[CRIU] [PATCH 2/5] fifo: Add checkpoint restore for fifos
Cyrill Gorcunov
gorcunov at openvz.org
Tue Jun 26 04:07:19 EDT 2012
Checpoint and restore of fifo is similar to
pipes c/r except the pipe end-points are named
file.
Because the fifo has a name we use regular files
facility for fifo path c/r.
Still there is a trick used to "open" fifo:
the opening procedure migh sleep if a fifo's peer
is not yet opened, so before doing a real open
we yield a fake open procedure (with O_RDWR flag)
which prevents us from sleeping even if peer
is not yet ready.
Other than that -- nothing special.
Signed-off-by: Cyrill Gorcunov <gorcunov at openvz.org>
---
Makefile | 1 +
cr-dump.c | 9 ++-
cr-restore.c | 4 +
cr-show.c | 40 +++++++---
crtools.c | 2 +
fifo.c | 218 +++++++++++++++++++++++++++++++++++++++++++++++++++
files-reg.c | 8 --
include/crtools.h | 4 +
include/fifo.h | 10 +++
include/files-reg.h | 10 +++
include/image.h | 8 ++
11 files changed, 294 insertions(+), 20 deletions(-)
create mode 100644 fifo.c
create mode 100644 include/fifo.h
diff --git a/Makefile b/Makefile
index 3853028..2e8df3f 100644
--- a/Makefile
+++ b/Makefile
@@ -46,6 +46,7 @@ OBJS += sk-queue.o
OBJS += files.o
OBJS += files-reg.o
OBJS += pipes.o
+OBJS += fifo.o
OBJS += file-ids.o
OBJS += namespaces.o
OBJS += uts_ns.o
diff --git a/cr-dump.c b/cr-dump.c
index 0d8833e..4f66c51 100644
--- a/cr-dump.c
+++ b/cr-dump.c
@@ -37,6 +37,7 @@
#include "files.h"
#include "files-reg.h"
#include "pipes.h"
+#include "fifo.h"
#include "shmem.h"
#include "sk-inet.h"
#include "eventfd.h"
@@ -312,8 +313,12 @@ static int dump_one_file(pid_t pid, int fd, int lfd, char fd_flags,
if (S_ISREG(p.stat.st_mode) || S_ISDIR(p.stat.st_mode))
return dump_reg_file(&p, lfd, cr_fdset);
- if (S_ISFIFO(p.stat.st_mode) && (statfs.f_type == PIPEFS_MAGIC))
- return dump_pipe(&p, lfd, cr_fdset);
+ if (S_ISFIFO(p.stat.st_mode)) {
+ if (statfs.f_type == PIPEFS_MAGIC)
+ return dump_pipe(&p, lfd, cr_fdset);
+ else
+ return dump_fifo(&p, lfd, cr_fdset);
+ }
return dump_unsupp_fd(&p);
}
diff --git a/cr-restore.c b/cr-restore.c
index 79dadac..0459820 100644
--- a/cr-restore.c
+++ b/cr-restore.c
@@ -36,6 +36,7 @@
#include "files.h"
#include "files-reg.h"
#include "pipes.h"
+#include "fifo.h"
#include "sk-inet.h"
#include "eventfd.h"
#include "eventpoll.h"
@@ -301,6 +302,9 @@ static int prepare_shared(void)
if (collect_pipes())
return -1;
+ if (collect_fifo())
+ return -1;
+
if (collect_inet_sockets())
return -1;
diff --git a/cr-show.c b/cr-show.c
index 49f9588..c1de368 100644
--- a/cr-show.c
+++ b/cr-show.c
@@ -61,6 +61,7 @@ static char *fdtype2s(u8 type)
[FDINFO_REG] = "reg",
[FDINFO_INETSK] = "isk",
[FDINFO_PIPE] = "pipe",
