[CRIU] [PATCH 4/5] files: save inherited file descriptors in fdstore
Andrei Vagin
avagin at openvz.org
Thu Sep 27 10:02:26 MSK 2018
From: Andrei Vagin <avagin at virtuozzo.com>
In this case:
* don't need to care whether they intercept with restored file
descriptors.
* they don't copied into each restored process
* don't need to close them one by one
Signed-off-by: Andrei Vagin <avagin at gmail.com>
---
criu/cr-restore.c | 9 +--
criu/files-reg.c | 4 ++
criu/files.c | 164 +++++++--------------------------------------------
criu/include/files.h | 3 +-
criu/util.c | 4 --
5 files changed, 30 insertions(+), 154 deletions(-)
diff --git a/criu/cr-restore.c b/criu/cr-restore.c
index 804a33f83..6086d6523 100644
--- a/criu/cr-restore.c
+++ b/criu/cr-restore.c
@@ -885,9 +885,6 @@ static int restore_one_alive_task(int pid, CoreEntry *core)
if (collect_zombie_pids(ta) < 0)
return -1;
- if (inherit_fd_fini() < 0)
- return -1;
-
if (prepare_proc_misc(pid, core->tc))
return -1;
@@ -1020,9 +1017,6 @@ static int restore_one_zombie(CoreEntry *core)
if (prepare_fds(current))
return -1;
- if (inherit_fd_fini() < 0)
- return -1;
-
if (lazy_pages_setup_zombie(vpid(current)))
return -1;
@@ -2410,6 +2404,9 @@ int cr_restore_tasks(void)
if (fdstore_init())
goto err;
+ if (inherit_fd_move_to_fdstore())
+ goto err;
+
if (crtools_prepare_shared() < 0)
goto err;
diff --git a/criu/files-reg.c b/criu/files-reg.c
index e3ed01f55..2404c89bc 100644
--- a/criu/files-reg.c
+++ b/criu/files-reg.c
@@ -1624,6 +1624,7 @@ int open_path(struct file_desc *d,
struct reg_file_info *rfi;
char *orig_path = NULL;
char path[PATH_MAX];
+ int inh_fd = -1;
if (inherited_fd(d, &tmp))
return tmp;
@@ -1633,6 +1634,7 @@ int open_path(struct file_desc *d,
if (rfi->rfe->ext) {
tmp = inherit_fd_lookup_id(rfi->rfe->name);
if (tmp >= 0) {
+ inh_fd = tmp;
mntns_root = open_pid_proc(PROC_SELF);
snprintf(path, sizeof(path), "fd/%d", tmp);
orig_path = rfi->path;
@@ -1691,8 +1693,10 @@ ext:
tmp = open_cb(mntns_root, rfi, arg);
if (tmp < 0) {
pr_perror("Can't open file %s", rfi->path);
+ close_safe(&inh_fd);
return -1;
}
+ close_safe(&inh_fd);
if ((rfi->rfe->has_size || rfi->rfe->has_mode) &&
!rfi->size_mode_checked) {
diff --git a/criu/files.c b/criu/files.c
index 115390f63..0f88912a4 100644
--- a/criu/files.c
+++ b/criu/files.c
@@ -45,6 +45,7 @@
#include "parasite.h"
#include "parasite-syscall.h"
#include "kerndat.h"
+#include "fdstore.h"
#include "protobuf.h"
#include "util.h"
@@ -1049,10 +1050,6 @@ static int send_fd_to_self(int fd, struct fdinfo_list_entry *fle)
if (fd == dfd)
return 0;
- /* make sure we won't clash with an inherit fd */
- if (inherit_fd_resolve_clash(dfd) < 0)
- return -1;
-
BUG_ON(dfd == get_service_fd(TRANSPORT_FD_OFF));
pr_info("\t\t\tGoing to dup %d into %d\n", fd, dfd);
@@ -1240,8 +1237,6 @@ splice:
return ret;
}
-static struct inherit_fd *inherit_fd_lookup_fd(int fd, const char *caller);
-
int close_old_fds(void)
{
DIR *dir;
@@ -1262,8 +1257,7 @@ int close_old_fds(void)
return -1;
}
- if ((!is_any_service_fd(fd)) && (dirfd(dir) != fd) &&
- !inherit_fd_lookup_fd(fd, __FUNCTION__))
+ if ((!is_any_service_fd(fd)) && (dirfd(dir) != fd))
close_safe(&fd);
}
@@ -1487,49 +1481,11 @@ struct inherit_fd {
struct list_head inh_list;
char *inh_id; /* file identifier */
int inh_fd; /* criu's descriptor to inherit */
- dev_t inh_dev;
- ino_t inh_ino;
- mode_t inh_mode;
- dev_t inh_rdev;
+ int inh_fd_id;
};
int inh_fd_max = -1;
-/*
- * Return 1 if inherit fd has been closed or reused, 0 otherwise.
