Add an implementation for an sqfs_file_t writing to stdout

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

2 files changed, 94 insertions, 13 deletions

diff --git a/include/common.h b/include/common.h
index d4e11c4..19c95a3 100644
--- a/include/common.h
+++ b/include/common.h
@@ -120,6 +120,8 @@ int sqfs_data_reader_dump(const char *name, sqfs_data_reader_t *data,
 
 sqfs_file_t *sqfs_get_stdin_file(const sparse_map_t *map, sqfs_u64 size);
 
+sqfs_file_t *sqfs_get_stdout_file(void);
+
 void register_stat_hooks(sqfs_data_writer_t *data, data_writer_stats_t *stats);
 
 int write_data_from_file(const char *filename, sqfs_data_writer_t *data,
diff --git a/lib/common/io_stdin.c b/lib/common/io_stdin.c
index 0e9fb17..9e96e45 100644
--- a/lib/common/io_stdin.c
+++ b/lib/common/io_stdin.c
@@ -18,18 +18,31 @@ typedef struct {
 	const sparse_map_t *map;
 	sqfs_u64 offset;
 	sqfs_u64 size;
-} sqfs_file_stdin_t;
+} sqfs_file_stdinout_t;
 
 
-static void stdin_destroy(sqfs_file_t *base)
+static void stdinout_destroy(sqfs_file_t *base)
 {
 	free(base);
 }
 
+static sqfs_u64 stdinout_get_size(const sqfs_file_t *base)
+{
+	return ((const sqfs_file_stdinout_t *)base)->size;
+}
+
+static int stdinout_truncate(sqfs_file_t *base, sqfs_u64 size)
+{
+	(void)base; (void)size;
+	return SQFS_ERROR_IO;
+}
+
+/*****************************************************************************/
+
 static int stdin_read_at(sqfs_file_t *base, sqfs_u64 offset,
 			 void *buffer, size_t size)
 {
-	sqfs_file_stdin_t *file = (sqfs_file_stdin_t *)base;
+	sqfs_file_stdinout_t *file = (sqfs_file_stdinout_t *)base;
 	size_t temp_size = 0;
 	sqfs_u8 *temp = NULL;
 	sqfs_u64 diff;
@@ -80,7 +93,7 @@ static int stdin_read_at(sqfs_file_t *base, sqfs_u64 offset,
 static int stdin_read_condensed(sqfs_file_t *base, sqfs_u64 offset,
 				void *buffer, size_t size)
 {
-	sqfs_file_stdin_t *file = (sqfs_file_stdin_t *)base;
+	sqfs_file_stdinout_t *file = (sqfs_file_stdinout_t *)base;
 	sqfs_u64 poffset = 0, src_start;
 	size_t dst_start, diff, count;
 	const sparse_map_t *it;
@@ -138,20 +151,69 @@ static int stdin_write_at(sqfs_file_t *base, sqfs_u64 offset,
 	return SQFS_ERROR_IO;
 }
 
-static sqfs_u64 stdin_get_size(const sqfs_file_t *base)
+/*****************************************************************************/
+
+static int stdout_read_at(sqfs_file_t *base, sqfs_u64 offset,
+			  void *buffer, size_t size)
 {
-	return ((const sqfs_file_stdin_t *)base)->size;
+	(void)base; (void)offset; (void)buffer; (void)size;
+	return SQFS_ERROR_IO;
 }
 
-static int stdin_truncate(sqfs_file_t *base, sqfs_u64 size)
+static int stdout_write_at(sqfs_file_t *base, sqfs_u64 offset,
+			   const void *buffer, size_t size)
 {
-	(void)base; (void)size;
-	return SQFS_ERROR_IO;
+	sqfs_file_stdinout_t *file = (sqfs_file_stdinout_t *)base;
+	size_t temp_size = 0;
+	sqfs_u8 *temp = NULL;
+	sqfs_u64 diff;
+	ssize_t ret;
+
+	if (offset < file->size)
+		return SQFS_ERROR_IO;
+
+	if (offset > file->size) {
+		temp_size = 1024;
+		temp = alloca(temp_size);
+		memset(temp, 0, temp_size);
+	}
+
+	while (size > 0) {
+		if (offset > file->size) {
+			diff = offset - file->size;
+			diff = diff > (sqfs_u64)temp_size ? temp_size : diff;
+
+			ret = write(STDOUT_FILENO, temp, diff);
+		} else {
+			ret = write(STDOUT_FILENO, buffer, size);
+		}
+
+		if (ret < 0) {
+			if (errno == EINTR)
+				continue;
+			return SQFS_ERROR_IO;
+		}
+
+		if (ret == 0)
+			return SQFS_ERROR_OUT_OF_BOUNDS;
+
+		if (offset <= file->size) {
+			buffer = (char *)buffer + ret;
+			size -= ret;
+			offset += ret;
+		}
+
+		file->size += ret;
+	}
+
+	return 0;
 }
 
+/*****************************************************************************/
+
 sqfs_file_t *sqfs_get_stdin_file(const sparse_map_t *map, sqfs_u64 size)
 {
-	sqfs_file_stdin_t *file = calloc(1, sizeof(*file));
+	sqfs_file_stdinout_t *file = calloc(1, sizeof(*file));
 	sqfs_file_t *base = (sqfs_file_t *)file;
 
 	if (file == NULL)
@@ -160,10 +222,10 @@ sqfs_file_t *sqfs_get_stdin_file(const sparse_map_t *map, sqfs_u64 size)
 	file->size = size;
 	file->map = map;
 
-	base->destroy = stdin_destroy;
+	base->destroy = stdinout_destroy;
 	base->write_at = stdin_write_at;
-	base->get_size = stdin_get_size;
-	base->truncate = stdin_truncate;
+	base->get_size = stdinout_get_size;
+	base->truncate = stdinout_truncate;
 
 	if (map == NULL) {
 		base->read_at = stdin_read_at;
@@ -172,3 +234,20 @@ sqfs_file_t *sqfs_get_stdin_file(const sparse_map_t *map, sqfs_u64 size)
 	}
 	return base;
 }
+
+sqfs_file_t *sqfs_get_stdout_file(void)
+{
+	sqfs_file_stdinout_t *file = calloc(1, sizeof(*file));
+	sqfs_file_t *base = (sqfs_file_t *)file;
+
+	if (file == NULL)
+		return NULL;
+
+	base->destroy = stdinout_destroy;
+	base->write_at = stdout_write_at;
+	base->get_size = stdinout_get_size;
+	base->truncate = stdinout_truncate;
+	base->read_at = stdout_read_at;
+
+	return base;
+}