am c870a99c: recovery: write partitions more conservatively (2148133d) · Commits · e / tools / etwrp

applypatch/applypatch.c

+46 −24

Original line number	Diff line number	Diff line
		@@ -424,42 +424,50 @@ int WriteToPartition(unsigned char* data, size_t len,
		{
		size_t start = 0;
		int success = 0;
		FILE* f = fopen(partition, "r+b");
		if (f == NULL) {
		int fd = open(partition, O_RDWR);
		if (fd < 0) {
		printf("failed to open %s: %s\n", partition, strerror(errno));
		return -1;
		}
		int attempt;

		for (attempt = 0; attempt < 3; ++attempt) {
		printf("write %s attempt %d start at %d\n", partition, attempt+1, start);
		fseek(f, start, SEEK_SET);
		for (attempt = 0; attempt < 10; ++attempt) {
		off_t next_sync = start + (1<<20);
		printf("raw write %s attempt %d start at %d\n", partition, attempt+1, start);
		lseek(fd, start, SEEK_SET);
		while (start < len) {
		size_t to_write = len - start;
		if (to_write > (1<<20)) to_write = 1<<20;
		if (to_write > 4096) to_write = 4096;

		if (fwrite(data+start, 1, to_write, f) != to_write) {
		printf("short write writing to %s (%s)\n",
		ssize_t written = write(fd, data+start, to_write);
		if (written < 0) {
		if (errno == EINTR) {
		written = 0;
		} else {
		printf("failed write writing to %s (%s)\n",
		partition, strerror(errno));
		return -1;
		}
		start += to_write;
		if (start < len) {
		usleep(50000); // 50 ms
		}
		start += written;
		if (start >= next_sync) {
		fsync(fd);
		next_sync = start + (1<<20);
		}
		}
		fsync(fd);

		// drop caches so our subsequent verification read
		// won't just be reading the cache.
		sync();
		FILE* dc = fopen("/proc/sys/vm/drop_caches", "w");
		fwrite("3\n", 2, 1, dc);
		fclose(dc);
		int dc = open("/proc/sys/vm/drop_caches", O_WRONLY);
		write(dc, "3\n", 2);
		close(dc);
		sleep(1);
		printf(" caches dropped\n");

		// verify
		fseek(f, 0, SEEK_SET);
		lseek(fd, 0, SEEK_SET);
		unsigned char buffer[4096];
		start = len;
		size_t p;
		@@ -467,11 +475,23 @@ int WriteToPartition(unsigned char* data, size_t len,
		size_t to_read = len - p;
		if (to_read > sizeof(buffer)) to_read = sizeof(buffer);

		if (fread(buffer, 1, to_read, f) != to_read) {
		printf("short verify read %s at %d: %s\n",
		size_t so_far = 0;
		while (so_far < to_read) {
		ssize_t read_count = read(fd, buffer+so_far, to_read-so_far);
		if (read_count < 0) {
		if (errno == EINTR) {
		read_count = 0;
		} else {
		printf("verify read error %s at %d: %s\n",
		partition, p, strerror(errno));
		start = p;
		break;
		return -1;
		}
		}
		if (read_count < to_read) {
		printf("short verify read %s at %d: %d %d %s\n",
		partition, p, read_count, to_read, strerror(errno));
		}
		so_far += read_count;
		}

		if (memcmp(buffer, data+p, to_read)) {
		@@ -486,6 +506,8 @@ int WriteToPartition(unsigned char* data, size_t len,
		success = true;
		break;
		}

		sleep(2);
		}

		if (!success) {
		@@ -493,7 +515,7 @@ int WriteToPartition(unsigned char* data, size_t len,
		return -1;
		}

		if (fclose(f) != 0) {
		if (close(fd) != 0) {
		printf("error closing %s (%s)\n", partition, strerror(errno));
		return -1;
		}