[CRIU] [PATCH] core: Implement xgetpid()
Kirill Tkhai
ktkhai at virtuozzo.com
Wed Mar 15 10:35:52 PDT 2017
GLibc's getpid() caches pids, and it's unreliable.
For example, the following program returns different
results between getpid() and syscall(__NR_getpid):
parent: pid=32369
parent: fork pid=32370
1)child: pid=32370
2)child: pid=32369
Fix that by using raw xgetpid() everywhere.
***
define _GNU_SOURCE
#include <sched.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/syscall.h>
#include <sys/mman.h>
#include <signal.h>
int child(void *a)
{
printf("1)child: pid=%d\n", syscall(__NR_getpid));
printf("2)child: pid=%d\n", getpid());
return 0;
}
int main(void)
{
int stack_size = 2 * 1024 * 1024;
char *stack = mmap(NULL, stack_size, PROT_WRITE | PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
pid_t pid;
if (stack == MAP_FAILED) {
perror("Can't allocate stack");
exit(1);
}
printf("parent: pid=%d\n", getpid());
pid = clone(child, stack + stack_size, CLONE_VM | CLONE_FILES | SIGCHLD, NULL);
printf("parent: fork pid=%d\n", pid);
}
Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
---
criu/action-scripts.c | 3 ++-
criu/autofs.c | 9 +++++----
criu/cgroup.c | 3 ++-
criu/cr-check.c | 9 +++++----
criu/cr-dump.c | 3 ++-
criu/cr-restore.c | 9 +++++----
criu/cr-service.c | 3 ++-
criu/files.c | 3 ++-
criu/image.c | 3 ++-
criu/include/libc-wrappers.h | 12 ++++++++++++
criu/kerndat.c | 3 ++-
criu/log.c | 5 +++--
criu/mount.c | 5 +++--
criu/namespaces.c | 7 ++++---
criu/pstree.c | 7 ++++---
criu/shmem.c | 3 ++-
criu/sk-unix.c | 3 ++-
criu/tty.c | 3 ++-
criu/util.c | 9 +++++----
criu/vdso.c | 2 +-
20 files changed, 67 insertions(+), 37 deletions(-)
create mode 100644 criu/include/libc-wrappers.h
diff --git a/criu/action-scripts.c b/criu/action-scripts.c
index 4fa8e2843..d5bab291a 100644
--- a/criu/action-scripts.c
+++ b/criu/action-scripts.c
@@ -3,6 +3,7 @@
#include <limits.h>
#include <stdlib.h>
+#include "libc-wrappers.h"
#include "cr_options.h"
#include "common/list.h"
#include "xmalloc.h"
@@ -62,7 +63,7 @@ static int run_shell_scripts(const char *action)
}
if (!(env_set & ENV_IMGDIR)) {
- sprintf(image_dir, "/proc/%ld/fd/%d", (long) getpid(), get_service_fd(IMG_FD_OFF));
+ sprintf(image_dir, "/proc/%ld/fd/%d", (long) xgetpid(), get_service_fd(IMG_FD_OFF));
if (setenv("CRTOOLS_IMAGE_DIR", image_dir, 1)) {
pr_perror("Can't set CRTOOLS_IMAGE_DIR=%s", image_dir);
return -1;
diff --git a/criu/autofs.c b/criu/autofs.c
index a436e9fa9..43349fb67 100644
--- a/criu/autofs.c
+++ b/criu/autofs.c
@@ -16,6 +16,7 @@
#include "crtools.h"
#include "util.h"
+#include "libc-wrappers.h"
#include "images/autofs.pb-c.h"
#define AUTOFS_OPT_UNKNOWN INT_MIN
@@ -295,7 +296,7 @@ static int autofs_revisit_options(struct mount_info *pm)
return -ENOMEM;
}
- f = fopen_proc(getpid(), "mountinfo");
+ f = fopen_proc(xgetpid(), "mountinfo");
