shadow/lib/sgetgrent.c

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/*
* Copyright (c) 1990 - 1994, Julianne Frances Haugh
* Copyright (c) 1996 - 1998, Marek Michałkiewicz
* Copyright (c) 2005 , Tomasz Kłoczko
* Copyright (c) 2008 , Nicolas François
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the copyright holders or contributors may not be used to
* endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <config.h>
#ident "$Id$"
#include <stdio.h>
#include <sys/types.h>
#include <grp.h>
#include "defines.h"
#include "prototypes.h"
#define NFIELDS 4
/*
* list - turn a comma-separated string into an array of (char *)'s
*
* list() converts the comma-separated list of member names into
* an array of character pointers.
*
* WARNING: I profiled this once with and without strchr() calls
* and found that using a register variable and an explicit loop
* works best. For large /etc/group files, this is a major win.
*
* FINALLY added dynamic allocation. Still need to fix sgetsgent().
* --marekm
*/
static char **list (char *s)
{
static char **members = 0;
static int size = 0; /* max members + 1 */
int i;
char **rbuf;
i = 0;
for (;;) {
/* check if there is room for another pointer (to a group
member name, or terminating NULL). */
if (i >= size) {
size = i + 100; /* at least: i + 1 */
if (members) {
rbuf =
realloc (members, size * sizeof (char *));
} else {
/* for old (before ANSI C) implementations of
realloc() that don't handle NULL properly */
rbuf = malloc (size * sizeof (char *));
}
if (!rbuf) {
if (members)
free (members);
members = 0;
size = 0;
return (char **) 0;
}
members = rbuf;
}
if (!s || s[0] == '\0')
break;
members[i++] = s;
while (('\0' != *s) && (',' != *s)) {
s++;
}
if ('\0' != *s) {
*s++ = '\0';
}
}
members[i] = (char *) 0;
return members;
}
struct group *sgetgrent (const char *buf)
{
static char *grpbuf = 0;
static size_t size = 0;
static char *grpfields[NFIELDS];
static struct group grent;
int i;
char *cp;
if (strlen (buf) + 1 > size) {
/* no need to use realloc() here - just free it and
allocate a larger block */
if (grpbuf)
free (grpbuf);
size = strlen (buf) + 1000; /* at least: strlen(buf) + 1 */
grpbuf = malloc (size);
if (!grpbuf) {
size = 0;
return 0;
}
}
strcpy (grpbuf, buf);
cp = strrchr (grpbuf, '\n');
if (NULL != cp) {
*cp = '\0';
}
for (cp = grpbuf, i = 0; (i < NFIELDS) && (NULL != cp); i++) {
grpfields[i] = cp;
cp = strchr (cp, ':');
if (NULL != cp) {
*cp = '\0';
cp++;
}
}
if (i < (NFIELDS - 1) || *grpfields[2] == '\0') {
return (struct group *) 0;
}
grent.gr_name = grpfields[0];
grent.gr_passwd = grpfields[1];
grent.gr_gid = atoi (grpfields[2]);
grent.gr_mem = list (grpfields[3]);
if (NULL == grent.gr_mem) {
return (struct group *) 0; /* out of memory */
}
return &grent;
}