- *
- * Some parts of the file restore engine can close an inherit fd
- * explicitly by close() or implicitly by dup2() to reuse that descriptor.
- * In some specific functions (for example, send_fd_to_self()), we
- * check for clashes at the beginning of the function and, therefore,
- * these specific functions will not reuse an inherit fd. However, to
- * avoid adding a ton of clash detect and resolve code everywhere we close()
- * and/or dup2(), we just make sure that when we're dup()ing or close()ing
- * our inherit fd we're still dealing with the same fd that we inherited.
- */
-static int inherit_fd_reused(struct inherit_fd *inh)
-{
- struct stat sbuf;
-
- if (fstat(inh->inh_fd, &sbuf) == -1) {
- if (errno == EBADF) {
- pr_debug("Inherit fd %s -> %d has been closed\n",
- inh->inh_id, inh->inh_fd);
- return 1;
- }
- pr_perror("Can't fstat inherit fd %d", inh->inh_fd);
- return -1;
- }
-
- if (inh->inh_dev != sbuf.st_dev || inh->inh_ino != sbuf.st_ino ||
- inh->inh_mode != sbuf.st_mode || inh->inh_rdev != sbuf.st_rdev) {
- pr_info("Inherit fd %s -> %d has been reused\n",
- inh->inh_id, inh->inh_fd);
- return 1;
- }
- return 0;
-}
-
/*
* We can't print diagnostics messages in this function because the
* log file isn't initialized yet.
@@ -1596,10 +1552,6 @@ int inherit_fd_add(int fd, char *key)
inh->inh_id = key;
inh->inh_fd = fd;
- inh->inh_dev = sbuf.st_dev;
- inh->inh_ino = sbuf.st_ino;
- inh->inh_mode = sbuf.st_mode;
- inh->inh_rdev = sbuf.st_rdev;
list_add_tail(&inh->inh_list, &opts.inherit_fds);
return 0;
}
@@ -1618,6 +1570,20 @@ void inherit_fd_log(void)
}
}
+int inherit_fd_move_to_fdstore(void)
+{
+ struct inherit_fd *inh;
+
+ list_for_each_entry(inh, &opts.inherit_fds, inh_list) {
+ inh->inh_fd_id = fdstore_add(inh->inh_fd);
+ if (inh->inh_fd_id < 0)
+ return -1;
+ close_safe(&inh->inh_fd);
+ }
+
+ return 0;
+}
+
/*
* Look up the inherit fd list by a file identifier.
*/
@@ -1629,11 +1595,9 @@ int inherit_fd_lookup_id(char *id)
ret = -1;
list_for_each_entry(inh, &opts.inherit_fds, inh_list) {
if (!strcmp(inh->inh_id, id)) {
- if (!inherit_fd_reused(inh)) {
- ret = inh->inh_fd;
- pr_debug("Found id %s (fd %d) in inherit fd list\n",
- id, ret);
- }
+ ret = fdstore_get(inh->inh_fd_id);
+ pr_debug("Found id %s (fd %d) in inherit fd list\n",
+ id, ret);
break;
}
}
@@ -1656,96 +1620,12 @@ bool inherited_fd(struct file_desc *d, int *fd_p)
if (fd_p == NULL)
return true;
- *fd_p = dup(i_fd);
- if (*fd_p < 0)
- pr_perror("Inherit fd DUP failed");
- else
- pr_info("File %s will be restored from fd %d dumped "
+ *fd_p = i_fd;
+ pr_info("File %s will be restored from fd %d dumped "
"from inherit fd %d\n", id_str, *fd_p, i_fd);
return true;
}
-/*
- * Look up the inherit fd list by a file descriptor.
