src/bin/multiuser/su.cpp

   1 /*
   2  * Copyright 2017, Haiku, Inc. All Rights Reserved.
   3  * Distributed under the terms of the MIT License.
   4  *
   5  * Authors:
   6  *              Axel Dörfler, axeld@pinc-software.de
   7  *              Augustin Cavalier <waddlesplash>
   8  */
   9
  10
  11 #include <SupportDefs.h>
  12
  13 #include <errno.h>
  14 #include <pwd.h>
  15 #include <signal.h>
  16 #include <stdio.h>
  17 #include <stdlib.h>
  18 #include <string.h>
  19 #include <syslog.h>
  20 #include <termios.h>
  21 #include <unistd.h>
  22
  23 #include "multiuser_utils.h"
  24
  25
  26 extern const char* __progname;
  27 const char* kProgramName = __progname;
  28
  29 const uint32 kRetries = 3;
  30
  31
  32 static void
  33 usage()
  34 {
  35         fprintf(stderr, "usage: %s [-pl] [-c command] [username]\n", kProgramName);
  36         exit(1);
  37 }
  38
  39
  40 int
  41 main(int argc, char *argv[])
  42 {
  43         bool loginShell = false;
  44         const char* command = NULL;
  45
  46         char c;
  47         while ((c = getopt(argc, argv, "c:l")) != -1) {
  48                 switch (c) {
  49                         case 'l':
  50                                 loginShell = true;
  51                                 break;
  52
  53                         case 'c':
  54                                 command = optarg;
  55                                 break;
  56
  57                         default:
  58                                 usage();
  59                                 break;
  60                 }
  61         }
  62
  63         argc -= optind;
  64         argv += optind;
  65
  66         const char* user = NULL;
  67         if (argc > 0)
  68                 user = argv[0];
  69
  70         if (user == NULL)
  71                 user = "user";
  72                 // aka 'root' on Haiku
  73
  74         // login
  75
  76         openlog(kProgramName, 0, LOG_AUTH);
  77
  78         status_t status = B_ERROR;
  79         struct passwd* passwd = NULL;
  80
  81         status = authenticate_user("password: ", user, &passwd, NULL,
  82                 kRetries, false);
  83
  84         if (status < B_OK || !passwd) {
  85                 if (passwd != NULL)
  86                         syslog(LOG_NOTICE, "su failed for \"%s\"", passwd->pw_name);
  87                 else
  88                         syslog(LOG_NOTICE, "su attempt for non-existent user \"%s\"", user);
  89                 exit(1);
  90         }
  91
  92         // setup environment for the user
  93
  94         status = setup_environment(passwd, true, false);
  95         if (status < B_OK) {
  96                 // refused login
  97                 fprintf(stderr, "%s: Refused login. Setting up environment failed: %s\n",
  98                         kProgramName, strerror(status));
  99                 syslog(LOG_NOTICE, "su refused for \"%s\"", passwd->pw_name);
 100                 exit(1);
 101         }
 102
 103         syslog(LOG_INFO, "su as \"%s\"", passwd->pw_name);
 104
 105         // start shell
 106         const char* args[] = {getenv("SHELL"), NULL, NULL, NULL, NULL};
 107         int nextarg = 1;
 108         if (loginShell) {
 109                 args[nextarg++] = "-login";
 110         }
 111         if (command != NULL) {
 112                 args[nextarg++] = "-c";
 113                 args[nextarg++] = command;
 114         }
 115
 116         execv(args[0], (char **)args);
 117
 118         // try default shell
 119         args[0] = "/bin/sh";
 120         execv(args[0], (char **)args);
 121
 122         fprintf(stderr, "%s: starting the shell failed: %s", kProgramName,
 123                 strerror(errno));
 124
 125         return 1;
 126 }
 127