Current File : //root/postfix-3.2.0/src/postlock/postlock.c |
/*++
/* 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);
}
}