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-rw-r--r--include/sqfs/data_reader.h4
-rw-r--r--include/sqfs/dir_reader.h8
-rw-r--r--include/sqfs/inode.h3
-rw-r--r--include/sqfs/meta_reader.h4
-rw-r--r--include/sqfs/predef.h43
-rw-r--r--include/sqfs/xattr_reader.h4
6 files changed, 55 insertions, 11 deletions
diff --git a/include/sqfs/data_reader.h b/include/sqfs/data_reader.h
index c967a70..29077b7 100644
--- a/include/sqfs/data_reader.h
+++ b/include/sqfs/data_reader.h
@@ -94,7 +94,7 @@ SQFS_API int sqfs_data_reader_load_fragment_table(sqfs_data_reader_t *data,
* @param inode A pointer to the inode describing the file.
* @param size Returns the size of the data read.
* @param out Returns a pointer to the raw data that must be
- * released using free.
+ * released using @ref sqfs_free.
*
* @return Zero on succcess, an @ref SQFS_ERROR value on failure.
*/
@@ -112,7 +112,7 @@ SQFS_API int sqfs_data_reader_get_fragment(sqfs_data_reader_t *data,
* @param index The block index in the inodes block list.
* @param size Returns the size of the data read.
* @param out Returns a pointer to the raw data that must be
- * released using free.
+ * released using @ref sqfs_free.
*
* @return Zero on succcess, an @ref SQFS_ERROR value on failure.
*/
diff --git a/include/sqfs/dir_reader.h b/include/sqfs/dir_reader.h
index cf9f2a1..3bef7e3 100644
--- a/include/sqfs/dir_reader.h
+++ b/include/sqfs/dir_reader.h
@@ -231,7 +231,7 @@ SQFS_API int sqfs_dir_reader_find(sqfs_dir_reader_t *rd, const char *name);
*
* @param rd A pointer to a directory reader.
* @param out Returns a pointer to a directory entry on success that can be
- * freed with a single free call.
+ * freed with a single @ref sqfs_free call.
*
* @return Zero on success, an @ref SQFS_ERROR value on failure, a positive
* number if the end of the current directory listing has been reached.
@@ -246,7 +246,7 @@ SQFS_API int sqfs_dir_reader_read(sqfs_dir_reader_t *rd,
*
* @param rd A pointer to a directory reader.
* @param out Returns a pointer to a generic inode that can be freed with a
- * single free call.
+ * single @ref sqfs_free call.
*
* @return Zero on success, an @ref SQFS_ERROR value on failure.
*/
@@ -260,7 +260,7 @@ SQFS_API int sqfs_dir_reader_get_inode(sqfs_dir_reader_t *rd,
*
* @param rd A pointer to a directory reader.
* @param out Returns a pointer to a generic inode that can be freed with a
- * single free call.
+ * single @ref sqfs_free call.
*
* @return Zero on success, an @ref SQFS_ERROR value on failure.
*/
@@ -280,7 +280,7 @@ SQFS_API int sqfs_dir_reader_get_root_inode(sqfs_dir_reader_t *rd,
* be used to separate path components. Resolving '.' or '..' is
* not supported.
* @param out Returns a pointer to a generic inode that can be freed with a
- * single free call.
+ * single @ref sqfs_free call.
*
* @return Zero on success, an @ref SQFS_ERROR value on failure.
*/
diff --git a/include/sqfs/inode.h b/include/sqfs/inode.h
index 5359b54..0bc33db 100644
--- a/include/sqfs/inode.h
+++ b/include/sqfs/inode.h
@@ -718,7 +718,8 @@ SQFS_API int sqfs_inode_get_file_block_start(const sqfs_inode_generic_t *inode,
* fiddles the raw data out into a propperly aligned, external structure.
*
* @param inode A pointer to an inode.
- * @param out Returns the index entry. Can be freed with a single free call.
+ * @param out Returns the index entry. Can be freed with a single
+ * @ref sqfs_free call.
* @param index An index value between 0 and inodex_count.
