hush: fix var_leaks.tests and var_preserved.tests on NOMMU

function                                             old     new   delta
remove_nested_vars                                     -      77     +77
run_pipe                                            1756    1786     +30
pseudo_exec_argv                                     376     379      +3
leave_var_nest_level                                  98      32     -66
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 2/1 up/down: 110/-66)            Total: 44 bytes

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

diff --git a/shell/hush.c b/shell/hush.c
index 3a4b5d894fcd13a8dc142f40cb71e94ccde51155..8855613898aeb9b19dfb2fbe790f33b94ff89d27 100644 (file)
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -2266,6 +2266,7 @@ static int set_local_var(char *str, unsigned flags)
        }
 
        /* Not found or shadowed - create new variable struct */
+       debug_printf_env("%s: alloc new var '%s'/%u\n", __func__, str, local_lvl);
        cur = xzalloc(sizeof(*cur));
        cur->var_nest_level = local_lvl;
        cur->next = *cur_pp;
@@ -2420,7 +2421,7 @@ static void set_vars_and_save_old(char **strings)
                                 * global linked list.
                                 */
                        }
-                       //bb_error_msg("G.var_nest_level:%d", G.var_nest_level);
+                       debug_printf_env("%s: env override '%s'/%u\n", __func__, *s, G.var_nest_level);
                        set_local_var(*s, (G.var_nest_level << SETFLAG_VARLVL_SHIFT) | SETFLAG_EXPORT);
                } else if (HUSH_DEBUG) {
                        bb_error_msg_and_die("BUG in varexp4");
@@ -7358,6 +7359,58 @@ static void unset_func(const char *name)
 }
 # endif
 
+static void remove_nested_vars(void)
+{
+       struct variable *cur;
+       struct variable **cur_pp;
+
+       cur_pp = &G.top_var;
+       while ((cur = *cur_pp) != NULL) {
+               if (cur->var_nest_level <= G.var_nest_level) {
+                       cur_pp = &cur->next;
+                       continue;
+               }
+               /* Unexport */
+               if (cur->flg_export) {
+                       debug_printf_env("unexporting nested '%s'/%u\n", cur->varstr, cur->var_nest_level);
+                       bb_unsetenv(cur->varstr);
+               }
+               /* Remove from global list */
+               *cur_pp = cur->next;
+               /* Free */
+               if (!cur->max_len) {
+                       debug_printf_env("freeing nested '%s'/%u\n", cur->varstr, cur->var_nest_level);
+                       free(cur->varstr);
+               }
+               free(cur);
+       }
+}
+
+static void enter_var_nest_level(void)
+{
+       G.var_nest_level++;
+       debug_printf_env("var_nest_level++ %u\n", G.var_nest_level);
+
+       /* Try: f() { echo -n .; f; }; f
+        * struct variable::var_nest_level is uint16_t,
+        * thus limiting recursion to < 2^16.
+        * In any case, with 8 Mbyte stack SEGV happens
+        * not too long after 2^16 recursions anyway.
+        */
+       if (G.var_nest_level > 0xff00)
+               bb_error_msg_and_die("fatal recursion (depth %u)", G.var_nest_level);
+}
+
+static void leave_var_nest_level(void)
+{
+       G.var_nest_level--;
+       debug_printf_env("var_nest_level-- %u\n", G.var_nest_level);
+       if (HUSH_DEBUG && (int)G.var_nest_level < 0)
+               bb_error_msg_and_die("BUG: nesting underflow");
+
+       remove_nested_vars();
+}
+
 # if BB_MMU
 #define exec_function(to_free, funcp, argv) \
        exec_function(funcp, argv)
@@ -7392,7 +7445,7 @@ static void exec_function(char ***to_free,
 
        /* "we are in a function, ok to use return" */
        G_flag_return_in_progress = -1;
-       G.var_nest_level++;
+       enter_var_nest_level();
        IF_HUSH_LOCAL(G.func_nest_level++;)
 
        /* On MMU, funcp->body is always non-NULL */
@@ -7412,53 +7465,6 @@ static void exec_function(char ***to_free,
 # endif
 }
 
-static void enter_var_nest_level(void)
-{
-       G.var_nest_level++;
-       debug_printf_env("var_nest_level++ %u\n", G.var_nest_level);
-
-       /* Try: f() { echo -n .; f; }; f
-        * struct variable::var_nest_level is uint16_t,
-        * thus limiting recursion to < 2^16.
-        * In any case, with 8 Mbyte stack SEGV happens
-        * not too long after 2^16 recursions anyway.
-        */
-       if (G.var_nest_level > 0xff00)
-               bb_error_msg_and_die("fatal recursion (depth %u)", G.var_nest_level);
-}
-
-static void leave_var_nest_level(void)
-{
-       struct variable *cur;
-       struct variable **cur_pp;
-
-       cur_pp = &G.top_var;
-       while ((cur = *cur_pp) != NULL) {
-               if (cur->var_nest_level < G.var_nest_level) {
-                       cur_pp = &cur->next;
-                       continue;
-               }
-               /* Unexport */
-               if (cur->flg_export) {
-                       debug_printf_env("unexporting nested '%s'/%u\n", cur->varstr, cur->var_nest_level);
-                       bb_unsetenv(cur->varstr);
-               }
-               /* Remove from global list */
-               *cur_pp = cur->next;
-               /* Free */
-               if (!cur->max_len) {
-                       debug_printf_env("freeing nested '%s'/%u\n", cur->varstr, cur->var_nest_level);
-                       free(cur->varstr);
-               }
-               free(cur);
-       }
-
-       G.var_nest_level--;
-       debug_printf_env("var_nest_level-- %u\n", G.var_nest_level);
-       if (HUSH_DEBUG && (int)G.var_nest_level < 0)
-               bb_error_msg_and_die("BUG: nesting underflow");
-}
-
 static int run_function(const struct function *funcp, char **argv)
 {
        int rc;
@@ -7648,6 +7654,7 @@ static NOINLINE void pseudo_exec_argv(nommu_save_t *nommu_save,
        G.shadowed_vars_pp = NULL; /* "don't save, free them instead" */
 #else
        G.shadowed_vars_pp = &nommu_save->old_vars;
+       G.var_nest_level++;
 #endif
        set_vars_and_save_old(new_env);
        G.shadowed_vars_pp = sv_shadowed;
@@ -8522,6 +8529,7 @@ static NOINLINE int run_pipe(struct pipe *pi)
        while (cmd_no < pi->num_cmds) {
                struct fd_pair pipefds;
 #if !BB_MMU
+               int sv_var_nest_level = G.var_nest_level;
                volatile nommu_save_t nommu_save;
                nommu_save.old_vars = NULL;
                nommu_save.argv = NULL;
@@ -8615,6 +8623,8 @@ static NOINLINE int run_pipe(struct pipe *pi)
                /* Clean up after vforked child */
                free(nommu_save.argv);
                free(nommu_save.argv_from_re_execing);
+               G.var_nest_level = sv_var_nest_level;
+               remove_nested_vars();
                add_vars(nommu_save.old_vars);
 #endif
                free(argv_expanded);