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crtools: Make fdset operations robust against open() errors

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There are two cases for cr_fdset_open

 - It might be called with already allocated
   memory so we should reuse it.

 - It might be called with NULL pointing out
   that caller expects us to allocate memory.

If an open() error happens somewhere inside cr_fdset_open
it requires two error paths

 - Just close all files opened but don't free memory
   if it was not allocated by us

 - Close all files opened *and* free memory allocated
   by us.

In any case we should close all files opened so close_cr_fdset()
helper is splitted into two parts.

Also the caller should be ready for such semantics as well and
do not re-assign pointers obtained but simply test for NULL
on results.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
This commit is contained in:
Cyrill Gorcunov
2012-01-31 18:26:51 +04:00
parent 6c1e5978c4
commit 7705df5397
2 changed files with 55 additions and 38 deletions
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85
crtools.c
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@@ -123,22 +123,55 @@ static struct cr_fdset *alloc_cr_fdset(void)
return cr_fdset;
}
void __close_cr_fdset(struct cr_fdset *cr_fdset)
{
unsigned int i;
if (!cr_fdset)
return;
for (i = 0; i < CR_FD_MAX; i++) {
if (cr_fdset->fds[i] == -1)
continue;
pr_debug("Closed %d/%d\n", i, cr_fdset->fds[i]);
close_safe(&cr_fdset->fds[i]);
cr_fdset->fds[i] = -1;
}
}
void close_cr_fdset(struct cr_fdset **cr_fdset)
{
if (!cr_fdset || !*cr_fdset)
return;
__close_cr_fdset(*cr_fdset);
xfree(*cr_fdset);
*cr_fdset = NULL;
}
struct cr_fdset *cr_fdset_open(int pid, unsigned long use_mask, struct cr_fdset *cr_fdset)
{
struct cr_fdset *fdset;
unsigned int i;
int ret = -1;
char path[PATH_MAX];
if (cr_fdset == NULL) {
cr_fdset = alloc_cr_fdset();
if (!cr_fdset)
/*
* We either reuse existing fdset or create new one.
*/
if (!cr_fdset) {
fdset = alloc_cr_fdset();
if (!fdset)
goto err;
}
} else
fdset = cr_fdset;
for (i = 0; i < CR_FD_MAX; i++) {
if (!(use_mask & CR_FD_DESC_USE(i)))
continue;
if (cr_fdset->fds[i] != -1)
if (fdset->fds[i] != -1)
continue;
ret = get_image_path(path, sizeof(path),
@@ -157,15 +190,21 @@ struct cr_fdset *cr_fdset_open(int pid, unsigned long use_mask, struct cr_fdset
pr_perror("Unable to open %s", path);
goto err;
}
fdset->fds[i] = ret;
pr_debug("Opened %s with %d\n", path, ret);
if (write_img(ret, &fdset_template[i].magic))
goto err;
cr_fdset->fds[i] = ret;
}
return fdset;
err:
return cr_fdset;
if (fdset != cr_fdset)
__close_cr_fdset(fdset);
else
close_cr_fdset(&fdset);
return NULL;
}
struct cr_fdset *prep_cr_fdset_for_restore(int pid, unsigned long use_mask)
@@ -194,43 +233,23 @@ struct cr_fdset *prep_cr_fdset_for_restore(int pid, unsigned long use_mask)
pr_perror("Unable to open %s", path);
goto err;
}
cr_fdset->fds[i] = ret;
pr_debug("Opened %s with %d\n", path, ret);
if (read_img(ret, &magic) < 0)
goto err;
if (magic != fdset_template[i].magic) {
close(ret);
pr_err("Magic doesn't match for %s\n", path);
goto err;
}
cr_fdset->fds[i] = ret;
}
err:
return cr_fdset;
}
void close_cr_fdset(struct cr_fdset **cr_fdset)
{
struct cr_fdset *fdset;
unsigned int i;
if (!cr_fdset || !*cr_fdset)
return;
fdset = *cr_fdset;
for (i = 0; i < CR_FD_MAX; i++) {
if (fdset->fds[i] == -1)
continue;
pr_debug("Closed %d/%d\n", i, fdset->fds[i]);
close(fdset->fds[i]);
fdset->fds[i] = -1;
}
xfree(fdset);
*cr_fdset = NULL;
err:
close_cr_fdset(&cr_fdset);
return NULL;
}
int main(int argc, char *argv[])