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>

4 files changed, 131 insertions, 169 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);
 }
diff --git a/lib/io/src/win32/istream.c b/lib/io/src/win32/istream.c
index 0d002cc..46bed30 100644
--- a/lib/io/src/win32/istream.c
+++ b/lib/io/src/win32/istream.c
@@ -24,7 +24,6 @@ static int precache(istream_t *strm)
 {
 	file_istream_t *file = (file_istream_t *)strm;
 	DWORD diff, actual;
-	HANDLE hnd;
 
 	if (file->eof)
 		return 0;
@@ -38,12 +37,10 @@ static int precache(istream_t *strm)
 	file->buffer_used -= file->buffer_offset;
 	file->buffer_offset = 0;
 
-	hnd = file->path == NULL ? GetStdHandle(STD_INPUT_HANDLE) : file->hnd;
-
 	while (file->buffer_used < sizeof(file->buffer)) {
 		diff = sizeof(file->buffer) - file->buffer_used;
 
-		if (!ReadFile(hnd, file->buffer + file->buffer_used,
+		if (!ReadFile(file->hnd, file->buffer + file->buffer_used,
 			      diff, &actual, NULL)) {
 			DWORD error = GetLastError();
 
@@ -54,8 +51,7 @@ static int precache(istream_t *strm)
 			}
 
 			SetLastError(error);
-
-			w32_perror(file->path == NULL ? "stdin" : file->path);
+			w32_perror(file->path);
 			return -1;
 		}
 
@@ -103,28 +99,23 @@ static void file_advance_buffer(istream_t *strm, size_t count)
 
 static const char *file_get_filename(istream_t *strm)
 {
-	file_istream_t *file = (file_istream_t *)strm;
-
-	return file->path == NULL ? "stdin" : file->path;
+	return ((file_istream_t *)strm)->path;
 }
 
 static void file_destroy(sqfs_object_t *obj)
 {
 	file_istream_t *file = (file_istream_t *)obj;
 
-	if (file->path != NULL) {
-		CloseHandle(file->hnd);
-		free(file->path);
-	}
-
+	CloseHandle(file->hnd);
+	free(file->path);
 	free(file);
 }
 
-istream_t *istream_open_file(const char *path)
+istream_t *istream_open_handle(const char *path, HANDLE hnd)
 {
 	file_istream_t *file = calloc(1, sizeof(*file));
 	istream_t *strm = (istream_t *)file;
-	WCHAR *wpath = NULL;
+	BOOL ret;
 
 	if (file == NULL) {
 		perror(path);
@@ -133,25 +124,21 @@ istream_t *istream_open_file(const char *path)
 
 	sqfs_object_init(file, file_destroy, NULL);
 
-	wpath = path_to_windows(path);
-	if (wpath == NULL)
-		goto fail_free;
-
 	file->path = strdup(path);
 	if (file->path == NULL) {
 		perror(path);
 		goto fail_free;
 	}
 
-	file->hnd = CreateFileW(wpath, GENERIC_READ, FILE_SHARE_READ, NULL,
-			       OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
-
-	if (file->hnd == INVALID_HANDLE_VALUE) {
-		perror(path);
+	ret = DuplicateHandle(GetCurrentProcess(), hnd,
+			      GetCurrentProcess(), &file->hnd,
+			      0, FALSE, DUPLICATE_SAME_ACCESS);
+	if (!ret) {
+		w32_perror(path);
 		goto fail_path;
 	}
 
-	free(wpath);
+	CloseHandle(hnd);
 
 	strm->get_buffered_data = file_get_buffered_data;
 	strm->advance_buffer = file_advance_buffer;
@@ -160,25 +147,40 @@ istream_t *istream_open_file(const char *path)
 fail_path:
 	free(file->path);
 fail_free:
-	free(wpath);
 	free(file);
 	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;
+	WCHAR *wpath = path_to_windows(path);
+	istream_t *out;
+	HANDLE hnd;
 
