hush: handle empty execs
Sometimes variable expansions yield empty strings, and if they happen to
be a command someone wants to run like `$foo`, then hush currently
segfaults. So handle `` and $().
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/shell/hush.c b/shell/hush.c
index 2d333d7..1d2826d 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -3895,6 +3895,12 @@
argv_expanded = expand_strvec_to_strvec(argv + command->assignment_cnt);
}
+ /* if someone gives us an empty string: ``, $(), ... */
+ if (!argv_expanded[0]) {
+ debug_leave();
+ return 0;
+ }
+
x = find_builtin(argv_expanded[0]);
#if ENABLE_HUSH_FUNCTIONS
funcp = NULL;
diff --git a/shell/hush_test/hush-psubst/emptytick.right b/shell/hush_test/hush-psubst/emptytick.right
new file mode 100644
index 0000000..d4b70c5
--- /dev/null
+++ b/shell/hush_test/hush-psubst/emptytick.right
@@ -0,0 +1,14 @@
+0
+0
+0
+0
+0
+0
+0
+0
+0
+0
+0
+0
+0
+0
diff --git a/shell/hush_test/hush-psubst/emptytick.tests b/shell/hush_test/hush-psubst/emptytick.tests
new file mode 100755
index 0000000..af3a183
--- /dev/null
+++ b/shell/hush_test/hush-psubst/emptytick.tests
@@ -0,0 +1,16 @@
+true; ``; echo $?
+false; ``; echo $?
+true; `""`; echo $?
+false; `""`; echo $?
+true; ` `; echo $?
+false; ` `; echo $?
+
+true; $(); echo $?
+false; $(); echo $?
+true; $(""); echo $?
+false; $(""); echo $?
+true; $( ); echo $?
+false; $( ); echo $?
+
+true; exec ''; echo $?
+false; exec ''; echo $?