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v12.4.0
libvirt/tests/vircgroupmock.c
T
Laine Stump f83c0a5e6e consistently use glib g_getenv() instead of libc getenv() 
We've been using glib g_setenv() since commit
2c33532423 in December 2019 (switching
away from the gnulib version of setenv()). Most (but not all) of the
calls to get environment variables have remained using libc's getenv()
though, even though there is a g_getenv() wrapper in glib to match the
g_setenv() wrapper.

While getenv() doesn't have the thread safety problems of setenv(),
it's still recommended that users of g_setenv() also use g_getenv()
(for consistency, and because the glib functions handle UTF-8 properly
while libc getenv() may or may not depending on the setting of LANG in
the environment).

This patch changes all calls to getenv() to use g_getenv() instead,
with the exceptions of:

1) the call to getenv() in virt-login-shell.c (because
virt-login-shell runs setuid root, and we don't want glib or any other
gigantic library anywhere near a setuid program). In a few cases a
char * needs to be made const, and the return from getenv() needs to
be g_strdup()ed if it must stick around for any amount of time (since
the buffer returned from g_getenv() might be recycled/re-used if there
is another call to g_getenv()/g_setenv()).

2) the call to getenv() in libvirt_nss_log.c because it is compiled
into a loadable module that will be loaded into a process after the
process's normal startup, and so any initialization that might be
required for a glib function to operate properly may not be called.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2026-03-09 01:58:08 -04:00

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/*
* Copyright (C) 2013 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/>.
*/
#include <config.h>
#ifdef __linux__
# include "virmock.h"
# include <unistd.h>
# include <fcntl.h>
# include <sys/stat.h>
# include <sys/sysmacros.h>
# include <stdarg.h>
# include "testutilslxc.h"
# include "viralloc.h"
# include "vircgroupv2devices.h"
static int (*real_open)(const char *path, int flags, ...);
# if WITH___OPEN_2
static int (*real___open_2)(const char *path, int flags);
# endif
static FILE *(*real_fopen)(const char *path, const char *mode);
static int (*real_access)(const char *path, int mode);
static int (*real_mkdir)(const char *path, mode_t mode);
static char *fakerootdir;
static char *fakesysfscgroupdir;
static const char *fakedevicedir0 = FAKEDEVDIR0;
static const char *fakedevicedir1 = FAKEDEVDIR1;
# define SYSFS_CGROUP_PREFIX "/not/really/sys/fs/cgroup"
# define SYSFS_CPU_PRESENT "/sys/devices/system/cpu/present"
# define SYSFS_CPU_PRESENT_MOCKED "devices_system_cpu_present"
/*
* The plan:
*
* We fake out /proc/mounts, so make it look as is cgroups
* are mounted on /not/really/sys/fs/cgroup. We don't
* use /sys/fs/cgroup, because we want to make it easy to
* detect places where we've not mocked enough syscalls.
*
* In any open/access/mkdir calls we look at path and if
* it starts with /not/really/sys/fs/cgroup, we rewrite
* the path to point at a subdirectory of the temporary