-	if (file == NULL) {
-		perror("stdin");
+	if (wpath == NULL)
+		return NULL;
+
+	hnd = CreateFileW(wpath, GENERIC_READ, FILE_SHARE_READ, NULL,
+			  OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
+
+	if (hnd == INVALID_HANDLE_VALUE) {
+		w32_perror(path);
+		free(wpath);
 		return NULL;
 	}
 
-	sqfs_object_init(file, file_destroy, NULL);
+	free(wpath);
 
-	strm->get_buffered_data = file_get_buffered_data;
-	strm->advance_buffer = file_advance_buffer;
-	strm->get_filename = file_get_filename;
-	return strm;
+	out = istream_open_handle(path, hnd);
+	if (out == NULL)
+		CloseHandle(hnd);
+
+	return out;
+}
+
+istream_t *istream_open_stdin(void)
+{
+	HANDLE hnd = GetStdHandle(STD_INPUT_HANDLE);
+
+	return istream_open_handle("stdin", hnd);
 }
diff --git a/lib/io/src/win32/ostream.c b/lib/io/src/win32/ostream.c
index 0fe04f3..d18130f 100644
--- a/lib/io/src/win32/ostream.c
+++ b/lib/io/src/win32/ostream.c
@@ -15,14 +15,14 @@ typedef struct {
 	HANDLE hnd;
 } file_ostream_t;
 
-static int w32_append(HANDLE hnd, const char *filename,
-		      const void *data, size_t size)
+static int file_append(ostream_t *strm, const void *data, size_t size)
 {
+	file_ostream_t *file = (file_ostream_t *)strm;
 	DWORD diff;
 
 	while (size > 0) {
-		if (!WriteFile(hnd, data, size, &diff, NULL)) {
-			w32_perror(filename);
+		if (!WriteFile(file->hnd, data, size, &diff, NULL)) {
+			w32_perror(file->path);
 			return -1;
 		}
 
@@ -33,25 +33,6 @@ static int w32_append(HANDLE hnd, const char *filename,
 	return 0;
 }
 
-static int w32_flush(HANDLE hnd, const char *filename)
-{
-	if (!FlushFileBuffers(hnd)) {
-		w32_perror(filename);
-		return -1;
-	}
-
-	return 0;
-}
-
-/*****************************************************************************/
-
-static int file_append(ostream_t *strm, const void *data, size_t size)
-{
-	file_ostream_t *file = (file_ostream_t *)strm;
-
-	return w32_append(file->hnd, file->path, data, size);
-}
-
 static int file_append_sparse(ostream_t *strm, size_t size)
 {
 	file_ostream_t *file = (file_ostream_t *)strm;
@@ -75,7 +56,12 @@ static int file_flush(ostream_t *strm)
 {
 	file_ostream_t *file = (file_ostream_t *)strm;
 
-	return w32_flush(file->hnd, file->path);
+	if (!FlushFileBuffers(file->hnd)) {
+		w32_perror(file->path);
+		return -1;
+	}
+
+	return 0;
 }
 
 static void file_destroy(sqfs_object_t *obj)
@@ -94,41 +80,11 @@ static const char *file_get_filename(ostream_t *strm)
 	return file->path;
 }
 
-/*****************************************************************************/
-
-static int stdout_append(ostream_t *strm, const void *data, size_t size)
-{
-	(void)strm;
-	return w32_append(GetStdHandle(STD_OUTPUT_HANDLE), "stdout",
-			  data, size);
-}
-
-static int stdout_flush(ostream_t *strm)
-{
-	(void)strm;
-	return w32_flush(GetStdHandle(STD_OUTPUT_HANDLE), "stdout");
-}
-
-static void stdout_destroy(sqfs_object_t *obj)
-{
-	free(obj);
-}
-
-static const char *stdout_get_filename(ostream_t *strm)
-{
-	(void)strm;
-	return "stdout";
-}
-
-/*****************************************************************************/
-
-ostream_t *ostream_open_file(const char *path, int flags)
+ostream_t *ostream_open_handle(const char *path, HANDLE hnd, int flags)
 {
 	file_ostream_t *file = calloc(1, sizeof(*file));
-	sqfs_object_t *obj = (sqfs_object_t *)file;
 	ostream_t *strm = (ostream_t *)file;
-	int access_flags, creation_mode;
-	WCHAR *wpath = NULL;
+	BOOL ret;
 
