mirror of
https://gitlab.com/libvirt/libvirt.git
synced 2024-08-28 11:31:16 +00:00
Quite a few of the tests have a need to mock the stat() / lstat() functions and they are taking somewhat different & inconsistent approaches none of which are actually fully correct. This is shown by fact that 'make check' fails on 32-bit hosts. Investigation revealed that the code was calling into the native C library impl, not getting intercepted by our mocks. The POSIX stat() function might resolve to any number of different symbols in the C library. The may be an additional stat64() function exposed by the headers too. On 64-bit hosts the stat & stat64 functions are identical, always refering to the 64-bit ABI. On 32-bit hosts they refer to the 32-bit & 64-bit ABIs respectively. Libvirt uses _FILE_OFFSET_BITS=64 on 32-bit hosts, which causes the C library to transparently rewrite stat() calls to be stat64() calls. Libvirt will never see the 32-bit ABI from the traditional stat() call. We cannot assume this rewriting is done using a macro. It might be, but on GLibC it is done with a magic __asm__ statement to apply the rewrite at link time instead of at preprocessing. In GLibC there may be two additional functions exposed by the headers, __xstat() and __xstat64(). When these exist, stat() and stat64() are transparently rewritten to call __xstat() and __xstat64() respectively. The former symbols will not actally exist in the library at all, only the header. The leading "__" indicates the symbols are a private impl detail of the C library that applications should not care about. Unfortunately, because we are trying to mock replace the C library, we need to know about this internal impl detail. With all this in mind the list of functions we have to mock will depend on several factors - If _FILE_OFFSET_BITS is set, then we are on a 32-bit host, and we only need to mock stat64 and __xstat64. The other stat / __xstat functions exist, but we'll never call them so they can be ignored for mocking. - If _FILE_OFFSET_BITS is not set, then we are on a 64-bit host and we should mock stat, stat64, __xstat & __xstat64. Either may be called by app code. - If __xstat & __xstat64 exist, then stat & stat64 will not exist as symbols in the library, so the latter should not be mocked. The same all applies to lstat() These rules are complex enough that we don't want to duplicate them across every mock file, so this centralizes all the logic in a helper file virmockstathelper.c that should be #included when needed. The code merely need to provide a filename rewriting callback called virMockStatRedirect(). Optionally VIR_MOCK_STAT_HOOK can be defined as a macro if further processing is needed inline. Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
327 lines
8.7 KiB
C
327 lines
8.7 KiB
C
/*
|
|
* Copyright (C) 2019 Red Hat, Inc.
|
|
*
|
|
* 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/>.
|
|
*
|
|
* Helpers for dealing with the many variants of stat(). This
|
|
* C file should be included from any file that wants to mock
|
|
* stat() correctly.
|
|
*/
|
|
|
|
#include "virmock.h"
|
|
#include "viralloc.h"
|
|
|
|
#include <sys/stat.h>
|
|
#include <unistd.h>
|
|
|
|
/*
|
|
* The POSIX stat() function might resolve to any number of different
|
|
* symbols in the C library.
|
|
*
|
|
* The may be an additional stat64() function exposed by the headers
|
|
* too.
|
|
*
|
|
* On 64-bit hosts the stat & stat64 functions are identical, always
|
|
* refering to the 64-bit ABI.
|
|
*
|
|
* On 32-bit hosts they refer to the 32-bit & 64-bit ABIs respectively.
|
|
*
|
|
* Libvirt uses _FILE_OFFSET_BITS=64 on 32-bit hosts, which causes the
|
|
* C library to transparently rewrite stat() calls to be stat64() calls.
|
|
* Libvirt will never see the 32-bit ABI from the traditional stat()
|
|
* call. We cannot assume this rewriting is done using a macro. It might
|
|
* be, but on GLibC it is done with a magic __asm__ statement to apply
|
|
* the rewrite at link time instead of at preprocessing.
