libio: add open handle functions to istream/ostream

For the backends, this simplifies the code as both paths (open file
and open stdio) use the same basic code. Even when merging them only
in the backend, it would be done in a similar way. Making the
functions public allows other uses as well.

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

2 files changed, 40 insertions, 48 deletions

diff --git a/lib/io/src/unix/istream.c b/lib/io/src/unix/istream.c
index 60abff1..e96bc6c 100644
--- a/lib/io/src/unix/istream.c
+++ b/lib/io/src/unix/istream.c
@@ -105,7 +105,7 @@ static void file_destroy(sqfs_object_t *obj)
 	free(file);
 }
 
-istream_t *istream_open_file(const char *path)
+istream_t *istream_open_handle(const char *path, int fd)
 {
 	file_istream_t *file = calloc(1, sizeof(*file));
 	istream_t *strm = (istream_t *)file;
@@ -123,11 +123,12 @@ istream_t *istream_open_file(const char *path)
 		goto fail_free;
 	}
 
-	file->fd = open(path, O_RDONLY);
+	file->fd = dup(fd);
 	if (file->fd < 0) {
 		perror(path);
 		goto fail_path;
 	}
+	close(fd);
 
 	strm->get_buffered_data = file_get_buffered_data;
 	strm->advance_buffer = file_advance_buffer;
@@ -140,27 +141,25 @@ fail_free:
 	return NULL;
 }
 
-istream_t *istream_open_stdin(void)
+istream_t *istream_open_file(const char *path)
 {
-	file_istream_t *file = calloc(1, sizeof(*file));
-	istream_t *strm = (istream_t *)file;
+	istream_t *out;
+	int fd;
 
-	if (file == NULL)
-		goto fail;
+	fd = open(path, O_RDONLY);
+	if (fd < 0) {
+		perror(path);
+		return NULL;
+	}
 
-	sqfs_object_init(file, file_destroy, NULL);
+	out = istream_open_handle(path, fd);
+	if (out == NULL)
+		close(fd);
 
-	file->path = strdup("stdin");
-	if (file->path == NULL)
-		goto fail;
+	return out;
+}
 
-	file->fd = STDIN_FILENO;
-	strm->get_buffered_data = file_get_buffered_data;
-	strm->advance_buffer = file_advance_buffer;
-	strm->get_filename = file_get_filename;
-	return strm;
-fail:
-	perror("creating file wrapper for stdin");
-	free(file);
-	return NULL;
+istream_t *istream_open_stdin(void)
+{
+	return istream_open_handle("stdin", STDIN_FILENO);
 }
diff --git a/lib/io/src/unix/ostream.c b/lib/io/src/unix/ostream.c
index 5ef2af2..294a15e 100644
--- a/lib/io/src/unix/ostream.c
+++ b/lib/io/src/unix/ostream.c
@@ -90,9 +90,7 @@ static void file_destroy(sqfs_object_t *obj)
 {
 	file_ostream_t *file = (file_ostream_t *)obj;
 
-	if (file->fd != STDOUT_FILENO)
-		close(file->fd);
-
+	close(file->fd);
 	free(file->path);
 	free(file);
 }
@@ -104,7 +102,7 @@ static const char *file_get_filename(ostream_t *strm)
 	return file->path;
 }
 
-ostream_t *ostream_open_file(const char *path, int flags)
+ostream_t *ostream_open_handle(const char *path, int fd, int flags)
 {
 	file_ostream_t *file = calloc(1, sizeof(*file));
 	ostream_t *strm = (ostream_t *)file;
@@ -122,17 +120,14 @@ ostream_t *ostream_open_file(const char *path, int flags)
 		goto fail_free;
 	}
 
-	if (flags & OSTREAM_OPEN_OVERWRITE) {
-		file->fd = open(path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
-	} else {
-		file->fd = open(path, O_WRONLY | O_CREAT | O_EXCL, 0644);
-	}
-
+	file->fd = dup(fd);
 	if (file->fd < 0) {
 		perror(path);
 		goto fail_path;
 	}
 
+	close(fd);
+
 	if (flags & OSTREAM_OPEN_SPARSE)
 		strm->append_sparse = file_append_sparse;
 
@@ -147,27 +142,25 @@ fail_free:
 	return NULL;
 }
 
-ostream_t *ostream_open_stdout(void)
+ostream_t *ostream_open_file(const char *path, int flags)
 {
-	file_ostream_t *file = calloc(1, sizeof(*file));
-	ostream_t *strm = (ostream_t *)file;
+	ostream_t *out;
+	int fd;
 
-	if (file == NULL)
-		goto fail;
+	if (flags & OSTREAM_OPEN_OVERWRITE) {
+		fd = open(path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
+	} else {
+		fd = open(path, O_WRONLY | O_CREAT | O_EXCL, 0644);
+	}
 
-	file->path = strdup("stdout");
-	if (file->path == NULL)
-		goto fail;
+	out = ostream_open_handle(path, fd, flags);
+	if (out == NULL)
+		close(fd);
 
-	file->fd = STDOUT_FILENO;
-	strm->append = file_append;
-	strm->flush = file_flush;
-	strm->get_filename = file_get_filename;
+	return out;
+}
 
-	sqfs_object_init(file, file_destroy, NULL);
-	return strm;
-fail:
-	perror("creating file wrapper for stdout");
-	free(file);
-	return NULL;
+ostream_t *ostream_open_stdout(void)
+{
+	return ostream_open_handle("stdout", STDOUT_FILENO, 0);
 }