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libvirt/tests/vircgroupmock.c
Michal Privoznik 32799f1a9d vircgroupmock: Mock access() to some more files 
Currently, if access(path, mode) is invoked, we check if @path has this
special prefix SYSFS_PREFIX. If it does, we modify the path a bit and
call realaccess. If it doesn't we act just like a wrapper and call
realaccess directly. However, we are mocking fopen() as well. And as one
can clearly see there, fopen("/proc/cgroups") will succeed. Hence, we
have an error in our mocked access(): We need to check whether @path is
not equal to /proc/cgroups as it may not exists on real system we're
running however we definitely know how to fopen() it.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
2013-10-22 15:42:19 +01:00

616 lines
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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/>.
*
* Author: Daniel P. Berrange <berrange@redhat.com>
*/
#include <config.h>
#ifdef __linux__
# include "internal.h"
# include <stdio.h>
# include <dlfcn.h>
# include <stdlib.h>
# include <unistd.h>
# include <fcntl.h>
# include <sys/stat.h>
# include <stdarg.h>
static int (*realopen)(const char *path, int flags, ...);
static FILE *(*realfopen)(const char *path, const char *mode);
static int (*realaccess)(const char *path, int mode);
static int (*reallstat)(const char *path, struct stat *sb);
static int (*real__lxstat)(int ver, const char *path, struct stat *sb);
static int (*realmkdir)(const char *path, mode_t mode);
/* Don't make static, since it causes problems with clang
* when passed as an arg to asprintf()
* vircgroupmock.c:462:22: error: static variable 'fakesysfsdir' is used in an inline function with external linkage [-Werror,-Wstatic-in-inline]
*/
char *fakesysfsdir;
# define SYSFS_PREFIX "/not/really/sys/fs/cgroup/"
/*
* 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/acces/mkdir calls we look at path and if
* it starts with /not/really/sys/fs/cgroup, we rewrite
* the path to point at a temporary directory referred
* to by LIBVIRT_FAKE_SYSFS_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
*/
/*
* Intentionally missing the 'devices' mount.
* Co-mounting cpu & cpuacct controllers
* An anonymous controller for systemd
*/
const char *procmounts =
"rootfs / rootfs rw 0 0\n"
"tmpfs /run tmpfs rw,seclabel,nosuid,nodev,mode=755 0 0\n"
"tmpfs /not/really/sys/fs/cgroup tmpfs rw,seclabel,nosuid,nodev,noexec,mode=755 0 0\n"
"cgroup /not/really/sys/fs/cgroup/systemd cgroup rw,nosuid,nodev,noexec,relatime,release_agent=/usr/lib/systemd/systemd-cgroups-agent,name=systemd 0 0\n"
"cgroup /not/really/sys/fs/cgroup/cpuset cgroup rw,nosuid,nodev,noexec,relatime,cpuset 0 0\n"
"cgroup /not/really/sys/fs/cgroup/cpu,cpuacct cgroup rw,nosuid,nodev,noexec,relatime,cpuacct,cpu 0 0\n"
"cgroup /not/really/sys/fs/cgroup/freezer cgroup rw,nosuid,nodev,noexec,relatime,freezer 0 0\n"
"cgroup /not/really/sys/fs/cgroup/blkio cgroup rw,nosuid,nodev,noexec,relatime,blkio 0 0\n"
"cgroup /not/really/sys/fs/cgroup/memory cgroup rw,nosuid,nodev,noexec,relatime,memory 0 0\n"
"/dev/sda1 /boot ext4 rw,seclabel,relatime,data=ordered 0 0\n"
"tmpfs /tmp tmpfs rw,seclabel,relatime,size=1024000k 0 0\n";
const char *procselfcgroups =
"115:memory:/\n"
"8:blkio:/\n"
"6:freezer:/\n"
"3:cpuacct,cpu:/system\n"
"2:cpuset:/\n"
"1:name=systemd:/user/berrange/123\n";
const char *proccgroups =
"#subsys_name hierarchy num_cgroups enabled\n"
"cpuset 2 4 1\n"
"cpu 3 48 1\n"
"cpuacct 3 48 1\n"
"memory 4 4 1\n"