|
|
*
|
|
* In GLibC there may be two additional functions exposed by the headers,
|
|
* __xstat() and __xstat64(). When these exist, stat() and stat64() are
|
|
* transparently rewritten to call __xstat() and __xstat64() respectively.
|
|
* The former symbols will not actally exist in the library at all, only
|
|
* the header. The leading "__" indicates the symbols are a private impl
|
|
* detail of the C library that applications should not care about.
|
|
* Unfortunately, because we are trying to mock replace the C library,
|
|
* we need to know about this internal impl detail.
|
|
*
|
|
* With all this in mind the list of functions we have to mock will depend
|
|
* on several factors
|
|
*
|
|
* - If _FILE_OFFSET_BITS is set, then we are on a 32-bit host, and we
|
|
* only need to mock stat64 and __xstat64. The other stat / __xstat
|
|
* functions exist, but we'll never call them so they can be ignored
|
|
* for mocking.
|
|
*
|
|
* - If _FILE_OFFSET_BITS is not set, then we are on a 64-bit host and
|
|
* we should mock stat, stat64, __xstat & __xstat64. Either may be
|
|
* called by app code.
|
|
*
|
|
* - If __xstat & __xstat64 exist, then stat & stat64 will not exist
|
|
* as symbols in the library, so the latter should not be mocked.
|
|
*
|
|
* The same all applies to lstat()
|
|
*/
|
|
|
|
|
|
|
|
#if defined(HAVE_STAT) && !defined(HAVE___XSTAT) && !defined(_FILE_OFFSET_BITS)
|
|
# define MOCK_STAT
|
|
#endif
|
|
#if defined(HAVE_STAT64) && !defined(HAVE___XSTAT64)
|
|
# define MOCK_STAT64
|
|
#endif
|
|
#if defined(HAVE___XSTAT) && !defined(_FILE_OFFSET_BITS)
|
|
# define MOCK___XSTAT
|
|
#endif
|
|
#if defined(HAVE___XSTAT64)
|
|
# define MOCK___XSTAT64
|
|
#endif
|
|
#if defined(HAVE_LSTAT) && !defined(HAVE___LXSTAT) && !defined(_FILE_OFFSET_BITS)
|
|
# define MOCK_LSTAT
|
|
#endif
|
|
#if defined(HAVE_LSTAT64) && !defined(HAVE___LXSTAT64)
|
|
# define MOCK_LSTAT64
|
|
#endif
|
|
#if defined(HAVE___LXSTAT) && !defined(_FILE_OFFSET_BITS)
|
|
# define MOCK___LXSTAT
|
|
#endif
|
|
#if defined(HAVE___LXSTAT64)
|
|
# define MOCK___LXSTAT64
|
|
#endif
|
|
|
|
#ifdef MOCK_STAT
|
|
static int (*real_stat)(const char *path, struct stat *sb);
|
|
#endif
|
|
#ifdef MOCK_STAT64
|
|
static int (*real_stat64)(const char *path, struct stat64 *sb);
|
|
#endif
|
|
#ifdef MOCK___XSTAT
|
|
static int (*real___xstat)(int ver, const char *path, struct stat *sb);
|
|
#endif
|
|
#ifdef MOCK___XSTAT64
|
|
static int (*real___xstat64)(int ver, const char *path, struct stat64 *sb);
|
|
#endif
|
|
#ifdef MOCK_LSTAT
|
|
static int (*real_lstat)(const char *path, struct stat *sb);
|
|
#endif
|
|
