Replace file descriptor IO in data_writer with sqfs_file_t

First, this commit moves the create-blocks-from-fd function over to
libsquashfs and ports it to work on an sqfs_file_t instead.

Second, the function in the data_writer that reads from a file descriptor
is adjusted to use an sqfs_file_t instead.

Finally, the tools that use it have to be adjusted accordingly.

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

8 files changed, 223 insertions, 171 deletions

diff --git a/include/data_writer.h b/include/data_writer.h
index 5987cd6..c9e6f20 100644
--- a/include/data_writer.h
+++ b/include/data_writer.h
@@ -84,8 +84,8 @@ int data_writer_sync(data_writer_t *data);
 
   Returns 0 on success, prints errors to stderr.
 */
-int write_data_from_fd(data_writer_t *data, file_info_t *fi, int infd,
-		       int flags);
+int write_data_from_file(data_writer_t *data, file_info_t *fi,
+			 sqfs_file_t *file, int flags);
 
 /*
   Does the same as write_data_from_fd but the input file is the condensed
diff --git a/include/sqfs/io.h b/include/sqfs/io.h
index a544875..9784113 100644
--- a/include/sqfs/io.h
+++ b/include/sqfs/io.h
@@ -150,9 +150,31 @@ SQFS_API sqfs_file_t *sqfs_open_file(const char *filename, int flags);
  * reading sequentially.
  *
  * @param size The alleged "size" of the file.
+ *
+ * @return A pointer to a file object on success, NULL on allocation failure.
  */
 SQFS_API sqfs_file_t *sqfs_get_stdin_file(uint64_t size);
 
+
+/**
+ * @brief Read a chunk from a file and turn it into a block that can be
+ *        fed to a block processor.
+ *
+ * @member sqfs_file_t
+ *
+ * @param file A pointer to a file implementation.
+ * @param offset A byte offset into the file.
+ * @param size The number of bytes to read, starting at the given offset.
+ * @param user A user pointer to set for the block.
+ * @param flags The flags to store in the newly created block.
+ * @param out Returns a pointer to a block on success.
+ *
+ * @return Zero on success, an @ref E_SQFS_ERROR identifier on failure.
+ */
+SQFS_API int sqfs_file_create_block(sqfs_file_t *file, uint64_t offset,
+				    size_t size, void *user, uint32_t flags,
+				    sqfs_block_t **out);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/sqfs/Makemodule.am b/lib/sqfs/Makemodule.am
index b58a28b..7d228a4 100644
--- a/lib/sqfs/Makemodule.am
+++ b/lib/sqfs/Makemodule.am
@@ -7,14 +7,14 @@ LIBSQFS_HEARDS = include/sqfs/data.h include/sqfs/meta_writer.h \
 		include/sqfs/error.h include/sqfs/io.h
 
 libsquashfs_la_SOURCES = $(LIBSQFS_HEARDS) lib/sqfs/id_table.c lib/sqfs/super.c
-libsquashfs_la_SOURCES += lib/sqfs/readdir.c lib/sqfs/io.c lib/sqfs/xattr.c
+libsquashfs_la_SOURCES += lib/sqfs/readdir.c lib/sqfs/io_file.c lib/sqfs/xattr.c
 libsquashfs_la_SOURCES += lib/sqfs/write_table.c lib/sqfs/meta_writer.c
 libsquashfs_la_SOURCES += lib/sqfs/read_super.c lib/sqfs/meta_reader.c
 libsquashfs_la_SOURCES += lib/sqfs/read_inode.c lib/sqfs/write_inode.c
 libsquashfs_la_SOURCES += lib/sqfs/dir_writer.c lib/sqfs/xattr_reader.c
 libsquashfs_la_SOURCES += lib/sqfs/read_table.c lib/sqfs/comp/compressor.c
 libsquashfs_la_SOURCES += lib/sqfs/io_stdin.c lib/sqfs/comp/internal.h
-libsquashfs_la_SOURCES += lib/sqfs/blk_proc/process_block.c
+libsquashfs_la_SOURCES += lib/sqfs/blk_proc/process_block.c lib/sqfs/io.c
 libsquashfs_la_SOURCES += lib/sqfs/blk_proc/internal.h
 libsquashfs_la_CPPFLAGS = $(AM_CPPFLAGS)
 libsquashfs_la_CFLAGS = $(AM_CFLAGS) $(PTHREAD_CFLAGS) $(ZLIB_CFLAGS)
diff --git a/lib/sqfs/io.c b/lib/sqfs/io.c
index f8773d0..4afb489 100644
--- a/lib/sqfs/io.c
+++ b/lib/sqfs/io.c
@@ -9,143 +9,31 @@
 
