Handle removal of empty directories properly

This addresses FS#25141. We shouldn't remove every empty directory we
come across during the removal process unless it is truly not known to
any other package. This will prevent removal of essential directories
such as '/var/lock/'.

This is accomplished by first checking the empty/non-empty status of a
directory, which was previously done implicitly by calling rmdir() and
ignoring errors. We do this to avoid the next (new) check in most cases,
which is to look at all local packages to see if the to-be-removed
directory is present in another packages' filelist. If we do not find it
anywhere, then we remove it, else we keep the file around.

The pactest has been updated to test more cases, as well as finding a
flaw in the original expected to fail case- we need separate DIR and
FILE based EXIST rules.

Signed-off-by: Dan McGee <dan@archlinux.org>

1 files changed, 42 insertions, 0 deletions

diff --git a/lib/libalpm/util.c b/lib/libalpm/util.c
index cd7f19c9..62313d81 100644
--- a/lib/libalpm/util.c
+++ b/lib/libalpm/util.c
@@ -388,6 +388,48 @@ int _alpm_rmrf(const char *path)
 	return 0;
 }
 
+/**
+ * Determine if there are files in a directory
+ * @param handle the context handle
+ * @param path the full absolute directory path
+ * @param full_count whether to return an exact count of files
+ * @return a file count if full_count is != 0, else >0 if directory has
+ * contents, 0 if no contents, and -1 on error
+ */
+ssize_t _alpm_files_in_directory(alpm_handle_t *handle, const char *path,
+		int full_count)
+{
+	ssize_t files = 0;
+	struct dirent *ent;
+	DIR *dir = opendir(path);
+
+	if(!dir) {
+		if(errno == ENOTDIR) {
+			_alpm_log(handle, ALPM_LOG_DEBUG, "%s was not a directory\n", path);
+		} else {
+			_alpm_log(handle, ALPM_LOG_DEBUG, "could not read directory %s\n",
+					path);
+		}
+		return -1;
+	}
+	while((ent = readdir(dir)) != NULL) {
+		const char *name = ent->d_name;
+
+		if(strcmp(name, ".") == 0 || strcmp(name, "..") == 0) {
+			continue;
+		}
+
+		files++;
+
+		if(!full_count) {
+			break;
+		}
+	}
+
+	closedir(dir);
+	return files;
+}
+
 int _alpm_logaction(alpm_handle_t *handle, const char *fmt, va_list args)
 {
 	int ret = 0;