[CRIU] [PATCH 1/2] cg: use one path style throughout cg restore code
Tycho Andersen
tycho.andersen at canonical.com
Mon Oct 6 07:03:29 PDT 2014
This commit is in preparation for the (hopefully last :) restore special cpuset
patch.
Previously, we installed the cgroup service fd after calling
prepare_cgroup_dirs, which meant that we had to carry around the temporary
directory name in order to put things in the right place. The
restore_cgroup_prop function uses the cg service fd instead of carrying around
the full path. This means that we can't sue restore_cgroup_prop, without first
sanitizing the path. Instead, we install the service fd before calling
prepare_cgroup_dirs, and all the code just references that instead of carrying
around the temporary path.
Signed-off-by: Tycho Andersen <tycho.andersen at canonical.com>
---
cgroup.c | 44 ++++++++++++++++++++++++++------------------
include/util.h | 2 +-
util.c | 4 ++--
3 files changed, 29 insertions(+), 21 deletions(-)
diff --git a/cgroup.c b/cgroup.c
index 29e373d..9fd739c 100644
--- a/cgroup.c
+++ b/cgroup.c
@@ -1153,10 +1153,12 @@ static int prepare_cgroup_dirs(char *paux, size_t off, CgroupDirEntry **ents, si
{
size_t i;
CgroupDirEntry *e;
+ int cg = get_service_fd(CGROUP_YARD);
for (i = 0; i < n_ents; i++) {
size_t off2 = off;
e = ents[i];
+ struct stat st;
off2 += sprintf(paux + off, "/%s", e->dir_name);
@@ -1165,12 +1167,13 @@ static int prepare_cgroup_dirs(char *paux, size_t off, CgroupDirEntry **ents, si
* it does exist, prevent us from overwriting the properties
* later by removing the CgroupDirEntry's properties.
*/
- if (access(paux, F_OK) < 0) {
+ if (fstatat(cg, paux, &st, 0) < 0) {
if (errno != ENOENT) {
pr_perror("Failed accessing file %s", paux);
return -1;
}
- if (mkdirp(paux)) {
+
+ if (mkdirpat(cg, paux)) {
pr_perror("Can't make cgroup dir %s", paux);
return -1;
}
@@ -1211,7 +1214,7 @@ static int prepare_cgroup_dirs(char *paux, size_t off, CgroupDirEntry **ents, si
static int prepare_cgroup_sfd(CgroupEntry *ce)
{
- int off, i;
+ int off, i, ret;
char paux[PATH_MAX];
pr_info("Preparing cgroups yard\n");
@@ -1238,11 +1241,24 @@ static int prepare_cgroup_sfd(CgroupEntry *ce)
goto err;
}
+ pr_debug("Opening %s as cg yard\n", cg_yard);
+ i = open(cg_yard, O_DIRECTORY);
+ if (i < 0) {
+ pr_perror("Can't open cgyard");
+ goto err;
+ }
+
+ ret = install_service_fd(CGROUP_YARD, i);
+ close(i);
+ if (ret < 0)
+ goto err;
+
+
paux[off++] = '/';
for (i = 0; i < ce->n_controllers; i++) {
- int ctl_off = off;
- char opt[128];
+ int ctl_off = off, yard_off;
+ char opt[128], *yard;
CgControllerEntry *ctrl = ce->controllers[i];
if (ctrl->n_cnames < 1) {
@@ -1265,24 +1281,16 @@ static int prepare_cgroup_sfd(CgroupEntry *ce)
goto err;
}
+ /* We skip over the .criu.cgyard.XXXXXX/, since those will be
+ * referred to by the cg yard service fd. */
+ yard = paux + strlen(cg_yard) + 1;
+ yard_off = ctl_off - (strlen(cg_yard) + 1);
if (opts.manage_cgroups &&
- prepare_cgroup_dirs(paux, ctl_off, ctrl->dirs, ctrl->n_dirs))
+ prepare_cgroup_dirs(yard, yard_off, ctrl->dirs, ctrl->n_dirs))
goto err;
}
- pr_debug("Opening %s as cg yard\n", cg_yard);
- i = open(cg_yard, O_DIRECTORY);
- if (i < 0) {
- pr_perror("Can't open cgyard");
- goto err;
- }
-
- off = install_service_fd(CGROUP_YARD, i);
- close(i);
- if (off < 0)
- goto err;
-
return 0;
err:
diff --git a/include/util.h b/include/util.h
index 717aeee..0816029 100644
--- a/include/util.h
+++ b/include/util.h
@@ -212,7 +212,7 @@ static inline bool strstartswith(const char *str, const char *sub)
/*
* mkdir -p
*/
-int mkdirp(const char *path);
+int mkdirpat(int fd, const char *path);
/*
* Tests whether a path is a prefix of another path. This is different than
diff --git a/util.c b/util.c
index 8283730..dd76863 100644
--- a/util.c
+++ b/util.c
@@ -687,7 +687,7 @@ struct vma_area *alloc_vma_area(void)
return p;
}
-int mkdirp(const char *path)
+int mkdirpat(int fd, const char *path)
{
size_t i;
char made_path[PATH_MAX], *pos;
@@ -707,7 +707,7 @@ int mkdirp(const char *path)
pos = strchr(made_path + i, '/');
if (pos)
*pos = '\0';
- if (mkdir(made_path, 0755) < 0 && errno != EEXIST) {
+ if (mkdirat(fd, made_path, 0755) < 0 && errno != EEXIST) {
pr_perror("couldn't mkdirpat directory %s", made_path);
return -1;
}
--
1.9.1
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