The 'restart' variable was responsible for enablement of restart behavior and for restart delay. While it may seem convenient it leads to cluttering the exit/restart logic Reviewed by: kevans Pull Request: https://github.com/freebsd/freebsd-src/pull/672
737 lines
20 KiB
C
737 lines
20 KiB
C
/*-
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Copyright (c) 1999 Berkeley Software Design, Inc. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Berkeley Software Design Inc's name may not be used to endorse or
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* promote products derived from this software without specific prior
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* written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* From BSDI: daemon.c,v 1.2 1996/08/15 01:11:09 jch Exp
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/mman.h>
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#include <sys/wait.h>
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#include <fcntl.h>
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#include <err.h>
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#include <errno.h>
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#include <getopt.h>
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#include <libutil.h>
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#include <login_cap.h>
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#include <paths.h>
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#include <pwd.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdbool.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <string.h>
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#include <strings.h>
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#define SYSLOG_NAMES
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#include <syslog.h>
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#include <time.h>
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#include <assert.h>
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#define LBUF_SIZE 4096
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struct log_params {
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const char *output_filename;
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const char *syslog_tag;
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int syslog_priority;
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int syslog_facility;
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int keep_fds_open;
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int output_fd;
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bool syslog_enabled;
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};
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static void restrict_process(const char *);
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static void handle_term(int);
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static void handle_chld(int);
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static void handle_hup(int);
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static int open_log(const char *);
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static void reopen_log(struct log_params *);
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static bool listen_child(int, struct log_params *);
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static int get_log_mapping(const char *, const CODE *);
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static void open_pid_files(const char *, const char *, struct pidfh **,
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struct pidfh **);
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static void do_output(const unsigned char *, size_t, struct log_params *);
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static void daemon_sleep(time_t, long);
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static volatile sig_atomic_t terminate = 0;
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static volatile sig_atomic_t child_gone = 0;
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static volatile sig_atomic_t pid = 0;
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static volatile sig_atomic_t do_log_reopen = 0;
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static const char shortopts[] = "+cfHSp:P:ru:o:s:l:t:m:R:T:h";
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static const struct option longopts[] = {
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{ "change-dir", no_argument, NULL, 'c' },
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{ "close-fds", no_argument, NULL, 'f' },
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{ "sighup", no_argument, NULL, 'H' },
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{ "syslog", no_argument, NULL, 'S' },
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{ "output-file", required_argument, NULL, 'o' },
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{ "output-mask", required_argument, NULL, 'm' },
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{ "child-pidfile", required_argument, NULL, 'p' },
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{ "supervisor-pidfile", required_argument, NULL, 'P' },
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{ "restart", no_argument, NULL, 'r' },
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{ "restart-delay", required_argument, NULL, 'R' },
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{ "title", required_argument, NULL, 't' },
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{ "user", required_argument, NULL, 'u' },
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{ "syslog-priority", required_argument, NULL, 's' },
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{ "syslog-facility", required_argument, NULL, 'l' },
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{ "syslog-tag", required_argument, NULL, 'T' },
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{ "help", no_argument, NULL, 'h' },
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{ NULL, 0, NULL, 0 }
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};
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static _Noreturn void
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usage(int exitcode)
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{
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(void)fprintf(stderr,
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"usage: daemon [-cfHrS] [-p child_pidfile] [-P supervisor_pidfile]\n"
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" [-u user] [-o output_file] [-t title]\n"
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" [-l syslog_facility] [-s syslog_priority]\n"
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" [-T syslog_tag] [-m output_mask] [-R restart_delay_secs]\n"
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"command arguments ...\n");
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(void)fprintf(stderr,
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" --change-dir -c Change the current working directory to root\n"
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" --close-fds -f Set stdin, stdout, stderr to /dev/null\n"
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" --sighup -H Close and re-open output file on SIGHUP\n"
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" --syslog -S Send output to syslog\n"
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" --output-file -o <file> Append output of the child process to file\n"
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" --output-mask -m <mask> What to send to syslog/file\n"
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" 1=stdout, 2=stderr, 3=both\n"
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" --child-pidfile -p <file> Write PID of the child process to file\n"
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" --supervisor-pidfile -P <file> Write PID of the supervisor process to file\n"
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" --restart -r Restart child if it terminates (1 sec delay)\n"
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" --restart-delay -R <N> Restart child if it terminates after N sec\n"
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" --title -t <title> Set the title of the supervisor process\n"
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" --user -u <user> Drop privileges, run as given user\n"
