--oom

1 files changed, 87 insertions, 0 deletions

diff --git a/src/firejail/oom.c b/src/firejail/oom.c
new file mode 100644
index 000000000..11d08fc48
--- /dev/null
+++ b/src/firejail/oom.c
@@ -0,0 +1,87 @@
+/*
+ * Copyright (C) 2014-2022 Firejail Authors
+ *
+ * This file is part of firejail project
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#include "firejail.h"
+#include <sys/wait.h>
+
+void oom_set(const char *oom_string) {
+        int oom = atoi(oom_string);
+        uid_t uid = getuid();
+        if (uid == 0) {
+                if (oom < -1000 || oom > 1000) {
+                        fprintf(stderr, "Error: invalid oom value (-1000 to 1000)\n");
+                        exit(1);
+                }
+        }
+        else {
+                if (oom < 0 || oom > 1000) {
+                        fprintf(stderr, "Error: invalid oom value (0 to 1000)\n");
+                        exit(1);
+                }
+        }
+
+        pid_t parent = getpid();
+        pid_t child = fork();
+        if (child == -1)
+                errExit("fork");
+        if (child == 0) {
+                EUID_ROOT();
+                // elevate privileges
+                if (setreuid(0, 0))
+                        errExit("setreuid");
+                if (setregid(0, 0))
+                        errExit("setregid");
+
+                char *fname;
+                if (asprintf(&fname, "/proc/%d/oom_score_adj", parent) == -1)
+                        errExit("asprintf");
+                FILE *fp = fopen(fname, "w");
+                if (!fp) {
+                        fprintf(stderr, "Error: cannot open %s\n", fname);
+                        exit(1);
+                }
+                fprintf(fp, "%d", oom);
+                fclose(fp);
+                free(fname);
+
+                if (asprintf(&fname, "/proc/%d/oom_score", parent) == -1)
+                        errExit("asprintf");
+                fp = fopen(fname, "r");
+                if (!fp) {
+                        fprintf(stderr, "Error: cannot open %s\n", fname);
+                        exit(1);
+                }
+                int newoom;
+                if (1 != fscanf(fp, "%d", &newoom)) {
+                        fprintf(stderr, "Error: connot read from %s\n", fname);
+                        exit(1);
+                }
+                fclose(fp);
+                free(fname);
+
+                if (!arg_quiet)
+                        printf("Out-Of-Memory score adjusted, new value %d\n", newoom);
+                exit(0);
+        }
+
+        int status;
+        if (waitpid(child, &status, 0) == -1 )
+                errExit("waitpid");
+}
+