[hackers] [slock] Simplify the oom-taming-function || FRIGN

From: <git_AT_suckless.org>
Date: Sun, 14 Feb 2016 01:34:51 +0100 (CET)

commit 3abbffa4934a62146e995ee7c2cf3ba50991b4ad
Author: FRIGN <dev_AT_frign.de>
AuthorDate: Sun Feb 14 01:28:37 2016 +0100
Commit: FRIGN <dev_AT_frign.de>
CommitDate: Sun Feb 14 01:28:37 2016 +0100

    Simplify the oom-taming-function
    
    There really is no need to source a defined variable from a linux
    header. The OOM-rank ranges from -1000 to 1000, so we can safely
    hardcode -1000, which is a sane thing to do given slock is suid and
    we don't want to play around too much here anyway.
    
    On another notice, let's not forget that this still is a shitty
    heuristic. The OOM-killer still can kill us (thus I also changed
    the wording in the error-message. We do not disable the OOM-killer,
    we're just hiding.

diff --git a/slock.c b/slock.c
index cf49555..3188ff7 100644
--- a/slock.c
+++ b/slock.c
_AT_@ -60,28 +60,20 @@ die(const char *errstr, ...)
 
 #ifdef __linux__
 #include <fcntl.h>
-#include <linux/oom.h>
 
 static void
 dontkillme(void)
 {
         int fd;
- int length;
- char value[64];
 
         fd = open("/proc/self/oom_score_adj", O_WRONLY);
- if (fd < 0 && errno == ENOENT)
+ if (fd < 0 && errno == ENOENT) {
                 return;
-
- /* convert OOM_SCORE_ADJ_MIN to string for writing */
- length = snprintf(value, sizeof(value), "%d\n", OOM_SCORE_ADJ_MIN);
-
- /* bail on truncation */
- if (length >= sizeof(value))
- die("buffer too small\n");
-
- if (fd < 0 || write(fd, value, length) != length || close(fd) != 0)
- die("cannot disable the out-of-memory killer for this process (make sure to suid or sgid slock)\n");
+ }
+ if (fd < 0 || write(fd, "-1000\n", (sizeof("-1000\n") - 1)) !=
+ (sizeof("-1000\n") - 1) || close(fd) != 0) {
+ die("can't tame the oom-killer. is suid or sgid set?\n");
+ }
 }
 #endif
 
Received on Sun Feb 14 2016 - 01:34:51 CET