIPTION
+/* The \fBpostlock\fR(1) command locks \fIfile\fR for exclusive
+/* access, and executes \fIcommand\fR. The locking method is
+/* compatible with the Postfix UNIX-style local delivery agent.
+/*
+/* Options:
+/* .IP "\fB-c \fIconfig_dir\fR"
+/* Read the \fBmain.cf\fR configuration file in the named directory
+/* instead of the default configuration directory.
+/* .IP "\fB-l \fIlock_style\fR"
+/* Override the locking method specified via the
+/* \fBmailbox_delivery_lock\fR configuration parameter (see below).
+/* .IP \fB-v\fR
+/* Enable verbose logging for debugging purposes. Multiple \fB-v\fR
+/* options make the software increasingly verbose.
+/* .PP
+/* Arguments:
+/* .IP \fIfile\fR
+/* A mailbox file. The user should have read/write permission.
+/* .IP \fIcommand...\fR
+/* The command to execute while \fIfile\fR is locked for exclusive
+/* access. The command is executed directly, i.e. without
+/* interpretation by a shell command interpreter.
+/* DIAGNOSTICS
+/* The result status is 75 (EX_TEMPFAIL) when \fBpostlock\fR(1)
+/* could not perform the requested operation. Otherwise, the
+/* exit status is the exit status from the command.
+/* BUGS
+/* With remote file systems, the ability to acquire a lock does not
+/* necessarily eliminate access conflicts. Avoid file access by
+/* processes running on different machines.
+/* ENVIRONMENT
+/* .ad
+/* .fi
+/* .IP \fBMAIL_CONFIG\fR
+/* Directory with Postfix configuration files.
+/* .IP \fBMAIL_VERBOSE\fR
+/* Enable verbose logging for debugging purposes.
+/* CONFIGURATION PARAMETERS
+/* .ad
+/* .fi
+/* The following \fBmain.cf\fR parameters are especially relevant to
+/* this program.
+/* The text below provides only a parameter summary. See
+/* \fBpostconf\fR(5) for more details including examples.
+/* LOCKING CONTROLS
+/* .ad
+/* .fi
+/* .IP "\fBdeliver_lock_attempts (20)\fR"
+/* The maximal number of attempts to acquire an exclusive lock on a
+/* mailbox file or \fBbounce\fR(8) logfile.
+/* .IP "\fBdeliver_lock_delay (1s)\fR"
+/* The time between attempts to acquire an exclusive lock on a mailbox
+/* file or \fBbounce\fR(8) logfile.
+/* .IP "\fBstale_lock_time (500s)\fR"
+/* The time after which a stale exclusive mailbox lockfile is removed.
+/* .IP "\fBmailbox_delivery_lock (see 'postconf -d' output)\fR"
+/* How to lock a UNIX-style \fBlocal\fR(8) mailbox before attempting delivery.
+/* RESOURCE AND RATE CONTROLS
+/* .ad
+/* .fi
+/* .IP "\fBfork_attempts (5)\fR"
+/* The maximal number of attempts to fork() a child process.
+/* .IP "\fBfork_delay (1s)\fR"
+/* The delay between attempts to fork() a child process.
+/* MISCELLANEOUS CONTROLS
+/* .ad
+/* .fi
+/* .IP "\fBconfig_directory (see 'postconf -d' output)\fR"
+/* The default location of the Postfix main.cf and master.cf
+/* configuration files.
+/* .IP "\fBimport_environment (see 'postconf -d' output)\fR"
+/* The list of environment parameters that a privileged Postfix
+/* process will import from a non-Postfix parent process, or name=value
+/* environment overrides.
+/* SEE ALSO
+/* postconf(5), configuration parameters
+/* LICENSE
+/* .ad
+/* .fi
+/* The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/* Wietse Venema
+/* IBM T.J. Watson Research
+/* P.O. Box 704
+/* Yorktown Heights, NY 10598, USA
+/*
+/* Wietse Venema
+/* Google, Inc.