* directory referred to by LIBVIRT_FAKE_ROOT_DIR env
* variable that is set by the main test suite
*
* In mkdir() calls, we simulate the cgroups behaviour
* whereby creating the directory auto-creates a bunch
* of files beneath it
*/
static int make_file(const char *path,
const char *name,
const char *value)
{
int fd = -1;
int ret = -1;
char *filepath = NULL;
if (asprintf(&filepath, "%s/%s", path, name) < 0)
return -1;
if ((fd = real_open(filepath, O_CREAT|O_WRONLY, 0600)) < 0)
goto cleanup;
if (write(fd, value, strlen(value)) != strlen(value)) /* sc_avoid_write */
goto cleanup;
ret = 0;
cleanup:
if (fd != -1 && close(fd) < 0)
ret = -1;
free(filepath);
return ret;
}
static int make_controller_v1(const char *path, mode_t mode)
{
const char *controller;
if (!STRPREFIX(path, fakesysfscgroupdir)) {
errno = EINVAL;
return -1;
}
controller = path + strlen(fakesysfscgroupdir) + 1;
if (STREQ(controller, "cpu"))
return symlink("cpu,cpuacct", path);
if (STREQ(controller, "cpuacct"))
return symlink("cpu,cpuacct", path);
if (real_mkdir(path, mode) < 0)
return -1;
# define MAKE_FILE(name, value) \
do { \
if (make_file(path, name, value) < 0) \
return -1; \
} while (0)
if (STRPREFIX(controller, "cpu,cpuacct")) {
MAKE_FILE("cpu.cfs_period_us", "100000\n");
MAKE_FILE("cpu.cfs_quota_us", "-1\n");
MAKE_FILE("cpu.shares", "1024\n");
MAKE_FILE("cpuacct.stat",
"user 216687025\n"
"system 43421396\n");
MAKE_FILE("cpuacct.usage", "2787788855799582\n");
MAKE_FILE("cpuacct.usage_percpu",
"7059492996 0 0 0 0 0 0 0 4180532496 0 0 0 0 0 0 0 "
"1957541268 0 0 0 0 0 0 0 2065932204 0 0 0 0 0 0 0 "
"18228689414 0 0 0 0 0 0 0 4245525148 0 0 0 0 0 0 0 "
"2911161568 0 0 0 0 0 0 0 1407758136 0 0 0 0 0 0 0 "
"1836807700 0 0 0 0 0 0 0 1065296618 0 0 0 0 0 0 0 "
"2046213266 0 0 0 0 0 0 0 747889778 0 0 0 0 0 0 0 "
"709566900 0 0 0 0 0 0 0 444777342 0 0 0 0 0 0 0 "
"5683512916 0 0 0 0 0 0 0 635751356 0 0 0 0 0 0 0\n");
} else if (STRPREFIX(controller, "cpuset")) {
if (STREQ(controller, "cpuset"))
MAKE_FILE("cpuset.cpus", "0-1");
else
MAKE_FILE("cpuset.cpus", ""); /* Values don't inherit */
MAKE_FILE("cpuset.memory_migrate", "0\n");
if (STREQ(controller, "cpuset"))
MAKE_FILE("cpuset.mems", "0");
else
MAKE_FILE("cpuset.mems", ""); /* Values don't inherit */
} else if (STRPREFIX(controller, "memory")) {
MAKE_FILE("memory.limit_in_bytes", "9223372036854775807\n");
MAKE_FILE("memory.memsw.limit_in_bytes", ""); /* Not supported */
MAKE_FILE("memory.memsw.usage_in_bytes", ""); /* Not supported */
MAKE_FILE("memory.soft_limit_in_bytes", "9223372036854775807\n");
MAKE_FILE("memory.stat",
"cache 1336619008\n"
"rss 97792000\n"
"mapped_file 42090496\n"
"pgpgin 13022605027\n"
"pgpgout 13023820533\n"
"pgfault 54429417056\n"
"pgmajfault 315715\n"
"inactive_anon 145887232\n"
"active_anon 67100672\n"
"inactive_file 627400704\n"
"active_file 661872640\n"
"unevictable 3690496\n"
"hierarchical_memory_limit 9223372036854775807\n"
"total_cache 1336635392\n"
"total_rss 118689792\n"
"total_mapped_file 42106880\n"
"total_pgpgin 13022606816\n"
"total_pgpgout 13023820793\n"
"total_pgfault 54429422313\n"
"total_pgmajfault 315715\n"
"total_inactive_anon 145891328\n"