+ [FDINFO_FIFO] = "fifo",
[FDINFO_UNIXSK] = "usk",
[FDINFO_EVENTFD] = "efd",
[FDINFO_EVENTPOLL] = "epl",
@@ -174,24 +175,23 @@ void show_ghost_file(int fd, struct cr_options *o)
pr_img_tail(CR_FD_GHOST_FILE);
}
-void show_pipes_data(int fd_pipes, struct cr_options *o)
+void __show_pipes_data(int fd, struct cr_options *o)
{
struct pipe_data_entry e;
- int ret;
-
- pr_img_head(CR_FD_PIPES_DATA);
while (1) {
- ret = read_img_eof(fd_pipes, &e);
- if (ret <= 0)
- goto out;
+ if (read_img_eof(fd, &e) <= 0)
+ break;
pr_msg("pipeid: 0x%8x bytes: 0x%8x off: 0x%8x\n",
e.pipe_id, e.bytes, e.off);
-
- lseek(fd_pipes, e.off + e.bytes, SEEK_CUR);
+ lseek(fd, e.off + e.bytes, SEEK_CUR);
}
+}
-out:
+void show_pipes_data(int fd_pipes, struct cr_options *o)
+{
+ pr_img_head(CR_FD_PIPES_DATA);
+ __show_pipes_data(fd_pipes, o);
pr_img_tail(CR_FD_PIPES_DATA);
}
@@ -216,6 +216,26 @@ out:
pr_img_tail(CR_FD_PIPES);
}
+void show_fifo_data(int fd, struct cr_options *o)
+{
+ pr_img_head(CR_FD_FIFO_DATA);
+ __show_pipes_data(fd, o);
+ pr_img_tail(CR_FD_FIFO_DATA);
+}
+
+void show_fifo(int fd, struct cr_options *o)
+{
+ struct fifo_entry e;
+
+ pr_img_head(CR_FD_FIFO);
+ while (1) {
+ if (read_img_eof(fd, &e) <= 0)
+ break;
+ pr_msg("id: 0x%8x pipeid: 0x%8x\n", e.id, e.pipe_id);
+ }
+ pr_img_tail(CR_FD_FIFO);
+}
+
void show_fs(int fd_fs, struct cr_options *o)
{
struct fs_entry fe;
diff --git a/crtools.c b/crtools.c
index d4d2305..c7c8c04 100644
--- a/crtools.c
+++ b/crtools.c
@@ -60,6 +60,8 @@ struct cr_fd_desc_tmpl fdset_template[CR_FD_MAX] = {
FD_ENTRY(VMAS, "vmas-%d", show_vmas),
FD_ENTRY(PIPES, "pipes", show_pipes),
FD_ENTRY(PIPES_DATA, "pipes-data", show_pipes_data),
+ FD_ENTRY(FIFO, "fifo", show_fifo),
+ FD_ENTRY(FIFO_DATA, "fifo-data", show_fifo_data),
FD_ENTRY(PSTREE, "pstree", show_pstree),
FD_ENTRY(SIGACT, "sigacts-%d", show_sigacts),
FD_ENTRY(UNIXSK, "unixsk", show_unixsk),
diff --git a/fifo.c b/fifo.c
new file mode 100644
index 0000000..92caa7d
--- /dev/null
+++ b/fifo.c
@@ -0,0 +1,218 @@
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdlib.h>
+
+#include "crtools.h"
+#include "image.h"
+#include "files.h"
+#include "files-reg.h"
+#include "pipes.h"
+
+#include "fifo.h"
+
+struct fifo_info {
+ struct list_head list;
+ struct file_desc d;
+ struct fifo_entry fe;
+
+ u32 bytes;
+ off_t off;
+};
+
+static LIST_HEAD(fifo_head);
+
+static int dump_one_fifo(int lfd, u32 id, const struct fd_parms *p)
+{
+ int img_data = fdset_fd(glob_fdset, CR_FD_FIFO_DATA);
+ int img = fdset_fd(glob_fdset, CR_FD_FIFO);
+ struct fifo_entry e;
+
+ /*
+ * It's a trick here, we use regular files dumping
+ * code to save path to a fifo, then we reuse it
+ * on restore.