+/* 111 8th Avenue
+/* New York, NY 10011, USA
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+
+/* Utility library. */
+
+#include <msg.h>
+#include <vstring.h>
+#include <vstream.h>
+#include <msg_vstream.h>
+#include <iostuff.h>
+#include <warn_stat.h>
+#include <clean_env.h>
+
+/* Global library. */
+
+#include <mail_params.h>
+#include <mail_version.h>
+#include <dot_lockfile.h>
+#include <deliver_flock.h>
+#include <mail_conf.h>
+#include <sys_exits.h>
+#include <mbox_conf.h>
+#include <mbox_open.h>
+#include <dsn_util.h>
+#include <mail_parm_split.h>
+
+/* Application-specific. */
+
+/* usage - explain */
+
+static NORETURN usage(char *myname)
+{
+ msg_fatal("usage: %s [-c config_dir] [-l lock_style] [-v] folder command...", myname);
+}
+
+/* fatal_exit - all failures are deemed recoverable */
+
+static void fatal_exit(void)
+{
+ exit(EX_TEMPFAIL);
+}
+
+MAIL_VERSION_STAMP_DECLARE;
+
+/* main - go for it */
+
+int main(int argc, char **argv)
+{
+ DSN_BUF *why;
+ char *folder;
+ char **command;
+ int ch;
+ int fd;
+ struct stat st;
+ int count;
+ WAIT_STATUS_T status;
+ pid_t pid;
+ int lock_mask;
+ char *lock_style = 0;
+ MBOX *mp;
+ ARGV *import_env;
+
+ /*
+ * Fingerprint executables and core dumps.
+ */
+ MAIL_VERSION_STAMP_ALLOCATE;
+
+ /*
+ * Be consistent with file permissions.
+ */
+ umask(022);
+
+ /*
+ * To minimize confusion, make sure that the standard file descriptors
+ * are open before opening anything else. XXX Work around for 44BSD where
+ * fstat can return EBADF on an open file descriptor.
+ */
+ for (fd = 0; fd < 3; fd++)
+ if (fstat(fd, &st) == -1
+ && (close(fd), open("/dev/null", O_RDWR, 0)) != fd)
+ msg_fatal("open /dev/null: %m");
+
+ /*
+ * Process environment options as early as we can. We are not set-uid,
+ * and we are supposed to be running in a controlled environment.
+ */
+ if (getenv(CONF_ENV_VERB))
+ msg_verbose = 1;
+
+ /*
+ * Set up logging and error handling. Intercept fatal exits so we can
+ * return a distinguished exit status.
+ */
+ msg_vstream_init(argv[0], VSTREAM_ERR);
+ msg_cleanup(fatal_exit);
+
+ /*
+ * Parse JCL.
+ */
+ while ((ch = GETOPT(argc, argv, "c:l:v")) > 0) {
+ switch (ch) {
+ default:
+ usage(argv[0]);
+ break;
+ case 'c':
+ if (setenv(CONF_ENV_PATH, optarg, 1) < 0)
+ msg_fatal("out of memory");
+ break;
+ case 'l':
+ lock_style = optarg;
+ break;
+ case 'v':
+ msg_verbose++;
+ break;
+ }
+ }
+ if (optind + 2 > argc)
+ usage(argv[0]);
+ folder = argv[optind];
+ command = argv + optind + 1;
+
+ /*
+ * Read the config file. The command line lock style can override the
+ * configured lock style.
+ */
+ mail_conf_read();
+ /* Enforce consistent operation of different Postfix parts. */
+ import_env = mail_parm_split(VAR_IMPORT_ENVIRON, var_import_environ);
+ update_env(import_env->argv);
+ argv_free(import_env);
+ lock_mask = mbox_lock_mask(lock_style ? lock_style :
+ get_mail_conf_str(VAR_MAILBOX_LOCK, DEF_MAILBOX_LOCK, 1, 0));
+
+ /*
+ * Lock the folder for exclusive access. Lose the lock upon exit. The
+ * command is not supposed to disappear into the background.
+ */
+ why = dsb_create();
+ if ((mp = mbox_open(folder, O_APPEND | O_WRONLY | O_CREAT,
+ S_IRUSR | S_IWUSR, (struct stat *) 0,
+ -1, -1, lock_mask, "5.2.0", why)) == 0)
+ msg_fatal("open file %s: %s", folder, vstring_str(why->reason));
+ dsb_free(why);
+
+ /*
+ * Run the command. Remove the lock after completion.
+ */
+ for (count = 1; (pid = fork()) == -1; count++) {
+ msg_warn("fork %s: %m", command[0]);
+ if (count >= var_fork_tries) {
+ mbox_release(mp);
+ exit(EX_TEMPFAIL);
+ }
+ sleep(var_fork_delay);
+ }
+ switch (pid) {
+ case 0:
+ (void) msg_cleanup((MSG_CLEANUP_FN) 0);
+ execvp(command[0], command);
+ msg_fatal("execvp %s: %m", command[0]);
+ default:
+ if (waitpid(pid, &status, 0) < 0)
+ msg_fatal("waitpid: %m");
+ vstream_fclose(mp->fp);
+ mbox_release(mp);
+ exit(WIFEXITED(status) ? WEXITSTATUS(status) : 1);
+ }
+}