[PATCH] D48451: [sanitizers_common] when spawning a subprocess for symbolizers, use posix_spawn instead of fork()

[Alex Gaynor via Phabricator via llvm-commits]

alex updated this revision to Diff 153084.
alex added a comment.

- Use at_scope_exit to simplify destroying the posix_spawn_file_actions


Repository:
  rCRT Compiler Runtime

https://reviews.llvm.org/D48451

Files:
  lib/sanitizer_common/sanitizer_posix_libcdep.cc


Index: lib/sanitizer_common/sanitizer_posix_libcdep.cc
===================================================================
--- lib/sanitizer_common/sanitizer_posix_libcdep.cc
+++ lib/sanitizer_common/sanitizer_posix_libcdep.cc
@@ -29,6 +29,7 @@
 #include <fcntl.h>
 #include <pthread.h>
 #include <signal.h>
+#include <spawn.h>
 #include <stdlib.h>
 #include <sys/mman.h>
 #include <sys/resource.h>
@@ -45,6 +46,8 @@
 #define MAP_NORESERVE 0
 #endif
 
+extern char **environ;
+
 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
 
 namespace __sanitizer {
@@ -434,6 +437,65 @@
 }
 #endif // !SANITIZER_GO
 
+// Android < P (r28) does not have posix_spawn, so for now we use the old fork-
+// based implementation there. Hopefully some day we'll only care about recent
+// Android and we can drop that.
+#if !SANITIZER_ANDROID || __ANDROID_API__ >= 28
+pid_t StartSubprocess(const char *program, const char *const argv[],
+                      fd_t stdin_fd, fd_t stdout_fd, fd_t stderr_fd) {
+  auto file_closer = at_scope_exit([&] {
+    if (stdin_fd != kInvalidFd) {
+      internal_close(stdin_fd);
+    }
+    if (stdout_fd != kInvalidFd) {
+      internal_close(stdout_fd);
+    }
+    if (stderr_fd != kInvalidFd) {
+      internal_close(stderr_fd);
+    }
+  });
+
+  posix_spawn_file_actions_t fa;
+  int result = posix_spawn_file_actions_init(&fa);
+  if (result != 0) {
+    Report("WARNING: posix_spawn_file_actions_init failed (result %d)\n", result);
+    return -1;
+  }
+  auto file_actions_destroyer = at_scope_exit([&] {
+    posix_spawn_file_actions_destroy(&fa);
+  });
+
+  if (stdin_fd != kInvalidFd) {
+    result = posix_spawn_file_actions_adddup2(&fa, stdin_fd, STDIN_FILENO);
+    if (result != 0) {
+      Report("WARNING: posix_spawn_file_actions_adddup2 failed (result %d)\n", result);
+      return -1;
+    }
+  }
+  if (stdout_fd != kInvalidFd) {
+    result = posix_spawn_file_actions_adddup2(&fa, stdout_fd, STDOUT_FILENO);
+    if (result != 0) {
+      Report("WARNING: posix_spawn_file_actions_adddup2 failed (result %d)\n", result);
+      return -1;
+    }
+  }
+  if (stderr_fd != kInvalidFd) {
+    result = posix_spawn_file_actions_adddup2(&fa, stderr_fd, STDERR_FILENO);
+    if (result != 0) {
+      Report("WARNING: posix_spawn_file_actions_adddup2 failed (result %d)\n", result);
+      return -1;
+    }
+  }
+
+  pid_t pid;
+  result = posix_spawn(&pid, program, &fa, nullptr, const_cast<char **>(argv), environ);
+  if (result != 0) {
+    Report("WARNING: failed to spawn process (result %d)\n", result);
+    return -1;
+  }
+  return pid;
+}
+#else
 pid_t StartSubprocess(const char *program, const char *const argv[],
                       fd_t stdin_fd, fd_t stdout_fd, fd_t stderr_fd) {
   auto file_closer = at_scope_exit([&] {
@@ -484,6 +546,7 @@
 
   return pid;
 }
+#endif
 
 bool IsProcessRunning(pid_t pid) {
   int process_status;


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