libsparse: add support for including fds
Add sparse_file_add_fd to include all or part of the contents
of an fd in the output file. Will be useful for re-sparsing files
where fd will point to the input sparse file.
Change-Id: I5d4ab07fb37231e8e9c1912f62a2968c8b0a00ef
diff --git a/libsparse/backed_block.c b/libsparse/backed_block.c
index b259190..8c3fab0 100644
--- a/libsparse/backed_block.c
+++ b/libsparse/backed_block.c
@@ -35,6 +35,10 @@
int64_t offset;
} file;
struct {
+ int fd;
+ int64_t offset;
+ } fd;
+ struct {
uint32_t val;
} fill;
};
@@ -78,10 +82,20 @@
return bb->file.filename;
}
+int backed_block_fd(struct backed_block *bb)
+{
+ assert(bb->type == BACKED_BLOCK_FD);
+ return bb->fd.fd;
+}
+
int64_t backed_block_file_offset(struct backed_block *bb)
{
- assert(bb->type == BACKED_BLOCK_FILE);
- return bb->file.offset;
+ assert(bb->type == BACKED_BLOCK_FILE || bb->type == BACKED_BLOCK_FD);
+ if (bb->type == BACKED_BLOCK_FILE) {
+ return bb->file.offset;
+ } else { /* bb->type == BACKED_BLOCK_FD */
+ return bb->fd.offset;
+ }
}
uint32_t backed_block_fill_val(struct backed_block *bb)
@@ -211,3 +225,22 @@
return queue_bb(bbl, bb);
}
+
+/* Queues a chunk of a fd to be written to the specified data blocks */
+int backed_block_add_fd(struct backed_block_list *bbl, int fd, int64_t offset,
+ unsigned int len, unsigned int block)
+{
+ struct backed_block *bb = calloc(1, sizeof(struct backed_block));
+ if (bb == NULL) {
+ return -ENOMEM;
+ }
+
+ bb->block = block;
+ bb->len = len;
+ bb->type = BACKED_BLOCK_FD;
+ bb->fd.fd = fd;
+ bb->fd.offset = offset;
+ bb->next = NULL;
+
+ return queue_bb(bbl, bb);
+}
diff --git a/libsparse/backed_block.h b/libsparse/backed_block.h
index 3166505..ca2ad1d 100644
--- a/libsparse/backed_block.h
+++ b/libsparse/backed_block.h
@@ -25,6 +25,7 @@
enum backed_block_type {
BACKED_BLOCK_DATA,
BACKED_BLOCK_FILE,
+ BACKED_BLOCK_FD,
BACKED_BLOCK_FILL,
};
@@ -34,6 +35,8 @@
unsigned int len, unsigned int block);
int backed_block_add_file(struct backed_block_list *bbl, const char *filename,
int64_t offset, unsigned int len, unsigned int block);
+int backed_block_add_fd(struct backed_block_list *bbl, int fd,
+ int64_t offset, unsigned int len, unsigned int block);
struct backed_block *backed_block_iter_new(struct backed_block_list *bbl);
struct backed_block *backed_block_iter_next(struct backed_block *bb);
@@ -41,6 +44,7 @@
unsigned int backed_block_block(struct backed_block *bb);
void *backed_block_data(struct backed_block *bb);
const char *backed_block_filename(struct backed_block *bb);
+int backed_block_fd(struct backed_block *bb);
int64_t backed_block_file_offset(struct backed_block *bb);
uint32_t backed_block_fill_val(struct backed_block *bb);
enum backed_block_type backed_block_type(struct backed_block *bb);
diff --git a/libsparse/include/sparse/sparse.h b/libsparse/include/sparse/sparse.h
index db06884..6484333 100644
--- a/libsparse/include/sparse/sparse.h
+++ b/libsparse/include/sparse/sparse.h
@@ -111,6 +111,32 @@
unsigned int block);
/**
+ * sparse_file_add_file - associate a chunk of a file with a sparse file
+ *
+ * @s - sparse file cookie
+ * @filename - filename of the file to be copied
+ * @file_offset - offset into the copied file
+ * @len - length of the copied block
+ * @block - offset in blocks into the sparse file to place the file chunk
+ *
+ * Associates a chunk of an existing fd with a sparse file cookie.