#ifdef MOCK_LSTAT64
|
|
static int (*real_lstat64)(const char *path, struct stat64 *sb);
|
|
#endif
|
|
#ifdef MOCK___LXSTAT
|
|
static int (*real___lxstat)(int ver, const char *path, struct stat *sb);
|
|
#endif
|
|
#ifdef MOCK___LXSTAT64
|
|
static int (*real___lxstat64)(int ver, const char *path, struct stat64 *sb);
|
|
#endif
|
|
|
|
static bool init;
|
|
static bool debug;
|
|
|
|
#define fdebug(msg, ...) do { if (debug) fprintf(stderr, msg, __VA_ARGS__); } while (0)
|
|
|
|
static void virMockStatInit(void)
|
|
{
|
|
if (init)
|
|
return;
|
|
|
|
init = true;
|
|
debug = getenv("VIR_MOCK_STAT_DEBUG");
|
|
|
|
#ifdef MOCK_STAT
|
|
VIR_MOCK_REAL_INIT(stat);
|
|
fdebug("real stat %p\n", real_stat);
|
|
#endif
|
|
#ifdef MOCK_STAT64
|
|
VIR_MOCK_REAL_INIT(stat64);
|
|
fdebug("real stat64 %p\n", real_stat64);
|
|
#endif
|
|
#ifdef MOCK___XSTAT
|
|
VIR_MOCK_REAL_INIT(__xstat);
|
|
fdebug("real __xstat %p\n", real___xstat);
|
|
#endif
|
|
#ifdef MOCK___XSTAT64
|
|
VIR_MOCK_REAL_INIT(__xstat64);
|
|
fdebug("real __xstat64 %p\n", real___xstat64);
|
|
#endif
|
|
#ifdef MOCK_LSTAT
|
|
VIR_MOCK_REAL_INIT(lstat);
|
|
fdebug("real lstat %p\n", real_lstat);
|
|
#endif
|
|
#ifdef MOCK_LSTAT64
|
|
VIR_MOCK_REAL_INIT(lstat64);
|
|
fdebug("real lstat64 %p\n", real_lstat64);
|
|
#endif
|
|
#ifdef MOCK___LXSTAT
|
|
VIR_MOCK_REAL_INIT(__lxstat);
|
|
fdebug("real __lxstat %p\n", real___lxstat);
|
|
#endif
|
|
#ifdef MOCK___LXSTAT64
|
|
VIR_MOCK_REAL_INIT(__lxstat64);
|
|
fdebug("real __lxstat64 %p\n", real___lxstat64);
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* @stat: the path being queried
|
|
* @newpath: fill with redirected path, or leave NULL to use orig path
|
|
*
|
|
* Return 0 on success, -1 on allocation error
|
|
*/
|
|
static int virMockStatRedirect(const char *path, char **newpath);
|
|
|
|
#ifndef VIR_MOCK_STAT_HOOK
|
|
# define VIR_MOCK_STAT_HOOK do { } while (0)
|
|
#endif
|
|
|
|
#ifdef MOCK_STAT
|
|
int stat(const char *path, struct stat *sb)
|
|
{
|
|
VIR_AUTOFREE(char *) newpath = NULL;
|
|
|
|
virMockStatInit();
|
|
|
|
if (virMockStatRedirect(path, &newpath) < 0)
|
|
abort();
|
|
fdebug("stat redirect %s to %s sb=%p\n", path, newpath ? newpath : path, sb);
|
|
|
|
VIR_MOCK_STAT_HOOK;
|
|
|
|
return real_stat(newpath ? newpath : path, sb);
|
|
}
|
|
#endif
|
|
|
|
#ifdef MOCK_STAT64
|
|
int stat64(const char *path, struct stat64 *sb)
|
|
{
|
|
VIR_AUTOFREE(char *) newpath = NULL;
|
|
|
|
virMockStatInit();
|
|
|
|
if (virMockStatRedirect(path, &newpath) < 0)
|
|
abort();
|
|
fdebug("stat64 redirect %s to %s sb=%p\n", path, newpath ? newpath : path, sb);
|
|
|
|
VIR_MOCK_STAT_HOOK;
