Fail loudly is scriptlets cannot be run via /bin/sh

If /bin/sh is missing in the root directory, scriptlets cannot be executed, as
we're explicitly calling it.

Signed-off-by: Aaron Griffin <aaronmgriffin@gmail.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/lib/libalpm/trans.c b/lib/libalpm/trans.c
index 9eb27c30..462b4d8b 100644
--- a/lib/libalpm/trans.c
+++ b/lib/libalpm/trans.c
@@ -552,6 +552,13 @@ int _alpm_runscriptlet(const char *root, const char *installfn,
 		return(0);
 	}
 
+	snprintf(tmpdir, PATH_MAX, "%sbin/sh", root);
+	if(stat(tmpdir, &buf)) {
+		/* not found */
+		_alpm_log(PM_LOG_ERROR, _("No /bin/sh in root dir (%s), aborting scriptlet\n"), root);
+		return(0);
+	}
+
 	if(!strcmp(script, "pre_upgrade") || !strcmp(script, "pre_install")) {
 		snprintf(tmpdir, PATH_MAX, "%stmp/", root);
 		if(stat(tmpdir, &buf)) {