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authorLennart Poettering <lennart@poettering.net>2014-08-15 11:55:43 +0200
committerLennart Poettering <lennart@poettering.net>2014-08-15 11:57:07 +0200
commit70c949a42b2b0d0c9a2a567890483940cdc5f72c (patch)
tree11bd2bc1e49e2e89e19528b669f5af04cea3a9d6 /src
parentce049dcda4a9d0c9a44667ca82bc9e21d7ea7748 (diff)
cgroup: never try to create files in cgroupfs, only open them for writing
This should have the benefit that cg_set_attribute() returns ENOENT instead of EACCESS when we use it for non-existing attributes.
Diffstat (limited to 'src')
-rw-r--r--src/shared/cgroup-util.c12
-rw-r--r--src/shared/fileio.c22
-rw-r--r--src/shared/fileio.h1
3 files changed, 29 insertions, 6 deletions
diff --git a/src/shared/cgroup-util.c b/src/shared/cgroup-util.c
index f683ae990e..e8cb9c73ac 100644
--- a/src/shared/cgroup-util.c
+++ b/src/shared/cgroup-util.c
@@ -643,7 +643,7 @@ int cg_attach(const char *controller, const char *path, pid_t pid) {
snprintf(c, sizeof(c), PID_FMT"\n", pid);
- return write_string_file(fs, c);
+ return write_string_file_no_create(fs, c);
}
int cg_attach_fallback(const char *controller, const char *path, pid_t pid) {
@@ -817,7 +817,7 @@ int cg_install_release_agent(const char *controller, const char *agent) {
sc = strstrip(contents);
if (sc[0] == 0) {
- r = write_string_file(fs, agent);
+ r = write_string_file_no_create(fs, agent);
if (r < 0)
return r;
} else if (!streq(sc, agent))
@@ -837,7 +837,7 @@ int cg_install_release_agent(const char *controller, const char *agent) {
sc = strstrip(contents);
if (streq(sc, "0")) {
- r = write_string_file(fs, "1");
+ r = write_string_file_no_create(fs, "1");
if (r < 0)
return r;
@@ -858,7 +858,7 @@ int cg_uninstall_release_agent(const char *controller) {
if (r < 0)
return r;
- r = write_string_file(fs, "0");
+ r = write_string_file_no_create(fs, "0");
if (r < 0)
return r;
@@ -869,7 +869,7 @@ int cg_uninstall_release_agent(const char *controller) {
if (r < 0)
return r;
- r = write_string_file(fs, "");
+ r = write_string_file_no_create(fs, "");
if (r < 0)
return r;
@@ -1591,7 +1591,7 @@ int cg_set_attribute(const char *controller, const char *path, const char *attri
if (r < 0)
return r;
- return write_string_file(p, value);
+ return write_string_file_no_create(p, value);
}
static const char mask_names[] =
diff --git a/src/shared/fileio.c b/src/shared/fileio.c
index cbb40c2379..18960abf02 100644
--- a/src/shared/fileio.c
+++ b/src/shared/fileio.c
@@ -58,6 +58,28 @@ int write_string_file(const char *fn, const char *line) {
return write_string_stream(f, line);
}
+int write_string_file_no_create(const char *fn, const char *line) {
+ _cleanup_fclose_ FILE *f = NULL;
+ int fd;
+
+ assert(fn);
+ assert(line);
+
+ /* We manually build our own version of fopen(..., "we") that
+ * without O_CREAT */
+ fd = open(fn, O_WRONLY|O_CLOEXEC|O_NOCTTY);
+ if (fd < 0)
+ return -errno;
+
+ f = fdopen(fd, "we");
+ if (!f) {
+ safe_close(fd);
+ return -errno;
+ }
+
+ return write_string_stream(f, line);
+}
+
int write_string_file_atomic(const char *fn, const char *line) {
_cleanup_fclose_ FILE *f = NULL;
_cleanup_free_ char *p = NULL;
diff --git a/src/shared/fileio.h b/src/shared/fileio.h
index 5122a9a4de..c256915799 100644
--- a/src/shared/fileio.h
+++ b/src/shared/fileio.h
@@ -27,6 +27,7 @@
int write_string_stream(FILE *f, const char *line);
int write_string_file(const char *fn, const char *line);
+int write_string_file_no_create(const char *fn, const char *line);
int write_string_file_atomic(const char *fn, const char *line);
int read_one_line_file(const char *fn, char **line);