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memfd: add --inherit-fd support

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Upon file restore, inherited_fd() is called to check for a user-defined
inerit-fd override. Note that the MEMFD_INODE image is read at each
invocation (memfd name is not cached).

Signed-off-by: Nicolas Viennot <Nicolas.Viennot@twosigma.com>
This commit is contained in:
Nicolas Viennot
2019-12-18 23:32:32 +00:00
committed by Andrei Vagin
parent 875ac4d03f
commit b25684e24a
2 changed files with 37 additions and 0 deletions
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1
criu/crtools.c
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@@ -392,6 +392,7 @@ usage:
" pipe[inode]\n"
" socket[inode]\n"
" file[mnt_id:inode]\n"
" /memfd:name\n"
" path/to/file\n"
" --empty-ns net Create a namespace, but don't restore its properties\n"
" (assuming it will be restored by action scripts)\n"

36
criu/memfd.c
View File

@@ -276,6 +276,9 @@ static 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);
@@ -325,9 +328,42 @@ static int memfd_open_fe_fd(struct file_desc *fd, int *new_fd)
return 0;
}
static char *memfd_d_name(struct file_desc *d, char *buf, size_t s)
{
MemfdInodeEntry *mie = NULL;
struct cr_img *img = NULL;
struct memfd_info *mfi;
char *ret = NULL;
mfi = container_of(d, struct memfd_info, d);
img = open_image(CR_FD_MEMFD_INODE, O_RSTR, mfi->inode->id);
if (!img)
goto out;
if (pb_read_one(img, &mie, PB_MEMFD_INODE) < 0)
goto out;
if (snprintf(buf, s, "%s%s", MEMFD_PREFIX, mie->name) >= s) {
pr_err("Buffer too small for memfd name %s\n", mie->name);
goto out;
}
ret = buf;
out:
if (img)
close_image(img);
if (mie)
memfd_inode_entry__free_unpacked(mie, NULL);
return ret;
}
static struct file_desc_ops memfd_desc_ops = {
.type = FD_TYPES__MEMFD,
.open = memfd_open_fe_fd,
.name = memfd_d_name,
};
static int collect_one_memfd(void *o, ProtobufCMessage *msg, struct cr_img *i)