[compiler-rt] Reapply "Fix prctl to handle PR_GET_PDEATHSIG. (#101749)" (PR #104469)

[Kirill Stoimenov via llvm-commits]

https://github.com/kstoimenov updated https://github.com/llvm/llvm-project/pull/104469

>From 557ccfd2c924a167c3c6f55fe4e8453770cf1f29 Mon Sep 17 00:00:00 2001
From: Kirill Stoimenov <kstoimenov at google.com>
Date: Thu, 15 Aug 2024 16:35:50 +0000
Subject: [PATCH 1/2] Reapply "Fix prctl to handle PR_GET_PDEATHSIG. (#101749)"

Reapply with a fix.

This reverts commit 046524e8fe425cbc86c3371f2bf29fbb39d98435.
---
 .../sanitizer_common/sanitizer_common_interceptors.inc    | 7 +++++--
 .../test/sanitizer_common/TestCases/Linux/prctl.cpp       | 8 ++++++++
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc b/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
index 49c9dcbef358ff..0fa491a9641a6c 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
@@ -1255,6 +1255,7 @@ INTERCEPTOR(int, prctl, int option, unsigned long arg2, unsigned long arg3,
   static const int PR_SET_VMA = 0x53564d41;
   static const int PR_SCHED_CORE = 62;
   static const int PR_SCHED_CORE_GET = 0;
+  static const int PR_GET_PDEATHSIG = 2;
   if (option == PR_SET_VMA && arg2 == 0UL) {
     char *name = (char *)arg5;
     COMMON_INTERCEPTOR_READ_RANGE(ctx, name, internal_strlen(name) + 1);
@@ -1270,7 +1271,9 @@ INTERCEPTOR(int, prctl, int option, unsigned long arg2, unsigned long arg3,
     COMMON_INTERCEPTOR_WRITE_RANGE(ctx, name, internal_strlen(name) + 1);
   } else if (res != -1 && option == PR_SCHED_CORE &&
              arg2 == PR_SCHED_CORE_GET) {
-    COMMON_INTERCEPTOR_WRITE_RANGE(ctx, (u64*)(arg5), sizeof(u64));
+    COMMON_INTERCEPTOR_WRITE_RANGE(ctx, (u64 *)(arg5), sizeof(u64));
+  } else if (res != -1 && option == PR_GET_PDEATHSIG) {
+    COMMON_INTERCEPTOR_WRITE_RANGE(ctx, (u64 *)(arg2), sizeof(u64));
   }
   return res;
 }
@@ -9980,7 +9983,7 @@ INTERCEPTOR(SSIZE_T, getrandom, void *buf, SIZE_T buflen, unsigned int flags) {
   void *ctx;
   COMMON_INTERCEPTOR_ENTER(ctx, getrandom, buf, buflen, flags);
   // If GRND_NONBLOCK is set in the flags, it is non blocking.
-  static const int grnd_nonblock = 1; 
+  static const int grnd_nonblock = 1;
   SSIZE_T n;
   if ((flags & grnd_nonblock))
     n = REAL(getrandom)(buf, buflen, flags);
diff --git a/compiler-rt/test/sanitizer_common/TestCases/Linux/prctl.cpp b/compiler-rt/test/sanitizer_common/TestCases/Linux/prctl.cpp
index d0be7f4fa87899..cbff02d66efa78 100644
--- a/compiler-rt/test/sanitizer_common/TestCases/Linux/prctl.cpp
+++ b/compiler-rt/test/sanitizer_common/TestCases/Linux/prctl.cpp
@@ -41,6 +41,14 @@ int main() {
     }
   }
 
+  int signum;
+  res = prctl(PR_GET_PDEATHSIG, reinterpret_cast<unsigned long>(&signum));
+  if (res < 0) {
+    assert(errno == EINVAL);
+  } else {
+    assert(signum == 0);
+  }
+
   char invname[81], vlname[] = "prctl";
   for (auto i = 0; i < sizeof(invname); i++) {
     invname[i] = 0x1e;

>From 3868ea10e46f25d2eff2b57c04f3842d5836f5ae Mon Sep 17 00:00:00 2001
From: Kirill Stoimenov <kstoimenov at google.com>
Date: Thu, 15 Aug 2024 16:38:39 +0000
Subject: [PATCH 2/2] Fix the type.

---
 .../lib/sanitizer_common/sanitizer_common_interceptors.inc      | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc b/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
index 0fa491a9641a6c..e09a4a8ae25fd8 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
@@ -1273,7 +1273,7 @@ INTERCEPTOR(int, prctl, int option, unsigned long arg2, unsigned long arg3,
              arg2 == PR_SCHED_CORE_GET) {
     COMMON_INTERCEPTOR_WRITE_RANGE(ctx, (u64 *)(arg5), sizeof(u64));
   } else if (res != -1 && option == PR_GET_PDEATHSIG) {
-    COMMON_INTERCEPTOR_WRITE_RANGE(ctx, (u64 *)(arg2), sizeof(u64));
+    COMMON_INTERCEPTOR_WRITE_RANGE(ctx, (u64 *)(arg2), sizeof(int));
   }
   return res;
 }