[compiler-rt] [compiler-rt] intercept macOs's freadlink call. (PR #83679)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-compiler-rt-sanitizer

Author: David CARLIER (devnexen)

<details>
<summary>Changes</summary>

available since macOs Ventura.

---
Full diff: https://github.com/llvm/llvm-project/pull/83679.diff


3 Files Affected:

- (modified) compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc (+19) 
- (modified) compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h (+1) 
- (added) compiler-rt/test/sanitizer_common/TestCases/Darwin/freadlink.c (+29) 


``````````diff
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc b/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
index 3ecdb55cdbf72f..9a43ada118da8a 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
@@ -10250,6 +10250,24 @@ INTERCEPTOR(int, cpuset_getaffinity, int level, int which, __int64_t id, SIZE_T
 #define INIT_CPUSET_GETAFFINITY
 #endif
 
+#if SANITIZER_INTERCEPT_FREADLINK
+INTERCEPTOR(SSIZE_T, freadlink, int fd, char *buf, SIZE_T bufsiz) {
+  void* ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, freadlink, fd, buf, bufsiz);
+  COMMON_INTERCEPTOR_FD_ACCESS(ctx, fd);
+  SSIZE_T res = REAL(freadlink)(fd, buf, bufsiz);
+  if (res > 0)
+    COMMON_INTERCEPTOR_WRITE_RANGE(ctx, buf, res);
+  if (res >= 0 && fd > 0)
+    COMMON_INTERCEPTOR_FD_ACQUIRE(ctx, fd);
+  return res;
+}
+
+#define INIT_FREADLINK COMMON_INTERCEPT_FUNCTION(freadlink)
+#else
+#define INIT_FREADLINK
+#endif
+
 #include "sanitizer_common_interceptors_netbsd_compat.inc"
 
 namespace __sanitizer {
@@ -10569,6 +10587,7 @@ static void InitializeCommonInterceptors() {
   INIT___XUNAME;
   INIT_ARGP_PARSE;
   INIT_CPUSET_GETAFFINITY;
+  INIT_FREADLINK;
 
   INIT___PRINTF_CHK;
 }
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h b/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h
index de55c736d0e144..42a06b3cc6f4d3 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h
@@ -598,6 +598,7 @@
 #define SANITIZER_INTERCEPT_PROCCTL SI_FREEBSD
 #define SANITIZER_INTERCEPT_ARGP_PARSE SI_GLIBC
 #define SANITIZER_INTERCEPT_CPUSET_GETAFFINITY SI_FREEBSD
+#define SANITIZER_INTERCEPT_FREADLINK SI_MAC
 
 // This macro gives a way for downstream users to override the above
 // interceptor macros irrespective of the platform they are on. They have
diff --git a/compiler-rt/test/sanitizer_common/TestCases/Darwin/freadlink.c b/compiler-rt/test/sanitizer_common/TestCases/Darwin/freadlink.c
new file mode 100644
index 00000000000000..53658cdb66aa3d
--- /dev/null
+++ b/compiler-rt/test/sanitizer_common/TestCases/Darwin/freadlink.c
@@ -0,0 +1,29 @@
+// RUN: %clang -O0 %s -o %t && %run %t
+
+#include <assert.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+int main(int argc, char **argv) {
+  char symlink_path[PATH_MAX];
+  snprintf(symlink_path, sizeof(symlink_path), "%s_%d.symlink", argv[0],
+           getpid());
+  remove(symlink_path);
+  int res = symlink(argv[0], symlink_path);
+  assert(!res);
+
+  int fd;
+  char readlink_path[PATH_MAX];
+  fd = open(symlink_path, O_RDONLY);
+  ssize_t res2 = freadlink(fd, readlink_path, sizeof(readlink_path));
+  assert(res2 >= 0);
+  readlink_path[res2] = '\0';
+  assert(!strcmp(readlink_path, argv[0]));
+  close(fd);
+
+  return 0;
+}

``````````

</details>


https://github.com/llvm/llvm-project/pull/83679