Remove use of ssize_t from library API

ssize_t is only available on POSIX platforms and even there it is
only defined to hold at least -1 in the range of negative numbers.

This commit replaces ssize_t return types with sqfs_s32 and the
coresponding function arguments with sqfs_u32. Because the range
of positiv numbers for a signed 32 bit number is only half that of
the unsigned version, additional checks have to be added.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

9 files changed, 76 insertions, 43 deletions

diff --git a/lib/sqfs/comp/gzip.c b/lib/sqfs/comp/gzip.c
index 3dd8d10..3886e60 100644
--- a/lib/sqfs/comp/gzip.c
+++ b/lib/sqfs/comp/gzip.c
@@ -107,7 +107,7 @@ static int flag_to_zlib_strategy(int flag)
 }
 
 static int find_strategy(gzip_compressor_t *gzip, const sqfs_u8 *in,
-			 size_t size, sqfs_u8 *out, size_t outsize)
+			 sqfs_u32 size, sqfs_u8 *out, sqfs_u32 outsize)
 {
 	int ret, strategy, selected = Z_DEFAULT_STRATEGY;
 	size_t i, length, minlength = 0;
@@ -148,13 +148,16 @@ static int find_strategy(gzip_compressor_t *gzip, const sqfs_u8 *in,
 	return selected;
 }
 
-static ssize_t gzip_do_block(sqfs_compressor_t *base, const sqfs_u8 *in,
-			     size_t size, sqfs_u8 *out, size_t outsize)
+static sqfs_s32 gzip_do_block(sqfs_compressor_t *base, const sqfs_u8 *in,
+			      sqfs_u32 size, sqfs_u8 *out, sqfs_u32 outsize)
 {
 	gzip_compressor_t *gzip = (gzip_compressor_t *)base;
 	int ret, strategy = 0;
 	size_t written;
 
+	if (size >= 0x7FFFFFFF)
+		return 0;
+
 	if (gzip->compress && gzip->opt.strategies != 0) {
 		strategy = find_strategy(gzip, in, size, out, outsize);
 		if (strategy < 0)
@@ -193,7 +196,7 @@ static ssize_t gzip_do_block(sqfs_compressor_t *base, const sqfs_u8 *in,
 		if (gzip->compress && written >= size)
 			return 0;
 
-		return (ssize_t)written;
+		return written;
 	}
 
 	if (ret != Z_OK && ret != Z_BUF_ERROR)
diff --git a/lib/sqfs/comp/lz4.c b/lib/sqfs/comp/lz4.c
index 35fd629..dcee7d8 100644
--- a/lib/sqfs/comp/lz4.c
+++ b/lib/sqfs/comp/lz4.c
@@ -59,12 +59,15 @@ static int lz4_read_options(sqfs_compressor_t *base, sqfs_file_t *file)
 	return 0;
 }
 
-static ssize_t lz4_comp_block(sqfs_compressor_t *base, const sqfs_u8 *in,
-			      size_t size, sqfs_u8 *out, size_t outsize)
+static sqfs_s32 lz4_comp_block(sqfs_compressor_t *base, const sqfs_u8 *in,
+			       sqfs_u32 size, sqfs_u8 *out, sqfs_u32 outsize)
 {
 	lz4_compressor_t *lz4 = (lz4_compressor_t *)base;
 	int ret;
 
+	if (size >= 0x7FFFFFFF)
+		return 0;
+
 	if (lz4->high_compression) {
 		ret = LZ4_compress_HC((void *)in, (void *)out,
 				      size, outsize, LZ4HC_CLEVEL_MAX);
@@ -79,12 +82,15 @@ static ssize_t lz4_comp_block(sqfs_compressor_t *base, const sqfs_u8 *in,
 	return ret;
 }
 
-static ssize_t lz4_uncomp_block(sqfs_compressor_t *base, const sqfs_u8 *in,
-				size_t size, sqfs_u8 *out, size_t outsize)
+static sqfs_s32 lz4_uncomp_block(sqfs_compressor_t *base, const sqfs_u8 *in,
+				 sqfs_u32 size, sqfs_u8 *out, sqfs_u32 outsize)
 {
 	int ret;
 	(void)base;
 