+ */
+ if (dump_one_reg_file(lfd, id, p))
+ return -1;
+
+ pr_info("Dumping fifo %d with id %#x pipe_id %#x\n",
+ lfd, id, (u32)p->stat.st_ino);
+
+ e.id = id;
+ e.pipe_id = p->stat.st_ino;
+
+ if (write_img(img, &e) < 0)
+ return -1;
+
+ return dump_one_pipe_data(img_data, lfd, id, p);
+}
+
+static const struct fdtype_ops fifo_ops = {
+ .type = FDINFO_FIFO,
+ .make_gen_id = make_gen_id,
+ .dump = dump_one_fifo,
+};
+
+int dump_fifo(struct fd_parms *p, int lfd, const struct cr_fdset *set)
+{
+ return do_dump_gen_file(p, lfd, &fifo_ops, set);
+}
+
+static int open_fifo_fd(struct file_desc *d)
+{
+ struct fifo_info *info = container_of(d, struct fifo_info, d);
+ int new_fifo, fake_fifo = -1, img = -1;
+
+ struct reg_file_info *rfi;
+ struct file_desc *rd;
+
+ pr_info("\t\tCreating fifo pipe_id=%#x id=%#x\n",
+ info->fe.pipe_id, info->fe.id);
+
+ rd = find_file_desc_raw(FDINFO_REG, info->fe.id);
+ if (!rd) {
+ pr_perror("Can't find regfile for fifo %#x\n", info->fe.id);
+ return -1;
+ }
+
+ rfi = container_of(rd, struct reg_file_info, d);
+ if (!rfi->path) {
+ pr_err("Nil path found on regfile %#x for fifo %#x\n",
+ rfi->rfe.id, info->fe.id);
+ return -1;
+ }
+
+ if (rfi->remap_path) {
+ if (link(rfi->remap_path, rfi->path) < 0) {
+ pr_perror("Can't link %s -> %s\n",
+ rfi->remap_path, rfi->path);
+ return -1;
+ }
+ }
+
+ /*
+ * The fifos (except read-write fifos) do wait until
+ * another pipe-end get connected, so to be able to
+ * proceed the restoration procedure we open a fake
+ * fifo here.
+ */
+ fake_fifo = open(rfi->path, O_RDWR);
+ if (fake_fifo < 0) {
+ pr_perror("Can't open fake fifo %#08x [%s]",
+ info->fe.id, rfi->path);
+ return -1;
+ }
+
+ new_fifo = open(rfi->path, rfi->rfe.flags);
+ if (new_fifo < 0) {
+ pr_perror("Can't open fifo %#08x [%s]",
+ info->fe.id, rfi->path);
+ goto err_close_fake;
+ }
+
+ img = open_image_ro(CR_FD_FIFO_DATA);
+ if (img < 0)
+ goto err_close_new;
+
+ if (restore_pipe_data(img, fake_fifo, info->fe.id,
+ info->bytes, info->off))
+ goto err_unlink;
+
+ if (rfi->remap_path)
+ unlink(rfi->path);
+
+ if (restore_fown(new_fifo, &rfi->rfe.fown) < 0) {
+ pr_perror("Can't restore owner on fifo %#08x",
+ info->fe.id);
+ goto err_close_new;
+ }
+
+err_close_fake:
+ close_safe(&img);
+ close_safe(&fake_fifo);
+ return new_fifo;
+
+err_close_new:
+ close_safe(&new_fifo);
+ goto err_close_fake;
+
+err_unlink:
+ if (rfi->remap_path)
+ unlink(rfi->path);
+ goto err_close_new;
+}
+
+static struct file_desc_ops fifo_desc_ops = {
+ .type = FDINFO_FIFO,
+ .open = open_fifo_fd,
+};
+
+static int handle_fifo_data(void)
+{
+ int img, ret;
+
+ img = open_image_ro(CR_FD_FIFO_DATA);
+ if (img < 0)
+ return -1;
+
+ while (1) {
+ struct pipe_data_entry pde;
+ struct fifo_info *info;
+
+ ret = read_img_eof(img, &pde);
+ if (ret <= 0)
+ break;
+
+ list_for_each_entry(info, &fifo_head, list) {
+ if (info->fe.pipe_id != pde.pipe_id)
+ continue;
+
+ info->off = lseek(img, 0, SEEK_CUR) + pde.off;
+ info->bytes = pde.bytes;
+
+ lseek(img, pde.bytes + pde.off, SEEK_CUR);
+ break;
+ }
+ }
+
+ close(img);
+ return ret;
+}
+
+int collect_fifo(void)
+{
+ struct fifo_info *info = NULL;
+ int img, ret = -1;
+
+ img = open_image_ro(CR_FD_FIFO);
+ if (img < 0)
+ return -1;
+
+ while (1) {
+ info = xmalloc(sizeof(*info));
