Minor cleanup of the standard read/write I/O modules:

 * Use public API, don't access struct archive directly.  (People should be able to copy these into their applications as a template for custom I/O callbacks.)
 * Set "skip" only for regular files.  ("skip" allows the low-level library to catch attempts to add an archive to itself or extract over itself.)
 * Simplify the write_open functions by just calling stat() at the beginning.  Somehow, these functions had acquired some complex logic that tried to avoid the stat() call but never succeeded.

MFC after: 10 days

1 files changed, 4 insertions, 3 deletions

diff --git a/lib/libarchive/archive_read_open_file.c b/lib/libarchive/archive_read_open_file.c
index 0da7d7c..1538c5b 100644
--- a/lib/libarchive/archive_read_open_file.c
+++ b/lib/libarchive/archive_read_open_file.c
@@ -110,9 +110,10 @@ file_open(struct archive *a, void *client_data)
 		return (ARCHIVE_FATAL);
 	}
 	if (fstat(mine->fd, &st) == 0) {
-		/* Set dev/ino of archive file so extract won't overwrite. */
-		a->skip_file_dev = st.st_dev;
-		a->skip_file_ino = st.st_ino;
+		/* If we're reading a file from disk, ensure that we don't
+		   overwrite it with an extracted file. */
+		if (S_ISREG(st.st_mode))
+			archive_read_extract_set_skip_file(a, st.st_dev, st.st_ino);
 		/* Remember mode so close can decide whether to flush. */
 		mine->st_mode = st.st_mode;
 	} else {