1We currently need this patch because ASan only searches PATH to find the 2llvm-symbolizer binary to symbolize ASan traces. On testing machines, this 3can be installed in PATH easily. However, for e.g. the ASan Nightly Project, 4where we ship an ASan build, including llvm-symbolizer, to the user, we 5cannot expect llvm-symbolizer to be on PATH. Instead, we should try to look 6it up next to the binary. This patch implements the functionality for Linux 7only until there is similar functionality provided upstream. 8 9diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_file.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_file.cpp 10index 79930d79425..cfb4f90c0d5 100644 11--- a/compiler-rt/lib/sanitizer_common/sanitizer_file.cpp 12+++ b/compiler-rt/lib/sanitizer_common/sanitizer_file.cpp 13@@ -20,6 +20,10 @@ 14 #include "sanitizer_common.h" 15 #include "sanitizer_file.h" 16 17+#if SANITIZER_LINUX 18+#include "sanitizer_posix.h" 19+#endif 20+ 21 namespace __sanitizer { 22 23 void CatastrophicErrorWrite(const char *buffer, uptr length) { 24@@ -194,6 +198,34 @@ char *FindPathToBinary(const char *name) { 25 if (*end == '\0') break; 26 beg = end + 1; 27 } 28+ 29+#if SANITIZER_LINUX 30+ // If we cannot find the requested binary in PATH, we should try to locate 31+ // it next to the binary, in case it is shipped with the build itself 32+ // (e.g. llvm-symbolizer shipped with sanitizer build to symbolize on client. 33+ if (internal_readlink("/proc/self/exe", buffer.data(), kMaxPathLength) < 0) 34+ return nullptr; 35+ 36+ uptr buf_len = internal_strlen(buffer.data()); 37+ 38+ /* Avoid using dirname() here */ 39+ while (buf_len > 0) { 40+ if (buffer[buf_len - 1] == '/') 41+ break; 42+ buf_len--; 43+ } 44+ 45+ if (!buf_len) 46+ return nullptr; 47+ 48+ if (buf_len + name_len + 1 <= kMaxPathLength) { 49+ internal_memcpy(&buffer[buf_len], name, name_len); 50+ buffer[buf_len + name_len] = '\0'; 51+ if (FileExists(buffer.data())) 52+ return internal_strdup(buffer.data()); 53+ } 54+#endif 55+ 56 return nullptr; 57 } 58 59