if (!f)
goto free_str;
@@ -787,12 +788,12 @@ static int autofs_post_open(struct file_desc *d, int fd)
if (i->entry->has_read_fd) {
pr_info("%s: pid %d, closing write end %d\n", __func__,
- getpid(), i->entry->fd);
+ xgetpid(), i->entry->fd);
close(i->entry->fd);
}
pr_info("%s: pid %d, closing artificial pipe end %d\n", __func__,
- getpid(), fd);
+ xgetpid(), fd);
close(fd);
return 0;
}
@@ -940,7 +941,7 @@ static int autofs_add_mount_info(void *data)
if (entry->fd == -1)
/* Catatonic mounts have no owner. Keep them with init. */
- master = pstree_item_by_virt(getpid());
+ master = pstree_item_by_virt(xgetpid());
else
master = pstree_item_by_virt(entry->pgrp);
BUG_ON(!master);
diff --git a/criu/cgroup.c b/criu/cgroup.c
index a1b3eb23f..36f0cbd4e 100644
--- a/criu/cgroup.c
+++ b/criu/cgroup.c
@@ -23,6 +23,7 @@
#include "protobuf.h"
#include "images/core.pb-c.h"
#include "images/cgroup.pb-c.h"
+#include "libc-wrappers.h"
/*
* This structure describes set of controller groups
@@ -642,7 +643,7 @@ int dump_task_cgroup(const struct pstree_item *item, u32 *cg_id, struct parasite
if (item)
pid = item->pid->real;
else
- pid = getpid();
+ pid = xgetpid();
pr_info("Dumping cgroups for %d\n", pid);
if (parse_task_cgroup(pid, args, &ctls, &n_ctls))
diff --git a/criu/cr-check.c b/criu/cr-check.c
index c8261255f..ca5e8de6d 100644
--- a/criu/cr-check.c
+++ b/criu/cr-check.c
@@ -49,6 +49,7 @@
#include "cr_options.h"
#include "libnetlink.h"
#include "net.h"
+#include "libc-wrappers.h"
#include "linux/userfaultfd.h"
#include "restorer.h"
@@ -172,7 +173,7 @@ static int check_sock_peek_off(void)
static int check_kcmp(void)
{
- int ret = syscall(SYS_kcmp, getpid(), -1, -1, -1, -1);
+ int ret = syscall(SYS_kcmp, xgetpid(), -1, -1, -1, -1);
if (ret < 0 && errno == ENOSYS) {
pr_perror("System call kcmp is not supported");
@@ -266,7 +267,7 @@ static int check_proc_stat(void)
struct proc_pid_stat stat;
int ret;
- ret = parse_pid_stat(getpid(), &stat);
+ ret = parse_pid_stat(xgetpid(), &stat);
if (ret) {
pr_msg("procfs: stat extension is not supported\n");
return -1;
@@ -544,7 +545,7 @@ static int check_sigqueuinfo()
signal(SIGUSR1, SIG_IGN);
- if (syscall(SYS_rt_sigqueueinfo, getpid(), SIGUSR1, &info) < 0) {
+ if (syscall(SYS_rt_sigqueueinfo, xgetpid(), SIGUSR1, &info) < 0) {
pr_perror("Unable to send siginfo with positive si_code to itself");
return -1;
}
@@ -1135,7 +1136,7 @@ int cr_check(void)
if (root_item == NULL)
return -1;
- root_item->pid->real = getpid();
+ root_item->pid->real = xgetpid();
if (collect_pstree_ids())
return -1;
diff --git a/criu/cr-dump.c b/criu/cr-dump.c
index 5f1f668bb..be51b2095 100644
--- a/criu/cr-dump.c
+++ b/criu/cr-dump.c
@@ -32,6 +32,7 @@
#include "images/file-lock.pb-c.h"
#include "images/rlimit.pb-c.h"
#include "images/siginfo.pb-c.h"
+#include "libc-wrappers.h"
#include "common/list.h"
