[compiler-rt][memprof] memccpy interception

Author: devnexen

compiler-rt/lib/memprof/memprof_interceptors.cpp

@@ -306,6 +306,22 @@ INTERCEPTOR(long long, atoll, const char *nptr) {
   return result;
 }
 
+#if SANITIZER_INTERCEPT_MEMCCPY
+INTERCEPTOR(void *, memccpy, void *dest, const void *src, int c, usize size) {
+  void *ctx;
+  MEMPROF_INTERCEPTOR_ENTER(ctx, memccpy);
+  if (UNLIKELY(!memprof_inited))
+    return internal_memccpy(dest, src, c, size);
+  ENSURE_MEMPROF_INITED();
+  void *res = REAL(memccpy)(dest, src, c, size);
+  if (res != nullptr)
+    size = static_cast<char *>(res) - static_cast<char *>(dest);
+  MEMPROF_READ_RANGE(src, size);
+  MEMPROF_WRITE_RANGE(dest, size);
+  return res;
+}
+#endif
+
 // ---------------------- InitializeMemprofInterceptors ---------------- {{{1
 namespace __memprof {
 void InitializeMemprofInterceptors() {
@@ -333,6 +349,10 @@ void InitializeMemprofInterceptors() {
   MEMPROF_INTERCEPT_FUNC(pthread_create);
   MEMPROF_INTERCEPT_FUNC(pthread_join);
 
+#if SANITIZER_INTERCEPT_MEMCCPY
+  MEMPROF_INTERCEPT_FUNC(memccpy);
+#endif
+
   InitializePlatformInterceptors();
 
   VReport(1, "MemProfiler: libc interceptors initialized\n");

compiler-rt/lib/sanitizer_common/sanitizer_libc.cpp

@@ -49,6 +49,16 @@ int internal_memcmp(const void* s1, const void* s2, uptr n) {
   return 0;
 }
 
+void *internal_memccpy(void *dest, const void *src, int c, uptr n) {
+  char *d = (char *)dest;
+  const char *s = (const char *)src;
+  uptr i = 0;
+  for (; i < n && s[i] != c; ++i) d[i] = s[i];
+  if (n > 0 && i < n - 1)
+    return d + i + 1;
+  return nullptr;
+}
+
 extern "C" {
 SANITIZER_INTERFACE_ATTRIBUTE void *__sanitizer_internal_memcpy(void *dest,
                                                                 const void *src,

compiler-rt/lib/sanitizer_common/sanitizer_libc.h

@@ -41,6 +41,7 @@ s64 internal_atoll(const char *nptr);
 void *internal_memchr(const void *s, int c, uptr n);
 void *internal_memrchr(const void *s, int c, uptr n);
 int internal_memcmp(const void* s1, const void* s2, uptr n);
+void *internal_memccpy(void *d, const void *s, int c, uptr n);
 ALWAYS_INLINE void *internal_memcpy(void *dest, const void *src, uptr n) {
   return __sanitizer_internal_memcpy(dest, src, n);
 }

compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h

@@ -198,6 +198,7 @@ SANITIZER_WEAK_IMPORT void *aligned_alloc(__sanitizer::usize __alignment,
 #define SANITIZER_INTERCEPT_MEMMEM (SI_POSIX && !SI_MAC_DEPLOYMENT_BELOW_10_7)
 #define SANITIZER_INTERCEPT_MEMCHR SI_NOT_FUCHSIA
 #define SANITIZER_INTERCEPT_MEMRCHR (SI_FREEBSD || SI_LINUX || SI_NETBSD)
+#define SANITIZER_INTERCEPT_MEMCCPY (SI_FREEBSD || SI_LINUX || SI_NETBSD)
 
 #define SANITIZER_INTERCEPT_READ SI_POSIX
 #define SANITIZER_INTERCEPT_PREAD SI_POSIX

compiler-rt/test/memprof/TestCases/memprof_memccpy.cpp

@@ -0,0 +1,17 @@
+// RUN: %clangxx_memprof -O0 %s -o %t
+// %env_memprof_opts=print_text=true:log_path=stdout %run %t | FileCheck %s
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int main() {
+  char *p = strdup("memccpy");
+  char *d = (char *)malloc(4);
+  void *r = memccpy(d, p, 'c', 8);
+  int cmp = memcmp(r, "mem", 3);
+  free(d);
+  free(p);
+  return cmp;
+}
+// CHECK: Memory allocation stack id