"total_active_anon 88010752\n"
"total_inactive_file 627400704\n"
"total_active_file 661872640\n"
"total_unevictable 3690496\n"
"recent_rotated_anon 112807028\n"
"recent_rotated_file 2547948\n"
"recent_scanned_anon 113796164\n"
"recent_scanned_file 8199863\n");
MAKE_FILE("memory.usage_in_bytes", "1455321088\n");
MAKE_FILE("memory.use_hierarchy", "0\n");
} else if (STRPREFIX(controller, "freezer")) {
MAKE_FILE("freezer.state", "THAWED");
} else if (STRPREFIX(controller, "blkio")) {
MAKE_FILE("blkio.throttle.io_service_bytes",
"8:0 Read 59542107136\n"
"8:0 Write 411440480256\n"
"8:0 Sync 248486822912\n"
"8:0 Async 222495764480\n"
"8:0 Total 470982587392\n"
"9:0 Read 59542107137\n"
"9:0 Write 411440480257\n"
"9:0 Sync 248486822912\n"
"9:0 Async 222495764480\n"
"9:0 Total 470982587392\n");
MAKE_FILE("blkio.throttle.io_serviced",
"8:0 Read 4832583\n"
"8:0 Write 36641903\n"
"8:0 Sync 30723171\n"
"8:0 Async 10751315\n"
"8:0 Total 41474486\n"
"9:0 Read 4832584\n"
"9:0 Write 36641904\n"
"9:0 Sync 30723171\n"
"9:0 Async 10751315\n"
"9:0 Total 41474486\n");
MAKE_FILE("blkio.throttle.read_bps_device", "");
MAKE_FILE("blkio.throttle.read_iops_device", "");
MAKE_FILE("blkio.throttle.write_bps_device", "");
MAKE_FILE("blkio.throttle.write_iops_device", "");
MAKE_FILE("blkio.weight", "1000\n");
MAKE_FILE("blkio.weight_device", "");
} else {
errno = EINVAL;
return -1;
}
# undef MAKE_FILE
return 0;
}
static int make_controller_v2(const char *path, mode_t mode)
{
if (!STRPREFIX(path, fakesysfscgroupdir)) {
errno = EINVAL;
return -1;
}
if (real_mkdir(path, mode) < 0 && errno != EEXIST)
return -1;
# define MAKE_FILE(name, value) \
do { \
if (make_file(path, name, value) < 0) \
return -1; \
} while (0)
MAKE_FILE("cgroup.controllers", "cpu io memory\n");
MAKE_FILE("cgroup.subtree_control", "");
MAKE_FILE("cgroup.type", "domain\n");
MAKE_FILE("cpu.max", "max 100000\n");
MAKE_FILE("cpu.stat",
"usage_usec 0\n"
"user_usec 0\n"
"system_usec 0\n"
"nr_periods 0\n"
"nr_throttled 0\n"
"throttled_usec 0\n");
MAKE_FILE("cpu.weight", "100\n");
MAKE_FILE("memory.current", "1455321088\n");
MAKE_FILE("memory.high", "max\n");
MAKE_FILE("memory.max", "max\n");
MAKE_FILE("memory.stat",
"anon 0\n"
"file 0\n"
"kernel_stack 0\n"
"slab 0\n"
"sock 0\n"
"shmem 0\n"
"file_mapped 0\n"
"file_dirty 0\n"
"file_writeback 0\n"
"inactive_anon 0\n"
"active_anon 0\n"
"inactive_file 0\n"
"active_file 0\n"
"unevictable 0\n"
"slab_reclaimable 0\n"
"slab_unreclaimable 0\n"
"pgfault 0\n"
"pgmajfault 0\n"
"pgrefill 0\n"
"pgscan 0\n"
"pgsteal 0\n"
"pgactivate 0\n"
"pgdeactivate 0\n"
"pglazyfree 0\n"
"pglazyfreed 0\n"
"workingset_refault 0\n"
"workingset_activate 0\n"
"workingset_nodereclaim 0\n");
MAKE_FILE("memory.swap.current", "0\n");
MAKE_FILE("memory.swap.max", "max\n");
MAKE_FILE("io.stat", "8:0 rbytes=26828800 wbytes=77062144 rios=2256 wios=7849 dbytes=0 dios=0\n");
MAKE_FILE("io.max", "");
MAKE_FILE("io.weight", "default 100\n");
# undef MAKE_FILE
return 0;
}
static void init_syms(void)
{
if (real_fopen)
return;
VIR_MOCK_REAL_INIT(fopen);
VIR_MOCK_REAL_INIT(access);
VIR_MOCK_REAL_INIT(mkdir);