#include "imgset.h"
@@ -786,7 +787,7 @@ static int collect_pstree_ids_predump(void)
*/
crt.i.pid->state = TASK_ALIVE;
- crt.i.pid->real = getpid();
+ crt.i.pid->real = xgetpid();
if (predump_task_ns_ids(&crt.i))
return -1;
diff --git a/criu/cr-restore.c b/criu/cr-restore.c
index d0a970bc5..a9a4f3e4a 100644
--- a/criu/cr-restore.c
+++ b/criu/cr-restore.c
@@ -93,6 +93,7 @@
#include "images/rlimit.pb-c.h"
#include "images/pagemap.pb-c.h"
#include "images/siginfo.pb-c.h"
+#include "libc-wrappers.h"
#include "restore.h"
@@ -1200,7 +1201,7 @@ static void restore_sid(void)
exit(1);
}
} else {
- sid = getsid(getpid());
+ sid = getsid(xgetpid());
if (sid != current->sid) {
/* Skip the root task if it's not init */
if (current == root_item && vpid(root_item) != INIT_PID)
@@ -1300,7 +1301,7 @@ static int create_children_and_session(void)
if (!restore_before_setsid(child))
continue;
- BUG_ON(child->born_sid != -1 && getsid(getpid()) != child->born_sid);
+ BUG_ON(child->born_sid != -1 && getsid(xgetpid()) != child->born_sid);
ret = fork_with_pid(child);
if (ret < 0)
@@ -1348,7 +1349,7 @@ static int restore_task_with_children(void *_arg)
goto err;
}
- pid = getpid();
+ pid = xgetpid();
if (vpid(current) != pid) {
pr_err("Pid %d do not match expected %d\n", pid, vpid(current));
set_task_cr_err(EEXIST);
@@ -1737,7 +1738,7 @@ static int prepare_userns_hook(void)
* inside container due to permissions.
* But you still can set this value if it was unset.
*/
- saved_loginuid = parse_pid_loginuid(getpid(), &ret, false);
+ saved_loginuid = parse_pid_loginuid(xgetpid(), &ret, false);
if (ret < 0)
return -1;
diff --git a/criu/cr-service.c b/criu/cr-service.c
index 69e1a5557..5de91af0b 100644
--- a/criu/cr-service.c
+++ b/criu/cr-service.c
@@ -39,6 +39,7 @@
#include <sys/un.h>
#include <sys/socket.h>
#include "common/scm.h"
+#include "libc-wrappers.h"
#include "setproctitle.h"
@@ -1153,7 +1154,7 @@ int cr_service(bool daemon_mode)
}
if (opts.pidfile) {
- if (write_pidfile(getpid()) == -1) {
+ if (write_pidfile(xgetpid()) == -1) {
pr_perror("Can't write pidfile");
goto err;
}
diff --git a/criu/files.c b/criu/files.c
index d68c7057b..8124db4c8 100644
--- a/criu/files.c
+++ b/criu/files.c
@@ -48,6 +48,7 @@
#include "util.h"
#include "images/fs.pb-c.h"
#include "images/ext-file.pb-c.h"
+#include "libc-wrappers.h"
#include "plugin.h"
@@ -638,7 +639,7 @@ int restore_fown(int fd, FownEntry *fown)
{
struct f_owner_ex owner;
uid_t uids[3];
- pid_t pid = getpid();
+ pid_t pid = xgetpid();
if (fown->signum) {
if (fcntl(fd, F_SETSIG, fown->signum)) {
diff --git a/criu/image.c b/criu/image.c
index 57d3c7b5f..615b1cc2a 100644
--- a/criu/image.c
+++ b/criu/image.c
@@ -17,6 +17,7 @@
#include "images/inventory.pb-c.h"
#include "images/pagemap.pb-c.h"
#include "img-remote.h"
+#include "libc-wrappers.h"
bool ns_per_id = false;
bool img_common_magic = true;
