Be more robust when copying package data

This changes the signature of _alpm_pkg_dup() to return an integer error
code and provide the new package in a passed pointer argument. All
callers are now more robust with checking the return value of this
function to ensure a fatal error did not occur.

We allow load failures to proceed as otherwise we have a chicken and egg
problem- if a 'desc' local database entry is missing, the best way of
restoring said file is `pacman -Sf --dbonly packagename`. This patch
fixes a segfault that was occurring in this case.

Fixes the segfault reported in FS#25667.

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

1 files changed, 9 insertions, 3 deletions

diff --git a/lib/libalpm/deps.c b/lib/libalpm/deps.c
index 704a9046..47b7637a 100644
--- a/lib/libalpm/deps.c
+++ b/lib/libalpm/deps.c
@@ -512,13 +512,14 @@ static int can_remove_package(alpm_db_t *db, alpm_pkg_t *pkg,
  * @param db package database to do dependency tracing in
  * @param *targs pointer to a list of packages
  * @param include_explicit if 0, explicitly installed packages are not included
+ * @return 0 on success, -1 on errors
  */
-void _alpm_recursedeps(alpm_db_t *db, alpm_list_t *targs, int include_explicit)
+int _alpm_recursedeps(alpm_db_t *db, alpm_list_t *targs, int include_explicit)
 {
 	alpm_list_t *i, *j;
 
 	if(db == NULL || targs == NULL) {
-		return;
+		return -1;
 	}
 
 	for(i = targs; i; i = i->next) {
@@ -527,13 +528,18 @@ void _alpm_recursedeps(alpm_db_t *db, alpm_list_t *targs, int include_explicit)
 			alpm_pkg_t *deppkg = j->data;
 			if(_alpm_dep_edge(pkg, deppkg)
 					&& can_remove_package(db, deppkg, targs, include_explicit)) {
+				alpm_pkg_t *copy;
 				_alpm_log(db->handle, ALPM_LOG_DEBUG, "adding '%s' to the targets\n",
 						deppkg->name);
 				/* add it to the target list */
-				targs = alpm_list_add(targs, _alpm_pkg_dup(deppkg));
+				if(_alpm_pkg_dup(deppkg, &copy)) {
+					return -1;
+				}
+				targs = alpm_list_add(targs, copy);
 			}
 		}
 	}
+	return 0;
 }
 
 /**