- djm@cvs.openbsd.org 2010/01/30 02:54:53

[openssh.git] / openbsd-compat / port-linux.c

diff --git a/openbsd-compat/port-linux.c b/openbsd-compat/port-linux.c
index eea6b19b178071d38632a089465d3c6210214c0e..2f38072416e78e13585255ca90f3f85fe9006e9f 100644 (file)
--- a/openbsd-compat/port-linux.c
+++ b/openbsd-compat/port-linux.c
@@ -23,15 +23,17 @@
 
 #include "includes.h"
 
+#if defined(WITH_SELINUX) || defined(LINUX_OOM_ADJUST)
 #include <errno.h>
 #include <stdarg.h>
 #include <string.h>
+#include <stdio.h>
 
-#ifdef WITH_SELINUX
 #include "log.h"
 #include "xmalloc.h"
 #include "port-linux.h"
 
+#ifdef WITH_SELINUX
 #include <selinux/selinux.h>
 #include <selinux/flask.h>
 #include <selinux/get_context_list.h>
@@ -204,3 +206,60 @@ ssh_selinux_change_context(const char *newname)
        xfree(newctx);
 }
 #endif /* WITH_SELINUX */
+
+#ifdef LINUX_OOM_ADJUST
+#define OOM_ADJ_PATH   "/proc/self/oom_adj"
+/*
+ * The magic "don't kill me", as documented in eg:
+ * http://lxr.linux.no/#linux+v2.6.32/Documentation/filesystems/proc.txt
+ */
+#define OOM_ADJ_NOKILL -17
+
+static int oom_adj_save = INT_MIN;
+
+/*
+ * Tell the kernel's out-of-memory killer to avoid sshd.
+ * Returns the previous oom_adj value or zero.
+ */
+void
+oom_adjust_setup(void)
+{
+       FILE *fp;
+
+       debug3("%s", __func__);
+       if ((fp = fopen(OOM_ADJ_PATH, "r+")) != NULL) {
+               if (fscanf(fp, "%d", &oom_adj_save) != 1)
+                       logit("error reading %s: %s", OOM_ADJ_PATH, strerror(errno));
+               else {
+                       rewind(fp);
+                       if (fprintf(fp, "%d\n", OOM_ADJ_NOKILL) <= 0)
+                               logit("error writing %s: %s",
+                                   OOM_ADJ_PATH, strerror(errno));
+                       else
+                               verbose("Set %s from %d to %d",
+                                   OOM_ADJ_PATH, oom_adj_save, OOM_ADJ_NOKILL);
+               }
+               fclose(fp);
+       }
+}
+
+/* Restore the saved OOM adjustment */
+void
+oom_adjust_restore(void)
+{
+       FILE *fp;
+
+       debug3("%s", __func__);
+       if (oom_adj_save == INT_MIN || (fp = fopen(OOM_ADJ_PATH, "w")) == NULL)
+               return;
+
+       if (fprintf(fp, "%d\n", oom_adj_save) <= 0)
+               logit("error writing %s: %s", OOM_ADJ_PATH, strerror(errno));
+       else
+               verbose("Set %s to %d", OOM_ADJ_PATH, oom_adj_save);
+
+       fclose(fp);
+       return;
+}
+#endif /* LINUX_OOM_ADJUST */
+#endif /* WITH_SELINUX || LINUX_OOM_ADJUST */