+	if (outsize >= 0x7FFFFFFF)
+		return 0;
+
 	ret = LZ4_decompress_safe((void *)in, (void *)out, size, outsize);
 
 	if (ret < 0)
diff --git a/lib/sqfs/comp/lzma.c b/lib/sqfs/comp/lzma.c
index f4211fb..0238df0 100644
--- a/lib/sqfs/comp/lzma.c
+++ b/lib/sqfs/comp/lzma.c
@@ -39,15 +39,15 @@ static int lzma_read_options(sqfs_compressor_t *base, sqfs_file_t *file)
 	return SQFS_ERROR_UNSUPPORTED;
 }
 
-static ssize_t lzma_comp_block(sqfs_compressor_t *base, const sqfs_u8 *in,
-			       size_t size, sqfs_u8 *out, size_t outsize)
+static sqfs_s32 lzma_comp_block(sqfs_compressor_t *base, const sqfs_u8 *in,
+				sqfs_u32 size, sqfs_u8 *out, sqfs_u32 outsize)
 {
 	lzma_compressor_t *lzma = (lzma_compressor_t *)base;
 	lzma_stream strm = LZMA_STREAM_INIT;
 	lzma_options_lzma opt;
 	int ret;
 
-	if (outsize < LZMA_HEADER_SIZE)
+	if (outsize < LZMA_HEADER_SIZE || size >= 0x7FFFFFFF)
 		return 0;
 
 	lzma_lzma_preset(&opt, LZMA_DEFAULT_LEVEL);
@@ -83,8 +83,8 @@ static ssize_t lzma_comp_block(sqfs_compressor_t *base, const sqfs_u8 *in,
 	return strm.total_out;
 }
 
-static ssize_t lzma_uncomp_block(sqfs_compressor_t *base, const sqfs_u8 *in,
-				 size_t size, sqfs_u8 *out, size_t outsize)
+static sqfs_s32 lzma_uncomp_block(sqfs_compressor_t *base, const sqfs_u8 *in,
+				  sqfs_u32 size, sqfs_u8 *out, sqfs_u32 outsize)
 {
 	sqfs_u8 lzma_header[LZMA_HEADER_SIZE];
 	lzma_stream strm = LZMA_STREAM_INIT;
@@ -92,6 +92,9 @@ static ssize_t lzma_uncomp_block(sqfs_compressor_t *base, const sqfs_u8 *in,
 	int ret;
 	(void)base;
 
+	if (size >= 0x7FFFFFFF)
+		return 0;
+
 	if (size < sizeof(lzma_header))
 		return SQFS_ERROR_CORRUPTED;
 
diff --git a/lib/sqfs/comp/lzo.c b/lib/sqfs/comp/lzo.c
index 9af3321..498c250 100644
--- a/lib/sqfs/comp/lzo.c
+++ b/lib/sqfs/comp/lzo.c
@@ -112,13 +112,16 @@ static int lzo_read_options(sqfs_compressor_t *base, sqfs_file_t *file)
 	return 0;
 }
 
-static ssize_t lzo_comp_block(sqfs_compressor_t *base, const sqfs_u8 *in,
-			      size_t size, sqfs_u8 *out, size_t outsize)
+static sqfs_s32 lzo_comp_block(sqfs_compressor_t *base, const sqfs_u8 *in,
+			       sqfs_u32 size, sqfs_u8 *out, sqfs_u32 outsize)
 {
 	lzo_compressor_t *lzo = (lzo_compressor_t *)base;
 	lzo_uint len = outsize;
 	int ret;
 
+	if (size >= 0x7FFFFFFF)
+		return 0;
+
 	if (lzo->algorithm == SQFS_LZO1X_999 &&
 	    lzo->level != SQFS_LZO_DEFAULT_LEVEL) {
 		ret = lzo1x_999_compress_level(in, size, out, &len,
@@ -138,13 +141,16 @@ static ssize_t lzo_comp_block(sqfs_compressor_t *base, const sqfs_u8 *in,
 	return 0;
 }
 
-static ssize_t lzo_uncomp_block(sqfs_compressor_t *base, const sqfs_u8 *in,
-				size_t size, sqfs_u8 *out, size_t outsize)
+static sqfs_s32 lzo_uncomp_block(sqfs_compressor_t *base, const sqfs_u8 *in,
+				 sqfs_u32 size, sqfs_u8 *out, sqfs_u32 outsize)
 {
 	lzo_compressor_t *lzo = (lzo_compressor_t *)base;
 	lzo_uint len = outsize;
 	int ret;
 
