Recognize zipped libraries when parsing maps.

This commit recognizes *.zip and *.apk files mmapped with executable
flag set and changes name of associated module to the corresponding
zipped entry path following the "{zip path}!/{zip entry name}" format.
File offset of the module is updated as well to reflect offset within
the zipped file data instead of the offset within the archive.

src/cc/bcc_proc.c

@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+#include "bcc_proc.h"
+
 #include <ctype.h>
 #include <dirent.h>
 #include <fcntl.h>
@@ -29,9 +31,9 @@
 #include <sys/types.h>
 #include <unistd.h>
 
-#include "bcc_perf_map.h"
-#include "bcc_proc.h"
 #include "bcc_elf.h"
+#include "bcc_perf_map.h"
+#include "bcc_zip.h"
 
 #ifdef __x86_64__
 // https://www.kernel.org/doc/Documentation/x86/x86_64/mm.txt
@@ -121,12 +123,49 @@ static char *_procutils_memfd_path(const int pid, const uint64_t inum) {
  return path;
 }
 
+static int _procfs_might_be_zip_path(const char *path) {
+ return strstr(path, ".zip") || strstr(path, ".apk");
+}
+
+static char *_procfs_find_zip_entry(const char *path, int pid,
+ uint32_t *offset) {
+ char ns_relative_path[PATH_MAX];
+ int rc = snprintf(ns_relative_path, sizeof(ns_relative_path),
+ "/proc/%d/root%s", pid, path);
+ if (rc < 0 || rc >= sizeof(ns_relative_path)) {
+ return NULL;
+ }
+
+ struct bcc_zip_archive *archive = bcc_zip_archive_open(ns_relative_path);
+ if (archive == NULL) {
+ return NULL;
+ }
+
+ struct bcc_zip_entry entry;
+ if (bcc_zip_archive_find_entry_at_offset(archive, *offset, &entry) ||
+ entry.compression) {
+ bcc_zip_archive_close(archive);
+ return NULL;
+ }
+
+ char *result = malloc(strlen(path) + entry.name_length + 3);
+ if (result == NULL) {
+ bcc_zip_archive_close(archive);
+ return NULL;
+ }
+
+ sprintf(result, "%s!/%.*s", path, entry.name_length, entry.name);
+ *offset -= entry.data_offset;
+ bcc_zip_archive_close(archive);
+ return result;
+}
+
 // return: 0 -> callback returned < 0, stopped iterating
 // -1 -> callback never indicated to stop
 int _procfs_maps_each_module(FILE *procmap, int pid,
  bcc_procutils_modulecb callback, void *payload) {
  char buf[PATH_MAX + 1], perm[5];
- char *name;
+ char *name, *resolved_name;
  mod_info mod;
  uint8_t enter_ns;
  while (true) {
@@ -148,14 +187,25 @@ int _procfs_maps_each_module(FILE *procmap, int pid,
  if (!bcc_mapping_is_file_backed(name))
  continue;
 
+ resolved_name = NULL;
  if (strstr(name, "/memfd:")) {
- char *memfd_name = _procutils_memfd_path(pid, mod.inode);
- if (memfd_name != NULL) {
- strcpy(buf, memfd_name);
- free(memfd_name);
- mod.name = buf;
+ resolved_name = _procutils_memfd_path(pid, mod.inode);
+ if (resolved_name != NULL) {
  enter_ns = 0;
  }
+ } else if (_procfs_might_be_zip_path(mod.name)) {
+ uint32_t zip_entry_offset = mod.file_offset;
+ resolved_name = _procfs_find_zip_entry(mod.name, pid, &zip_entry_offset);
+ if (resolved_name != NULL) {
+ mod.file_offset = zip_entry_offset;
+ }
+ }
+
+ if (resolved_name != NULL) {
+ strncpy(buf, resolved_name, PATH_MAX);
+ buf[PATH_MAX] = 0;
+ free(resolved_name);
+ mod.name = buf;
  }
 
  if (callback(&mod, enter_ns, payload) < 0)

tests/cc/test_c_api.cc

@@ -112,14 +112,19 @@ TEST_CASE("resolve symbol name in external library using loaded libraries", "[c_
  bcc_procutils_free(sym.module);
 }
 
+namespace {
+
+static std::string zipped_lib_path() {
+ return CMAKE_CURRENT_BINARY_DIR "/archive.zip!/libdebuginfo_test_lib.so";
+}
+
+} // namespace
+
 TEST_CASE("resolve symbol name in external zipped library", "[c_api]") {
  struct bcc_symbol sym;
- std::string lib_path =
- CMAKE_CURRENT_BINARY_DIR "/archive.zip!/libdebuginfo_test_lib.so";
-
- REQUIRE(bcc_resolve_symname(lib_path.c_str(), "symbol", 0x0, 0, nullptr,
- &sym) == 0);
- REQUIRE(sym.module == lib_path);
+ REQUIRE(bcc_resolve_symname(zipped_lib_path().c_str(), "symbol", 0x0, 0,
+ nullptr, &sym) == 0);
+ REQUIRE(sym.module == zipped_lib_path());
  REQUIRE(sym.offset != 0);
  bcc_procutils_free(sym.module);
 }
@@ -781,6 +786,27 @@ TEST_CASE("searching for modules in /proc/[pid]/maps", "[c_api][!mayfail]") {
  }
 
  fclose(dummy_maps);
+
+ SECTION("seach for lib in zip") {
+ std::string line =
+ "7f151476e000-7f1514779000 r-xp 00001000 00:1b "
+ "72809479 " CMAKE_CURRENT_BINARY_DIR "/archive.zip\n";
+ dummy_maps = fmemopen(nullptr, line.size(), "w+");
+ REQUIRE(fwrite(line.c_str(), line.size(), 1, dummy_maps) == 1);
+ fseek(dummy_maps, 0, SEEK_SET);
+
+ struct mod_search search;
+ memset(&search, 0, sizeof(struct mod_search));
+ std::string zip_entry_path = zipped_lib_path();
+ search.name = zip_entry_path.c_str();
+ int res = _procfs_maps_each_module(dummy_maps, getpid(),
+ _bcc_syms_find_module, &search);
+ REQUIRE(res == 0);
+ REQUIRE(search.start == 0x7f151476e000);
+ REQUIRE(search.file_offset < 0x1000);
+
+ fclose(dummy_maps);
+ }
 }
 
 TEST_CASE("resolve global addr in libc in this process", "[c_api][!mayfail]") {