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" --syslog-priority -s <prio> Set syslog priority\n"
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" --syslog-facility -l <flty> Set syslog facility\n"
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" --syslog-tag -T <tag> Set syslog tag\n"
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" --help -h Show this help\n");
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exit(exitcode);
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}
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int
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main(int argc, char *argv[])
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{
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bool supervision_enabled = false;
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bool log_reopen = false;
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bool child_eof = false;
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bool restart_enabled = false;
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char *p = NULL;
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const char *child_pidfile = NULL;
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const char *parent_pidfile = NULL;
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const char *title = NULL;
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const char *user = NULL;
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int ch = 0;
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int keep_cur_workdir = 1;
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int pipe_fd[2] = { -1, -1 };
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int restart_delay = 1;
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int stdmask = STDOUT_FILENO | STDERR_FILENO;
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struct log_params logparams = {
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.syslog_enabled = false,
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.syslog_priority = LOG_NOTICE,
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.syslog_tag = "daemon",
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.syslog_facility = LOG_DAEMON,
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.keep_fds_open = 1,
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.output_fd = -1,
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.output_filename = NULL
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};
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struct pidfh *parent_pidfh = NULL;
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struct pidfh *child_pidfh = NULL;
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sigset_t mask_orig;
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sigset_t mask_read;
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sigset_t mask_term;
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sigset_t mask_susp;
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sigemptyset(&mask_susp);
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sigemptyset(&mask_read);
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sigemptyset(&mask_term);
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sigemptyset(&mask_orig);
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while ((ch = getopt_long(argc, argv, shortopts, longopts, NULL)) != -1) {
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switch (ch) {
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case 'c':
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keep_cur_workdir = 0;
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break;
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case 'f':
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logparams.keep_fds_open = 0;
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break;
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case 'H':
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log_reopen = true;
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break;
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case 'l':
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logparams.syslog_facility = get_log_mapping(optarg,
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facilitynames);
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if (logparams.syslog_facility == -1) {
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errx(5, "unrecognized syslog facility");
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}
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logparams.syslog_enabled = true;
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break;
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case 'm':
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stdmask = strtol(optarg, &p, 10);
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if (p == optarg || stdmask < 0 || stdmask > 3) {
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errx(6, "unrecognized listening mask");
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}
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break;
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case 'o':
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logparams.output_filename = optarg;
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break;
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case 'p':
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child_pidfile = optarg;
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break;
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case 'P':
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parent_pidfile = optarg;
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break;
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case 'r':
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restart_enabled = true;
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break;
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case 'R':
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restart_enabled = true;
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restart_delay = strtol(optarg, &p, 0);
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if (p == optarg || restart_delay < 1) {
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errx(6, "invalid restart delay");
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}
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break;
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case 's':
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logparams.syslog_priority = get_log_mapping(optarg,
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prioritynames);
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if (logparams.syslog_priority == -1) {
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errx(4, "unrecognized syslog priority");
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}
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logparams.syslog_enabled = true;
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break;
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case 'S':
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logparams.syslog_enabled = true;
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break;
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case 't':
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title = optarg;
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break;
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case 'T':
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logparams.syslog_tag = optarg;
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logparams.syslog_enabled = true;
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break;
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case 'u':
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user = optarg;
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break;
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case 'h':
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usage(0);
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__builtin_unreachable();
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default:
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usage(1);
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}
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}
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argc -= optind;