"devices 5 4 1\n"
"freezer 6 4 1\n"
"blkio 8 4 1\n";
const char *procmountsallinone =
"rootfs / rootfs rw 0 0\n"
"sysfs /sys sysfs rw,nosuid,nodev,noexec,relatime 0 0\n"
"proc /proc proc rw,nosuid,nodev,noexec,relatime 0 0\n"
"udev /dev devtmpfs rw,relatime,size=16458560k,nr_inodes=4114640,mode=755 0 0\n"
"devpts /dev/pts devpts rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000 0 0\n"
"nfsd /proc/fs/nfsd nfsd rw,relatime 0 0\n"
"cgroup /not/really/sys/fs/cgroup cgroup rw,relatime,blkio,devices,memory,cpuacct,cpu,cpuset 0 0\n";
const char *procselfcgroupsallinone =
"6:blkio,devices,memory,cpuacct,cpu,cpuset:/";
const char *proccgroupsallinone =
"#subsys_name hierarchy num_cgroups enabled\n"
"cpuset 6 1 1\n"
"cpu 6 1 1\n"
"cpuacct 6 1 1\n"
"memory 6 1 1\n"
"devices 6 1 1\n"
"blkio 6 1 1\n";
const char *procmountslogind =
"none /not/really/sys/fs/cgroup tmpfs rw,rootcontext=system_u:object_r:sysfs_t:s0,seclabel,relatime,size=4k,mode=755 0 0\n"
"systemd /not/really/sys/fs/cgroup/systemd cgroup rw,nosuid,nodev,noexec,relatime,name=systemd 0 0\n";
const char *procselfcgroupslogind =
"1:name=systemd:/\n";
const char *proccgroupslogind =
"#subsys_name hierarchy num_cgroups enabled\n"
"cpuset 0 1 1\n"
"cpu 0 1 1\n"
"cpuacct 0 1 1\n"
"memory 0 1 0\n"
"devices 0 1 1\n"
"freezer 0 1 1\n"
"net_cls 0 1 1\n"
"blkio 0 1 1\n"
"perf_event 0 1 1\n";
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 = realopen(filepath, O_CREAT|O_WRONLY, 0600)) < 0)
goto cleanup;
if (write(fd, value, strlen(value)) != strlen(value))
goto cleanup;
ret = 0;
cleanup:
if (fd != -1 && close(fd) < 0)
ret = -1;
free(filepath);
return ret;
}
static int make_controller(const char *path, mode_t mode)
{
int ret = -1;
const char *controller;
if (!STRPREFIX(path, fakesysfsdir)) {
errno = EINVAL;
return -1;
}
controller = path + strlen(fakesysfsdir) + 1;
if (STREQ(controller, "cpu"))
return symlink("cpu,cpuacct", path);
if (STREQ(controller, "cpuacct"))
return symlink("cpu,cpuacct", path);
if (realmkdir(path, mode) < 0)
goto cleanup;
# define MAKE_FILE(name, value) \
do { \
if (make_file(path, name, value) < 0) \
goto cleanup; \
} 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.rt_period_us", "1000000\n");
MAKE_FILE("cpu.rt_runtime_us", "950000\n");
MAKE_FILE("cpu.shares", "1024\n");
MAKE_FILE("cpu.stat",
"nr_periods 0\n"
"nr_throttled 0\n"
"throttled_time 0\n");
MAKE_FILE("cpuacct.stat",
"user 216687025\n"
"system 43421396\n");
MAKE_FILE("cpuacct.usage", "2787788855799582\n");
MAKE_FILE("cpuacct.usage_per_cpu", "1413142688153030 1374646168910542\n");
} else if (STRPREFIX(controller, "cpuset")) {
MAKE_FILE("cpuset.cpu_exclusive", "1\n");
if (STREQ(controller, "cpuset"))
MAKE_FILE("cpuset.cpus", "0-1");
else
MAKE_FILE("cpuset.cpus", ""); /* Values don't inherit */
MAKE_FILE("cpuset.mem_exclusive", "1\n");
MAKE_FILE("cpuset.mem_hardwall", "0\n");
MAKE_FILE("cpuset.memory_migrate", "0\n");
MAKE_FILE("cpuset.memory_pressure", "0\n");
MAKE_FILE("cpuset.memory_pressure_enabled", "0\n");
MAKE_FILE("cpuset.memory_spread_page", "0\n");
MAKE_FILE("cpuset.memory_spread_slab", "0\n");
if (STREQ(controller, "cpuset"))
MAKE_FILE("cpuset.mems", "0");
else
MAKE_FILE("cpuset.mems", ""); /* Values don't inherit */
MAKE_FILE("cpuset.sched_load_balance", "1\n");
MAKE_FILE("cpuset.sched_relax_domain_level", "-1\n");
} else if (STRPREFIX(controller, "memory")) {
MAKE_FILE("memory.failcnt", "0\n");
MAKE_FILE("memory.force_empty", ""); /* Write only */
MAKE_FILE("memory.kmem.tcp.failcnt", "0\n");