- */
-static struct inherit_fd *inherit_fd_lookup_fd(int fd, const char *caller)
-{
- struct inherit_fd *ret;
- struct inherit_fd *inh;
-
- ret = NULL;
- list_for_each_entry(inh, &opts.inherit_fds, inh_list) {
- if (inh->inh_fd == fd) {
- if (!inherit_fd_reused(inh)) {
- ret = inh;
- pr_debug("Found fd %d (id %s) in inherit fd list (caller %s)\n",
- fd, inh->inh_id, caller);
- }
- break;
- }
- }
- return ret;
-}
-
-/*
- * If the specified fd clashes with an inherit fd,
- * move the inherit fd.
- */
-int inherit_fd_resolve_clash(int fd)
-{
- int newfd;
- struct inherit_fd *inh;
-
- inh = inherit_fd_lookup_fd(fd, __FUNCTION__);
- if (inh == NULL)
- return 0;
-
- newfd = dup(fd);
- if (newfd == -1) {
- pr_perror("Can't dup inherit fd %d", fd);
- return -1;
- }
-
- if (close(fd) == -1) {
- close(newfd);
- pr_perror("Can't close inherit fd %d", fd);
- return -1;
- }
-
- inh->inh_fd = newfd;
- pr_debug("Inherit fd %d moved to %d to resolve clash\n", fd, inh->inh_fd);
- return 0;
-}
-
-/*
- * Close all inherit fds.
- */
-int inherit_fd_fini()
-{
- int reused;
- struct inherit_fd *inh;
-
- list_for_each_entry(inh, &opts.inherit_fds, inh_list) {
- if (inh->inh_fd < 0) {
- pr_err("File %s in inherit fd list has invalid fd %d\n",
- inh->inh_id, inh->inh_fd);
- return -1;
- }
-
- reused = inherit_fd_reused(inh);
- if (reused < 0)
- return -1;
-
- if (!reused) {
- pr_debug("Closing inherit fd %d -> %s\n", inh->inh_fd,
- inh->inh_id);
- if (close_safe(&inh->inh_fd) < 0)
- return -1;
- }
- }
- return 0;
-}
-
int open_transport_socket(void)
{
pid_t pid = vpid(current);
diff --git a/criu/include/files.h b/criu/include/files.h
index 75757bd1d..2c1e1e723 100644
--- a/criu/include/files.h
+++ b/criu/include/files.h
@@ -190,8 +190,7 @@ extern int dump_unsupp_fd(struct fd_parms *p, int lfd,
extern int inherit_fd_parse(char *optarg);
extern int inherit_fd_add(int fd, char *key);
extern void inherit_fd_log(void);
-extern int inherit_fd_resolve_clash(int fd);
-extern int inherit_fd_fini(void);
+extern int inherit_fd_move_to_fdstore(void);
extern int inherit_fd_lookup_id(char *id);
diff --git a/criu/util.c b/criu/util.c
index 4b171b801..a2be58ab0 100644
--- a/criu/util.c
+++ b/criu/util.c
@@ -242,10 +242,6 @@ int reopen_fd_as_safe(char *file, int line, int new_fd, int old_fd, bool allow_r
int tmp;
if (old_fd != new_fd) {
- /* make sure we won't clash with an inherit fd */
- if (inherit_fd_resolve_clash(new_fd) < 0)
- return -1;
-
if (!allow_reuse_fd) {
if (fcntl(new_fd, F_GETFD) != -1 || errno != EBADF) {
pr_err("fd %d already in use (called at %s:%d)\n",
--
2.14.4
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