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argv += optind;
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if (argc == 0) {
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usage(1);
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}
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if (!title) {
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title = argv[0];
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}
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if (logparams.output_filename) {
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logparams.output_fd = open_log(logparams.output_filename);
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if (logparams.output_fd == -1) {
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err(7, "open");
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}
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}
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if (logparams.syslog_enabled) {
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openlog(logparams.syslog_tag, LOG_PID | LOG_NDELAY,
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logparams.syslog_facility);
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}
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/*
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* Try to open the pidfile before calling daemon(3),
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* to be able to report the error intelligently
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*/
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open_pid_files(child_pidfile, parent_pidfile, &child_pidfh, &parent_pidfh);
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if (daemon(keep_cur_workdir, logparams.keep_fds_open) == -1) {
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warn("daemon");
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goto exit;
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}
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/* Write out parent pidfile if needed. */
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pidfile_write(parent_pidfh);
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/*
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* Supervision mode is enabled if one of the following options are used:
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* --child-pidfile -p
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* --supervisor-pidfile -P
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* --restart -r / --restart-delay -R
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* --syslog -S
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* --syslog-facility -l
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* --syslog-priority -s
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* --syslog-tag -T
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*
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* In supervision mode daemon executes the command in a forked process
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* and observes the child by waiting for SIGCHILD. In supervision mode
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* daemon must never exit before the child, this is necessary to prevent
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* orphaning the child and leaving a stale pid file.
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* To achieve this daemon catches SIGTERM and
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* forwards it to the child, expecting to get SIGCHLD eventually.
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*/
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supervision_enabled = child_pidfile != NULL ||
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parent_pidfile != NULL ||
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restart_enabled == true ||
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logparams.output_fd != -1 ||
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logparams.syslog_enabled == true;
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if (supervision_enabled) {
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struct sigaction act_term = { 0 };
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struct sigaction act_chld = { 0 };
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struct sigaction act_hup = { 0 };
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/* Avoid PID racing with SIGCHLD and SIGTERM. */
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act_term.sa_handler = handle_term;
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sigemptyset(&act_term.sa_mask);
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sigaddset(&act_term.sa_mask, SIGCHLD);
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act_chld.sa_handler = handle_chld;
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sigemptyset(&act_chld.sa_mask);
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sigaddset(&act_chld.sa_mask, SIGTERM);
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act_hup.sa_handler = handle_hup;
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sigemptyset(&act_hup.sa_mask);
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/* Block these when avoiding racing before sigsuspend(). */
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sigaddset(&mask_susp, SIGTERM);
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sigaddset(&mask_susp, SIGCHLD);
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/* Block SIGTERM when we lack a valid child PID. */
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sigaddset(&mask_term, SIGTERM);
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/*
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* When reading, we wish to avoid SIGCHLD. SIGTERM
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* has to be caught, otherwise we'll be stuck until
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* the read() returns - if it returns.
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*/
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sigaddset(&mask_read, SIGCHLD);
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/* Block SIGTERM to avoid racing until we have forked. */
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if (sigprocmask(SIG_BLOCK, &mask_term, &mask_orig)) {
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warn("sigprocmask");
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goto exit;
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}
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if (sigaction(SIGTERM, &act_term, NULL) == -1) {
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warn("sigaction");
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goto exit;
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}
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if (sigaction(SIGCHLD, &act_chld, NULL) == -1) {
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warn("sigaction");
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goto exit;
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}
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/*
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* Try to protect against pageout kill. Ignore the
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* error, madvise(2) will fail only if a process does
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* not have superuser privileges.
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*/
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(void)madvise(NULL, 0, MADV_PROTECT);
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if (log_reopen && logparams.output_fd >= 0 &&
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sigaction(SIGHUP, &act_hup, NULL) == -1) {
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warn("sigaction");
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goto exit;
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}
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restart:
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if (pipe(pipe_fd)) {
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err(1, "pipe");
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}
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/*
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* Spawn a child to exec the command.