# if defined(__GLIBC__) && defined(_FILE_OFFSET_BITS) && _FILE_OFFSET_BITS == 64
VIR_MOCK_REAL_INIT_ALIASED(open, "open64");
# else
VIR_MOCK_REAL_INIT(open);
# endif
# if WITH___OPEN_2
VIR_MOCK_REAL_INIT(__open_2);
# endif
}
static int make_controller(const char *path, mode_t mode)
{
const char *mock;
bool unified = false;
bool hybrid = false;
mock = g_getenv("VIR_CGROUP_MOCK_MODE");
if (mock) {
if (STREQ(mock, "unified")) {
unified = true;
} else if (STREQ(mock, "hybrid")) {
hybrid = true;
} else if (STRNEQ(mock, "legacy")) {
fprintf(stderr, "invalid mode '%s'\n", mock);
abort();
}
}
if (unified || (hybrid && strstr(path, "unified"))) {
return make_controller_v2(path, mode);
} else {
return make_controller_v1(path, mode);
}
}
static void init_sysfs(void)
{
const char *mock;
const char *newfakerootdir;
bool unified = false;
bool hybrid = false;
if (!(newfakerootdir = g_getenv("LIBVIRT_FAKE_ROOT_DIR"))) {
fprintf(stderr, "Missing LIBVIRT_FAKE_ROOT_DIR env variable\n");
abort();
}
if (fakerootdir && STREQ(fakerootdir, newfakerootdir))
return;
VIR_FREE(fakerootdir);
fakerootdir = g_strdup(newfakerootdir);
mock = g_getenv("VIR_CGROUP_MOCK_MODE");
if (mock) {
if (STREQ(mock, "unified")) {
unified = true;
} else if (STREQ(mock, "hybrid")) {
hybrid = true;
} else if (STRNEQ(mock, "legacy")) {
fprintf(stderr, "invalid mode '%s'\n", mock);
abort();
}
}
VIR_FREE(fakesysfscgroupdir);
fakesysfscgroupdir = g_strdup_printf("%s%s",
fakerootdir, SYSFS_CGROUP_PREFIX);
if (g_mkdir_with_parents(fakesysfscgroupdir, 0777) < 0) {
fprintf(stderr, "Cannot create %s\n", fakesysfscgroupdir);
abort();
}
# define MAKE_CONTROLLER(subpath) \
do { \
char *path; \
if (asprintf(&path, "%s/%s", fakesysfscgroupdir, subpath) < 0) \
abort(); \
if (make_controller(path, 0755) < 0) { \
fprintf(stderr, "Cannot initialize %s\n", path); \
free(path); \
abort(); \
} \
free(path); \
} while (0)
if (unified) {
MAKE_CONTROLLER("");
} else if (hybrid) {
MAKE_CONTROLLER("unified");
MAKE_CONTROLLER("cpuset");
MAKE_CONTROLLER("freezer");
} else {
MAKE_CONTROLLER("cpu");
MAKE_CONTROLLER("cpuacct");
MAKE_CONTROLLER("cpu,cpuacct");
MAKE_CONTROLLER("cpuset");
MAKE_CONTROLLER("blkio");
MAKE_CONTROLLER("memory");
MAKE_CONTROLLER("freezer");
if (make_file(fakesysfscgroupdir,
SYSFS_CPU_PRESENT_MOCKED, "8-23,48-159\n") < 0)
abort();
}
}
FILE *fopen(const char *path, const char *mode)
{
char *filepath = NULL;
const char *type = NULL;
FILE *rc = NULL;
const char *filename = g_getenv("VIR_CGROUP_MOCK_FILENAME");
init_syms();
if (STREQ(path, "/proc/mounts")) {
if (STREQ(mode, "r")) {
type = "mounts";
} else {
errno = EACCES;
return NULL;
}
}
if (STREQ(path, "/proc/cgroups")) {
if (STREQ(mode, "r")) {
type = "cgroups";
} else {
errno = EACCES;
return NULL;
}
}
if (STREQ(path, "/proc/self/cgroup")) {
if (STREQ(mode, "r")) {
type = "self.cgroup";
} else {
errno = EACCES;
return NULL;
}
}
if (type) {
if (!filename) {
errno = EACCES;
return NULL;
}
filepath = g_strdup_printf("%s/vircgroupdata/%s.%s",
abs_srcdir, filename, type);
rc = real_fopen(filepath, mode);
free(filepath);
return rc;
}
return real_fopen(path, mode);
}
int access(const char *path, int mode)
{
int ret;
init_syms();
if (STRPREFIX(path, SYSFS_CGROUP_PREFIX)) {