+ * The region [block * block_size : block * block_size + len) must not already
+ * be used in the sparse file. If len is not a multiple of the block size the
+ * data will be padded with zeros.
+ *
+ * Allows adding large amounts of data to a sparse file without needing to keep
+ * it all mapped. File size is limited by available virtual address space,
+ * exceptionally large files may need to be added in multiple chunks.
+ *
+ * The fd must remain open until the sparse file is closed or the fd block is
+ * removed from the sparse file.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+int sparse_file_add_fd(struct sparse_file *s,
+ int fd, int64_t file_offset, unsigned int len, unsigned int block);
+
+/**
* sparse_file_write - write a sparse file to a file
*
* @s - sparse file cookie
diff --git a/libsparse/output_file.c b/libsparse/output_file.c
index f911f8c..4193fd1 100644
--- a/libsparse/output_file.c
+++ b/libsparse/output_file.c
@@ -511,38 +511,28 @@
return out->sparse_ops->write_fill_chunk(out, len, fill_val);
}
-/* Write a contiguous region of data blocks from a file */
-int write_file_chunk(struct output_file *out, unsigned int len,
- const char *file, int64_t offset)
+int write_fd_chunk(struct output_file *out, unsigned int len,
+ int fd, int64_t offset)
{
int ret;
int64_t aligned_offset;
int aligned_diff;
int buffer_size;
- int file_fd = open(file, O_RDONLY | O_BINARY);
- if (file_fd < 0) {
- return -errno;
- }
-
aligned_offset = offset & ~(4096 - 1);
aligned_diff = offset - aligned_offset;
buffer_size = len + aligned_diff;
#ifndef USE_MINGW
- char *data = mmap64(NULL, buffer_size, PROT_READ, MAP_SHARED, file_fd,
+ char *data = mmap64(NULL, buffer_size, PROT_READ, MAP_SHARED, fd,
aligned_offset);
if (data == MAP_FAILED) {
- ret = -errno;
- close(file_fd);
- return ret;
+ return -errno;
}
#else
char *data = malloc(buffer_size);
if (!data) {
- ret = -errno;
- close(file_fd);
- return ret;
+ return -errno;
}
memset(data, 0, buffer_size);
#endif
@@ -554,6 +544,23 @@
#else
free(data);
#endif
+
+ return ret;
+}
+
+/* Write a contiguous region of data blocks from a file */
+int write_file_chunk(struct output_file *out, unsigned int len,
+ const char *file, int64_t offset)
+{
+ int ret;
+
+ int file_fd = open(file, O_RDONLY | O_BINARY);
+ if (file_fd < 0) {
+ return -errno;
+ }
+
+ ret = write_fd_chunk(out, len, file_fd, offset);
+
close(file_fd);
return ret;
diff --git a/libsparse/output_file.h b/libsparse/output_file.h
index cb2feb7..d23abf3 100644
--- a/libsparse/output_file.h
+++ b/libsparse/output_file.h
@@ -31,6 +31,8 @@
uint32_t fill_val);
int write_file_chunk(struct output_file *out, unsigned int len,
const char *file, int64_t offset);
+int write_fd_chunk(struct output_file *out, unsigned int len,
+ int fd, int64_t offset);
int write_skip_chunk(struct output_file *out, int64_t len);
void close_output_file(struct output_file *out);
diff --git a/libsparse/sparse.c b/libsparse/sparse.c
index fce9dbb..4ebcf0f 100644
--- a/libsparse/sparse.c
+++ b/libsparse/sparse.c
@@ -70,6 +70,12 @@
len, block);
}
+int sparse_file_add_fd(struct sparse_file *s,
+ int fd, int64_t file_offset, unsigned int len, unsigned int block)
+{
+ return backed_block_add_fd(s->backed_block_list, fd, file_offset,
+ len, block);
+}
unsigned int sparse_count_chunks(struct sparse_file *s)
{
struct backed_block *bb;
@@ -122,6 +128,10 @@
write_file_chunk(out, backed_block_len(bb),
backed_block_filename(bb), backed_block_file_offset(bb));
break;
+ case BACKED_BLOCK_FD:
+ write_fd_chunk(out, backed_block_len(bb),
+ backed_block_fd(bb), backed_block_file_offset(bb));
+ break;
case BACKED_BLOCK_FILL:
write_fill_chunk(out, backed_block_len(bb),
backed_block_fill_val(bb));