Merge changes I3f56a83e,Icce8c1b5 am: adae766986 (53c82487) · Commits · e / os / android_system_core

fs_mgr/fs_mgr_fstab.cpp

+29 −71

Original line number	Diff line number	Diff line
		@@ -530,67 +530,37 @@ bool EraseFstabEntry(Fstab* fstab, const std::string& mount_point) {

		} // namespace

		bool ReadFstabFromFp(FILE* fstab_file, bool proc_mounts, Fstab* fstab_out) {
		ssize_t len;
		size_t alloc_len = 0;
		char *line = NULL;
		const char *delim = " \t";
		char save_ptr, p;
		bool ParseFstabFromString(const std::string& fstab_str, bool proc_mounts, Fstab* fstab_out) {
		const int expected_fields = proc_mounts ? 4 : 5;

		Fstab fstab;

		while ((len = getline(&line, &alloc_len, fstab_file)) != -1) {
		/* if the last character is a newline, shorten the string by 1 byte */
		if (line[len - 1] == '\n') {
		line[len - 1] = '\0';
		}
		for (const auto& line : android::base::Split(fstab_str, "\n")) {
		auto fields = android::base::Tokenize(line, " \t");

		/* Skip any leading whitespace */
		p = line;
		while (isspace(*p)) {
		p++;
		}
		/* ignore comments or empty lines */
		if (p == '#' \|\| p == '\0')
		// Ignore empty lines and comments.
		if (fields.empty() \|\| android::base::StartsWith(fields.front(), '#')) {
		continue;

		FstabEntry entry;

		if (!(p = strtok_r(line, delim, &save_ptr))) {
		LERROR << "Error parsing mount source";
		goto err;
		}
		entry.blk_device = p;

		if (!(p = strtok_r(NULL, delim, &save_ptr))) {
		LERROR << "Error parsing mount_point";
		goto err;
		}
		entry.mount_point = p;

		if (!(p = strtok_r(NULL, delim, &save_ptr))) {
		LERROR << "Error parsing fs_type";
		goto err;
		if (fields.size() < expected_fields) {
		LERROR << "Error parsing fstab: expected " << expected_fields << " fields, got "
		<< fields.size();
		return false;
		}
		entry.fs_type = p;

		if (!(p = strtok_r(NULL, delim, &save_ptr))) {
		LERROR << "Error parsing mount_flags";
		goto err;
		}
		FstabEntry entry;
		auto it = fields.begin();

		ParseMountFlags(p, &entry);
		entry.blk_device = std::move(*it++);
		entry.mount_point = std::move(*it++);
		entry.fs_type = std::move(*it++);
		ParseMountFlags(std::move(*it++), &entry);

		// For /proc/mounts, ignore everything after mnt_freq and mnt_passno
		if (proc_mounts) {
		p += strlen(p);
		} else if (!(p = strtok_r(NULL, delim, &save_ptr))) {
		LERROR << "Error parsing fs_mgr_options";
		goto err;
		}

		if (!ParseFsMgrFlags(p, &entry)) {
		if (!proc_mounts && !ParseFsMgrFlags(std::move(*it++), &entry)) {
		LERROR << "Error parsing fs_mgr_flags";
		goto err;
		return false;
		}

		if (entry.fs_mgr_flags.logical) {
		@@ -602,21 +572,17 @@ bool ReadFstabFromFp(FILE* fstab_file, bool proc_mounts, Fstab* fstab_out) {

		if (fstab.empty()) {
		LERROR << "No entries found in fstab";
		goto err;
		return false;
		}

		/* If an A/B partition, modify block device to be the real block device */
		if (!fs_mgr_update_for_slotselect(&fstab)) {
		LERROR << "Error updating for slotselect";
		goto err;
		return false;
		}
		free(line);

		*fstab_out = std::move(fstab);
		return true;

		err:
		free(line);
		return false;
		}

		void TransformFstabForDsu(Fstab* fstab, const std::string& dsu_slot,
		@@ -715,16 +681,16 @@ void EnableMandatoryFlags(Fstab* fstab) {
		}

		bool ReadFstabFromFile(const std::string& path, Fstab* fstab_out) {
		auto fstab_file = std::unique_ptr<FILE, decltype(&fclose)>{fopen(path.c_str(), "re"), fclose};
		if (!fstab_file) {
		PERROR << __FUNCTION__ << "(): cannot open file: '" << path << "'";
		const bool is_proc_mounts = (path == "/proc/mounts");

		std::string fstab_str;
		if (!android::base::ReadFileToString(path, &fstab_str, /* follow_symlinks = */ true)) {
		PERROR << __FUNCTION__ << "(): failed to read file: '" << path << "'";
		return false;
		}

		bool is_proc_mounts = path == "/proc/mounts";

		Fstab fstab;
		if (!ReadFstabFromFp(fstab_file.get(), is_proc_mounts, &fstab)) {
		if (!ParseFstabFromString(fstab_str, is_proc_mounts, &fstab)) {
		LERROR << __FUNCTION__ << "(): failed to load fstab from : '" << path << "'";
		return false;
		}
		@@ -771,15 +737,7 @@ bool ReadFstabFromDt(Fstab* fstab, bool verbose) {
		return false;
		}

		std::unique_ptr<FILE, decltype(&fclose)> fstab_file(
		fmemopen(static_cast<void>(const_cast<char>(fstab_buf.c_str())),
		fstab_buf.length(), "r"), fclose);
		if (!fstab_file) {
		if (verbose) PERROR << __FUNCTION__ << "(): failed to create a file stream for fstab dt";
		return false;
		}

		if (!ReadFstabFromFp(fstab_file.get(), false, fstab)) {
		if (!ParseFstabFromString(fstab_buf, /* proc_mounts = */ false, fstab)) {
		if (verbose) {
		LERROR << __FUNCTION__ << "(): failed to load fstab from kernel:" << std::endl
		<< fstab_buf;

fs_mgr/fuzz/fs_mgr_fstab_fuzzer.cpp

+2 −6

Original line number	Diff line number	Diff line
		@@ -19,12 +19,8 @@
		#include <fstab/fstab.h>

		extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
		std::unique_ptr<FILE, decltype(&fclose)> fstab_file(
		fmemopen(static_cast<void>(const_cast<uint8_t>(data)), size, "r"), fclose);
		if (fstab_file == nullptr) {
		return 0;
		}
		std::string make_fstab_str(reinterpret_cast<const char*>(data), size);
		android::fs_mgr::Fstab fstab;
		android::fs_mgr::ReadFstabFromFp(fstab_file.get(), /* proc_mounts= */ false, &fstab);
		android::fs_mgr::ParseFstabFromString(make_fstab_str, /* proc_mounts = */ false, &fstab);
		return 0;
		}

fs_mgr/include_fstab/fstab/fstab.h

+2 −2

Original line number	Diff line number	Diff line
		@@ -94,8 +94,8 @@ struct FstabEntry {
		// Unless explicitly requested, a lookup on mount point should always return the 1st one.
		using Fstab = std::vector<FstabEntry>;

		// Exported for testability. Regular users should use ReadFstabFromfile().
		bool ReadFstabFromFp(FILE* fstab_file, bool proc_mounts, Fstab* fstab_out);
		// Exported for testability. Regular users should use ReadFstabFromFile().
		bool ParseFstabFromString(const std::string& fstab_str, bool proc_mounts, Fstab* fstab_out);

		bool ReadFstabFromFile(const std::string& path, Fstab* fstab);
		bool ReadFstabFromDt(Fstab* fstab, bool verbose = true);