char *newpath;
init_sysfs();
if (asprintf(&newpath, "%s%s",
fakesysfscgroupdir,
path + strlen(SYSFS_CGROUP_PREFIX)) < 0) {
errno = ENOMEM;
return -1;
}
ret = real_access(newpath, mode);
free(newpath);
} else if (STREQ(path, "/proc/cgroups") ||
STREQ(path, "/proc/self/cgroup") ||
STREQ(path, SYSFS_CPU_PRESENT)) {
/* These files are readable for all. */
ret = (mode == F_OK || mode == R_OK) ? 0 : -1;
} else if (STREQ(path, "/proc/mounts")) {
/* This one is accessible anytime for anybody. In fact, it's just
* a symlink to /proc/self/mounts. */
ret = 0;
} else {
ret = real_access(path, mode);
}
return ret;
}
# define VIR_MOCK_STAT_HOOK \
do { \
if (STRPREFIX(path, fakedevicedir0)) { \
sb->st_mode = S_IFBLK; \
sb->st_rdev = makedev(8, 0); \
return 0; \
} else if (STRPREFIX(path, fakedevicedir1)) { \
sb->st_mode = S_IFBLK; \
sb->st_rdev = makedev(9, 0); \
return 0; \
} \
} while (0)
# include "virmockstathelpers.c"
static int
virMockStatRedirect(const char *path, char **newpath)
{
if (STREQ(path, SYSFS_CPU_PRESENT)) {
init_sysfs();
if (asprintf(newpath, "%s/%s",
fakesysfscgroupdir,
SYSFS_CPU_PRESENT_MOCKED) < 0)
return -1;
} else if (STRPREFIX(path, SYSFS_CGROUP_PREFIX)) {
init_sysfs();
if (asprintf(newpath, "%s%s",
fakesysfscgroupdir,
path + strlen(SYSFS_CGROUP_PREFIX)) < 0)
return -1;
}
return 0;
}
int mkdir(const char *path, mode_t mode)
{
int ret;
init_syms();
if (STRPREFIX(path, SYSFS_CGROUP_PREFIX)) {
char *newpath;
init_sysfs();
if (asprintf(&newpath, "%s%s",
fakesysfscgroupdir,
path + strlen(SYSFS_CGROUP_PREFIX)) < 0) {
errno = ENOMEM;
return -1;
}
ret = make_controller(newpath, mode);
free(newpath);
} else {
ret = real_mkdir(path, mode);
}
return ret;
}
int open(const char *path, int flags, ...)
{
int ret;
char *newpath = NULL;
init_syms();
if (STREQ(path, SYSFS_CPU_PRESENT)) {
init_sysfs();
if (asprintf(&newpath, "%s/%s",
fakesysfscgroupdir,
SYSFS_CPU_PRESENT_MOCKED) < 0) {
errno = ENOMEM;
return -1;
}
}
if (STRPREFIX(path, SYSFS_CGROUP_PREFIX)) {
init_sysfs();
if (asprintf(&newpath, "%s%s",
fakesysfscgroupdir,
path + strlen(SYSFS_CGROUP_PREFIX)) < 0) {
errno = ENOMEM;
return -1;
}
}
if (flags & O_CREAT) {
va_list ap;
mode_t mode;
va_start(ap, flags);
mode = (mode_t) va_arg(ap, int);
va_end(ap);
ret = real_open(newpath ? newpath : path, flags, mode);
} else {
ret = real_open(newpath ? newpath : path, flags);
}
free(newpath);
return ret;
}
# if WITH___OPEN_2
int
__open_2(const char *path, int flags)
{
int ret;
char *newpath = NULL;
init_syms();
if (STREQ(path, SYSFS_CPU_PRESENT)) {
init_sysfs();
if (asprintf(&newpath, "%s/%s",
fakesysfscgroupdir,
SYSFS_CPU_PRESENT_MOCKED) < 0) {
errno = ENOMEM;
return -1;
}
}
if (STRPREFIX(path, SYSFS_CGROUP_PREFIX)) {
init_sysfs();
if (asprintf(&newpath, "%s%s",
fakesysfscgroupdir,
path + strlen(SYSFS_CGROUP_PREFIX)) < 0) {
errno = ENOMEM;
return -1;
}
}
ret = real___open_2(newpath ? newpath : path, flags);
free(newpath);
return ret;
}
# endif
bool
virCgroupV2DevicesAvailable(virCgroup *group G_GNUC_UNUSED)
{
return true;
}
#else
/* Nothing to override on non-__linux__ platforms */
#endif
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