+	if (outsize >= 0x7FFFFFFF)
+		return 0;
+
 	ret = lzo1x_decompress_safe(in, size, out, &len, lzo->buffer);
 
 	if (ret != LZO_E_OK)
diff --git a/lib/sqfs/comp/xz.c b/lib/sqfs/comp/xz.c
index d905f2d..9e03df8 100644
--- a/lib/sqfs/comp/xz.c
+++ b/lib/sqfs/comp/xz.c
@@ -74,9 +74,9 @@ static int xz_read_options(sqfs_compressor_t *base, sqfs_file_t *file)
 	return 0;
 }
 
-static ssize_t compress(xz_compressor_t *xz, lzma_vli filter,
-			const sqfs_u8 *in, size_t size,
-			sqfs_u8 *out, size_t outsize)
+static sqfs_s32 compress(xz_compressor_t *xz, lzma_vli filter,
+			 const sqfs_u8 *in, sqfs_u32 size,
+			 sqfs_u8 *out, sqfs_u32 outsize)
 {
 	lzma_filter filters[5];
 	lzma_options_lzma opt;
@@ -135,13 +135,16 @@ static lzma_vli flag_to_vli(int flag)
 	return LZMA_VLI_UNKNOWN;
 }
 
-static ssize_t xz_comp_block(sqfs_compressor_t *base, const sqfs_u8 *in,
-			     size_t size, sqfs_u8 *out, size_t outsize)
+static sqfs_s32 xz_comp_block(sqfs_compressor_t *base, const sqfs_u8 *in,
+			      sqfs_u32 size, sqfs_u8 *out, sqfs_u32 outsize)
 {
 	xz_compressor_t *xz = (xz_compressor_t *)base;
 	lzma_vli filter, selected = LZMA_VLI_UNKNOWN;
-	size_t i, smallest;
-	ssize_t ret;
+	sqfs_s32 ret, smallest;
+	size_t i;
+
+	if (size >= 0x7FFFFFFF)
+		return 0;
 
 	ret = compress(xz, LZMA_VLI_UNKNOWN, in, size, out, outsize);
 	if (ret < 0 || xz->flags == 0)
@@ -159,7 +162,7 @@ static ssize_t xz_comp_block(sqfs_compressor_t *base, const sqfs_u8 *in,
 		if (ret < 0)
 			return ret;
 
-		if (ret > 0 && (smallest == 0 || (size_t)ret < smallest)) {
+		if (ret > 0 && (smallest == 0 || ret < smallest)) {
 			smallest = ret;
 			selected = filter;
 		}
@@ -171,8 +174,8 @@ static ssize_t xz_comp_block(sqfs_compressor_t *base, const sqfs_u8 *in,
 	return compress(xz, selected, in, size, out, outsize);
 }
 
-static ssize_t xz_uncomp_block(sqfs_compressor_t *base, const sqfs_u8 *in,
-			       size_t size, sqfs_u8 *out, size_t outsize)
+static sqfs_s32 xz_uncomp_block(sqfs_compressor_t *base, const sqfs_u8 *in,
+				sqfs_u32 size, sqfs_u8 *out, sqfs_u32 outsize)
 {
 	sqfs_u64 memlimit = 32 * 1024 * 1024;
 	size_t dest_pos = 0;
@@ -180,12 +183,15 @@ static ssize_t xz_uncomp_block(sqfs_compressor_t *base, const sqfs_u8 *in,
 	lzma_ret ret;
 	(void)base;
 
+	if (outsize >= 0x7FFFFFFF)
+		return 0;
+
 	ret = lzma_stream_buffer_decode(&memlimit, 0, NULL,
 					in, &src_pos, size,
 					out, &dest_pos, outsize);
 
 	if (ret == LZMA_OK && size == src_pos)
-		return (ssize_t)dest_pos;
+		return dest_pos;
 
 	return SQFS_ERROR_COMPRESSOR;
 }
diff --git a/lib/sqfs/comp/zstd.c b/lib/sqfs/comp/zstd.c
index 81e369b..b2e5d8b 100644
--- a/lib/sqfs/comp/zstd.c
+++ b/lib/sqfs/comp/zstd.c
@@ -51,12 +51,15 @@ static int zstd_read_options(sqfs_compressor_t *base, sqfs_file_t *file)
 	return 0;
 }
 
