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/* GLIB - Library of useful routines for C programming
*
* Copyright (C) 2020 Red Hat, Inc.
*
* Author: Jakub Jelen <jjelen@redhat.com>
*
* SPDX-License-Identifier: LGPL-2.1-or-later
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General
* Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#include <dlfcn.h>
#include <glib.h>
#include <pwd.h>
#include <sys/types.h>
#include <unistd.h>
#ifndef __APPLE__
#define GET_REAL(func) \
(real_##func = dlsym (RTLD_NEXT, #func))
#define DEFINE_WRAPPER(return_type, func, argument_list) \
static return_type (* real_##func) argument_list; \
return_type func argument_list
#else
#define GET_REAL(func) \
func
/* https://opensource.apple.com/source/dyld/dyld-852.2/include/mach-o/dyld-interposing.h */
#define DYLD_INTERPOSE(_replacement,_replacee) \
__attribute__((used)) static struct{ const void* replacement; const void* replacee; } _interpose_##_replacee \
__attribute__ ((section ("__DATA,__interpose"))) = { (const void*)(unsigned long)&_replacement, (const void*)(unsigned long)&_replacee };
#define DEFINE_WRAPPER(return_type, func, argument_list) \
static return_type wrap_##func argument_list; \
DYLD_INTERPOSE(wrap_##func, func) \
static return_type wrap_##func argument_list
#endif /* __APPLE__ */
/* This is used in gutils.c used to make sure utility functions
* handling user information do not crash on bad data (for example
* caused by getpwuid returning some NULL elements.
*/
#undef getpwuid
/* Only modify the result if running inside a GLib test. Otherwise, we risk
* breaking test harness code, or test wrapper processes (as this binary is
* loaded via LD_PRELOAD, it will affect all wrapper processes). */
static inline int
should_modify_result (void)
{
const char *path = g_test_get_path ();
return (path != NULL && *path != '\0');
}
static struct passwd my_pw;
DEFINE_WRAPPER (struct passwd *, getpwuid, (uid_t uid))
{
struct passwd *pw = GET_REAL (getpwuid) (uid);
my_pw = *pw;
if (should_modify_result ())
my_pw.pw_name = NULL;
return &my_pw;
}
DEFINE_WRAPPER (int, getpwnam_r, (const char *name,
struct passwd *pwd,
char buf[],
size_t buflen,
struct passwd **result))
{
int code = GET_REAL (getpwnam_r) (name, pwd, buf, buflen, result);
if (should_modify_result ())
pwd->pw_name = NULL;
return code;
}
DEFINE_WRAPPER (int, getpwuid_r, (uid_t uid,
struct passwd *restrict pwd,
char buf[],
size_t buflen,
struct passwd **result))
{
int code = GET_REAL (getpwuid_r) (uid, pwd, buf, buflen, result);
if (should_modify_result ())
pwd->pw_name = NULL;
return code;
}
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