POTD skeleton #57.

Signed-off-by: Toni Uhlig <matzeton@googlemail.com>

1 files changed, 42 insertions, 7 deletions

diff --git a/src/utils.c b/src/utils.c
index 69fcb0e..945f8a5 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -387,20 +387,55 @@ int create_device_files(const char *mount_path)
     return s;
 }
 
-int update_uid_map(pid_t pid, unsigned int uid_map[3])
+int update_guid_map(pid_t pid, unsigned int map[3], int update_uidmap)
 {
-    int s;
-    const char *const path_pid = "/proc/%d/uid_map";
-    const char *const path_self = "/proc/self/uid_map";
-    char path[32];
+    int s, fd;
+    ssize_t written;
+    const char *const path_pid = "/proc/%d/%s";
+    const char *const path_self = "/proc/self/%s";
+    char buf[64];
 
     if (pid < 0) {
-        s = snprintf(path, sizeof path, "%s", path_self);
+        s = snprintf(buf, sizeof buf, path_self,
+                (update_uidmap ? "uid_map" : "gid_map"));
     } else {
-        s = snprintf(path, sizeof path, path_pid, pid);
+        s = snprintf(buf, sizeof buf, path_pid, pid,
+                (update_uidmap ? "uid_map" : "gid_map"));
     }
     if (s <= 0)
         return 1;
 
+    fd = open(buf, O_WRONLY);
+    if (fd < 0)
+        return 1;
+
+    s = snprintf(buf, sizeof buf, "%u %u %u\n", map[0], map[1], map[2]);
+    written = write(fd, buf, s);
+    if (written <= 0)
+        return 1;
+
+    return 0;
+}
+
+int update_setgroups_self(int allow)
+{
+    int fd;
+    ssize_t written;
+    const char *const path_self = "/proc/self/setgroups";
+    const char *const str_allow = "allow";
+    const char *const str_deny = "deny";
+
+    fd = open(path_self, O_WRONLY);
+    if (fd < 0)
+        return 1;
+
+    if (allow) {
+        written = write(fd, str_allow, sizeof str_allow);
+    } else {
+        written = write(fd, str_deny, sizeof str_deny);
+    }
+    if (written <= 0)
+        return 1;
+
     return 0;
 }