user/dhcpcd/main.c

   1 /* $Id: main.c,v 1.15 2002-03-07 02:29:14 gerg Exp $
   2  *
   3  * dhcpcd - DHCP client daemon -
   4  * Copyright (C) 1996 - 1997 Yoichi Hariguchi <yoichi@fore.com>
   5  *
   6  * dhcpcd is an RFC2131 and RFC1541 compliant DHCP client daemon.
   7  *
   8  * This is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  16  * See the GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21  */
  22
  23 #include <sys/types.h>
  24 #include <sys/stat.h>
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <errno.h>
  28 #include <string.h>
  29 #include <syslog.h>
  30 #include <time.h>
  31 #include <fcntl.h>
  32 #include <unistd.h>
  33 #include <net/if.h>
  34 #include <arpa/inet.h>
  35 #include "if.h"
  36 #include "dhcp.h"
  37 #include "signal-handler.h"
  38 #include "error-handler.h"
  39 #include "daemon.h"
  40 #include "client.h"
  41 #include "memory.h"
  42
  43 #define DEFAULT_IF      "eth0"
  44
  45 char *CommandFile = NULL;               /* invoked command file name when dhcpcd
  46                                                                  * succeeds in getting an IP address
  47                                                                  */
  48 int       BeRFC1541 = 0;                        /* default is InternetDraft mode */
  49 char *Hostname = NULL;                  /* hostname in the DHCP msg for xmit */
  50 int   Persistent = 0;                   /* Keep trying until you get address */
  51 int   ArpCheck = 1;                             /* Check if address already used? */
  52
  53 #ifdef LLIP_SUPPORT
  54 #include "llip.h"
  55 int     AutoIP  = 0;
  56 #endif
  57
  58 char  pidfile[128];                     /* file name in which pid is stored */
  59 static char VersionStr[] = "dhcpcd 0.70\n";
  60
  61 void    usage();
  62
  63 char  Ifname[16];                       /* global interface name */
  64
  65
  66 int
  67 main(argc, argv)
  68 int argc;
  69 char *argv[];
  70 {
  71         char  ifname[16];                       /* interface name */
  72         char *clientId = NULL;          /* ptr to client identifier user specified */
  73         int   killFlag = 0;                     /* if 1: kill the running proc and exit */
  74
  75         int res;
  76         DebugFlag = 0;                          /* default is NON debug mode */
  77         srand((u_int)time(NULL));
  78         signalSetup();
  79         umask(0);                                       /* clear umask */
  80         classIDsetup(NULL);                     /* setup default class identifier */
  81         /* option handling
  82          */
  83         while ( *++argv ) {
  84                 if ( **argv == '-' ) {
  85                         switch ( argv[0][1] ) {
  86                           case 'c':
  87                                 if ( *++argv == NULL ) {
  88                                         usage();
  89                                 }
  90                                 if ( (CommandFile = malloc(strlen(*argv)+1)) == NULL ) {
  91                                         usage();
  92                                 }
  93                                 strcpy(CommandFile, *argv);
  94                                 break;
  95                           case 'd':
  96                                 DebugFlag = 1;
  97                                 break;
  98                           case 'p':
  99                                 Persistent = 1;
 100                                 break;
 101                           case 'a':
 102                                 ArpCheck = 0;
 103                                 break;
 104                           case 'h':
 105                                 if ( *++argv == NULL ) {
 106                                         usage();
 107                                 }
 108                                 Hostname = smalloc(strlen(*argv)+1);
 109                                 strcpy(Hostname, *argv);
 110                                 break;
 111                           case 'i':
 112                                 if ( *++argv == NULL ) {
 113                                         usage();
 114                                 }
 115                                 classIDsetup(*argv); /* overwrite class identifier */
 116                                 break;
 117                           case 'I':
 118                                 if ( *++argv == NULL ) {
 119                                         usage();
 120                                 }
 121                                 clientId = *argv;
 122                                 break;
 123                           case 'k':
 124                                 killFlag = 1;   /* kill running process and exit */
 125                                 break;
 126                           case 'l':
 127                                 ++argv;
 128                                 if ( *argv == NULL || **argv == '-' ) {
 129                                         usage();
 130                                 }
 131                                 SuggestLeaseTime = atol(*argv);
 132                                 break;
 133                           case 'r':
 134                                 BeRFC1541 = 1;  /* Be RFC1541 compliant */
 135                                 break;
 136                           case 'v':
 137                                 fflush(stdout);
 138                                 fputs(VersionStr, stderr);
 139                                 fflush(NULL);
 140                                 exit(0);
 141 #ifdef LLIP_SUPPORT
 142                         case 'A': /* auto IP support if no dhcp lease is obtained */
 143                                 AutoIP=1;
 144                                 Persistent=1;
 145                                 break;
 146 #else
 147                         case 'A': /* auto IP support option is ignored but logged */
 148                                 syslog(LOG_WARNING, "-A (enable auto IP) option was specified but will be ignored.");
 149                                 break;
 150 #endif
 151                           default:
 152                                 usage();
 153                         }
 154                 } else {
 155                         break;
 156                 }
 157         }
 158
 159         if ( getuid() != 0 && geteuid() != 0 ) {
 160                 errQuit("Must be root");
 161         }
 162         if ( *argv ) {
 163                 strncpy(ifname, *argv, sizeof(ifname));
 164         } else {
 165                 strncpy(ifname, DEFAULT_IF, sizeof(ifname));
 166         }
 167 #ifndef EMBED
 168         /*
 169          * Don't do this for now...
