1 /* GNU's read utmp module.
3 Copyright (C) 1992-2001, 2003, 2004, 2005, 2006 Free Software
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software Foundation,
18 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
20 /* Written by jla; revised by djm */
29 #include <sys/types.h>
39 # include "unlocked-io.h"
43 # define SIZE_MAX ((size_t) -1)
46 /* Copy UT->ut_name into storage obtained from malloc. Then remove any
47 trailing spaces from the copy, NUL terminate it, and return the copy. */
50 extract_trimmed_name (const STRUCT_UTMP *ut)
52 char *p, *trimmed_name;
54 trimmed_name = xmalloc (sizeof (UT_USER (ut)) + 1);
55 strncpy (trimmed_name, UT_USER (ut), sizeof (UT_USER (ut)));
56 /* Append a trailing NUL. Some systems pad names shorter than the
57 maximum with spaces, others pad with NULs. Remove any trailing
59 trimmed_name[sizeof (UT_USER (ut))] = '\0';
60 for (p = trimmed_name + strlen (trimmed_name);
61 trimmed_name < p && p[-1] == ' ';
67 /* Is the utmp entry U desired by the user who asked for OPTIONS? */
70 desirable_utmp_entry (STRUCT_UTMP const *u, int options)
72 bool user_proc = IS_USER_PROCESS (u);
73 if ((options & READ_UTMP_USER_PROCESS) && !user_proc)
75 if ((options & READ_UTMP_CHECK_PIDS)
78 || (kill (UT_PID (u), 0) < 0 && errno == ESRCH)))
83 /* Read the utmp entries corresponding to file FILE into freshly-
84 malloc'd storage, set *UTMP_BUF to that pointer, set *N_ENTRIES to
85 the number of entries, and return zero. If there is any error,
86 return -1, setting errno, and don't modify the parameters.
87 If OPTIONS & READ_UTMP_CHECK_PIDS is nonzero, omit entries whose
88 process-IDs do not currently exist. */
90 #ifdef UTMP_NAME_FUNCTION
93 read_utmp (char const *file, size_t *n_entries, STRUCT_UTMP **utmp_buf,
98 STRUCT_UTMP *utmp = NULL;
101 /* Ignore the return value for now.
102 Solaris' utmpname returns 1 upon success -- which is contrary
103 to what the GNU libc version does. In addition, older GNU libc
104 versions are actually void. */
105 UTMP_NAME_FUNCTION (file);
109 while ((u = GET_UTMP_ENT ()) != NULL)
110 if (desirable_utmp_entry (u, options))
112 if (n_read == n_alloc)
113 utmp = x2nrealloc (utmp, &n_alloc, sizeof *utmp);
129 read_utmp (char const *file, size_t *n_entries, STRUCT_UTMP **utmp_buf,
134 STRUCT_UTMP *utmp = NULL;
136 FILE *f = fopen (file, "r");
143 if (n_read == n_alloc)
144 utmp = x2nrealloc (utmp, &n_alloc, sizeof *utmp);
145 if (fread (&utmp[n_read], sizeof utmp[n_read], 1, f) == 0)
147 n_read += desirable_utmp_entry (&utmp[n_read], options);
150 saved_errno = ferror (f) ? errno : 0;
153 if (saved_errno != 0)