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6591c335 UD |
1 | /* Copyright (C) 1998 Free Software Foundation, Inc. |
2 | This file is part of the GNU C Library. | |
3 | Contributed by Zack Weinberg <zack@rabi.phys.columbia.edu>, 1998. | |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
6 | modify it under the terms of the GNU Library General Public License as | |
7 | published by the Free Software Foundation; either version 2 of the | |
8 | License, or (at your option) any later version. | |
9 | ||
10 | The GNU C Library is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | Library General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Library General Public | |
16 | License along with the GNU C Library; see the file COPYING.LIB. If not, | |
17 | write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
18 | Boston, MA 02111-1307, USA. */ | |
19 | ||
20 | #include <errno.h> | |
21 | #include <stdlib.h> | |
22 | #include <unistd.h> | |
23 | #include <sys/resource.h> | |
24 | #include <sys/stat.h> | |
25 | #include <sys/types.h> | |
26 | #include <sys/wait.h> | |
27 | ||
28 | #include <assert.h> | |
29 | ||
30 | #include "pty-internal.h" | |
31 | ||
32 | /* Given a fd on a master pseudoterminal, chown the file associated | |
33 | with the slave to the calling process, and set its group and | |
34 | mode appropriately. Note that this is an unprivileged operation. */ | |
35 | ||
36 | /* This "generic Unix" implementation works because we provide the program | |
37 | /usr/libexec/pt_chown, and it only depends on ptsname() working. */ | |
38 | static const char helper[] = LIBEXECDIR "/pt_chown"; | |
da2d1bc5 | 39 | static char *const argv[] = { "pt_chown", NULL }; |
6591c335 UD |
40 | |
41 | int | |
42 | grantpt (fd) | |
43 | int fd; | |
44 | { | |
45 | struct stat st; | |
46 | int w, pid; | |
47 | char namebuf[PTYNAMELEN]; | |
48 | ||
49 | /* Some systems do it for us. */ | |
50 | if (ptsname_r (fd, namebuf, PTYNAMELEN) == NULL) | |
51 | return -1; | |
52 | if (stat (namebuf, &st)) | |
53 | return -1; | |
54 | ||
55 | if (st.st_uid == getuid ()) | |
56 | return 0; | |
57 | ||
58 | /* We have to do it in user space. */ | |
59 | ||
60 | pid = fork (); | |
61 | if (pid == -1) | |
62 | return -1; | |
63 | else if (pid == 0) | |
64 | { | |
65 | /* Disable core dumps in the child. */ | |
66 | struct rlimit off = { 0, 0 }; | |
67 | setrlimit (RLIMIT_CORE, &off); | |
68 | ||
69 | /* The helper does its thing on fd PTY_FD. */ | |
70 | if (fd != PTY_FD) | |
71 | if (dup2 (fd, PTY_FD) == -1) | |
72 | _exit (FAIL_EBADF); | |
73 | ||
da2d1bc5 | 74 | execve (helper, argv, 0); |
6591c335 UD |
75 | _exit (FAIL_EXEC); |
76 | } | |
77 | else | |
78 | { | |
79 | if (waitpid (pid, &w, 0) == -1) | |
80 | return -1; | |
81 | if (!WIFEXITED (w)) | |
82 | { | |
83 | __set_errno (ENOEXEC); | |
84 | return -1; | |
85 | } | |
86 | else | |
87 | switch (WEXITSTATUS(w)) | |
88 | { | |
89 | case 0: | |
90 | break; | |
91 | case FAIL_EBADF: | |
92 | __set_errno (EBADF); | |
93 | return -1; | |
94 | case FAIL_EINVAL: | |
95 | __set_errno (EINVAL); | |
96 | return -1; | |
97 | case FAIL_EACCES: | |
98 | __set_errno (EACCES); | |
99 | return -1; | |
100 | case FAIL_EXEC: | |
101 | __set_errno (ENOEXEC); | |
102 | return -1; | |
103 | ||
104 | default: | |
105 | assert(! "getpt: internal error: invalid exit code from pt_chown"); | |
106 | } | |
107 | } | |
108 | ||
109 | /* Success. */ | |
110 | return 0; | |
111 | } |