@@ -135,7 +136,7 @@ int prepare_inventory(InventoryEntry *he)
}
crt.i.pid->state = TASK_ALIVE;
- crt.i.pid->real = getpid();
+ crt.i.pid->real = xgetpid();
if (get_task_ids(&crt.i))
return -1;
diff --git a/criu/include/libc-wrappers.h b/criu/include/libc-wrappers.h
new file mode 100644
index 000000000..d38875433
--- /dev/null
+++ b/criu/include/libc-wrappers.h
@@ -0,0 +1,12 @@
+#ifndef __LIBC_WRAPPERS
+#define __LIBC_WRAPPERS
+
+#include <sys/syscall.h>
+#include <unistd.h>
+
+static inline int xgetpid()
+{
+ return (int)syscall(__NR_getpid);
+}
+
+#endif
diff --git a/criu/kerndat.c b/criu/kerndat.c
index 162ac28bd..205014bf3 100644
--- a/criu/kerndat.c
+++ b/criu/kerndat.c
@@ -31,6 +31,7 @@
#include <compel/plugins/std/syscall-codes.h>
#include <compel/compel.h>
#include "linux/userfaultfd.h"
+#include "libc-wrappers.h"
struct kerndat_s kdat = {
};
@@ -289,7 +290,7 @@ int kerndat_get_dirty_track(void)
* was at least once re-set. (this is to be removed in
* a couple of kernel releases)
*/
- ret = do_task_reset_dirty_track(getpid());
+ ret = do_task_reset_dirty_track(xgetpid());
if (ret < 0)
return ret;
if (ret == 1)
diff --git a/criu/log.c b/criu/log.c
index a2beabdb0..77abdb4f5 100644
--- a/criu/log.c
+++ b/criu/log.c
@@ -20,6 +20,7 @@
#include "rst-malloc.h"
#include "common/lock.h"
#include "string.h"
+#include "libc-wrappers.h"
#define DEFAULT_LOGFD STDERR_FILENO
/* Enable timestamps if verbosity is increased from default */
@@ -182,14 +183,14 @@ int log_init_by_pid(void)
reset_buf_off();
if (!opts.log_file_per_pid) {
- buf_off += snprintf(buffer + buf_off, sizeof buffer - buf_off, "%6d: ", getpid());
+ buf_off += snprintf(buffer + buf_off, sizeof buffer - buf_off, "%6d: ", xgetpid());
return 0;
}
if (!opts.output)
return 0;
- snprintf(path, PATH_MAX, "%s.%d", opts.output, getpid());
+ snprintf(path, PATH_MAX, "%s.%d", opts.output, xgetpid());
return log_init(path);
}
diff --git a/criu/mount.c b/criu/mount.c
index 147001bcf..850d5bae3 100644
--- a/criu/mount.c
+++ b/criu/mount.c
@@ -28,6 +28,7 @@
#include "external.h"
#include "images/mnt.pb-c.h"
+#include "libc-wrappers.h"
/*
* Put a : in here since those are invalid on
@@ -1721,7 +1722,7 @@ static int apply_sb_flags(void *args, int fd, pid_t pid)
snprintf(path, sizeof(path), "/proc/self/fd/%d", fd);
- if (pid != getpid() && switch_ns(pid, &mnt_ns_desc, &rst))
+ if (pid != xgetpid() && switch_ns(pid, &mnt_ns_desc, &rst))
return -1;
err = mount(NULL, path, NULL, MS_REMOUNT | flags, NULL);
@@ -2429,7 +2430,7 @@ static int rst_collect_local_mntns(enum ns_type typ)
{
struct ns_id *nsid;
- nsid = rst_new_ns_id(0, getpid(), &mnt_ns_desc, typ);
+ nsid = rst_new_ns_id(0, xgetpid(), &mnt_ns_desc, typ);
if (!nsid)
return -1;
diff --git a/criu/namespaces.c b/criu/namespaces.c
index a4c3063db..b89e70c4b 100644
--- a/criu/namespaces.c
+++ b/criu/namespaces.c