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*/
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child_gone = 0;
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pid = fork();
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}
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/* fork failed, this can only happen when supervision is enabled */
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if (pid == -1) {
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warn("fork");
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goto exit;
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}
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/* fork succeeded, this is child's branch or supervision is disabled */
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if (pid == 0) {
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pidfile_write(child_pidfh);
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if (user != NULL) {
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restrict_process(user);
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}
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/*
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* In supervision mode, the child gets the original sigmask,
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* and dup'd pipes.
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*/
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if (supervision_enabled) {
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close(pipe_fd[0]);
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if (sigprocmask(SIG_SETMASK, &mask_orig, NULL)) {
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err(1, "sigprogmask");
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}
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if (stdmask & STDERR_FILENO) {
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if (dup2(pipe_fd[1], STDERR_FILENO) == -1) {
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err(1, "dup2");
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}
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}
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if (stdmask & STDOUT_FILENO) {
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if (dup2(pipe_fd[1], STDOUT_FILENO) == -1) {
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err(1, "dup2");
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}
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}
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if (pipe_fd[1] != STDERR_FILENO &&
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pipe_fd[1] != STDOUT_FILENO) {
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close(pipe_fd[1]);
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}
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}
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execvp(argv[0], argv);
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/* execvp() failed - report error and exit this process */
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err(1, "%s", argv[0]);
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}
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/*
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* else: pid > 0
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* fork succeeded, this is the parent branch, this can only happen when
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* supervision is enabled
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*
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* Unblock SIGTERM after we know we have a valid child PID to signal.
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*/
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if (sigprocmask(SIG_UNBLOCK, &mask_term, NULL)) {
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warn("sigprocmask");
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goto exit;
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}
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close(pipe_fd[1]);
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pipe_fd[1] = -1;
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setproctitle("%s[%d]", title, (int)pid);
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/*
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* As we have closed the write end of pipe for parent process,
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* we might detect the child's exit by reading EOF. The child
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* might have closed its stdout and stderr, so we must wait for
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* the SIGCHLD to ensure that the process is actually gone.
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*/
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for (;;) {
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/*
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* We block SIGCHLD when listening, but SIGTERM we accept
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* so the read() won't block if we wish to depart.
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*
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* Upon receiving SIGTERM, we have several options after
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* sending the SIGTERM to our child:
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* - read until EOF
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* - read until EOF but only for a while
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* - bail immediately
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*
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* We go for the third, as otherwise we have no guarantee
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* that we won't block indefinitely if the child refuses
