mir/criu
2
0
Fork 0
mirror of https://github.com/checkpoint-restore/criu synced 2025-08-29 13:28:27 +00:00
Code Issues Releases Wiki Activity

pipe: don't reopen pipes via /proc, if it's not required

Browse Source 
The system call open can add O_LARGEFILE.

A point is reopend for unsharing a file descriptor. So here are two
types of points. One is returned by pipe() and all other ones are
got via opening /proc/PID/fd.

Currently I know only one difference between these types, it's
O_LARGEFILE.

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Tested-by: Alexander Kartashov <alekskartashov@parallels.com
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
This commit is contained in:
Andrey Vagin 2013-03-19 23:00:59 +04:00 committed by Pavel Emelyanov
parent 74053de77d
commit f2664d6524
2 changed files with 48 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

55
pipes.c
View File

@ -28,7 +28,8 @@ struct pipe_info {
* This is pure circular list without head */
struct list_head list; /* list head for fdinfo_list_entry-s */
struct file_desc d;
int create;
unsigned int create : 1,
reopen : 1;
};
static LIST_HEAD(pipes);
@ -117,6 +118,7 @@ void mark_pipe_master(void)
while (1) {
struct fdinfo_list_entry *fle;
struct pipe_info *pi, *pic, *p;
struct pipe_info *pr = NULL, *pw = NULL;
if (list_empty(&pipes))
break;
@ -129,6 +131,15 @@ void mark_pipe_master(void)
fle = file_master(&pi->d);
p = pi;
if (!(pi->pe->flags & O_LARGEFILE)) {
if (pi->pe->flags & O_WRONLY) {
if (pw == NULL)
pw = pi;
} else {
if (pr == NULL)
pr = pi;
}
}
list_for_each_entry(pic, &pi->pipe_list, pipe_list) {
struct fdinfo_list_entry *f;
@ -140,9 +151,23 @@ void mark_pipe_master(void)
fle = f;
}
if (!(pic->pe->flags & O_LARGEFILE)) {
if (pic->pe->flags & O_WRONLY) {
if (pw == NULL)
pw = pic;
} else {
if (pr == NULL)
pr = pic;
}
}
show_saved_pipe_fds(pic);
}
p->create = 1;
if (pr)
pr->reopen = 0;
if (pw)
pw->reopen = 0;
pr_info(" by %#x\n", p->pe->id);
}
@ -222,10 +247,22 @@ err:
return ret;
}
static int reopen_pipe(int fd, int flags, struct pipe_info *pi)
{
int ret;
char path[32];
pr_err("%s %p %d\n", __func__, pi, fd);
snprintf(path, sizeof(path), "/proc/self/fd/%d", fd);
ret = open(path, flags);
close(fd);
return ret;
}
static int recv_pipe_fd(struct pipe_info *pi)
{
struct fdinfo_list_entry *fle;
char path[32];
int tmp, fd;
fle = file_master(&pi->d);
@ -240,12 +277,12 @@ static int recv_pipe_fd(struct pipe_info *pi)
}
close(fd);
snprintf(path, sizeof(path), "/proc/self/fd/%d", tmp);
fd = open(path, pi->pe->flags);
close(tmp);
if (pi->reopen)
fd = reopen_pipe(tmp, pi->pe->flags, pi);
else
fd = tmp;
if (fd >= 0) {
if (restore_fown(fd, pi->pe->fown)) {
if (rst_file_params(fd, pi->pe->fown, pi->pe->flags)) {
close(fd);
return -1;
}
@ -302,6 +339,9 @@ static int open_pipe(struct file_desc *d)
close(pfd[!(pi->pe->flags & O_WRONLY)]);
tmp = pfd[pi->pe->flags & O_WRONLY];
if (pi->reopen)
tmp = reopen_pipe(tmp, pi->pe->flags, pi);
if (rst_file_params(tmp, pi->pe->fown, pi->pe->flags))
return -1;
@ -329,6 +369,7 @@ static int collect_one_pipe(void *o, ProtobufCMessage *base)
pi->pe = pb_msg(base, PipeEntry);
pi->create = 0;
pi->reopen = 1;
pr_info("Collected pipe entry ID %#x PIPE ID %#x\n",
pi->pe->id, pi->pe->pipe_id);

10
test/zdtm/live/static/file_fown.c
View File

@ -40,16 +40,6 @@ static void fill_pipe_params(struct params *p, int *pipes)
p->pipe_flags[0] = fcntl(pipes[0], F_GETFL);
p->pipe_flags[1] = fcntl(pipes[1], F_GETFL);
/*
* The kernel's O_LARGEFILE set automatically
* on open() in x86-64, so unmask it explicitly
* we restore pipes via open call while the former
* pipes are created with pipe() and have no O_LARGEFILE
* set.
*/
p->pipe_flags[0] &= ~00100000;
p->pipe_flags[1] &= ~00100000;
test_msg("pipe_flags0 %08o\n", p->pipe_flags[0]);
test_msg("pipe_flags1 %08o\n", p->pipe_flags[1]);