shadow/lib/sgetgrent.c

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/*
* Copyright 1990 - 1994, Julianne Frances Haugh
* 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. Neither the name of Julianne F. Haugh nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY JULIE HAUGH 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 JULIE HAUGH 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>
#include "rcsid.h"
RCSID("$Id: sgetgrent.c,v 1.4 1998/04/02 21:51:45 marekm Exp $")
#include <stdio.h>
#include <grp.h>
#include "defines.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 (*s && *s != ',')
s++;
if (*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);
if ((cp = strrchr(grpbuf, '\n')))
*cp = '\0';
for (cp = grpbuf, i = 0; i < NFIELDS && cp; i++) {
grpfields[i] = cp;
if ((cp = strchr(cp, ':')))
*cp++ = 0;
}
if (i < (NFIELDS-1) || *grpfields[2] == '\0')
return 0;
grent.gr_name = grpfields[0];
grent.gr_passwd = grpfields[1];
grent.gr_gid = atoi(grpfields[2]);
grent.gr_mem = list(grpfields[3]);
if (!grent.gr_mem)
return (struct group *) 0; /* out of memory */
return &grent;
}