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* to depart. To handle the second option, a different
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* approach would be needed (procctl()?)
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*/
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if (child_gone && child_eof) {
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break;
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}
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if (terminate) {
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goto exit;
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}
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if (child_eof) {
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if (sigprocmask(SIG_BLOCK, &mask_susp, NULL)) {
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warn("sigprocmask");
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goto exit;
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}
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while (!terminate && !child_gone) {
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sigsuspend(&mask_orig);
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}
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if (sigprocmask(SIG_UNBLOCK, &mask_susp, NULL)) {
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warn("sigprocmask");
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goto exit;
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}
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continue;
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}
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if (sigprocmask(SIG_BLOCK, &mask_read, NULL)) {
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warn("sigprocmask");
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goto exit;
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}
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child_eof = !listen_child(pipe_fd[0], &logparams);
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if (sigprocmask(SIG_UNBLOCK, &mask_read, NULL)) {
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warn("sigprocmask");
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goto exit;
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}
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}
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if (restart_enabled && !terminate) {
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daemon_sleep(restart_delay, 0);
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}
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if (sigprocmask(SIG_BLOCK, &mask_term, NULL)) {
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warn("sigprocmask");
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goto exit;
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}
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if (restart_enabled && !terminate) {
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close(pipe_fd[0]);
|
|
pipe_fd[0] = -1;
|
|
goto restart;
|
|
}
|
|
exit:
|
|
close(logparams.output_fd);
|
|
close(pipe_fd[0]);
|
|
close(pipe_fd[1]);
|
|
if (logparams.syslog_enabled) {
|
|
closelog();
|
|
}
|
|
pidfile_remove(child_pidfh);
|
|
pidfile_remove(parent_pidfh);
|
|
exit(1); /* If daemon(3) succeeded exit status does not matter. */
|
|
}
|
|
|
|
static void
|
|
daemon_sleep(time_t secs, long nsecs)
|
|
{
|
|
struct timespec ts = { secs, nsecs };
|
|
|
|
while (!terminate && nanosleep(&ts, &ts) == -1) {
|
|
if (errno != EINTR) {
|
|
err(1, "nanosleep");
|
|
}
|
|
}
|
|
}
|
|
|
|
static void
|
|
open_pid_files(const char *pidfile, const char *ppidfile,
|
|
struct pidfh **pfh, struct pidfh **ppfh)
|
|
{
|
|
pid_t fpid;
|
|
int serrno;
|
|
|
|
if (pidfile) {
|
|
*pfh = pidfile_open(pidfile, 0600, &fpid);
|
|
if (*pfh == NULL) {
|
|
if (errno == EEXIST) {
|
|
errx(3, "process already running, pid: %d",
|
|
fpid);
|
|
}
|
|
err(2, "pidfile ``%s''", pidfile);
|
|
}
|
|
}
|
|
/* Do the same for the actual daemon process. */
|
|
if (ppidfile) {
|
|
*ppfh = pidfile_open(ppidfile, 0600, &fpid);
|
|
if (*ppfh == NULL) {
|
|
serrno = errno;
|
|
pidfile_remove(*pfh);
|
|
errno = serrno;
|
|
if (errno == EEXIST) {
|
|
errx(3, "process already running, pid: %d",
|
|
fpid);
|
|
}
|
|
err(2, "ppidfile ``%s''", ppidfile);
|
|
}
|
|
}
|
|
}
|
|
|
|
static int
|
|
get_log_mapping(const char *str, const CODE *c)
|
|
{
|
|
const CODE *cp;
|
|
for (cp = c; cp->c_name; cp++)
|
|
if (strcmp(cp->c_name, str) == 0) {
|
|
return cp->c_val;
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
static void
|
|
restrict_process(const char *user)
|
|
{
|
|
struct passwd *pw = NULL;
|
|
|
|
pw = getpwnam(user);
|
|
if (pw == NULL) {
|
|
errx(1, "unknown user: %s", user);
|
|
}
|
|
|
|
if (setusercontext(NULL, pw, pw->pw_uid, LOGIN_SETALL) != 0) {
|
|
errx(1, "failed to set user environment");
|
|
}
|
|
|
|
setenv("USER", pw->pw_name, 1);
|
|
setenv("HOME", pw->pw_dir, 1);
|
|
setenv("SHELL", *pw->pw_shell ? pw->pw_shell : _PATH_BSHELL, 1);
|
|
}
|
|
|
|
/*
|
|
* We try to collect whole lines terminated by '\n'. Otherwise we collect a
|
|
* full buffer, and then output it.
|
|
*
|
|
* Return value of false is assumed to mean EOF or error, and true indicates to
|
|
* continue reading.
|
|
*/
|
|
static bool
|
|
listen_child(int fd, struct log_params *logpar)
|
|
{
|
|
static unsigned char buf[LBUF_SIZE];
|
|
static size_t bytes_read = 0;
|
|
int rv;
|
|
|
|
assert(logpar);
|
|
assert(bytes_read < LBUF_SIZE - 1);
|
|
|
|
if (do_log_reopen) {
|
|
reopen_log(logpar);
|
|
}
|
|
rv = read(fd, buf + bytes_read, LBUF_SIZE - bytes_read - 1);
|
|
if (rv > 0) {
|
|
unsigned char *cp;
|
|
|
|
bytes_read += rv;
|
|
assert(bytes_read <= LBUF_SIZE - 1);
|
|
/* Always NUL-terminate just in case. */
|
|
buf[LBUF_SIZE - 1] = '\0';
|
|
/*
|
|
* Chomp line by line until we run out of buffer.