 	if (file == NULL) {
 		perror(path);
@@ -137,33 +93,21 @@ ostream_t *ostream_open_file(const char *path, int flags)
 
 	sqfs_object_init(file, file_destroy, NULL);
 
-	wpath = path_to_windows(path);
-	if (wpath == NULL)
-		goto fail_free;
-
 	file->path = strdup(path);
 	if (file->path == NULL) {
 		perror(path);
 		goto fail_free;
 	}
 
-	access_flags = GENERIC_WRITE;
-
-	if (flags & OSTREAM_OPEN_OVERWRITE) {
-		creation_mode = CREATE_ALWAYS;
-	} else {
-		creation_mode = CREATE_NEW;
-	}
-
-	file->hnd = CreateFileW(wpath, access_flags, 0, NULL, creation_mode,
-				FILE_ATTRIBUTE_NORMAL, NULL);
-
-	if (file->hnd == INVALID_HANDLE_VALUE) {
+	ret = DuplicateHandle(GetCurrentProcess(), hnd,
+			      GetCurrentProcess(), &file->hnd,
+			      0, FALSE, DUPLICATE_SAME_ACCESS);
+	if (!ret) {
 		w32_perror(path);
 		goto fail_path;
 	}
 
-	free(wpath);
+	CloseHandle(hnd);
 
 	if (flags & OSTREAM_OPEN_SPARSE)
 		strm->append_sparse = file_append_sparse;
@@ -176,24 +120,48 @@ fail_path:
 	free(file->path);
 fail_free:
 	free(file);
-	free(wpath);
 	return NULL;
 }
 
-ostream_t *ostream_open_stdout(void)
+ostream_t *ostream_open_file(const char *path, int flags)
 {
-	ostream_t *strm = calloc(1, sizeof(*strm));
-	sqfs_object_t *obj = (sqfs_object_t *)strm;
+	WCHAR *wpath = path_to_windows(path);
+	int access_flags, creation_mode;
+	ostream_t *out;
+	HANDLE hnd;
 
-	if (strm == NULL) {
-		perror("creating stdout file wrapper");
+	if (wpath == NULL)
 		return NULL;
+
+	access_flags = GENERIC_WRITE;
+
+	if (flags & OSTREAM_OPEN_OVERWRITE) {
+		creation_mode = CREATE_ALWAYS;
+	} else {
+		creation_mode = CREATE_NEW;
 	}
 
-	sqfs_object_init(strm, stdout_destroy, NULL);
+	hnd = CreateFileW(wpath, access_flags, 0, NULL, creation_mode,
+			  FILE_ATTRIBUTE_NORMAL, NULL);
 
-	strm->append = stdout_append;
-	strm->flush = stdout_flush;
-	strm->get_filename = stdout_get_filename;
-	return strm;
+	if (hnd == INVALID_HANDLE_VALUE) {
+		w32_perror(path);
+		free(wpath);
+		return NULL;
+	}
+
+	free(wpath);
+
+	out = ostream_open_handle(path, hnd, flags);
+	if (out == NULL)
+		CloseHandle(hnd);
+
+	return out;
+}
+
+ostream_t *ostream_open_stdout(void)
+{
+	HANDLE hnd = GetStdHandle(STD_OUTPUT_HANDLE);
+
+	return ostream_open_handle("stdout", hnd, 0);
 }