Restore OOM killer adjustment for child processes (thanks, Vaclav Ovsik;

closes: #480020).

2 files changed, 60 insertions, 2 deletions

diff --git a/openbsd-compat/port-linux.c b/openbsd-compat/port-linux.c
index 485929133..a9aa773ef 100644
--- a/openbsd-compat/port-linux.c
+++ b/openbsd-compat/port-linux.c
@@ -18,7 +18,7 @@
  */
 
 /*
- * Linux-specific portability code - just SELinux support at present
+ * Linux-specific portability code
  */
 
 #include "includes.h"
@@ -27,11 +27,19 @@
 #include <stdarg.h>
 #include <string.h>
 
+#ifdef OOM_ADJUST
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#endif
+
+#include "log.h"
+
 #ifdef WITH_SELINUX
 #include "key.h"
 #include "hostfile.h"
 #include "auth.h"
-#include "log.h"
 #ifdef HAVE_GETSEUSERBYNAME
 #include "xmalloc.h"
 #endif
@@ -186,3 +194,47 @@ ssh_selinux_setup_pty(char *pwname, const char *tty)
         debug3("%s: done", __func__);
 }
 #endif /* WITH_SELINUX */
+
+#ifdef OOM_ADJUST
+/* Get the out-of-memory adjustment file for the current process */
+int
+oom_adj_open(void)
+{
+        int fd = open("/proc/self/oom_adj", O_RDWR);
+        if (fd < 0)
+                logit("error opening /proc/self/oom_adj: %s", strerror(errno));
+        return fd;
+}
+
+/* Get the current OOM adjustment */
+int
+oom_adj_get(char *buf, size_t maxlen)
+{
+        ssize_t n;
+        int fd = oom_adj_open();
+        if (fd < 0)
+                return -1;
+        n = read(fd, buf, maxlen);
+        if (n < 0)
+                logit("error reading /proc/self/oom_adj: %s", strerror(errno));
+        else
+                buf[n] = '\0';
+        close(fd);
+        return n < 0 ? -1 : 0;
+}
+
+/* Set the current OOM adjustment */
+int
+oom_adj_set(const char *buf)
+{
+        ssize_t n;
+        int fd = oom_adj_open();
+        if (fd < 0)
+                return -1;
+        n = write(fd, buf, strlen(buf));
+        if (n < 0)
+                logit("error writing /proc/self/oom_adj: %s", strerror(errno));
+        close(fd);
+        return n < 0 ? -1 : 0;
+}
+#endif
diff --git a/openbsd-compat/port-linux.h b/openbsd-compat/port-linux.h
index 05e520e1c..cb8a253c4 100644
--- a/openbsd-compat/port-linux.h
+++ b/openbsd-compat/port-linux.h
@@ -24,4 +24,10 @@ void ssh_selinux_setup_pty(char *, const char *);
 void ssh_selinux_setup_exec_context(char *);
 #endif
 
+#ifdef OOM_ADJUST
+int oom_adj_open(void);
+int oom_adj_get(char *buf, size_t maxlen);
+int oom_adj_set(const char *buf);
+#endif
+
 #endif /* ! _PORT_LINUX_H */