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authorIago López Galeiras <iago@endocode.com>2015-05-13 15:45:49 +0200
committerLennart Poettering <lennart@poettering.net>2015-05-13 16:03:07 +0200
commit875e1014dd9d55cd0692dcce843598cffb2d09b0 (patch)
tree56dc288f358172ede7ab92d9b3fab5e409d3cdfd
parent54b4755f15438c86991d5a4eaadc47150f7e5a84 (diff)
nspawn: skip symlink to a combined cgroup hierarchy if it already exists
If a symlink to a combined cgroup hierarchy already exists and points to the right path, skip it. This avoids an error when the cgroups are set manually before calling nspawn.
-rw-r--r--src/nspawn/nspawn.c10
-rw-r--r--src/shared/util.c22
-rw-r--r--src/shared/util.h1
3 files changed, 30 insertions, 3 deletions
diff --git a/src/nspawn/nspawn.c b/src/nspawn/nspawn.c
index 1ba55932bf..fbf23440f7 100644
--- a/src/nspawn/nspawn.c
+++ b/src/nspawn/nspawn.c
@@ -1325,7 +1325,6 @@ static int mount_cgroup(const char *dest) {
if (r < 0)
return log_error_errno(r, "Failed to determine our own cgroup path: %m");
-
for (;;) {
_cleanup_free_ char *controller = NULL, *origin = NULL, *combined = NULL;
@@ -1365,8 +1364,13 @@ static int mount_cgroup(const char *dest) {
if (r < 0)
return r;
- if (symlink(combined, target) < 0)
- return log_error_errno(errno, "Failed to create symlink for combined hierarchy: %m");
+ r = symlink_idempotent(combined, target);
+ if (r == -EINVAL) {
+ log_error("Invalid existing symlink for combined hierarchy");
+ return r;
+ }
+ if (r < 0)
+ return log_error_errno(r, "Failed to create symlink for combined hierarchy: %m");
}
}
diff --git a/src/shared/util.c b/src/shared/util.c
index 466dce439f..72711e133a 100644
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -2765,6 +2765,28 @@ int symlink_atomic(const char *from, const char *to) {
return 0;
}
+int symlink_idempotent(const char *from, const char *to) {
+ _cleanup_free_ char *p = NULL;
+ int r;
+
+ assert(from);
+ assert(to);
+
+ if (symlink(from, to) < 0) {
+ if (errno != EEXIST)
+ return -errno;
+
+ r = readlink_malloc(to, &p);
+ if (r < 0)
+ return r;
+
+ if (!streq(p, from))
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
int mknod_atomic(const char *path, mode_t mode, dev_t dev) {
_cleanup_free_ char *t = NULL;
int r;
diff --git a/src/shared/util.h b/src/shared/util.h
index 4a67d5c716..8565fd6e48 100644
--- a/src/shared/util.h
+++ b/src/shared/util.h
@@ -404,6 +404,7 @@ bool machine_name_is_valid(const char *s) _pure_;
char* strshorten(char *s, size_t l);
+int symlink_idempotent(const char *from, const char *to);
int symlink_atomic(const char *from, const char *to);
int mknod_atomic(const char *path, mode_t mode, dev_t dev);