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memfd: don't set fd attributes not needed for vma mapping

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There is only one user of memfd_open() outside of memfd.c: open_filemap().
It is restoring a file-backed mapping and doesn't need nor expect to
update F_SETOWN nor the fd's position.  Check the inherited_fd() handling
in the callers to simplify the code.

Signed-off-by: Michał Mirosław <emmir@google.com>
This commit is contained in:
Michał Mirosław 2023-08-24 21:07:51 +02:00 • committed by Andrei Vagin
parent 8c17535f3f
commit 0085f992cb
2 changed files with 25 additions and 24 deletions
Download patch file Download diff file Expand all files Collapse all files

3
criu/files-reg.c
View file

@ -2508,7 +2508,8 @@ static int open_filemap(int pid, struct vma_area *vma)
*/
ret = dup(plugin_fd);
} else if (vma->e->status & VMA_AREA_MEMFD) {
ret = memfd_open(vma->vmfd, &flags);
if (!inherited_fd(vma->vmfd, &ret))
ret = memfd_open(vma->vmfd, &flags);
} else {
ret = open_path(vma->vmfd, do_open_reg_noseek_flags, &flags);
}

46
criu/memfd.c
View file

@ -331,14 +331,11 @@ int memfd_open(struct file_desc *d, u32 *fdflags)
mfi = container_of(d, struct memfd_info, d);
mfe = mfi->mfe;
if (inherited_fd(d, &fd))
return fd;
pr_info("Restoring memfd id=%d\n", mfe->id);
fd = memfd_open_inode(mfi->inode);
if (fd < 0)
goto err;
return -1;
/* Reopen the fd with original permissions */
flags = fdflags ? *fdflags : mfe->flags;
@ -348,40 +345,43 @@ int memfd_open(struct file_desc *d, u32 *fdflags)
* important though.
*/
_fd = __open_proc(PROC_SELF, 0, flags, "fd/%d", fd);
if (_fd < 0) {
if (_fd < 0)
pr_perror("Can't reopen memfd id=%d", mfe->id);
goto err;
}
close(fd);
fd = _fd;
return _fd;
}
static int memfd_open_fe_fd(struct file_desc *d, int *new_fd)
{
MemfdFileEntry *mfe;
int fd;
if (inherited_fd(d, new_fd))
return 0;
fd = memfd_open(d, NULL);
if (fd < 0)
return -1;
mfe = container_of(d, struct memfd_info, d)->mfe;
if (restore_fown(fd, mfe->fown) < 0)
goto err;
if (lseek(fd, mfe->pos, SEEK_SET) < 0) {
pr_perror("Can't restore file position of memfd id=%d", mfe->id);
pr_perror("Can't restore file position of %d for memfd id=%d", fd, mfe->id);
goto err;
}
return fd;
*new_fd = fd;
return 0;
err:
if (fd >= 0)
close(fd);
close(fd);
return -1;
}
static int memfd_open_fe_fd(struct file_desc *fd, int *new_fd)
{
int tmp;
tmp = memfd_open(fd, NULL);
if (tmp < 0)
return -1;
*new_fd = tmp;
return 0;
}
static char *memfd_d_name(struct file_desc *d, char *buf, size_t s)
{
MemfdInodeEntry *mie = NULL;