1 | /* Copyright (C) 1996-2017 Free Software Foundation, Inc. |
2 | This file is part of the GNU C Library. |
3 | Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996. |
4 | |
5 | The GNU C Library is free software; you can redistribute it and/or |
6 | modify it under the terms of the GNU Lesser General Public |
7 | License as published by the Free Software Foundation; either |
8 | version 2.1 of the 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 | Lesser General Public License for more details. |
14 | |
15 | You should have received a copy of the GNU Lesser General Public |
16 | License along with the GNU C Library; if not, see |
17 | <http://www.gnu.org/licenses/>. */ |
18 | |
19 | #include <assert.h> |
20 | #include <errno.h> |
21 | #include <limits.h> |
22 | #include <string.h> |
23 | #include <unistd.h> |
24 | #include <stdlib.h> |
25 | #include <utmp.h> |
26 | |
27 | |
28 | /* Return the result of ttyname in the buffer pointed to by TTY, which should |
29 | be of length BUF_LEN. If it is too long to fit in this buffer, a |
30 | sufficiently long buffer is allocated using malloc, and returned in TTY. |
31 | 0 is returned upon success, -1 otherwise. */ |
32 | static int |
33 | tty_name (int fd, char **tty, size_t buf_len) |
34 | { |
35 | int rv; /* Return value. 0 = success. */ |
36 | char *buf = *tty; /* Buffer for ttyname, initially the user's. */ |
37 | |
38 | for (;;) |
39 | { |
40 | char *new_buf; |
41 | |
42 | if (buf_len) |
43 | { |
44 | rv = ttyname_r (fd, buf, buf_len); |
45 | |
46 | if (rv != 0 || memchr (buf, '\0', buf_len)) |
47 | /* We either got an error, or we succeeded and the |
48 | returned name fit in the buffer. */ |
49 | break; |
50 | |
51 | /* Try again with a longer buffer. */ |
52 | buf_len += buf_len; /* Double it */ |
53 | } |
54 | else |
55 | /* No initial buffer; start out by mallocing one. */ |
56 | buf_len = 128; /* First time guess. */ |
57 | |
58 | if (buf != *tty) |
59 | /* We've already malloced another buffer at least once. */ |
60 | new_buf = realloc (buf, buf_len); |
61 | else |
62 | new_buf = malloc (buf_len); |
63 | if (! new_buf) |
64 | { |
65 | rv = -1; |
66 | __set_errno (ENOMEM); |
67 | break; |
68 | } |
69 | buf = new_buf; |
70 | } |
71 | |
72 | if (rv == 0) |
73 | *tty = buf; /* Return buffer to the user. */ |
74 | else if (buf != *tty) |
75 | free (buf); /* Free what we malloced when returning an error. */ |
76 | |
77 | return rv; |
78 | } |
79 | |
80 | void |
81 | login (const struct utmp *ut) |
82 | { |
83 | #ifdef PATH_MAX |
84 | char _tty[PATH_MAX + UT_LINESIZE]; |
85 | #else |
86 | char _tty[512 + UT_LINESIZE]; |
87 | #endif |
88 | char *tty = _tty; |
89 | int found_tty; |
90 | const char *ttyp; |
91 | struct utmp copy = *ut; |
92 | |
93 | /* Fill in those fields we supply. */ |
94 | #if _HAVE_UT_TYPE - 0 |
95 | copy.ut_type = USER_PROCESS; |
96 | #endif |
97 | #if _HAVE_UT_PID - 0 |
98 | copy.ut_pid = getpid (); |
99 | #endif |
100 | |
101 | /* Seek tty. */ |
102 | found_tty = tty_name (STDIN_FILENO, &tty, sizeof (_tty)); |
103 | if (found_tty < 0) |
104 | found_tty = tty_name (STDOUT_FILENO, &tty, sizeof (_tty)); |
105 | if (found_tty < 0) |
106 | found_tty = tty_name (STDERR_FILENO, &tty, sizeof (_tty)); |
107 | |
108 | if (found_tty >= 0) |
109 | { |
110 | /* We only want to insert the name of the tty without path. |
111 | But take care of name like /dev/pts/3. */ |
112 | if (strncmp (tty, "/dev/" , 5) == 0) |
113 | ttyp = tty + 5; /* Skip the "/dev/". */ |
114 | else |
115 | ttyp = basename (tty); |
116 | |
117 | /* Position to record for this tty. */ |
118 | strncpy (copy.ut_line, ttyp, UT_LINESIZE); |
119 | |
120 | /* Tell that we want to use the UTMP file. */ |
121 | if (utmpname (_PATH_UTMP) == 0) |
122 | { |
123 | /* Open UTMP file. */ |
124 | setutent (); |
125 | |
126 | /* Write the entry. */ |
127 | pututline (©); |
128 | |
129 | /* Close UTMP file. */ |
130 | endutent (); |
131 | } |
132 | |
133 | if (tty != _tty) |
134 | free (tty); /* Free buffer malloced by tty_name. */ |
135 | } |
136 | else |
137 | /* We provide a default value so that the output does not contain |
138 | an random bytes in this field. */ |
139 | strncpy (copy.ut_line, "???" , UT_LINESIZE); |
140 | |
141 | /* Update the WTMP file. Here we have to add a new entry. */ |
142 | updwtmp (_PATH_WTMP, ©); |
143 | } |
144 | |