Slightly safer OOM killer disablement in linux

1 files changed, 12 insertions, 1 deletions

diff --git a/slock.c b/slock.c
index d6053af..b3bee92 100644
--- a/slock.c
+++ b/slock.c
@@ -60,16 +60,27 @@ 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)
                 return;
-        if (fd < 0 || write(fd, "-1000\n", 6) != 6 || close(fd) != 0)
+
+        /* 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\n");
 }
 #endif