summaryrefslogtreecommitdiff
path: root/login/programs/pt_chown.c
blob: 6ed8e82d5b5de0637a1648c9761afc9cc9329345 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
/* pt_chmod - helper program for `grantpt'.
   Copyright (C) 1998 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by C. Scott Ananian <cananian@alumni.princeton.edu>, 1998.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include <argp.h>
#include <errno.h>
#include <error.h>
#include <grp.h>
#include <libintl.h>
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>

#include "pty-private.h"

/* Get libc version number.  */
#include "../version.h"

#define PACKAGE _libc_intl_domainname

/* Name and version of program.  */
static void print_version (FILE *stream, struct argp_state *state);
void (*argp_program_version_hook) (FILE *, struct argp_state *) = print_version;

/* Function to print some extra text in the help message.  */
static char *more_help (int key, const char *text, void *input);

/* Data structure to communicate with argp functions.  */
static struct argp argp =
{
  NULL, NULL, NULL, NULL, NULL, more_help
};


/* Print the version information.  */
static void
print_version (FILE *stream, struct argp_state *state)
{
  fprintf (stream, "pt_chmod (GNU %s) %s\n", PACKAGE, VERSION);
  fprintf (stream, gettext ("\
Copyright (C) %s Free Software Foundation, Inc.\n\
This is free software; see the source for copying conditions.  There is NO\n\
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n\
"), "1998");
}

static char *
more_help (int key, const char *text, void *input)
{
  char *cp;
  
  switch (key)
    {
    case ARGP_KEY_HELP_PRE_DOC:
      asprintf (&cp, gettext ("\
Set the owner, group and access permission of the terminal passed on\
 file descriptor `%d'.  This is the helper program for the `grantpt'\
 function.  It is not intended to be run directly from the command\
 line.\n"),
		PTY_FILENO);
      return cp;
    case ARGP_KEY_HELP_EXTRA:
      /* We print some extra information.  */
      asprintf (&cp, gettext ("\
The owner is set to the current user, the group is set to `%s',\
 and the access permission is set to `%o'.\n\n\
%s"),
		TTY_GROUP, S_IRUSR|S_IWUSR|S_IWGRP, gettext ("\
Report bugs using the `glibcbug' script to <bugs@gnu.org>.\n"));
      return cp;
    default:
      break;
    }
  return (char *) text;
}

int
main (int argc, char *argv[])
{
  char *pty;
  int remaining;
  struct stat st;
  struct group *p;
  gid_t gid;

  /* Set locale via LC_ALL.  */
  setlocale (LC_ALL, "");

  /* Set the text message domain.  */
  textdomain (PACKAGE);

  /* parse and process arguments.  */
  argp_parse (&argp, argc, argv, 0, &remaining, NULL);

  if (remaining < argc)
    {
      /* We should not be called with any non-option parameters.  */
      error (0, 0, gettext ("too many arguments"));
      argp_help (&argp, stdout, ARGP_HELP_SEE | ARGP_HELP_EXIT_ERR,
		 program_invocation_short_name);
      exit (EXIT_FAILURE);
    }
  
  /* Check if we are properly installed.  */
  if (geteuid () != 0)
    error (FAIL_EXEC, 0, gettext ("needs to be installed setuid `root'"));

  /* Check that PTY_FILENO is a valid master pseudo terminal.  */
  pty = ptsname (PTY_FILENO);
  if (pty == NULL)
    return errno == EBADF ? FAIL_EBADF : FAIL_EINVAL;
  close (PTY_FILENO);

  /* Check that the returned slave pseudo terminal is a
     character device.  */
  if (stat (pty, &st) < 0 || !S_ISCHR(st.st_mode))
    return FAIL_EINVAL;

  /* Get the group ID of the special `tty' group.  */
  p = getgrnam (TTY_GROUP);
  gid = p ? p->gr_gid : getgid ();

  /* Set the owner to the real user ID, and the group to that special
     group ID.  */
  if (chown (pty, getuid (), gid) < 0)
    return FAIL_EACCES;

  /* Set the permission mode to readable and writable by the owner,
     and writable by the group.  */
  if (chmod (pty, S_IRUSR|S_IWUSR|S_IWGRP) < 0)
    return FAIL_EACCES;

  exit (EXIT_SUCCESS);
}