 #include "sqfs/io.h"
 #include "sqfs/error.h"
+#include "sqfs/block_processor.h"
+#include "util.h"
 
 #include <stdlib.h>
-#include <unistd.h>
-#include <errno.h>
-#include <fcntl.h>
 
-
-typedef struct {
-	sqfs_file_t base;
-
-	uint64_t size;
-	int fd;
-} sqfs_file_stdio_t;
-
-
-static void stdio_destroy(sqfs_file_t *base)
-{
-	sqfs_file_stdio_t *file = (sqfs_file_stdio_t *)base;
-
-	close(file->fd);
-	free(file);
-}
-
-static int stdio_read_at(sqfs_file_t *base, uint64_t offset,
-			 void *buffer, size_t size)
-{
-	sqfs_file_stdio_t *file = (sqfs_file_stdio_t *)base;
-	ssize_t ret;
-
-	while (size > 0) {
-		ret = pread(file->fd, buffer, size, offset);
-
-		if (ret < 0) {
-			if (errno == EINTR)
-				continue;
-			return SQFS_ERROR_IO;
-		}
-
-		if (ret == 0)
-			return SQFS_ERROR_OUT_OF_BOUNDS;
-
-		buffer = (char *)buffer + ret;
-		size -= ret;
-		offset += ret;
-	}
-
-	return 0;
-}
-
-static int stdio_write_at(sqfs_file_t *base, uint64_t offset,
-			  const void *buffer, size_t size)
+int sqfs_file_create_block(sqfs_file_t *file, uint64_t offset,
+			   size_t size, void *user, uint32_t flags,
+			   sqfs_block_t **out)
 {
-	sqfs_file_stdio_t *file = (sqfs_file_stdio_t *)base;
-	ssize_t ret;
-
-	while (size > 0) {
-		ret = pwrite(file->fd, buffer, size, offset);
-
-		if (ret < 0) {
-			if (errno == EINTR)
-				continue;
-			return SQFS_ERROR_IO;
-		}
+	sqfs_block_t *blk = alloc_flex(sizeof(*blk), 1, size);
+	int err;
 
-		if (ret == 0)
-			return SQFS_ERROR_OUT_OF_BOUNDS;
+	if (blk == NULL)
+		return SQFS_ERROR_ALLOC;
 
-		buffer = (const char *)buffer + ret;
-		size -= ret;
-		offset += ret;
+	err = file->read_at(file, offset, blk->data, size);
+	if (err) {
+		free(blk);
+		return err;
 	}
 
-	if (offset >= file->size)
-		file->size = offset;
+	blk->user = user;
+	blk->size = size;
+	blk->flags = flags;
 
