freebsd-dev/contrib/tar/lib/readutmp.c
2002-06-04 10:37:47 +00:00

134 lines
3.4 KiB
C

/* GNU's read utmp module.
Copyright (C) 1992-2000 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software Foundation,
Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
/* Written by jla; revised by djm */
#include <config.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#if defined(STDC_HEADERS) || defined(HAVE_STRING_H)
# include <string.h>
#else
# include <strings.h>
#endif /* STDC_HEADERS || HAVE_STRING_H */
#include "readutmp.h"
char *xmalloc ();
char *realloc ();
/* Copy UT->ut_name into storage obtained from malloc. Then remove any
trailing spaces from the copy, NUL terminate it, and return the copy. */
char *
extract_trimmed_name (const STRUCT_UTMP *ut)
{
char *p, *trimmed_name;
trimmed_name = xmalloc (sizeof (UT_USER (ut)) + 1);
strncpy (trimmed_name, UT_USER (ut), sizeof (UT_USER (ut)));
/* Append a trailing space character. Some systems pad names shorter than
the maximum with spaces, others pad with NULs. Remove any spaces. */
trimmed_name[sizeof (UT_USER (ut))] = ' ';
p = strchr (trimmed_name, ' ');
if (p != NULL)
*p = '\0';
return trimmed_name;
}
/* Read the utmp entries corresponding to file FILENAME into freshly-
malloc'd storage, set *UTMP_BUF to that pointer, set *N_ENTRIES to
the number of entries, and return zero. If there is any error,
return non-zero and don't modify the parameters. */
#ifdef UTMP_NAME_FUNCTION
int
read_utmp (const char *filename, int *n_entries, STRUCT_UTMP **utmp_buf)
{
int n_read;
STRUCT_UTMP *u;
STRUCT_UTMP *utmp = NULL;
/* Ignore the return value for now.
Solaris' utmpname returns 1 upon success -- which is contrary
to what the GNU libc version does. In addition, older GNU libc
versions are actually void. */
UTMP_NAME_FUNCTION (filename);
SET_UTMP_ENT ();
n_read = 0;
while ((u = GET_UTMP_ENT ()) != NULL)
{
++n_read;
utmp = (STRUCT_UTMP *) realloc (utmp, n_read * sizeof (STRUCT_UTMP));
if (utmp == NULL)
return 1;
utmp[n_read - 1] = *u;
}
END_UTMP_ENT ();
*n_entries = n_read;
*utmp_buf = utmp;
return 0;
}
#else
int
read_utmp (const char *filename, int *n_entries, STRUCT_UTMP **utmp_buf)
{
FILE *utmp;
struct stat file_stats;
size_t n_read;
size_t size;
STRUCT_UTMP *buf;
utmp = fopen (filename, "r");
if (utmp == NULL)
return 1;
fstat (fileno (utmp), &file_stats);
size = file_stats.st_size;
if (size > 0)
buf = (STRUCT_UTMP *) xmalloc (size);
else
{
fclose (utmp);
return 1;
}
/* Use < instead of != in case the utmp just grew. */
n_read = fread (buf, 1, size, utmp);
if (ferror (utmp) || fclose (utmp) == EOF
|| n_read < size)
return 1;
*n_entries = size / sizeof (STRUCT_UTMP);
*utmp_buf = buf;
return 0;
}
#endif