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sysctl: use raw file descriptor in sysctl_write (#7753)

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The kernel returns specific error codes which may be lost if we use the
libc buffered io functions.

Fixes: https://github.com/systemd/systemd/issues/7744
This commit is contained in:
Mike Gilbert 2017-12-30 06:16:49 -05:00 committed by Lennart Poettering
parent d31b0033b7
commit 521251d275
1 changed files with 16 additions and 1 deletions
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17
src/shared/sysctl-util.c
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@ -18,9 +18,13 @@
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include "fd-util.h"
#include "fileio.h"
#include "log.h"
#include "macro.h"
@ -53,6 +57,7 @@ char *sysctl_normalize(char *s) {
int sysctl_write(const char *property, const char *value) {
char *p;
_cleanup_close_ int fd = -1;
assert(property);
assert(value);
@ -60,7 +65,17 @@ int sysctl_write(const char *property, const char *value) {
log_debug("Setting '%s' to '%s'", property, value);
p = strjoina("/proc/sys/", property);
return write_string_file(p, value, WRITE_STRING_FILE_DISABLE_BUFFER);
fd = open(p, O_WRONLY|O_CLOEXEC);
if (fd < 0)
return -errno;
if (!endswith(value, "\n"))
value = strjoina(value, "\n");
if (write(fd, value, strlen(value)) < 0)
return -errno;
return 0;
}
int sysctl_read(const char *property, char **content) {