+	*out = blk;
 	return 0;
 }
-
-static uint64_t stdio_get_size(const sqfs_file_t *base)
-{
-	const sqfs_file_stdio_t *file = (const sqfs_file_stdio_t *)base;
-
-	return file->size;
-}
-
-static int stdio_truncate(sqfs_file_t *base, uint64_t size)
-{
-	sqfs_file_stdio_t *file = (sqfs_file_stdio_t *)base;
-
-	if (ftruncate(file->fd, size))
-		return SQFS_ERROR_IO;
-
-	file->size = size;
-	return 0;
-}
-
-
-sqfs_file_t *sqfs_open_file(const char *filename, int flags)
-{
-	sqfs_file_stdio_t *file;
-	int open_mode, temp;
-	sqfs_file_t *base;
-
-	if (flags & ~SQFS_FILE_OPEN_ALL_FLAGS) {
-		errno = EINVAL;
-		return NULL;
-	}
-
-	file = calloc(1, sizeof(*file));
-	base = (sqfs_file_t *)file;
-	if (file == NULL)
-		return NULL;
-
-	if (flags & SQFS_FILE_OPEN_READ_ONLY) {
-		open_mode = O_RDONLY;
-	} else {
-		open_mode = O_CREAT | O_RDWR;
-
-		if (flags & SQFS_FILE_OPEN_OVERWRITE) {
-			open_mode |= O_TRUNC;
-		} else {
-			open_mode |= O_EXCL;
-		}
-	}
-
-	file->fd = open(filename, open_mode, 0600);
-	if (file->fd < 0) {
-		temp = errno;
-		free(file);
-		errno = temp;
-		return NULL;
-	}
-
-	base->destroy = stdio_destroy;
-	base->read_at = stdio_read_at;
-	base->write_at = stdio_write_at;
-	base->get_size = stdio_get_size;
-	base->truncate = stdio_truncate;
-	return base;
-}
diff --git a/lib/sqfs/io_file.c b/lib/sqfs/io_file.c
new file mode 100644
index 0000000..b57eddd
--- /dev/null
+++ b/lib/sqfs/io_file.c
@@ -0,0 +1,151 @@
+/* SPDX-License-Identifier: LGPL-3.0-or-later */
+/*
+ * io_file.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#define SQFS_BUILDING_DLL
+#include "config.h"
+
+#include "sqfs/io.h"
+#include "sqfs/error.h"
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <fcntl.h>
+
+
+typedef struct {
+	sqfs_file_t base;
+
+	uint64_t size;
+	int fd;
+} sqfs_file_stdio_t;
+
+
+static void stdio_destroy(sqfs_file_t *base)
+{
+	sqfs_file_stdio_t *file = (sqfs_file_stdio_t *)base;
+
+	close(file->fd);
+	free(file);
+}
+
+static int stdio_read_at(sqfs_file_t *base, uint64_t offset,
+			 void *buffer, size_t size)
+{
+	sqfs_file_stdio_t *file = (sqfs_file_stdio_t *)base;
+	ssize_t ret;
+
+	while (size > 0) {
+		ret = pread(file->fd, buffer, size, offset);
+
+		if (ret < 0) {
+			if (errno == EINTR)
+				continue;
+			return SQFS_ERROR_IO;
+		}
+
+		if (ret == 0)
+			return SQFS_ERROR_OUT_OF_BOUNDS;
+
+		buffer = (char *)buffer + ret;
+		size -= ret;
+		offset += ret;
+	}
+
+	return 0;
+}
+
+static int stdio_write_at(sqfs_file_t *base, uint64_t offset,
+			  const void *buffer, size_t size)
+{
+	sqfs_file_stdio_t *file = (sqfs_file_stdio_t *)base;
+	ssize_t ret;
+
+	while (size > 0) {
+		ret = pwrite(file->fd, buffer, size, offset);
+
+		if (ret < 0) {
+			if (errno == EINTR)
+				continue;
+			return SQFS_ERROR_IO;
+		}
+
+		if (ret == 0)
+			return SQFS_ERROR_OUT_OF_BOUNDS;
+
+		buffer = (const char *)buffer + ret;
+		size -= ret;
+		offset += ret;
+	}
+
+	if (offset >= file->size)
+		file->size = offset;
+
+	return 0;
+}
+
+static uint64_t stdio_get_size(const sqfs_file_t *base)
+{
+	const sqfs_file_stdio_t *file = (const sqfs_file_stdio_t *)base;
+
+	return file->size;
+}
+
+static int stdio_truncate(sqfs_file_t *base, uint64_t size)
+{
+	sqfs_file_stdio_t *file = (sqfs_file_stdio_t *)base;
+
+	if (ftruncate(file->fd, size))
+		return SQFS_ERROR_IO;
+
+	file->size = size;
+	return 0;
+}
+
+
+sqfs_file_t *sqfs_open_file(const char *filename, int flags)
+{
+	sqfs_file_stdio_t *file;
+	int open_mode, temp;
+	sqfs_file_t *base;
+
+	if (flags & ~SQFS_FILE_OPEN_ALL_FLAGS) {
+		errno = EINVAL;
+		return NULL;
+	}
+
+	file = calloc(1, sizeof(*file));
+	base = (sqfs_file_t *)file;
+	if (file == NULL)
+		return NULL;
+
+	if (flags & SQFS_FILE_OPEN_READ_ONLY) {
+		open_mode = O_RDONLY;
+	} else {
+		open_mode = O_CREAT | O_RDWR;
+
+		if (flags & SQFS_FILE_OPEN_OVERWRITE) {
+			open_mode |= O_TRUNC;
+		} else {
+			open_mode |= O_EXCL;
+		}
+	}
+
+	file->fd = open(filename, open_mode, 0600);
+	if (file->fd < 0) {
+		temp = errno;
+		free(file);
+		errno = temp;
+		return NULL;
+	}
+
+	base->destroy = stdio_destroy;
+	base->read_at = stdio_read_at;
+	base->write_at = stdio_write_at;
+	base->get_size = stdio_get_size;
+	base->truncate = stdio_truncate;
+	return base;
+}
diff --git a/lib/sqfshelper/data_writer.c b/lib/sqfshelper/data_writer.c
index 43d5851..edd1770 100644
--- a/lib/sqfshelper/data_writer.c
+++ b/lib/sqfshelper/data_writer.c
@@ -319,34 +319,11 @@ static int add_sentinel_block(data_writer_t *data, file_info_t *fi,
 	return sqfs_block_processor_enqueue(data->proc, blk);
 }
 
