/*
- * Copyright 2014 Facebook, Inc.
+ * Copyright 2014-present Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
#include <folly/experimental/symbolizer/ElfCache.h>
-namespace folly { namespace symbolizer {
+#include <link.h>
+
+/*
+ * This is declared in `link.h' on Linux platforms, but apparently not on the
+ * Mac version of the file. It's harmless to declare again, in any case.
+ *
+ * Note that declaring it with `extern "C"` results in linkage conflicts.
+ */
+extern struct r_debug _r_debug;
+
+namespace folly {
+namespace symbolizer {
+
+size_t countLoadedElfFiles() {
+ // _r_debug synchronization is... lacking to say the least. It's
+ // meant as an aid for debuggers and synchronization is done by
+ // calling dl_debug_state() which debuggers are supposed to
+ // intercept by setting a breakpoint on.
+
+ // Can't really do that here, so we apply the hope-and-pray strategy.
+ if (_r_debug.r_version != 1 || _r_debug.r_state != r_debug::RT_CONSISTENT) {
+ // computo ergo sum
+ return 1;
+ }
+
+ // r_map -> head of a linked list of 'link_map_t' entries,
+ // one per ELF 'binary' in the process address space.
+ size_t count = 0;
+ for (auto lmap = _r_debug.r_map; lmap != nullptr; lmap = lmap->l_next) {
+ ++count;
+ }
+ return count;
+}
SignalSafeElfCache::SignalSafeElfCache(size_t capacity) {
map_.reserve(capacity);
return nullptr;
}
- Path path(p);
- auto pos = map_.find(path);
+ scratchpad_.assign(p);
+ auto pos = map_.find(scratchpad_);
if (pos != map_.end()) {
return slots_[pos->second];
}
auto& f = slots_[n];
const char* msg = "";
- int r = f->openNoThrow(path.data(), true, &msg);
+ int r = f->openAndFollow(scratchpad_.data(), true, &msg);
if (r != ElfFile::kSuccess) {
return nullptr;
}
- map_[path] = n;
+ map_[scratchpad_] = n;
return f;
}
-ElfCache::ElfCache(size_t capacity) : capacity_(capacity) { }
+ElfCache::ElfCache(size_t capacity) : capacity_(capacity) {}
std::shared_ptr<ElfFile> ElfCache::getFile(StringPiece p) {
std::lock_guard<std::mutex> lock(mutex_);
// No negative caching
const char* msg = "";
- int r = entry->file.openNoThrow(path.c_str(), true, &msg);
+ int r = entry->file.openAndFollow(path.c_str(), true, &msg);
if (r != ElfFile::kSuccess) {
return nullptr;
}
// share ownership
return std::shared_ptr<ElfFile>(e, &e->file);
}
-
-}} // namespaces
+} // namespace symbolizer
+} // namespace folly