4.3BSD - /usr/src/new/courier/daemon/courierd.c

   1: #ifndef lint
   2: static char sccsid[] = "@(#)courierd.c	4.4 (Berkeley) 9/17/85";
   3: #endif
   4: 
   5: /*
   6:  * Courier program instantiation server
   7:  *
   8:  * When a connection is made, it reads the program name as a Courier string.
   9:  * The directory /usr/new/lib/courier is used as a database of program names;
  10:  * the executable program must either reside there or have a link there.
  11:  * The program is spawned with user and group ID equal to that of the
  12:  * executable file, and must write a single zero byte back to the caller to
  13:  * indicate successful instantiation.
  14:  * If instantiation was unsuccessful, the daemon will write back a null-
  15:  * terminated error message.
  16:  */
  17: #include <sys/types.h>
  18: #include <sys/socket.h>
  19: #include <sys/stat.h>
  20: #include <sys/wait.h>
  21: 
  22: #include <netinet/in.h>
  23: 
  24: #include <stdio.h>
  25: #include <signal.h>
  26: #include <errno.h>
  27: #include <netdb.h>
  28: #include <setjmp.h>
  29: #include <syslog.h>
  30: 
  31: #include "../lib/courier.h"
  32: 
  33: #define LIBCOURIER "/usr/new/lib/courier"
  34: 
  35: jmp_buf alarmbuf;
  36: int catch();
  37: 
  38: main(argc, argv)
  39:     int argc;
  40:     char **argv;
  41: {
  42:     struct sockaddr_in sin;
  43:     Cardinal n, nbytes;
  44:     struct stat statbuf;
  45:     char name[200];
  46:     int len;
  47: 
  48:     len = sizeof (sin);
  49:     if (getpeername(0, &sin, &len) < 0) {
  50:         fprintf(stderr, "%s: ", argv[0]), perror("getpeername");
  51:         _exit(1);
  52:     }
  53:     openlog("courier", LOG_ODELAY, LOG_DAEMON);
  54:     if (chdir(LIBCOURIER)) {
  55:         syslog(LOG_ERR, "chdir: %s: %m", LIBCOURIER);
  56:         _exit(2);
  57:     }
  58:     setpgrp(0, getpid());
  59:     signal(SIGHUP, SIG_DFL);
  60:     signal(SIGINT, SIG_DFL);
  61:     signal(SIGQUIT, SIG_DFL);
  62:     signal(SIGALRM, catch);
  63: 
  64:     dup2(0, 1);
  65: 
  66:     alarm(60);
  67:     if (setjmp(alarmbuf) == 0)
  68:         read(0, &n, sizeof(Cardinal));
  69:     alarm(0);
  70: 
  71:     UnpackCardinal(&nbytes, &n);
  72:     /*
  73: 	 * Courier strings are always word-aligned, so if the byte count is odd,
  74: 	 * we must also read the padding byte.
  75: 	 */
  76:     read(0, name, nbytes + (nbytes % 2));
  77:     name[nbytes] = '\0';
  78: 
  79:     if (name[0] == '/' || name[0] == '.' || stat(name, &statbuf) != 0)
  80:         goto bad;
  81:     setgroups(0, 0);
  82:     setregid(statbuf.st_gid, statbuf.st_gid);
  83:     setreuid(statbuf.st_uid, statbuf.st_uid);
  84:     execl(name, name, 0);
  85: bad:
  86:     error("Unknown Courier program.\n");
  87:     syslog(LOG_ERR, "Unknown Courier program");
  88:     exit(1);
  89: }
  90: 
  91: /*
  92:  * Catch alarm clock so read's will timeout.
  93:  */
  94: catch()
  95: {
  96: 
  97:     longjmp(alarmbuf, 1);
  98: }
  99: 
 100: /*
 101:  * Write back a null-terminated error message.
 102:  */
 103: error(s)
 104:     char *s;
 105: {
 106:     write(1, s, strlen(s)+1);
 107: }

Defined functions

Defined variables

Defined macros