+ if (!info) {
+ ret = -1;
+ break;
+ }
+
+ ret = read_img_eof(img, &info->fe);
+ if (ret <= 0)
+ break;
+
+ pr_info("Collected fifo entry ID %#x PIPE ID %#x\n",
+ info->fe.id, info->fe.pipe_id);
+
+ file_desc_add(&info->d, info->fe.id, &fifo_desc_ops);
+ list_add(&info->list, &fifo_head);
+ }
+
+ if (!ret)
+ ret = handle_fifo_data();
+
+ xfree(info);
+ close(img);
+
+ return ret;
+}
diff --git a/files-reg.c b/files-reg.c
index 24e3be2..682c0e2 100644
--- a/files-reg.c
+++ b/files-reg.c
@@ -14,14 +14,6 @@
#include "files-reg.h"
-struct reg_file_info {
- struct file_desc d;
-
- struct reg_file_entry rfe;
- char *remap_path;
- char *path;
-};
-
struct ghost_file {
struct list_head list;
u32 id;
diff --git a/include/crtools.h b/include/crtools.h
index 4a7875d..7c8ce3b 100644
--- a/include/crtools.h
+++ b/include/crtools.h
@@ -54,6 +54,8 @@ enum {
CR_FD_UNIXSK,
CR_FD_PIPES,
CR_FD_PIPES_DATA,
+ CR_FD_FIFO,
+ CR_FD_FIFO_DATA,
CR_FD_REMAP_FPATH,
CR_FD_EVENTFD,
CR_FD_EVENTPOLL,
@@ -104,6 +106,8 @@ void show_mm(int fd_mm, struct cr_options *o);
void show_vmas(int fd_vma, struct cr_options *o);
void show_pipes(int fd_pipes, struct cr_options *o);
void show_pipes_data(int fd_pipes, struct cr_options *o);
+void show_fifo(int fd, struct cr_options *o);
+void show_fifo_data(int fd_pipes, struct cr_options *o);
void show_pstree(int fd_pstree, struct cr_options *o);
void show_sigacts(int fd_sigacts, struct cr_options *o);
void show_itimers(int fd, struct cr_options *o);
diff --git a/include/fifo.h b/include/fifo.h
new file mode 100644
index 0000000..031e7cf
--- /dev/null
+++ b/include/fifo.h
@@ -0,0 +1,10 @@
+#ifndef FIFO_H__
+#define FIFO_H__
+
+struct fd_parms;
+struct cr_fdset;
+
+extern int dump_fifo(struct fd_parms *p, int lfd, const struct cr_fdset *set);
+extern int collect_fifo(void);
+
+#endif /* FIFO_H__ */
diff --git a/include/files-reg.h b/include/files-reg.h
index 1dc5ff5..977d260 100644
--- a/include/files-reg.h
+++ b/include/files-reg.h
@@ -2,10 +2,20 @@
#define FILES_REG_H__
#include "types.h"
+#include "files.h"
+#include "image.h"
struct cr_fdset;
struct fd_parms;
+struct reg_file_info {
+ struct file_desc d;
+
+ struct reg_file_entry rfe;
+ char *remap_path;
+ char *path;
+};
+
extern int open_reg_by_id(u32 id);
extern void clear_ghost_files(void);
extern int collect_reg_files(void);
diff --git a/include/image.h b/include/image.h
index afd1561..238519d 100644
--- a/include/image.h
+++ b/include/image.h
@@ -17,6 +17,8 @@
#define VMAS_MAGIC 0x54123737 /* Tula */
#define PIPES_MAGIC 0x56513555 /* Tver */
#define PIPES_DATA_MAGIC 0x56453709 /* Dubna */
+#define FIFO_MAGIC 0x58364939 /* Kirov */
+#define FIFO_DATA_MAGIC 0x59333054 /* Tosno */
#define SIGACT_MAGIC 0x55344201 /* Murom */
#define UNIXSK_MAGIC 0x54373943 /* Ryazan */
#define INETSK_MAGIC 0x56443851 /* Pereslavl */
@@ -45,6 +47,7 @@ enum fd_types {
FDINFO_UND,
FDINFO_REG,
FDINFO_PIPE,
+ FDINFO_FIFO,
FDINFO_INETSK,
FDINFO_UNIXSK,
FDINFO_EVENTFD,
@@ -161,6 +164,11 @@ struct pipe_data_entry {
u8 data[0];
} __packed;
+struct fifo_entry {
+ u32 id;
+ u32 pipe_id;
+} __packed;
+
/*
* splice() connect cache pages to pipe buffer, so
* some part of pages may be loosed if data are not
--
1.7.7.6
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