-static ssize_t zstd_comp_block(sqfs_compressor_t *base, const sqfs_u8 *in,
-			       size_t size, sqfs_u8 *out, size_t outsize)
+static sqfs_s32 zstd_comp_block(sqfs_compressor_t *base, const sqfs_u8 *in,
+				sqfs_u32 size, sqfs_u8 *out, sqfs_u32 outsize)
 {
 	zstd_compressor_t *zstd = (zstd_compressor_t *)base;
 	size_t ret;
 
+	if (size >= 0x7FFFFFFF)
+		return 0;
+
 	ret = ZSTD_compressCCtx(zstd->zctx, out, outsize, in, size,
 				zstd->level);
 
@@ -66,12 +69,15 @@ static ssize_t zstd_comp_block(sqfs_compressor_t *base, const sqfs_u8 *in,
 	return ret < size ? ret : 0;
 }
 
-static ssize_t zstd_uncomp_block(sqfs_compressor_t *base, const sqfs_u8 *in,
-				 size_t size, sqfs_u8 *out, size_t outsize)
+static sqfs_s32 zstd_uncomp_block(sqfs_compressor_t *base, const sqfs_u8 *in,
+				  sqfs_u32 size, sqfs_u8 *out, sqfs_u32 outsize)
 {
 	size_t ret;
 	(void)base;
 
+	if (outsize >= 0x7FFFFFFF)
+		return 0;
+
 	ret = ZSTD_decompress(out, outsize, in, size);
 
 	if (ZSTD_isError(ret))
diff --git a/lib/sqfs/data_reader.c b/lib/sqfs/data_reader.c
index 0befb9d..12a8feb 100644
--- a/lib/sqfs/data_reader.c
+++ b/lib/sqfs/data_reader.c
@@ -40,8 +40,8 @@ static int get_block(sqfs_data_reader_t *data, sqfs_u64 off, sqfs_u32 size,
 		     size_t unpacked_size, sqfs_block_t **out)
 {
 	sqfs_block_t *blk = alloc_flex(sizeof(*blk), 1, unpacked_size);
-	size_t on_disk_size;
-	ssize_t ret;
+	sqfs_u32 on_disk_size;
+	sqfs_s32 ret;
 	int err;
 
 	if (blk == NULL)
@@ -264,14 +264,17 @@ int sqfs_data_reader_get_fragment(sqfs_data_reader_t *data,
 	return 0;
 }
 
-ssize_t sqfs_data_reader_read(sqfs_data_reader_t *data,
-			      const sqfs_inode_generic_t *inode,
-			      sqfs_u64 offset, void *buffer, size_t size)
+sqfs_s32 sqfs_data_reader_read(sqfs_data_reader_t *data,
+			       const sqfs_inode_generic_t *inode,
+			       sqfs_u64 offset, void *buffer, sqfs_u32 size)
 {
-	sqfs_u32 frag_idx, frag_off;
-	size_t i, diff, total = 0;
+	sqfs_u32 frag_idx, frag_off, diff, total = 0;
 	sqfs_u64 off, filesz;
 	char *ptr;
+	size_t i;
+
+	if (size >= 0x7FFFFFFF)
+		size = 0x7FFFFFFE;
 
 	/* work out file location and size */
 	sqfs_inode_get_file_size(inode, &filesz);
diff --git a/lib/sqfs/meta_reader.c b/lib/sqfs/meta_reader.c
index d3c3565..b2fdfa9 100644
--- a/lib/sqfs/meta_reader.c
+++ b/lib/sqfs/meta_reader.c
@@ -71,8 +71,8 @@ int sqfs_meta_reader_seek(sqfs_meta_reader_t *m, sqfs_u64 block_start,
 {
 	bool compressed;
 	sqfs_u16 header;
-	ssize_t ret;
-	size_t size;
+	sqfs_u32 size;
+	sqfs_s32 ret;
 	int err;
 
 	if (block_start < m->start || block_start >= m->limit)
diff --git a/lib/sqfs/meta_writer.c b/lib/sqfs/meta_writer.c
index a5ce366..3cf3e3e 100644
--- a/lib/sqfs/meta_writer.c
+++ b/lib/sqfs/meta_writer.c
@@ -89,8 +89,8 @@ void sqfs_meta_writer_destroy(sqfs_meta_writer_t *m)
 int sqfs_meta_writer_flush(sqfs_meta_writer_t *m)
 {
 	meta_block_t *outblk;
-	size_t count;
-	ssize_t ret;
+	sqfs_u32 count;
+	sqfs_s32 ret;
 
 	if (m->offset == 0)
 		return 0;