pkg2sqfs: always padd image file to device block size

The kernel implementation apparently requires that.

Signed-off-by: David Oberhollenzer <goliath@infraroot.at>

sqfs/pkg2sqfs.c

@@ -3,12 +3,13 @@
 
 static struct option long_opts[] = {
 	{ "block-size", required_argument, NULL, 'b' },
+	{ "dev-block-size", required_argument, NULL, 'B' },
 	{ "force", no_argument, NULL, 'f' },
 	{ "version", no_argument, NULL, 'V' },
 	{ "help", no_argument, NULL, 'h' },
 };
 
-static const char *short_opts = "b:fhV";
+static const char *short_opts = "b:B:fhV";
 
 extern char *__progname;
 
@@ -28,11 +29,13 @@ static const char *help_string =
 "\n"
 "Possible options:\n"
 "\n"
-"  --block-size, -b <size>  Block size to use for Squashfs image.\n"
-"                           Defaults to %u.\n"
-"  --force, -f              Overwrite the output file if it already exists.\n"
-"  --help, -h               Print help text and exit.\n"
-"  --version, -V            Print version information and exit.\n"
+"  --block-size, -b <size>     Block size to use for Squashfs image.\n"
+"                              Defaults to %u.\n"
+"  --dev-block-size, -B <size> Device block size to padd the image to.\n"
+"                              Defaults to %u.\n"
+"  --force, -f                 Overwrite the output file if it exists.\n"
+"  --help, -h                  Print help text and exit.\n"
+"  --version, -V               Print version information and exit.\n"
 "\n";
 
 static void print_tree(int level, node_t *n)
@@ -82,6 +85,7 @@ int main(int argc, char **argv)
 	sqfs_info_t info;
 
 	memset(&info, 0, sizeof(info));
+	info.dev_blk_size = SQFS_DEVBLK_SIZE;
 
 	for (;;) {
 		i = getopt_long(argc, argv, short_opts, long_opts, NULL);
@@ -97,12 +101,21 @@ int main(int argc, char **argv)
 				return EXIT_FAILURE;
 			}
 			break;
+		case 'B':
+			info.dev_blk_size = strtonum(optarg, 4096, 0xFFFFFFFF,
+						     &errstr);
+			if (errstr != NULL) {
+				fprintf(stderr, "Block size '%s': %s\n",
+					optarg, errstr);
+				return EXIT_FAILURE;
+			}
+			break;
 		case 'f':
 			outmode = O_WRONLY | O_CREAT | O_TRUNC;
 			break;
 		case 'h':
 			printf(help_string, __progname,
-			       SQFS_DEFAULT_BLOCK_SIZE);
+			       SQFS_DEFAULT_BLOCK_SIZE, SQFS_DEVBLK_SIZE);
 			exit(EXIT_SUCCESS);
 		case 'V':
 			printf(version_string, __progname,
@@ -173,6 +186,9 @@ int main(int argc, char **argv)
 	if (sqfs_super_write(&info))
 		goto out_fragments;
 
+	if (sqfs_padd_file(&info))
+		goto out_fragments;
+
 	status = EXIT_SUCCESS;
 out_fragments:
 	free(info.fragments);

sqfs/pkg2sqfs.h

@@ -102,6 +102,8 @@ typedef struct {
 	int file_block_count;
 	file_info_t *frag_list;
 	size_t frag_offset;
+
+	size_t dev_blk_size;
 } sqfs_info_t;
 
 int pkg_data_to_sqfs(sqfs_info_t *info);
@@ -134,4 +136,6 @@ int meta_writer_append(meta_writer_t *m, const void *data, size_t size);
 int sqfs_write_table(sqfs_info_t *info, const void *data, size_t entsize,
 		     size_t count, uint64_t *start);
 
+int sqfs_padd_file(sqfs_info_t *info);
+
 #endif /* PKG2SQFS_H */

sqfs/squashfs.h

@@ -9,6 +9,7 @@
 #define SQFS_VERSION_MINOR 0
 #define SQFS_META_BLOCK_SIZE 8192
 #define SQFS_DEFAULT_BLOCK_SIZE 131072
+#define SQFS_DEVBLK_SIZE 4096
 
 typedef struct {
 	uint32_t magic;

sqfs/super.c

@@ -97,3 +97,39 @@ int sqfs_super_write(sqfs_info_t *info)
 
 	return 0;
 }
+
+int sqfs_padd_file(sqfs_info_t *info)
+{
+	size_t padd_sz = info->super.bytes_used % info->dev_blk_size;
+	uint8_t *buffer;
+	ssize_t ret;
+	off_t off;
+
+	if (padd_sz == 0)
+		return 0;
+
+	off = lseek(info->outfd, 0, SEEK_END);
+	if (off == (off_t)-1) {
+		perror("seek on output file");
+		return -1;
+	}
+
+	padd_sz = info->dev_blk_size - padd_sz;
+	buffer = alloca(padd_sz);
+	memset(buffer, 0, padd_sz);
+
+	ret = write_retry(info->outfd, buffer, padd_sz);
+
+	if (ret < 0) {
+		perror("Error padding squashfs image to page size");
+		return -1;
+	}
+
+	if (ret == 0) {
+		fputs("Truncated write trying to padd squashfs image\n",
+		      stderr);
+		return -1;
+	}
+
+	return 0;
+}