shadow/libmisc/list.c
Alejandro Colomar 191f04f7dc Use *array() allocation functions where appropriate
This prevents overflow from multiplication.

Signed-off-by: Alejandro Colomar <alx@kernel.org>
2023-02-23 20:28:43 -06:00

250 lines
4.5 KiB
C

/*
* SPDX-FileCopyrightText: 1991 - 1994, Julianne Frances Haugh
* SPDX-FileCopyrightText: 1996 - 1997, Marek Michałkiewicz
* SPDX-FileCopyrightText: 2003 - 2005, Tomasz Kłoczko
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <config.h>
#ident "$Id$"
#include <assert.h>
#include "prototypes.h"
#include "defines.h"
/*
* add_list - add a member to a list of group members
*
* the array of member names is searched for the new member
* name, and if not present it is added to a freshly allocated
* list of users.
*/
/*@only@*/ /*@out@*/char **add_list (/*@returned@*/ /*@only@*/char **list, const char *member)
{
int i;
char **tmp;
assert (NULL != member);
assert (NULL != list);
/*
* Scan the list for the new name. Return the original list
* pointer if it is present.
*/
for (i = 0; list[i] != NULL; i++) {
if (strcmp (list[i], member) == 0) {
return list;
}
}
/*
* Allocate a new list pointer large enough to hold all the
* old entries, and the new entries as well.
*/
tmp = (char **) xmallocarray (i + 2, sizeof member);
/*
* Copy the original list to the new list, then append the
* new member and NULL terminate the result. This new list
* is returned to the invoker.
*/
for (i = 0; list[i] != NULL; i++) {
tmp[i] = list[i];
}
tmp[i] = xstrdup (member);
tmp[i+1] = NULL;
return tmp;
}
/*
* del_list - delete a member from a list of group members
*
* the array of member names is searched for the old member
* name, and if present it is deleted from a freshly allocated
* list of users.
*/
/*@only@*/ /*@out@*/char **del_list (/*@returned@*/ /*@only@*/char **list, const char *member)
{
int i, j;
char **tmp;
assert (NULL != member);
assert (NULL != list);
/*
* Scan the list for the old name. Return the original list
* pointer if it is not present.
*/
for (i = j = 0; list[i] != NULL; i++) {
if (strcmp (list[i], member) != 0) {
j++;
}
}
if (j == i) {
return list;
}
/*
* Allocate a new list pointer large enough to hold all the
* old entries.
*/
tmp = (char **) xmallocarray (j + 1, sizeof member);
/*
* Copy the original list except the deleted members to the
* new list, then NULL terminate the result. This new list
* is returned to the invoker.
*/
for (i = j = 0; list[i] != NULL; i++) {
if (strcmp (list[i], member) != 0) {
tmp[j] = list[i];
j++;
}
}
tmp[j] = NULL;
return tmp;
}
/*
* Duplicate a list.
* The input list is not modified, but in order to allow the use of this
* function with list of members, the list elements are not enforced to be
* constant strings here.
*/
/*@only@*/ /*@out@*/char **dup_list (char *const *list)
{
int i;
char **tmp;
assert (NULL != list);
for (i = 0; NULL != list[i]; i++);
tmp = (char **) xmallocarray (i + 1, sizeof (char *));
i = 0;
while (NULL != *list) {
tmp[i] = xstrdup (*list);
i++;
list++;
}
tmp[i] = NULL;
return tmp;
}
/*
* Check if member is part of the input list
* The input list is not modified, but in order to allow the use of this
* function with list of members, the list elements are not enforced to be
* constant strings here.
*/
bool is_on_list (char *const *list, const char *member)
{
assert (NULL != member);
assert (NULL != list);
while (NULL != *list) {
if (strcmp (*list, member) == 0) {
return true;
}
list++;
}
return false;
}
/*
* comma_to_list - convert comma-separated list to (char *) array
*/
/*@only@*/char **comma_to_list (const char *comma)
{
char *members;
char **array;
int i;
char *cp;
char *cp2;
assert (NULL != comma);
/*
* Make a copy since we are going to be modifying the list
*/
members = xstrdup (comma);
/*
* Count the number of commas in the list
*/
for (cp = members, i = 0;; i++) {
cp2 = strchr (cp, ',');
if (NULL != cp2) {
cp = cp2 + 1;
} else {
break;
}
}
/*
* Add 2 - one for the ending NULL, the other for the last item
*/
i += 2;
/*
* Allocate the array we're going to store the pointers into.
*/
array = (char **) xmallocarray (i, sizeof (char *));
/*
* Empty list is special - 0 members, not 1 empty member. --marekm
*/
if ('\0' == *members) {
*array = NULL;
free (members);
return array;
}
/*
* Now go walk that list all over again, this time building the
* array of pointers.
*/
for (cp = members, i = 0;; i++) {
array[i] = cp;
cp2 = strchr (cp, ',');
if (NULL != cp2) {
*cp2 = '\0';
cp2++;
cp = cp2;
} else {
array[i + 1] = NULL;
break;
}
}
/*
* Return the new array of pointers
*/
return array;
}