|
|
|
|
return real_stat64(newpath ? newpath : path, sb);
|
|
}
|
|
#endif
|
|
|
|
#ifdef MOCK___XSTAT
|
|
int
|
|
__xstat(int ver, const char *path, struct stat *sb)
|
|
{
|
|
VIR_AUTOFREE(char *) newpath = NULL;
|
|
|
|
virMockStatInit();
|
|
|
|
if (virMockStatRedirect(path, &newpath) < 0)
|
|
abort();
|
|
fdebug("__xstat redirect %s to %s sb=%p\n", path, newpath ? newpath : path, sb);
|
|
|
|
VIR_MOCK_STAT_HOOK;
|
|
|
|
return real___xstat(ver, newpath ? newpath : path, sb);
|
|
}
|
|
#endif
|
|
|
|
#ifdef MOCK___XSTAT64
|
|
int
|
|
__xstat64(int ver, const char *path, struct stat64 *sb)
|
|
{
|
|
VIR_AUTOFREE(char *) newpath = NULL;
|
|
|
|
virMockStatInit();
|
|
|
|
if (virMockStatRedirect(path, &newpath) < 0)
|
|
abort();
|
|
fdebug("__xstat64 redirect %s to %s sb=%p\n", path, newpath ? newpath : path, sb);
|
|
|
|
VIR_MOCK_STAT_HOOK;
|
|
|
|
return real___xstat64(ver, newpath ? newpath : path, sb);
|
|
}
|
|
#endif
|
|
|
|
#ifdef MOCK_LSTAT
|
|
int
|
|
lstat(const char *path, struct stat *sb)
|
|
{
|
|
VIR_AUTOFREE(char *) newpath = NULL;
|
|
|
|
virMockStatInit();
|
|
|
|
if (virMockStatRedirect(path, &newpath) < 0)
|
|
abort();
|
|
fdebug("lstat redirect %s to %s sb=%p\n", path, newpath ? newpath : path, sb);
|
|
|
|
VIR_MOCK_STAT_HOOK;
|
|
|
|
return real_lstat(newpath ? newpath : path, sb);
|
|
}
|
|
#endif
|
|
|
|
#ifdef MOCK_LSTAT64
|
|
int
|
|
lstat64(const char *path, struct stat64 *sb)
|
|
{
|
|
VIR_AUTOFREE(char *) newpath = NULL;
|
|
|
|
virMockStatInit();
|
|
|
|
if (virMockStatRedirect(path, &newpath) < 0)
|
|
abort();
|
|
fdebug("lstat64 redirect %s to %s sb=%p\n", path, newpath ? newpath : path, sb);
|
|
|
|
VIR_MOCK_STAT_HOOK;
|
|
|
|
return real_lstat64(newpath ? newpath : path, sb);
|
|
}
|
|
#endif
|
|
|
|
#ifdef MOCK___LXSTAT
|
|
int
|
|
__lxstat(int ver, const char *path, struct stat *sb)
|
|
{
|
|
VIR_AUTOFREE(char *) newpath = NULL;
|
|
|
|
virMockStatInit();
|
|
|
|
if (virMockStatRedirect(path, &newpath) < 0)
|
|
abort();
|
|
fdebug("__lxstat redirect %s to %s sb=%p\n", path, newpath ? newpath : path, sb);
|
|
|
|
VIR_MOCK_STAT_HOOK;
|
|
|
|
return real___lxstat(ver, newpath ? newpath : path, sb);
|
|
}
|
|
#endif
|
|
|
|
#ifdef MOCK___LXSTAT64
|
|
int
|
|
__lxstat64(int ver, const char *path, struct stat64 *sb)
|
|
{
|
|
VIR_AUTOFREE(char *) newpath = NULL;
|
|
|
|
virMockStatInit();
|
|
|
|
if (virMockStatRedirect(path, &newpath) < 0)
|
|
abort();
|
|
fdebug("__lxstat64 redirect %s to %s sb=%p\n", path, newpath ? newpath : path, sb);
|
|
|
|
VIR_MOCK_STAT_HOOK;
|
|
|
|
return real___lxstat64(ver, newpath ? newpath : path, sb);
|
|
}
|
|
#endif
|