@@ -33,6 +33,7 @@
#include "common/scm.h"
#include "fdstore.h"
#include "proc_parse.h"
+#include "libc-wrappers.h"
static struct ns_desc *ns_desc_array[] = {
&net_ns_desc,
@@ -402,7 +403,7 @@ static unsigned int generate_ns_id(int pid, unsigned int kid, struct ns_desc *nd
if (nsid)
goto found;
- if (pid != getpid()) {
+ if (pid != xgetpid()) {
type = NS_OTHER;
if (pid == root_item->pid->real) {
BUG_ON(root_ns_mask & nd->cflag);
@@ -1442,7 +1443,7 @@ static inline void unsc_msg_init(struct unsc_msg *m, uns_call_t *c,
ch->cmsg_type = SCM_CREDENTIALS;
ucred = (struct ucred *) CMSG_DATA(ch);
- ucred->pid = getpid();
+ ucred->pid = xgetpid();
ucred->uid = getuid();
ucred->gid = getgid();
@@ -1564,7 +1565,7 @@ int __userns_call(const char *func_name, uns_call_t call, int flags,
}
if (!usernsd_pid)
- return call(arg, fd, getpid());
+ return call(arg, fd, xgetpid());
sk = get_service_fd(USERNSD_SK);
pr_debug("uns: calling %s (%d, %x)\n", func_name, fd, flags);
diff --git a/criu/pstree.c b/criu/pstree.c
index f86b75a70..8d60d5349 100644
--- a/criu/pstree.c
+++ b/criu/pstree.c
@@ -22,6 +22,7 @@
#include "protobuf.h"
#include "images/pstree.pb-c.h"
#include "crtools.h"
+#include "libc-wrappers.h"
struct pstree_item *root_item;
static struct rb_root pid_root_rb;
@@ -333,8 +334,8 @@ int dump_pstree(struct pstree_item *root_item)
static int prepare_pstree_for_shell_job(void)
{
- pid_t current_sid = getsid(getpid());
- pid_t current_gid = getpgid(getpid());
+ pid_t current_sid = getsid(xgetpid());
+ pid_t current_gid = getpgid(xgetpid());
struct pstree_item *pi;
@@ -651,7 +652,7 @@ static int prepare_pstree_ids(void)
struct pstree_item *item, *child, *helper, *tmp;
LIST_HEAD(helpers);
- pid_t current_pgid = getpgid(getpid());
+ pid_t current_pgid = getpgid(xgetpid());
/*
* Some task can be reparented to init. A helper task should be added
diff --git a/criu/shmem.c b/criu/shmem.c
index 21a9d8b9e..568279977 100644
--- a/criu/shmem.c
+++ b/criu/shmem.c
@@ -25,6 +25,7 @@
#include "pstree.h"
#include "protobuf.h"
#include "images/pagemap.pb-c.h"
+#include "libc-wrappers.h"
#ifndef SEEK_DATA
#define SEEK_DATA 3
@@ -557,7 +558,7 @@ static int open_shmem(int pid, struct vma_area *vma)
}
if (f == -1) {
- f = open_proc_rw(getpid(), "map_files/%lx-%lx",
+ f = open_proc_rw(xgetpid(), "map_files/%lx-%lx",
(unsigned long) addr,
(unsigned long) addr + si->size);
if (f < 0)
diff --git a/criu/sk-unix.c b/criu/sk-unix.c
index a44d9985c..d17c759c9 100644
--- a/criu/sk-unix.c
+++ b/criu/sk-unix.c
@@ -31,6 +31,7 @@
#include "protobuf.h"
#include "images/sk-unix.pb-c.h"
+#include "libc-wrappers.h"
#undef LOG_PREFIX
#define LOG_PREFIX "sk unix: "
@@ -1005,7 +1006,7 @@ static int bind_unix_sk(int sk, struct unix_sk_info *ui)
pr_info("found duplicate unix socket bound at %s\n", addr.sun_path);
- ret = snprintf(temp, sizeof(temp), "%s-%s-%d", addr.sun_path, "criu-temp", getpid());
