While installing a pkg, remove files with wrong hash before unpacking.

lib/package_unpack.c

@@ -23,12 +23,14 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include <sys/stat.h>
 #include <stdio.h>
 #include <stdbool.h>
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
 #include <fcntl.h>
+#include <unistd.h>
 
 #include <xbps_api.h>
 #include "xbps_api_impl.h"
@@ -143,6 +145,33 @@ remove_metafile(const char *file, const char *pkgname, const char *version)
 	return 0;
 }
 
+static int
+remove_file_wrong_hash(prop_dictionary_t d, const char *file)
+{
+	struct stat st;
+	const char *hash;
+	int rv = 0;
+
+	if (stat(file, &st) == -1)
+		if (errno != ENOENT)
+			return errno;
+
+	if (!S_ISREG(st.st_mode))
+		return 0;
+
+	/* Only check for regular files, not symlinks, dirs or conffiles. */
+	hash = xbps_get_file_hash_from_dict(d, "files", file);
+	if (hash) {
+		rv = xbps_check_file_hash(file, hash);
+		if (rv == ERANGE) {
+			(void)unlink(file);
+			xbps_warn_printf("Removed `%s' entry with "
+			   "with unmatched hash.\n", file);
+		}
+	}
+	return rv;
+}
+
 /*
  * Execute the unpack progress function callback if set and its
  * private data is also set. It's so sad that
@@ -376,6 +405,21 @@ unpack_archive(prop_dictionary_t pkg_repod,
 				continue;
 			}
 		}
+		/*
+		 * Check if current entry already exists on disk and
+		 * if the sha256 hash doesn't match, remove the file.
+		 * Only do this if we are _installing_ a package.
+		 */
+		if (!update) {
+			rv = remove_file_wrong_hash(filesd, entry_pname);
+			if (rv != 0) {
+				xbps_dbg_printf("remove_file_wrong_hash "
+				    "failed for `%s': %s\n", entry_pname,
+				    strerror(rv));
+				goto out;
+			}
+		}
+
 		/*
 		 * Extract entry from archive.
 		 */