MAKE_FILE("memory.kmem.tcp.limit_in_bytes", "9223372036854775807\n");
MAKE_FILE("memory.kmem.tcp.max_usage_in_bytes", "0\n");
MAKE_FILE("memory.kmem.tcp.usage_in_bytes", "16384\n");
MAKE_FILE("memory.limit_in_bytes", "9223372036854775807\n");
MAKE_FILE("memory.max_usage_in_bytes", "0\n");
MAKE_FILE("memory.memsw.failcnt", ""); /* Not supported */
MAKE_FILE("memory.memsw.limit_in_bytes", ""); /* Not supported */
MAKE_FILE("memory.memsw.max_usage_in_bytes", ""); /* Not supported */
MAKE_FILE("memory.memsw.usage_in_bytes", ""); /* Not supported */
MAKE_FILE("memory.move_charge_at_immigrate", "0\n");
MAKE_FILE("memory.numa_stat",
"total=367664 N0=367664\n"
"file=314764 N0=314764\n"
"anon=51999 N0=51999\n"
"unevictable=901 N0=901\n");
MAKE_FILE("memory.oom_control",
"oom_kill_disable 0\n"
"under_oom 0\n");
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.swappiness", "60\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.io_merged",
"8:0 Read 1100949\n"
"8:0 Write 2248076\n"
"8:0 Sync 63063\n"
"8:0 Async 3285962\n"
"8:0 Total 3349025\n");
MAKE_FILE("blkio.io_queued",
"8:0 Read 0\n"
"8:0 Write 0\n"
"8:0 Sync 0\n"
"8:0 Async 0\n"
"8:0 Total 0\n");
MAKE_FILE("blkio.io_service_bytes",
"8:0 Read 59542078464\n"
"8:0 Write 397369182208\n"
"8:0 Sync 234080922624\n"
"8:0 Async 222830338048\n"
"8:0 Total 456911260672\n");
MAKE_FILE("blkio.io_serviced",
"8:0 Read 3402504\n"
"8:0 Write 14966516\n"
"8:0 Sync 12064031\n"
"8:0 Async 6304989\n"
"8:0 Total 18369020\n");
MAKE_FILE("blkio.io_service_time",
"8:0 Read 10747537542349\n"
"8:0 Write 9200028590575\n"
"8:0 Sync 6449319855381\n"
"8:0 Async 13498246277543\n"
"8:0 Total 19947566132924\n");
MAKE_FILE("blkio.io_wait_time",
"8:0 Read 14687514824889\n"
"8:0 Write 357748452187691\n"
"8:0 Sync 55296974349413\n"
"8:0 Async 317138992663167\n"
"8:0 Total 372435967012580\n");
MAKE_FILE("blkio.reset_stats", ""); /* Write only */
MAKE_FILE("blkio.sectors", "8:0 892404806\n");
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");
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");
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.time", "8:0 61019089\n");
MAKE_FILE("blkio.weight", "1000\n");
MAKE_FILE("blkio.weight_device", "");
} else {
errno = EINVAL;
goto cleanup;
}
ret = 0;
cleanup:
return ret;
}
static void init_syms(void)
{
if (realfopen)
return;
# define LOAD_SYM(name) \
do { \
if (!(real ## name = dlsym(RTLD_NEXT, #name))) { \
fprintf(stderr, "Cannot find real '%s' symbol\n", #name); \
abort(); \
} \
} while (0)
# define LOAD_SYM_ALT(name1, name2) \
do { \
if (!(real ## name1 = dlsym(RTLD_NEXT, #name1)) && \
!(real ## name2 = dlsym(RTLD_NEXT, #name2))) { \
fprintf(stderr, "Cannot find real '%s' or '%s' symbol\n", #name1, #name2); \
abort(); \
} \
} while (0)
LOAD_SYM(fopen);
LOAD_SYM(access);
LOAD_SYM_ALT(lstat, __lxstat);
LOAD_SYM(mkdir);
LOAD_SYM(open);
}
static void init_sysfs(void)
{
if (fakesysfsdir)
return;
if (!(fakesysfsdir = getenv("LIBVIRT_FAKE_SYSFS_DIR"))) {
fprintf(stderr, "Missing LIBVIRT_FAKE_SYSFS_DIR env variable\n");
abort();
}
# define MAKE_CONTROLLER(subpath) \
do { \
char *path; \
if (asprintf(&path,"%s/%s", fakesysfsdir, subpath) < 0) \
abort(); \
if (make_controller(path, 0755) < 0) { \
fprintf(stderr, "Cannot initialize %s\n", path); \
abort(); \
} \
} while (0)
MAKE_CONTROLLER("cpu");
MAKE_CONTROLLER("cpuacct");
MAKE_CONTROLLER("cpu,cpuacct");
MAKE_CONTROLLER("cpu,cpuacct/system");
MAKE_CONTROLLER("cpuset");
MAKE_CONTROLLER("blkio");
MAKE_CONTROLLER("memory");
MAKE_CONTROLLER("freezer");
}
FILE *fopen(const char *path, const char *mode)