|
|
* This does not take NUL characters into account.
|
|
*/
|
|
while ((cp = memchr(buf, '\n', bytes_read)) != NULL) {
|
|
size_t bytes_line = cp - buf + 1;
|
|
assert(bytes_line <= bytes_read);
|
|
do_output(buf, bytes_line, logpar);
|
|
bytes_read -= bytes_line;
|
|
memmove(buf, cp + 1, bytes_read);
|
|
}
|
|
/* Wait until the buffer is full. */
|
|
if (bytes_read < LBUF_SIZE - 1) {
|
|
return true;
|
|
}
|
|
do_output(buf, bytes_read, logpar);
|
|
bytes_read = 0;
|
|
return true;
|
|
} else if (rv == -1) {
|
|
/* EINTR should trigger another read. */
|
|
if (errno == EINTR) {
|
|
return true;
|
|
} else {
|
|
warn("read");
|
|
return false;
|
|
}
|
|
}
|
|
/* Upon EOF, we have to flush what's left of the buffer. */
|
|
if (bytes_read > 0) {
|
|
do_output(buf, bytes_read, logpar);
|
|
bytes_read = 0;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* The default behavior is to stay silent if the user wants to redirect
|
|
* output to a file and/or syslog. If neither are provided, then we bounce
|
|
* everything back to parent's stdout.
|
|
*/
|
|
static void
|
|
do_output(const unsigned char *buf, size_t len, struct log_params *logpar)
|
|
{
|
|
assert(len <= LBUF_SIZE);
|
|
assert(logpar);
|
|
|
|
if (len < 1) {
|
|
return;
|
|
}
|
|
if (logpar->syslog_enabled) {
|
|
syslog(logpar->syslog_priority, "%.*s", (int)len, buf);
|
|
}
|
|
if (logpar->output_fd != -1) {
|
|
if (write(logpar->output_fd, buf, len) == -1)
|
|
warn("write");
|
|
}
|
|
if (logpar->keep_fds_open &&
|
|
!logpar->syslog_enabled &&
|
|
logpar->output_fd == -1) {
|
|
printf("%.*s", (int)len, buf);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* We use the global PID acquired directly from fork. If there is no valid
|
|
* child pid, the handler should be blocked and/or child_gone == 1.
|
|
*/
|
|
static void
|
|
handle_term(int signo)
|
|
{
|
|
if (pid > 0 && !child_gone) {
|
|
kill(pid, signo);
|
|
}
|
|
terminate = 1;
|
|
}
|
|
|
|
static void
|
|
handle_chld(int signo __unused)
|
|
{
|
|
|
|
for (;;) {
|
|
int rv = waitpid(-1, NULL, WNOHANG);
|
|
if (pid == rv) {
|
|
child_gone = 1;
|
|
break;
|
|
} else if (rv == -1 && errno != EINTR) {
|
|
warn("waitpid");
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void
|
|
handle_hup(int signo __unused)
|
|
{
|
|
|
|
do_log_reopen = 1;
|
|
}
|
|
|
|
static int
|
|
open_log(const char *outfn)
|
|
{
|
|
|
|
return open(outfn, O_CREAT | O_WRONLY | O_APPEND | O_CLOEXEC, 0600);
|
|
}
|
|
|
|
static void
|
|
reopen_log(struct log_params *logparams)
|
|
{
|
|
int outfd;
|
|
|
|
do_log_reopen = 0;
|
|
outfd = open_log(logparams->output_filename);
|
|
if (logparams->output_fd >= 0) {
|
|
close(logparams->output_fd);
|
|
}
|
|
logparams->output_fd = outfd;
|
|
}
|
|
|