[sanitizer] Add posix_spawn interceptor

[vitalybuka]

Summary

To make pid initialized for Msan.

[morehouse]

Should we also add an MSan test?

compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc

2456

Looks like the two interceptors could share implementation in a helper function.

compiler-rt/test/sanitizer_common/TestCases/Posix/posix_spawn.c

20

These macros are unused.

[eugenis]

compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc

2434

Why not check the argv[] array, too?

[vitalybuka]

update

[vitalybuka]

check argv envp

[eugenis]

LGTM

[morehouse]

The test fails to link on Android: https://lab.llvm.org/buildbot/#/builders/77/builds/11014/steps/16/logs/stdio

ld.lld: error: undefined symbol: posix_spawnattr_init
>>> referenced by posix_spawn.c:19 (/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm-project/compiler-rt/test/sanitizer_common/TestCases/Posix/posix_spawn.c:19)
>>>               /tmp/posix_spawn-9331fd.o:(main)
ld.lld: error: undefined symbol: posix_spawn_file_actions_init
>>> referenced by posix_spawn.c:23 (/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm-project/compiler-rt/test/sanitizer_common/TestCases/Posix/posix_spawn.c:23)
>>>               /tmp/posix_spawn-9331fd.o:(main)

[morehouse]

Disabled the test on Android: https://reviews.llvm.org/rGb298d6d16203

There might be a way to re-enable on Android by not using the init functions.

[jansvoboda11]

The test fails on macOS: https://green.lab.llvm.org/green/job/clang-stage2-Rthinlto/4694/
Can you please take a look and revert if the fix is not obvious? Cheers.

[vitalybuka]

In D112784#3100225, @jansvoboda11 wrote:

The test fails on macOS: https://green.lab.llvm.org/green/job/clang-stage2-Rthinlto/4694/
Can you please take a look and revert if the fix is not obvious? Cheers.

Sorry, just noticed, I'll revert of fix it soon.

[vitalybuka]

In D112784#3101520, @vitalybuka wrote:

In D112784#3100225, @jansvoboda11 wrote:

The test fails on macOS: https://green.lab.llvm.org/green/job/clang-stage2-Rthinlto/4694/
Can you please take a look and revert if the fix is not obvious? Cheers.

Sorry, just noticed, I'll revert of fix it soon.

For IOS 0d59efbba4e99140ef2dfb5c9f14a9d641e0ebe2

compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc

INTERCEPTOR(int, glob64, const char *pattern, int flags,
   return res;
 }
 #define INIT_GLOB64                \
   COMMON_INTERCEPT_FUNCTION(glob64);
 #else  // SANITIZER_INTERCEPT_GLOB64
 #define INIT_GLOB64
 #endif  // SANITIZER_INTERCEPT_GLOB64
 
+#if SANITIZER_INTERCEPT_POSIX_SPAWN
+
+template <class RealSpawnPtr>
+static int PosixSpawnImpl(void *ctx, RealSpawnPtr *real_posix_spawn, pid_t *pid,
+                          const char *file_or_path, const void *file_actions,
+                          const void *attrp, char *const argv[],
+                          char *const envp[]) {
+  COMMON_INTERCEPTOR_READ_RANGE(ctx, file_or_path,
+                                internal_strlen(file_or_path) + 1);
+  char *const *s = argv;
+  for (; *s; ++s)
+    COMMON_INTERCEPTOR_READ_RANGE(ctx, *s, internal_strlen(*s) + 1);
+  COMMON_INTERCEPTOR_READ_RANGE(ctx, argv, (s - argv + 1) / sizeof(*s));
+  s = envp;
+  for (; *s; ++s)
+    COMMON_INTERCEPTOR_READ_RANGE(ctx, *s, internal_strlen(*s) + 1);
+  COMMON_INTERCEPTOR_READ_RANGE(ctx, s, (s - envp + 1) / sizeof(*s));
+  int res =
+      real_posix_spawn(pid, file_or_path, file_actions, attrp, argv, envp);
+  if (res == 0)
+    COMMON_INTERCEPTOR_WRITE_RANGE(ctx, pid, sizeof(*pid));
+  return res;
+}
+INTERCEPTOR(int, posix_spawn, pid_t *pid, const char *path,
+            const void *file_actions, const void *attrp, char *const argv[],
+            char *const envp[]) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, posix_spawn, pid, path, file_actions, attrp,
+                           argv, envp);
+  return PosixSpawnImpl(ctx, REAL(posix_spawn), pid, path, file_actions, attrp,
+                        argv, envp);
+}
+INTERCEPTOR(int, posix_spawnp, pid_t *pid, const char *file,
+            const void *file_actions, const void *attrp, char *const argv[],
+            char *const envp[]) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, posix_spawnp, pid, file, file_actions, attrp,
+                           argv, envp);
+  return PosixSpawnImpl(ctx, REAL(posix_spawnp), pid, file, file_actions, attrp,
+                        argv, envp);
+}
+#  define INIT_POSIX_SPAWN                  \
+    COMMON_INTERCEPT_FUNCTION(posix_spawn); \
+    COMMON_INTERCEPT_FUNCTION(posix_spawnp);
+#else  // SANITIZER_INTERCEPT_POSIX_SPAWN
+#  define INIT_POSIX_SPAWN
+#endif  // SANITIZER_INTERCEPT_POSIX_SPAWN
+
 #if SANITIZER_INTERCEPT_WAIT
 // According to sys/wait.h, wait(), waitid(), waitpid() may have symbol version
 // suffixes on Darwin. See the declaration of INTERCEPTOR_WITH_SUFFIX for
 // details.
 INTERCEPTOR_WITH_SUFFIX(int, wait, int *status) {
   void *ctx;
   COMMON_INTERCEPTOR_ENTER(ctx, wait, status);
   // FIXME: under ASan the call below may write to freed memory and corrupt
#endif
   INIT_FGETGRENT_R;
   INIT_SETPWENT;
   INIT_CLOCK_GETTIME;
   INIT_CLOCK_GETCPUCLOCKID;
   INIT_GETITIMER;
   INIT_TIME;
   INIT_GLOB;
   INIT_GLOB64;
+  INIT_POSIX_SPAWN;
   INIT_WAIT;
   INIT_WAIT4;
   INIT_INET;
   INIT_PTHREAD_GETSCHEDPARAM;
   INIT_GETADDRINFO;
   INIT_GETNAMEINFO;
   INIT_GETSOCKNAME;
   INIT_GETHOSTBYNAME;

compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h

 #define SANITIZER_INTERCEPT_CLOCK_GETTIME \
   (SI_FREEBSD || SI_NETBSD || SI_LINUX || SI_SOLARIS)
 #define SANITIZER_INTERCEPT_CLOCK_GETCPUCLOCKID \
   (SI_LINUX || SI_FREEBSD || SI_NETBSD)
 #define SANITIZER_INTERCEPT_GETITIMER SI_POSIX
 #define SANITIZER_INTERCEPT_TIME SI_POSIX
 #define SANITIZER_INTERCEPT_GLOB (SI_GLIBC || SI_SOLARIS)
 #define SANITIZER_INTERCEPT_GLOB64 SI_GLIBC
+#define SANITIZER_INTERCEPT_POSIX_SPAWN SI_POSIX
 #define SANITIZER_INTERCEPT_WAIT SI_POSIX
 #define SANITIZER_INTERCEPT_INET SI_POSIX
 #define SANITIZER_INTERCEPT_PTHREAD_GETSCHEDPARAM SI_POSIX
 #define SANITIZER_INTERCEPT_GETADDRINFO SI_POSIX
 #define SANITIZER_INTERCEPT_GETNAMEINFO SI_POSIX
 #define SANITIZER_INTERCEPT_GETSOCKNAME SI_POSIX
 #define SANITIZER_INTERCEPT_GETHOSTBYNAME SI_POSIX
 #define SANITIZER_INTERCEPT_GETHOSTBYNAME2 SI_POSIX && !SI_SOLARIS

compiler-rt/test/sanitizer_common/TestCases/Posix/posix_spawn.c

+// RUN: %clang %s -o %t && %run %t 2>&1 | FileCheck %s
+
+#include <assert.h>
+#include <spawn.h>
+#include <stdio.h>
+#include <wait.h>
+
+int main(int argc, char **argv) {
+  if (argc > 1) {
+    // CHECK: SPAWNED
+    // CHECK: SPAWNED
+    printf("SPAWNED\n");
+    return 0;
+  }
+
+  int s;
+
+  posix_spawnattr_t attr;
+  s = posix_spawnattr_init(&attr);
+  assert(!s);
+
+  posix_spawn_file_actions_t file_actions;
+  s = posix_spawn_file_actions_init(&file_actions);
+  assert(!s);
+
+  char *const args[] = {argv[0], "2", NULL};
+  char *const env[] = {"A=B", NULL};
+
+  pid_t pid;
+  s = posix_spawn(&pid, argv[0], &file_actions, &attr, args, env);
+  assert(!s);
+
+  waitpid(pid, &s, WUNTRACED | WCONTINUED);
+
+  s = posix_spawnp(&pid, argv[0], &file_actions, &attr, args, env);
+  assert(!s);
+
+  waitpid(pid, &s, WUNTRACED | WCONTINUED);
+  return 0;
+}