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Apply patch for V8 bug 414

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commit 2312ff4b232a5931adcf01b4b9fec0f3ecc4f706 1 parent 6acac91
@ry ry authored
Showing with 38 additions and 11 deletions.
  1. +38 −11 deps/v8/src/platform-linux.cc
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49 deps/v8/src/platform-linux.cc
@@ -225,33 +225,60 @@ PosixMemoryMappedFile::~PosixMemoryMappedFile() {
void OS::LogSharedLibraryAddresses() {
#ifdef ENABLE_LOGGING_AND_PROFILING
- FILE *fp;
- fp = fopen("/proc/self/maps", "r");
+ // 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));
+
+ // This loop will terminate once the scanning hits an EOF.
while (true) {
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') {
- while (c = getc(fp), (c != EOF) && (c != '\n') && (c != '/'));
- char lib_name[1024];
- bool lib_has_name = false;
+ // 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);
- lib_has_name = fgets(lib_name, sizeof(lib_name), fp) != NULL;
- }
- if (lib_has_name && strlen(lib_name) > 0) {
+ 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 {
- snprintf(lib_name, sizeof(lib_name),
+ // 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 {
+ // 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;
}
- while (c = getc(fp), (c != EOF) && (c != '\n'));
}
+ free(lib_name);
fclose(fp);
#endif
}
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