*
* @return Zero on success, @ref SQFS_ERROR_OUT_OF_BOUNDS if the given index
diff --git a/include/sqfs/meta_reader.h b/include/sqfs/meta_reader.h
index bac1808..e0dc186 100644
--- a/include/sqfs/meta_reader.h
+++ b/include/sqfs/meta_reader.h
@@ -145,7 +145,7 @@ SQFS_API int sqfs_meta_reader_read_dir_header(sqfs_meta_reader_t *m,
*
* @param m A pointer to a meta data reader.
* @param ent Returns a pointer to a directory entry. Can be released with a
- * single free() call.
+ * single @ref sqfs_free call.
*
* @return Zero on success, an @ref SQFS_ERROR value on failure.
*/
@@ -167,7 +167,7 @@ SQFS_API int sqfs_meta_reader_read_dir_ent(sqfs_meta_reader_t *m,
* @param offset A byte offset within the uncompressed block where the
* inode is.
* @param out Returns a pointer to an inode. Can be released with a
- * single free() call.
+ * single @ref sqfs_free call.
*
* @return Zero on success, an @ref SQFS_ERROR value on failure.
*/
diff --git a/include/sqfs/predef.h b/include/sqfs/predef.h
index 55ccc86..3254186 100644
--- a/include/sqfs/predef.h
+++ b/include/sqfs/predef.h
@@ -156,4 +156,47 @@ static SQFS_INLINE void *sqfs_copy(const void *obj)
return NULL;
}
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief Free a block of memory created by the squashfs library
+ *
+ * Some objects in the squashfs library allocate temporary chunks of memory
+ * and return pointers to them, with the expectation that the user takes care
+ * of freeing them memory again.
+ *
+ * In the past this worked without hitches, because most sane operating systems
+ * have a single, global C library that everything is linked against. On
+ * systems like Windows that have a huge fragmentation of runtime libraries
+ * this fails, because the library and application can easily end up linked
+ * against different runtime libraries, making it impossible for the program
+ * to free the memory.
+ *
+ * To re-create the same situation on Linux, one would have to link a program
+ * and the squashfs library dynamically, while linking at least one of them
+ * statically against the C runtime, or intentionally linking against two
+ * different runtimes.
+ *
+ * This function mitigates the arising problem by exposing the free() function
+ * of the libraries runtime to the application, so it can propperly release
+ * memory again to the correct heap.
+ *
+ * To maintain API/ABI compatibillity, it is guaranteed that for all versions
+ * of libsquashfs with major version 1, this function does nothing other than
+ * call free() on the C runtime that the library was linked against. If just
+ * calling free() works on your system, it will continue to work, and older
+ * application will continue to work with newer versions of libsquashfs 1.x.
+ * Going forward, new applications using libsquashfs should use this function
+ * instead for better portabillity.
+ *
+ * @param ptr A pointer to a memory block returned by a libsquashfs function.
+ */
+SQFS_API void sqfs_free(void *ptr);
+
+#ifdef __cplusplus
+}
+#endif
+
#endif /* SQFS_PREDEF_H */
diff --git a/include/sqfs/xattr_reader.h b/include/sqfs/xattr_reader.h
index 8294bd8..a0242fb 100644
--- a/include/sqfs/xattr_reader.h
+++ b/include/sqfs/xattr_reader.h
@@ -160,7 +160,7 @@ SQFS_API int sqfs_xattr_reader_seek_kv(sqfs_xattr_reader_t *xr,
*
* @param xr A pointer to an xattr reader instance
* @param key_out Used to return the decoded key. The underlying memory can be
- * released using a single free() call.
+ * released using a single @ref sqfs_free call.
*
* @return Zero on success, a negative @ref SQFS_ERROR value on failure.
*/
@@ -181,7 +181,7 @@ int sqfs_xattr_reader_read_key(sqfs_xattr_reader_t *xr,
* @param xr A pointer to an xattr reader instance.
* @param key A pointer to the decoded key object.
* @param val_out Used to return the decoded value. The underlying memory can
- * be released using a single free() call.
+ * be released using a single @ref sqfs_free call.
*
* @return Zero on success, a negative @ref SQFS_ERROR value on failure.
*/