1 files changed, 50 insertions, 49 deletions

diff --git a/V8Binding/v8/src/platform-linux.cc b/V8Binding/v8/src/platform-linux.cc
index bccf9e6..6ec5070 100644
--- a/V8Binding/v8/src/platform-linux.cc
+++ b/V8Binding/v8/src/platform-linux.cc
@@ -223,62 +223,63 @@ PosixMemoryMappedFile::~PosixMemoryMappedFile() {
 }
 
 
+void OS::LogSharedLibraryAddresses() {
 #ifdef ENABLE_LOGGING_AND_PROFILING
-static uintptr_t StringToULong(char* buffer) {
-  return strtoul(buffer, NULL, 16);  // NOLINT
-}
-#endif
+  // This function assumes that the layout of the file is as follows:
+  // hex_start_addr-hex_end_addr rwxp <unused data> [binary_file_name]
+  // If we encounter an unexpected situation we abort scanning further entries.
+  FILE *fp = fopen("/proc/self/maps", "r");
+  if (fp == NULL) return;
 
+  // Allocate enough room to be able to store a full file name.
+  const int kLibNameLen = FILENAME_MAX + 1;
+  char* lib_name = reinterpret_cast<char*>(malloc(kLibNameLen));
 
-void OS::LogSharedLibraryAddresses() {
-#ifdef ENABLE_LOGGING_AND_PROFILING
-  static const int MAP_LENGTH = 1024;
-  int fd = open("/proc/self/maps", O_RDONLY);
-  if (fd < 0) return;
+  // This loop will terminate once the scanning hits an EOF.
   while (true) {
-    char addr_buffer[11];
-    addr_buffer[0] = '0';
-    addr_buffer[1] = 'x';
-    addr_buffer[10] = 0;
-    int result = read(fd, addr_buffer + 2, 8);
-    if (result < 8) break;
-    uintptr_t start = StringToULong(addr_buffer);
-    result = read(fd, addr_buffer + 2, 1);
-    if (result < 1) break;
-    if (addr_buffer[2] != '-') break;
-    result = read(fd, addr_buffer + 2, 8);
-    if (result < 8) break;
-    uintptr_t end = StringToULong(addr_buffer);
-    char buffer[MAP_LENGTH];
-    int bytes_read = -1;
-    do {
-      bytes_read++;
-      if (bytes_read >= MAP_LENGTH - 1)
-        break;
-      result = read(fd, buffer + bytes_read, 1);
-      if (result < 1) break;
-    } while (buffer[bytes_read] != '\n');
-    buffer[bytes_read] = 0;
-    // Ignore mappings that are not executable.
-    if (buffer[3] != 'x') continue;
-    char* start_of_path = index(buffer, '/');
-    // If there is no filename for this line then log it as an anonymous
-    // mapping and use the address as its name.
-    if (start_of_path == NULL) {
-      // 40 is enough to print a 64 bit address range.
-      ASSERT(sizeof(buffer) > 40);
-      snprintf(buffer,
-               sizeof(buffer),
-               "%08" V8PRIxPTR "-%08" V8PRIxPTR,
-               start,
-               end);
-      LOG(SharedLibraryEvent(buffer, start, end));
+    uintptr_t start, end;
+    char attr_r, attr_w, attr_x, attr_p;
+    // Parse the addresses and permission bits at the beginning of the line.
+    if (fscanf(fp, "%" V8PRIxPTR "-%" V8PRIxPTR, &start, &end) != 2) break;
+    if (fscanf(fp, " %c%c%c%c", &attr_r, &attr_w, &attr_x, &attr_p) != 4) break;
+
+    int c;
+    if (attr_r == 'r' && attr_x == 'x') {
+      // Found a readable and executable entry. Skip characters until we reach
+      // the beginning of the filename or the end of the line.
+      do {
+        c = getc(fp);
+      } while ((c != EOF) && (c != '\n') && (c != '/'));
+      if (c == EOF) break;  // EOF: Was unexpected, just exit.
+
+      // Process the filename if found.
+      if (c == '/') {
+        ungetc(c, fp);  // Push the '/' back into the stream to be read below.
+
+        // Read to the end of the line. Exit if the read fails.
+        if (fgets(lib_name, kLibNameLen, fp) == NULL) break;
+
+        // Drop the newline character read by fgets. We do not need to check
+        // for a zero-length string because we know that we at least read the
+        // '/' character.
+        lib_name[strlen(lib_name) - 1] = '\0';
+      } else {
+        // No library name found, just record the raw address range.
+        snprintf(lib_name, kLibNameLen,
+                 "%08" V8PRIxPTR "-%08" V8PRIxPTR, start, end);
+      }
+      LOG(SharedLibraryEvent(lib_name, start, end));
     } else {
-      buffer[bytes_read] = 0;
-      LOG(SharedLibraryEvent(start_of_path, start, end));
+      // Entry not describing executable data. Skip to end of line to setup
+      // reading the next entry.
+      do {
+        c = getc(fp);
+      } while ((c != EOF) && (c != '\n'));
+      if (c == EOF) break;
     }
   }
-  close(fd);
+  free(lib_name);
+  fclose(fp);
 #endif
 }