1 files changed, 55 insertions, 1 deletions

diff --git a/test/syscalls/linux/proc.cc b/test/syscalls/linux/proc.cc
index 7a0f33dff..e508ce27f 100644
--- a/test/syscalls/linux/proc.cc
+++ b/test/syscalls/linux/proc.cc
@@ -17,6 +17,7 @@
 #include <fcntl.h>
 #include <limits.h>
 #include <linux/magic.h>
+#include <linux/sem.h>
 #include <sched.h>
 #include <signal.h>
 #include <stddef.h>
@@ -1801,6 +1802,33 @@ TEST(ProcPidCmdline, SubprocessForkSameCmdline) {
   }
 }
 
+TEST(ProcPidCmdline, SubprocessSeekCmdline) {
+  FileDescriptor fd;
+  ASSERT_NO_ERRNO(WithSubprocess(
+      [&](int pid) -> PosixError {
+        // Running. Open /proc/pid/cmdline.
+        ASSIGN_OR_RETURN_ERRNO(
+            fd, Open(absl::StrCat("/proc/", pid, "/cmdline"), O_RDONLY));
+        return NoError();
+      },
+      [&](int pid) -> PosixError {
+        // Zombie, but seek should still succeed.
+        int ret = lseek(fd.get(), 0x801, 0);
+        if (ret < 0) {
+          return PosixError(errno);
+        }
+        return NoError();
+      },
+      [&](int pid) -> PosixError {
+        // Exited.
+        int ret = lseek(fd.get(), 0x801, 0);
+        if (ret < 0) {
+          return PosixError(errno);
+        }
+        return NoError();
+      }));
+}
+
 // Test whether /proc/PID/ symlinks can be read for a running process.
 TEST(ProcPidSymlink, SubprocessRunning) {
   char buf[1];
@@ -2409,6 +2437,28 @@ TEST(ProcFilesystems, PresenceOfShmMaxMniAll) {
   ASSERT_LE(shmall, ULONG_MAX - (1UL << 24));
 }
 
+TEST(ProcFilesystems, PresenceOfSem) {
+  uint32_t semmsl = 0;
+  uint32_t semmns = 0;
+  uint32_t semopm = 0;
+  uint32_t semmni = 0;
+  std::string proc_file;
+  proc_file = ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/sys/kernel/sem"));
+  ASSERT_FALSE(proc_file.empty());
+  std::vector<absl::string_view> sem_limits =
+      absl::StrSplit(proc_file, absl::ByAnyChar("\t"), absl::SkipWhitespace());
+  ASSERT_EQ(sem_limits.size(), 4);
+  ASSERT_TRUE(absl::SimpleAtoi(sem_limits[0], &semmsl));
+  ASSERT_TRUE(absl::SimpleAtoi(sem_limits[1], &semmns));
+  ASSERT_TRUE(absl::SimpleAtoi(sem_limits[2], &semopm));
+  ASSERT_TRUE(absl::SimpleAtoi(sem_limits[3], &semmni));
+
+  ASSERT_EQ(semmsl, SEMMSL);
+  ASSERT_EQ(semmns, SEMMNS);
+  ASSERT_EQ(semopm, SEMOPM);
+  ASSERT_EQ(semmni, SEMMNI);
+}
+
 // Check that /proc/mounts is a symlink to self/mounts.
 TEST(ProcMounts, IsSymlink) {
   auto link = ASSERT_NO_ERRNO_AND_VALUE(ReadLink("/proc/mounts"));
@@ -2459,7 +2509,7 @@ void CheckDuplicatesRecursively(std::string path) {
       return;
     }
     auto dir_closer = Cleanup([&dir]() { closedir(dir); });
-    std::unordered_set<std::string> children;
+    absl::node_hash_set<std::string> children;
     while (true) {
       // Readdir(3): If the end of the directory stream is reached, NULL is
       // returned and errno is not changed.  If an error occurs, NULL is
@@ -2478,6 +2528,10 @@ void CheckDuplicatesRecursively(std::string path) {
             absl::EndsWith(path, "/net")) {
           break;
         }
+        // We may also see permission failures traversing some files.
+        if (errno == EACCES && absl::StartsWith(path, "/proc/")) {
+          break;
+        }
 
         // Otherwise, no errors are allowed.
         ASSERT_EQ(errno, 0) << path;