usr/src/cmd/cmd-inet/lib/netcfgd/netcfgd.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*
  28  * netcfgd - network configuration daemon.  At present, this daemon implements
  29  * the configuration backend for libnwam (via calls to nwam_backend_init()
  30  * and nwam_backend_fini()).  Initialization of the backend creates a  door
  31  * that libnwam calls use to read, update and destroy persistent configuration.
  32  *
  33  * More long-term, netcfgd will be used to manage other sources of configuration
  34  * data and the backend functionality currently contained in libnwam will be
  35  * generalized.
  36  */
  37
  38 #include <errno.h>
  39 #include <signal.h>
  40 #include <stdio.h>
  41 #include <stdarg.h>
  42 #include <stdlib.h>
  43 #include <string.h>
  44 #include <syslog.h>
  45 #include <sys/types.h>
  46 #include <sys/stat.h>
  47 #include <unistd.h>
  48 #include <wait.h>
  49 #include <libnwam_priv.h>
  50 #include <libnwam.h>
  51
  52 static const char *progname;
  53 static boolean_t fg = B_FALSE;
  54
  55 /*
  56  * This function allows you to drop a dtrace probe here and trace
  57  * complete strings (not just those containing formatting).  It's
  58  * important that we actually format the strings so we could trace them
  59  * even if we choose not to log them.
  60  */
  61 static void
  62 log_out(int severity, const char *str)
  63 {
  64         if (fg) {
  65                 (void) fprintf(stderr, "%s: %s\n", progname, str);
  66         } else {
  67                 syslog(severity, str);
  68         }
  69 }
  70
  71 /* PRINTFLIKE2 */
  72 void
  73 nlog(int severity, const char *fmt, ...)
  74 {
  75         va_list ap;
  76         char *vbuf;
  77
  78         va_start(ap, fmt);
  79         if (vasprintf(&vbuf, fmt, ap) != -1) {
  80                 log_out(severity, vbuf);
  81                 free(vbuf);
  82         }
  83         va_end(ap);
  84 }
  85
  86 static void
  87 start_logging(void)
  88 {
  89         if (!fg)
  90                 openlog(progname, LOG_PID, LOG_DAEMON);
  91
  92         nlog(LOG_DEBUG, "%s started", progname);
  93 }
  94
  95 static void
  96 daemonize(void)
  97 {
  98         pid_t pid;
  99
 100         /*
 101          * A little bit of magic here.  By the first fork+setsid, we
 102          * disconnect from our current controlling terminal and become
 103          * a session group leader.  By forking again without calling
 104          * setsid again, we make certain that we are not the session
 105          * group leader and can never reacquire a controlling terminal.
 106          */
 107         if ((pid = fork()) == -1) {
 108                 nlog(LOG_ERR, "fork 1 failed");
 109                 exit(EXIT_FAILURE);
 110         }
 111         if (pid != 0) {
 112                 (void) wait(NULL);
 113                 nlog(LOG_DEBUG, "child %ld exited, daemonizing", pid);
 114                 _exit(0);
 115         }
 116         if (setsid() == (pid_t)-1) {
 117                 nlog(LOG_ERR, "setsid");
 118                 exit(EXIT_FAILURE);
 119         }
 120         if ((pid = fork()) == -1) {
 121                 nlog(LOG_ERR, "fork 2 failed");
 122                 exit(EXIT_FAILURE);
 123         }
 124         if (pid != 0) {
 125                 _exit(0);
 126         }
 127         (void) chdir("/");
 128         (void) umask(022);
 129 }
 130
 131 /* ARGSUSED */
 132 static void
 133 graceful_shutdown(int signo)
 134 {
 135         nwam_backend_fini();
 136         exit(EXIT_SUCCESS);
 137 }
 138
 139 int
 140 main(int argc, char *argv[])
 141 {
 142         int c;
 143         nwam_error_t err;
 144
 145         if ((progname = strrchr(argv[0], '/')) == NULL)
 146                 progname = argv[0];
 147         else
 148                 progname++;
 149
 150         while ((c = getopt(argc, argv, "f")) != -1) {
 151                 switch (c) {
 152                 case 'f':
 153                         fg = B_TRUE;
 154                         break;
 155                 default:
 156                         (void) fprintf(stderr, "%s: unrecognized option %c\n",
 157                             progname, optopt);
 158                         exit(EXIT_FAILURE);
 159                 }
 160         }
 161         start_logging();
 162
 163         if (!fg)
 164                 daemonize();
 165
 166         (void) signal(SIGTERM, graceful_shutdown);
 167         (void) signal(SIGQUIT, graceful_shutdown);
 168         (void) signal(SIGPIPE, SIG_IGN);
 169         (void) signal(SIGCHLD, SIG_IGN);
 170         (void) atexit(nwam_backend_fini);
 171
 172         if ((err = nwam_backend_init()) != NWAM_SUCCESS) {
 173                 nlog(LOG_ERR,
 174                     "couldn't initialize libnwam backend: %s",
 175                     nwam_strerror(err));
 176                 exit(EXIT_FAILURE);
 177         }
 178
 179         for (;;)
 180                 (void) pause();
 181
 182         /* NOTREACHED */
 183         return (EXIT_SUCCESS);
 184 }