+ ret = snprintf(temp, sizeof(temp), "%s-%s-%d", addr.sun_path, "criu-temp", xgetpid());
/* this shouldn't happen, since sun_addr is only 108 chars long */
if (ret < 0 || ret >= sizeof(temp)) {
pr_err("snprintf of %s failed?\n", addr.sun_path);
diff --git a/criu/tty.c b/criu/tty.c
index 0ff690c82..523491e0b 100644
--- a/criu/tty.c
+++ b/criu/tty.c
@@ -37,6 +37,7 @@
#include "parasite-syscall.h"
#include "parasite.h"
+#include "libc-wrappers.h"
#include "pstree.h"
#include "fdstore.h"
@@ -714,7 +715,7 @@ int tty_restore_ctl_terminal(struct file_desc *d, int fd)
out:
pr_info("Restore session %d by %d tty (index %d)\n",
- info->tie->sid, (int)getpid(), index);
+ info->tie->sid, (int)xgetpid(), index);
ret = tty_set_sid(slave);
if (!ret)
diff --git a/criu/util.c b/criu/util.c
index 9fd8ba285..0945f1929 100644
--- a/criu/util.c
+++ b/criu/util.c
@@ -50,6 +50,7 @@
#include "cr_options.h"
#include "servicefd.h"
#include "cr-service.h"
+#include "libc-wrappers.h"
#include "files.h"
#include "cr-errno.h"
@@ -255,7 +256,7 @@ static inline void set_proc_self_fd(int fd)
close(open_proc_self_fd);
open_proc_self_fd = fd;
- open_proc_self_pid = getpid();
+ open_proc_self_pid = xgetpid();
}
static inline int set_proc_pid_fd(int pid, int fd)
@@ -275,7 +276,7 @@ static inline int set_proc_pid_fd(int pid, int fd)
static inline int get_proc_fd(int pid)
{
if (pid == PROC_SELF) {
- if (open_proc_self_fd != -1 && open_proc_self_pid != getpid()) {
+ if (open_proc_self_fd != -1 && open_proc_self_pid != xgetpid()) {
close(open_proc_self_fd);
open_proc_self_fd = -1;
}
@@ -399,7 +400,7 @@ int init_service_fd(void)
* conflict with any 'real-life' ones
*/
- if (syscall(__NR_prlimit64, getpid(), RLIMIT_NOFILE, NULL, &rlimit)) {
+ if (syscall(__NR_prlimit64, xgetpid(), RLIMIT_NOFILE, NULL, &rlimit)) {
pr_perror("Can't get rlimit");
return -1;
}
@@ -834,7 +835,7 @@ int vaddr_to_pfn(unsigned long vaddr, u64 *pfn)
off = (vaddr / page_size()) * sizeof(u64);
ret = pread(fd, pfn, sizeof(*pfn), off);
if (ret != sizeof(*pfn)) {
- pr_perror("Can't read pme for pid %d", getpid());
+ pr_perror("Can't read pme for pid %d", xgetpid());
ret = -1;
} else {
*pfn &= PME_PFRAME_MASK;
diff --git a/criu/vdso.c b/criu/vdso.c
index 770853514..68d7be046 100644
--- a/criu/vdso.c
+++ b/criu/vdso.c
@@ -380,7 +380,7 @@ static void compat_vdso_helper(struct vdso_symtable *native, int pipe_fd,
exit_on(-1, err_fd, "Error: Compatible vdso's size is bigger than reserved buf\n");
/* Stop so CRIU could parse smaps to find 32-bit vdso's size */
- ret = syscall(__NR_kill, syscall(__NR_getpid), SIGSTOP);
+ ret = syscall(__NR_kill, xgetpid(), SIGSTOP);
exit_on(ret, err_fd, "Error: Can't stop myself with SIGSTOP (having a good time)\n");
ret = syscall(__NR_read, pipe_fd, &vdso_addr, sizeof(void *));
More information about the CRIU
mailing list