Allow invoking the linker on an executable.
The executable can be inside a zip file using the same syntax used for
shared objects: path.zip!/libentry.so.
The linker currently requires an absolute path. This restriction could be
loosened, but it didn't seem important? If it allowed non-absolute paths,
we'd need to decide how to handle:
- foo/bar (relative to CWD?)
- foo (search PATH / LD_LIBRARY_PATH, or also relative to CWD?)
- foo.zip!/bar (normalize_path() requires an absolute path)
The linker adjusts the argc/argv passed to main() and to constructor
functions to hide the initial linker argument, but doesn't adjust the auxv
vector or files like /proc/self/{exe,cmdline,auxv,stat}. Those files will
report that the kernel loaded the linker as an executable.
I think the linker_logger.cpp change guarding against (g_argv == NULL)
isn't actually necessary, but it seemed like a good idea given that I'm
delaying initialization of g_argv until after C++ constructors have run.
Bug: http://b/112050209
Test: bionic unit tests
Change-Id: I846faf98b16fd34218946f6167e8b451897debe5
diff --git a/linker/linker.cpp b/linker/linker.cpp
index 277b823..b605ed9 100644
--- a/linker/linker.cpp
+++ b/linker/linker.cpp
@@ -289,7 +289,7 @@
}
soinfo* soinfo_alloc(android_namespace_t* ns, const char* name,
- struct stat* file_stat, off64_t file_offset,
+ const struct stat* file_stat, off64_t file_offset,
uint32_t rtld_flags) {
if (strlen(name) >= PATH_MAX) {
async_safe_fatal("library name \"%s\" too long", name);
@@ -1011,6 +1011,28 @@
return true;
}
+static int open_library_at_path(ZipArchiveCache* zip_archive_cache,
+ const char* path, off64_t* file_offset,
+ std::string* realpath) {
+ int fd = -1;
+ if (strstr(path, kZipFileSeparator) != nullptr) {
+ fd = open_library_in_zipfile(zip_archive_cache, path, file_offset, realpath);
+ }
+
+ if (fd == -1) {
+ fd = TEMP_FAILURE_RETRY(open(path, O_RDONLY | O_CLOEXEC));
+ if (fd != -1) {
+ *file_offset = 0;
+ if (!realpath_fd(fd, realpath)) {
+ PRINT("warning: unable to get realpath for the library \"%s\". Will use given path.", path);
+ *realpath = path;
+ }
+ }
+ }
+
+ return fd;
+}
+
static int open_library_on_paths(ZipArchiveCache* zip_archive_cache,
const char* name, off64_t* file_offset,
const std::vector<std::string>& paths,
@@ -1021,22 +1043,7 @@
continue;
}
- int fd = -1;
- if (strstr(buf, kZipFileSeparator) != nullptr) {
- fd = open_library_in_zipfile(zip_archive_cache, buf, file_offset, realpath);
- }
-
- if (fd == -1) {
- fd = TEMP_FAILURE_RETRY(open(buf, O_RDONLY | O_CLOEXEC));
- if (fd != -1) {
- *file_offset = 0;
- if (!realpath_fd(fd, realpath)) {
- PRINT("warning: unable to get realpath for the library \"%s\". Will use given path.", buf);
- *realpath = buf;
- }
- }
- }
-
+ int fd = open_library_at_path(zip_archive_cache, buf, file_offset, realpath);
if (fd != -1) {
return fd;
}
@@ -1098,6 +1105,11 @@
return fd;
}
+int open_executable(const char* path, off64_t* file_offset, std::string* realpath) {
+ ZipArchiveCache zip_archive_cache;
+ return open_library_at_path(&zip_archive_cache, path, file_offset, realpath);
+}
+
const char* fix_dt_needed(const char* dt_needed, const char* sopath __unused) {
#if !defined(__LP64__)
// Work around incorrect DT_NEEDED entries for old apps: http://b/21364029