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/*
* Copyright (c) 2007 - 2009, 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.
*/
/*
* According to the Linux-PAM documentation:
*
* 4.1. Care about standard library calls
*
* In general, writers of authorization-granting applications should
* assume that each module is likely to call any or all 'libc' functions.
* For 'libc' functions that return pointers to static/dynamically
* allocated structures (ie. the library allocates the memory and the
* user is not expected to 'free()' it) any module call to this function
* is likely to corrupt a pointer previously obtained by the application.
* The application programmer should either re-call such a 'libc'
* function after a call to the Linux-PAM library, or copy the structure
* contents to some safe area of memory before passing control to the
* Linux-PAM library.
*
* Two important function classes that fall into this category are
* getpwnam(3) and syslog(3).
*
* This file provide wrapper to the getpwnam or getpwnam_r functions.
*/
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include "prototypes.h"
#define XFUNCTION_NAME XPREFIX (FUNCTION_NAME)
#define XPREFIX(name) XPREFIX1 (name)
#define XPREFIX1(name) x##name
#define REENTRANT_NAME APPEND_R (FUNCTION_NAME)
#define APPEND_R(name) APPEND_R1 (name)
#define APPEND_R1(name) name##_r
#define STRINGIZE(name) STRINGIZE1 (name)
#define STRINGIZE1(name) #name
/*@null@*/ /*@only@*/LOOKUP_TYPE *XFUNCTION_NAME (ARG_TYPE ARG_NAME)
{
#if HAVE_FUNCTION_R
LOOKUP_TYPE *result=NULL;
char *buffer=NULL;
/* we have to start with something */
size_t length = 0x100;
result = malloc(sizeof(LOOKUP_TYPE));
if (NULL == result) {
fprintf (shadow_logfd, _("%s: out of memory\n"),
"x" STRINGIZE(FUNCTION_NAME));
exit (13);
}
while (true) {
int status;
LOOKUP_TYPE *resbuf = NULL;
buffer = (char *)realloc (buffer, length);
if (NULL == buffer) {
fprintf (shadow_logfd, _("%s: out of memory\n"),
"x" STRINGIZE(FUNCTION_NAME));
exit (13);
}
errno = 0;
status = REENTRANT_NAME(ARG_NAME, result, buffer,
length, &resbuf);
if ((0 == status) && (resbuf == result)) {
/* Build a result structure that can be freed by
* the shadow *_free functions. */
LOOKUP_TYPE *ret_result = DUP_FUNCTION(result);
free(buffer);
free(result);
return ret_result;
}
if (ERANGE != errno) {
free (buffer);
free (result);
return NULL;
}
if (length <= ((size_t)-1 / 4)) {
length *= 4;
} else if (length == (size_t) -1) {
break;
} else {
length = (size_t) -1;
}
}
free(buffer);
free(result);
return NULL;
#else /* !HAVE_FUNCTION_R */
/* No reentrant function.
* Duplicate the structure to avoid other call to overwrite it.
*
* We should also restore the initial structure. But that would be
* overkill.
*/
LOOKUP_TYPE *result = FUNCTION_NAME(ARG_NAME);
if (result) {
result = DUP_FUNCTION(result);
if (NULL == result) {
fprintf (shadow_logfd, _("%s: out of memory\n"),
"x" STRINGIZE(FUNCTION_NAME));
exit (13);
}
}
return result;
#endif
}
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