postlog.c

[詳解]

/*++
/* NAME
/*  postlog 1
/* SUMMARY
/*  Postfix-compatible logging utility
/* SYNOPSIS
/* .fi
/* .ad
/*  \fBpostlog\fR [\fB-iv\fR] [\fB-c \fIconfig_dir\fR]
/*  [\fB-p \fIpriority\fR] [\fB-t \fItag\fR] [\fItext...\fR]
/* DESCRIPTION
/*  The \fBpostlog\fR(1) command implements a Postfix-compatible logging
/*  interface for use in, for example, shell scripts.
/*
/*  By default, \fBpostlog\fR(1) logs the \fItext\fR given on the command
/*  line as one record. If no \fItext\fR is specified on the command
/*  line, \fBpostlog\fR(1) reads from standard input and logs each input
/*  line as one record.
/*
/*  Logging is sent to \fBsyslogd\fR(8); when the standard error stream
/*  is connected to a terminal, logging is sent there as well.
/*
/*  The following options are implemented:
/* .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-i\fR
/*  Include the process ID in the logging tag.
/* .IP "\fB-p \fIpriority\fR (default: \fBinfo\fR)"
/*  Specifies the logging severity: \fBinfo\fR, \fBwarn\fR,
/*  \fBerror\fR, \fBfatal\fR, or \fBpanic\fR. With Postfix 3.1
/*  and later, the program will pause for 1 second after reporting
/*  a \fBfatal\fR or \fBpanic\fR condition, just like other
/*  Postfix programs.
/* .IP "\fB-t \fItag\fR"
/*  Specifies the logging tag, that is, the identifying name that
/*  appears at the beginning of each logging record. A default tag
/*  is used when none is specified.
/* .IP \fB-v\fR
/*  Enable verbose logging for debugging purposes. Multiple \fB-v\fR
/*  options make the software increasingly verbose.
/* ENVIRONMENT
/* .ad
/* .fi
/* .IP MAIL_CONFIG
/*  Directory with the \fBmain.cf\fR file.
/* 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.
/* .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.
/* .IP "\fBsyslog_facility (mail)\fR"
/*  The syslog facility of Postfix logging.
/* .IP "\fBsyslog_name (see 'postconf -d' output)\fR"
/*  A prefix that is prepended to the process name in syslog
/*  records, so that, for example, "smtpd" becomes "prefix/smtpd".
/* SEE ALSO
/*  postconf(5), configuration parameters
/*  syslogd(8), syslog daemon
/* 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 <string.h>
#include <syslog.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>

#ifdef STRCASECMP_IN_STRINGS_H
#include <strings.h>
#endif

/* Utility library. */

#include <msg.h>
#include <vstring.h>
#include <vstream.h>
#include <vstring_vstream.h>
#include <msg_output.h>
#include <msg_vstream.h>
#include <msg_syslog.h>
#include <warn_stat.h>
#include <clean_env.h>

/* Global library. */

#include <mail_params.h>        /* XXX right place for LOG_FACILITY? */
#include <mail_version.h>
#include <mail_conf.h>
#include <mail_task.h>
#include <mail_parm_split.h>

/* Application-specific. */

 /*
  * Support for the severity level mapping.
  */
struct level_table {
    char   *name;
    int     level;
};

static struct level_table level_table[] = {
    "info", MSG_INFO,
    "warn", MSG_WARN,
    "warning", MSG_WARN,
    "error", MSG_ERROR,
    "err", MSG_ERROR,
    "fatal", MSG_FATAL,
    "crit", MSG_FATAL,
    "panic", MSG_PANIC,
    0,
};

/* level_map - lookup facility or severity value */

static int level_map(char *name)
{
    struct level_table *t;

    for (t = level_table; t->name; t++)
    if (strcasecmp(t->name, name) == 0)
        return (t->level);
    msg_fatal("bad severity: \"%s\"", name);
}

/* log_argv - log the command line */

static void log_argv(int level, char **argv)
{
    VSTRING *buf = vstring_alloc(100);

    while (*argv) {
    vstring_strcat(buf, *argv++);
    if (*argv)
        vstring_strcat(buf, " ");
    }
    msg_text(level, vstring_str(buf));
    vstring_free(buf);
}

/* log_stream - log lines from a stream */

static void log_stream(int level, VSTREAM *fp)
{
    VSTRING *buf = vstring_alloc(100);

    while (vstring_get_nonl(buf, fp) != VSTREAM_EOF)
    msg_text(level, vstring_str(buf));
    vstring_free(buf);
}

MAIL_VERSION_STAMP_DECLARE;

/* main - logger */

int     main(int argc, char **argv)
{
    struct stat st;
    int     fd;
    int     ch;
    const char *tag;
    int     log_flags = 0;
    int     level = MSG_INFO;
    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");

    /*
     * Set up diagnostics.
     */
    tag = mail_task(argv[0]);
    if (isatty(STDERR_FILENO))
    msg_vstream_init(tag, VSTREAM_ERR);
    msg_syslog_init(tag, LOG_PID, LOG_FACILITY);

    /*
     * Check the Postfix library version as soon as we enable logging.
     */
    MAIL_VERSION_CHECK;

    /*
     * Parse switches.
     */
    tag = 0;
    while ((ch = GETOPT(argc, argv, "c:ip:t:v")) > 0) {
    switch (ch) {
    default:
        msg_fatal("usage: %s [-c config_dir] [-i] [-p priority] [-t tag] [-v] [text]", argv[0]);
        break;
    case 'c':
        if (setenv(CONF_ENV_PATH, optarg, 1) < 0)
        msg_fatal("out of memory");
        break;
    case 'i':
        log_flags |= LOG_PID;
        break;
    case 'p':
        level = level_map(optarg);
        break;
    case 't':
        tag = optarg;
        break;
    case 'v':
        msg_verbose++;
        break;
    }
    }

    /*
     * Process the main.cf file. This may change the syslog_name setting and
     * may require that mail_task() be re-evaluated.
     */
    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);
    if (tag == 0)
    tag = mail_task(argv[0]);

    /*
     * Re-initialize the logging, this time with the tag specified in main.cf
     * or on the command line.
     */
    if (isatty(STDERR_FILENO))
    msg_vstream_init(tag, VSTREAM_ERR);
    msg_syslog_init(tag, LOG_PID, LOG_FACILITY);

    /*
     * Log the command line or log lines from standard input.
     */
    if (argc > optind) {
    log_argv(level, argv + optind);
    } else {
    log_stream(level, VSTREAM_IN);
    }

    /*
     * Consistency with msg(3) functions.
     */
    if (level >= MSG_FATAL)
    sleep(1);
    exit(0);
}