 170          */
 171         if ( killFlag ) {
 172                 sprintf(pidfile, PIDFILE, ifname);
 173                 killCurProc(pidfile);
 174         }
 175         if ( !DebugFlag ) {
 176                 sprintf(pidfile, PIDFILE, ifname);
 177                 daemonInit(pidfile);
 178         }
 179 #endif
 180         sleep(1);
 181         logOpen("dhcpcd", LOG_PID, LOG_LOCAL0);
 182         ifReset(ifname);                        /* reset interface, 'Ifbuf' */
 183         clientIDsetup(clientId, ifname);
 184         dhcpMsgInit(ifname);
 185         dhcpClient();
 186         exit(0);
 187 }
 188
 189 void
 190 usage()
 191 {
 192         fflush(stdout);
 193 #ifndef LLIP_SUPPORT
 194         fputs("Usage: dhcpcd [-c filename] [-dpa] [-i classIdentifier] [-I clientIdentifier] [-k] [-l leasetime] [-h hostname] [ifname]\n",
 195                   stderr);
 196 #else
 197         fputs("Usage: dhcpcd [-c filename] [-dpaA] [-i classIdentifier] [-I clientIdentifier] [-k] [-l leasetime] [-h hostname] [ifname]\n", stderr);
 198 #endif
 199         fflush(NULL);
 200         exit(1);
 201 }
 202
 203 void die(int rc)
 204 {
 205 /*
 206  * Kill the pid file.
 207  */
 208         unlink(pidfile);
 209         exit(rc);
 210 }
 211
 212 /*
 213  * Write out the pid into the file specified by pidfile.
 214  * return code:    0   - everything worked like a dream
 215  *                 1   - there was a stale PID file
 216  *                -1   - something went wrong
 217  *                -2   - the program is already running
 218  */
 219 int writePidFile()
 220 {
 221         FILE    *file;
 222         pid_t   pid;
 223         int     fd, rc, old = 0;
 224
 225         pid = getpid();
 226         fd = open(pidfile, O_CREAT | O_EXCL | O_RDWR, S_IRWXU);
 227         if (fd < 0) {
 228                 if (errno == EEXIST) {
 229                         /* See if the old program is still alive */
 230                         if ((rc = isOldPid()) < 0) {
 231                                 return(-1);
 232                         } else if (rc == 1) {
 233                                 old = 1;
 234                         }else {
 235                                 return(-2);
 236                         }
 237                 } else {
 238                         fprintf(stderr, "DHCPCD: unexpected errno value"
 239                                 " - %d\n", errno);
 240                         return(-1);
 241                 }
 242         }
 243         close(fd);
 244
 245         if ((file = fopen(pidfile, "w")) == NULL) {
 246                 fprintf(stderr, "DHCPCD: open pid file errno=%d\n", errno);
 247                 return(-1);
 248         }
 249         rc = fprintf(file, "%d\n",  pid);
 250         fclose(file);
 251
 252         if (rc <= 0) {
 253                 fprintf(stderr, "DHCPCD: pif file errno=%d\n", errno);
 254                 return(-1);
 255         }
 256
 257         return(old);
 258 }
 259
 260
 261 /*
 262  * Check whether a pidfile contains the pid for a current active dhcpcd, or an
 263  * old defunct one (which would hang around in the case of a -9)
 264  * return code:   1  - the pidfile is NOT a currently active dhcpcd
 265  *                0  - the pidfile is a currently active dhcpcd
 266  */
 267 int isOldPid()
 268 {
 269         FILE    *file;
 270         char    fileName[48];
 271         char    oldCmd[7] = {'\0'};
 272         pid_t   pid;
 273         int     rc;
 274
 275         if ((file = fopen(pidfile, "r")) == NULL)
 276                 return(-1);
 277         rc = fscanf(file, "%d", &pid);
 278         fclose(file);
 279
 280         if (rc <= 0)
 281                 return(-1);
 282
 283         sprintf(fileName, "/proc/%d/cmdline", pid);
 284         if ((file = fopen(fileName, "r")) == NULL)
 285                 return(1);
 286         rc = fread(oldCmd, sizeof(oldCmd) - 1, 1, file);
 287         fclose(file);
 288
 289         if (rc != 1)
 290                 return(1);
 291
 292         oldCmd[6] = '\0';
 293         if(strcmp("dhcpcd", oldCmd) == 0)
 294                 return(0);
 295         return(1);
 296 }