{
const char *mock;
bool allinone = false, logind = false;
init_syms();
mock = getenv("VIR_CGROUP_MOCK_MODE");
if (mock) {
if (STREQ(mock, "allinone"))
allinone = true;
else if (STREQ(mock, "logind"))
logind = true;
}
if (STREQ(path, "/proc/mounts")) {
if (STREQ(mode, "r")) {
if (allinone)
return fmemopen((void *)procmountsallinone,
strlen(procmountsallinone), mode);
else if (logind)
return fmemopen((void *)procmountslogind,
strlen(procmountslogind), mode);
else
return fmemopen((void *)procmounts, strlen(procmounts), mode);
} else {
errno = EACCES;
return NULL;
}
}
if (STREQ(path, "/proc/cgroups")) {
if (STREQ(mode, "r")) {
if (allinone)
return fmemopen((void *)proccgroupsallinone,
strlen(proccgroupsallinone), mode);
else if (logind)
return fmemopen((void *)proccgroupslogind,
strlen(proccgroupslogind), mode);
else
return fmemopen((void *)proccgroups, strlen(proccgroups), mode);
} else {
errno = EACCES;
return NULL;
}
}
if (STREQ(path, "/proc/self/cgroup")) {
if (STREQ(mode, "r")) {
if (allinone)
return fmemopen((void *)procselfcgroupsallinone,
strlen(procselfcgroupsallinone), mode);
else if (logind)
return fmemopen((void *)procselfcgroupslogind,
strlen(procselfcgroupslogind), mode);
else
return fmemopen((void *)procselfcgroups, strlen(procselfcgroups), mode);
} else {
errno = EACCES;
return NULL;
}
}
return realfopen(path, mode);
}
int access(const char *path, int mode)
{
int ret;
init_syms();
if (STRPREFIX(path, SYSFS_PREFIX)) {
init_sysfs();
char *newpath;
if (asprintf(&newpath, "%s/%s",
fakesysfsdir,
path + strlen(SYSFS_PREFIX)) < 0) {
errno = ENOMEM;
return -1;
}
ret = realaccess(newpath, mode);
free(newpath);
} else if (STREQ(path, "/proc/cgroups") ||
STREQ(path, "/proc/self/cgroup")) {
/* 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 = realaccess(path, mode);
}
return ret;
}
int __lxstat(int ver, const char *path, struct stat *sb)
{
int ret;
init_syms();
if (STRPREFIX(path, SYSFS_PREFIX)) {
init_sysfs();
char *newpath;
if (asprintf(&newpath, "%s/%s",
fakesysfsdir,
path + strlen(SYSFS_PREFIX)) < 0) {
errno = ENOMEM;
return -1;
}
ret = real__lxstat(ver, newpath, sb);
free(newpath);
} else {
ret = real__lxstat(ver, path, sb);
}
return ret;
}
int lstat(const char *path, struct stat *sb)
{
int ret;
init_syms();
if (STRPREFIX(path, SYSFS_PREFIX)) {
init_sysfs();
char *newpath;
if (asprintf(&newpath, "%s/%s",
fakesysfsdir,
path + strlen(SYSFS_PREFIX)) < 0) {
errno = ENOMEM;
return -1;
}
ret = reallstat(newpath, sb);
free(newpath);
} else {
ret = reallstat(path, sb);
}
return ret;
}
int mkdir(const char *path, mode_t mode)
{
int ret;
init_syms();
if (STRPREFIX(path, SYSFS_PREFIX)) {
init_sysfs();
char *newpath;
if (asprintf(&newpath, "%s/%s",
fakesysfsdir,
path + strlen(SYSFS_PREFIX)) < 0) {
errno = ENOMEM;
return -1;
}
ret = make_controller(newpath, mode);
free(newpath);
} else {
ret = realmkdir(path, mode);
}
return ret;
}
int open(const char *path, int flags, ...)
{
int ret;
char *newpath = NULL;
init_syms();
if (STRPREFIX(path, SYSFS_PREFIX)) {
init_sysfs();
if (asprintf(&newpath, "%s/%s",
fakesysfsdir,
path + strlen(SYSFS_PREFIX)) < 0) {
errno = ENOMEM;
return -1;
}
}
if (flags & O_CREAT) {
va_list ap;
mode_t mode;
va_start(ap, flags);
mode = va_arg(ap, mode_t);
va_end(ap);
ret = realopen(newpath ? newpath : path, flags, mode);
} else {
ret = realopen(newpath ? newpath : path, flags);
}
free(newpath);
return ret;
}
#else
/* Nothing to override on non-__linux__ platforms */
#endif
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