-static sqfs_block_t *create_block(file_info_t *fi, int fd, size_t size,
-				  uint32_t flags)
-{
-	sqfs_block_t *blk = alloc_flex(sizeof(*blk), 1, size);
-
-	if (blk == NULL) {
-		perror(fi->input_file);
-		return NULL;
-	}
-
-	if (fd >= 0) {
-		if (read_data(fi->input_file, fd, blk->data, size)) {
-			free(blk);
-			return NULL;
-		}
-	}
-
-	blk->size = size;
-	blk->user = fi;
-	blk->flags = flags;
-	return blk;
-}
-
-int write_data_from_fd(data_writer_t *data, file_info_t *fi,
-		       int infd, int flags)
+int write_data_from_file(data_writer_t *data, file_info_t *fi,
+			 sqfs_file_t *file, int flags)
 {
 	uint32_t blk_flags = BLK_FIRST_BLOCK;
-	uint64_t file_size = fi->size;
+	uint64_t offset, file_size;
 	size_t diff, i = 0;
 	sqfs_block_t *blk;
 
@@ -356,16 +333,19 @@ int write_data_from_fd(data_writer_t *data, file_info_t *fi,
 	if (flags & DW_ALLIGN_DEVBLK)
 		blk_flags |= BLK_ALLIGN;
 
-	for (; file_size > 0; file_size -= diff) {
-		if (file_size > data->super->block_size) {
+	file_size = file->get_size(file);
+
+	for (offset = 0; offset < file_size; offset += diff) {
+		if (file_size - offset > data->super->block_size) {
 			diff = data->super->block_size;
 		} else {
-			diff = file_size;
+			diff = file_size - offset;
 		}
 
-		blk = create_block(fi, infd, diff, blk_flags);
-		if (blk == NULL)
+		if (sqfs_file_create_block(file, offset, diff, fi,
+					   blk_flags, &blk)) {
 			return -1;
+		}
 
 		blk->index = i++;
 
@@ -405,7 +385,7 @@ int write_data_from_fd(data_writer_t *data, file_info_t *fi,
 			return -1;
 	}
 
-	data->stats.bytes_read += fi->size;
+	data->stats.bytes_read += file_size;
 	data->stats.file_count += 1;
 	return 0;
 }
diff --git a/mkfs/mkfs.c b/mkfs/mkfs.c
index a046cbd..cb65eda 100644
--- a/mkfs/mkfs.c
+++ b/mkfs/mkfs.c
@@ -30,8 +30,9 @@ static int restore_working_dir(options_t *opt)
 
 static int pack_files(data_writer_t *data, fstree_t *fs, options_t *opt)
 {
+	sqfs_file_t *file;
 	file_info_t *fi;
-	int ret, infd;
+	int ret;
 
 	if (set_working_dir(opt))
 		return -1;
@@ -40,14 +41,16 @@ static int pack_files(data_writer_t *data, fstree_t *fs, options_t *opt)
 		if (!opt->quiet)
 			printf("packing %s\n", fi->input_file);
 
-		infd = open(fi->input_file, O_RDONLY);
-		if (infd < 0) {
+		file = sqfs_open_file(fi->input_file,
+				      SQFS_FILE_OPEN_READ_ONLY);
+		if (file == NULL) {
 			perror(fi->input_file);
 			return -1;
 		}
 
-		ret = write_data_from_fd(data, fi, infd, 0);
-		close(infd);
+		ret = write_data_from_file(data, fi, file, 0);
+		file->destroy(file);
+
 		if (ret)
 			return -1;
 	}
diff --git a/tar/tar2sqfs.c b/tar/tar2sqfs.c
index 13276b8..d693aa1 100644
--- a/tar/tar2sqfs.c
+++ b/tar/tar2sqfs.c
@@ -225,6 +225,7 @@ fail_arg:
 static int write_file(tar_header_decoded_t *hdr, file_info_t *fi,
 		      data_writer_t *data)
 {
+	sqfs_file_t *file;
 	int ret;
 
 	if (hdr->sparse != NULL) {
@@ -236,9 +237,16 @@ static int write_file(tar_header_decoded_t *hdr, file_info_t *fi,
 		return skip_padding(STDIN_FILENO, hdr->record_size);
 	}
 
-	if (write_data_from_fd(data, fi, STDIN_FILENO, 0))
+	file = sqfs_get_stdin_file(fi->size);
+	if (file == NULL) {
+		perror("packing files");
+		return -1;
+	}
+
+	if (write_data_from_file(data, fi, file, 0))
 		return -1;
 
+	file->destroy(file);
 	return skip_padding(STDIN_FILENO, fi->size);
 }