hush: fix a few more corner cases with empty-expanding `cmds`

See added testcases

function                                             old     new   delta
run_pipe                                            1723    1784     +61

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 12 insertions, 8 deletions

diff --git a/shell/hush.c b/shell/hush.c
index 43702360a..577faf466 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -608,7 +608,7 @@ typedef enum redir_type {
 
 struct command {
         pid_t pid;                  /* 0 if exited */
-        int assignment_cnt;         /* how many argv[i] are assignments? */
+        unsigned assignment_cnt;    /* how many argv[i] are assignments? */
 #if ENABLE_HUSH_LINENO_VAR
         unsigned lineno;
 #endif
@@ -8317,25 +8317,26 @@ static NOINLINE int run_pipe(struct pipe *pi)
                          * Ensure redirects take effect (that is, create files).
                          * Try "a=t >file"
                          */
- only_assignments:
+                        unsigned i;
                         G.expand_exitcode = 0;
-
+ only_assignments:
                         rcode = setup_redirects(command, &squirrel);
                         restore_redirects(squirrel);
+
                         /* Set shell variables */
                         if (G_x_mode)
                                 bb_putchar_stderr('+');
-                        while (*argv) {
-                                char *p = expand_string_to_string(*argv, /*unbackslash:*/ 1);
+                        i = 0;
+                        while (i < command->assignment_cnt) {
+                                char *p = expand_string_to_string(argv[i], /*unbackslash:*/ 1);
                                 if (G_x_mode)
                                         fprintf(stderr, " %s", p);
-                                debug_printf_exec("set shell var:'%s'->'%s'\n",
-                                                *argv, p);
+                                debug_printf_env("set shell var:'%s'->'%s'\n", *argv, p);
                                 if (set_local_var(p, /*flag:*/ 0)) {
                                         /* assignment to readonly var / putenv error? */
                                         rcode = 1;
                                 }
-                                argv++;
+                                i++;
                         }
                         if (G_x_mode)
                                 bb_putchar_stderr('\n');
@@ -8365,6 +8366,8 @@ static NOINLINE int run_pipe(struct pipe *pi)
                 /* If someone gives us an empty string: `cmd with empty output` */
                 if (!argv_expanded[0]) {
                         free(argv_expanded);
+                        /* `false` still has to set exitcode 1 */
+                        G.expand_exitcode = G.last_exitcode;
                         goto only_assignments;
                 }
 
@@ -10021,6 +10024,7 @@ static int helper_export_local(char **argv, unsigned flags)
                         /* (Un)exporting/making local NAME=VALUE */
                         name = xstrdup(name);
                 }
+                debug_printf_env("%s: set_local_var('%s')\n", __func__, name);
                 if (set_local_var(name, flags))
                         return EXIT_FAILURE;
         } while (*++argv);