commit ccce03d8305434836cb6a860bd0e34b1aa82f153
author Jiyong Park <jiyong@google.com> Thu Jan 23 13:04:41 2025 +0900
committer Jiyong Park <jiyong@google.com> Thu Jan 23 13:08:34 2025 +0900
tree 6ad9e8316cadee0072d45c87ad8e8e504984ebd7
parent a876951ff58f443ccd54dd0db5e9117af906d708

Make sure symlinks created by ueventd are correctly labeled

Bug: 391078491
Test: `ls -alZ /dev/block/by-name | grep "boot_[ab]"` in cuttlefish.
lrwxrwxrwx 1 root root u:object_r:boot_block_device:s0        15 2025-01-23 13:03 boot_a -> /dev/block/vda2
lrwxrwxrwx 1 root root u:object_r:boot_block_device:s0        15 2025-01-23 13:03 boot_b -> /dev/block/vda3
lrwxrwxrwx 1 root root u:object_r:boot_block_device:s0        15 2025-01-23 13:03 init_boot_a -> /dev/block/vda4
lrwxrwxrwx 1 root root u:object_r:boot_block_device:s0        15 2025-01-23 13:03 init_boot_b -> /dev/block/vda5
lrwxrwxrwx 1 root root u:object_r:boot_block_device:s0        15 2025-01-23 13:03 vendor_boot_a -> /dev/block/vda6
lrwxrwxrwx 1 root root u:object_r:boot_block_device:s0        15 2025-01-23 13:03 vendor_boot_b -> /dev/block/vda7

Previously it was
lrwxrwxrwx 1 root root u:object_r:boot_block_device:s0        15 2025-01-21 13:36 boot_a -> /dev/block/vda2
lrwxrwxrwx 1 root root u:object_r:block_device:s0             15 2025-01-21 13:36 boot_b -> /dev/block/vda3
lrwxrwxrwx 1 root root u:object_r:boot_block_device:s0        15 2025-01-21 13:36 init_boot_a -> /dev/block/vda4
lrwxrwxrwx 1 root root u:object_r:block_device:s0             15 2025-01-21 13:36 init_boot_b -> /dev/block/vda5
lrwxrwxrwx 1 root root u:object_r:boot_block_device:s0        15 2025-01-23 13:03 vendor_boot_a -> /dev/block/vda6
lrwxrwxrwx 1 root root u:object_r:block_device:s0             15 2025-01-23 13:03 vendor_boot_b -> /dev/block/vda7

Change-Id: I448514cbf44f1f86c7f3493de23ede4690c7c4ac

init/devices.cpp

diff --git a/init/devices.cpp b/init/devices.cpp
index aeaa431..cead726 100644
--- a/init/devices.cpp
+++ b/init/devices.cpp
@@ -599,7 +599,22 @@
                 PLOG(ERROR) << "Failed to create directory " << Dirname(link);
             }
 
-            if (symlink(target.c_str(), link.c_str())) {
+            // Create symlink and make sure it's correctly labeled
+            std::string secontext;
+            // Passing 0 for mode should work.
+            if (SelabelLookupFileContext(link, 0, &secontext) && !secontext.empty()) {
+                setfscreatecon(secontext.c_str());
+            }
+
+            int rc = symlink(target.c_str(), link.c_str());
+
+            if (!secontext.empty()) {
+                int save_errno = errno;
+                setfscreatecon(nullptr);
+                errno = save_errno;
+            }
+
+            if (rc < 0) {
                 if (errno != EEXIST) {
                     PLOG(ERROR) << "Failed to symlink " << devpath << " to " << link;
                 } else if (std::string link_path;