hush: fix a bug where we don't properly handle f() { a=A; b=B; }; a= f
function old new delta unset_local_var 20 274 +254 leave_var_nest_level - 98 +98 set_vars_and_save_old 128 164 +36 enter_var_nest_level - 32 +32 builtin_local 46 50 +4 pseudo_exec_argv 554 544 -10 redirect_and_varexp_helper 77 64 -13 run_pipe 1890 1641 -249 unset_local_var_len 267 - -267 ------------------------------------------------------------------------------ (add/remove: 2/1 grow/shrink: 3/3 up/down: 424/-539) Total: -115 bytes Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
parent
332e4115c9
commit
d358b0b65d
151
shell/hush.c
151
shell/hush.c
@ -475,7 +475,6 @@ static const char hush_version_str[] ALIGN1 = "HUSH_VERSION="BB_VER;
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*/
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#if !BB_MMU
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typedef struct nommu_save_t {
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char **new_env;
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struct variable *old_vars;
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char **argv;
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char **argv_from_re_execing;
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@ -2176,10 +2175,16 @@ static int set_local_var(char *str, unsigned flags)
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*eq_sign = '=';
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}
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if (cur->var_nest_level < local_lvl) {
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/* New variable is declared as local,
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/* New variable is local ("local VAR=VAL" or
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* "VAR=VAL cmd")
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* and existing one is global, or local
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* from enclosing function.
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* Remove and save old one: */
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* on a lower level that new one.
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* Remove and save old one:
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*/
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debug_printf_env("shadowing %s'%s'/%u by '%s'/%u\n",
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cur->flg_export ? "exported " : "",
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cur->varstr, cur->var_nest_level, str, local_lvl
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);
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*cur_pp = cur->next;
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cur->next = *G.shadowed_vars_pp;
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*G.shadowed_vars_pp = cur;
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@ -2197,6 +2202,7 @@ static int set_local_var(char *str, unsigned flags)
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}
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if (strcmp(cur->varstr + name_len, eq_sign + 1) == 0) {
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debug_printf_env("assignement '%s' does not change anything\n", str);
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free_and_exp:
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free(str);
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goto exp;
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@ -2204,6 +2210,7 @@ static int set_local_var(char *str, unsigned flags)
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if (cur->max_len != 0) {
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if (cur->max_len >= strlen(str)) {
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/* This one is from startup env, reuse space */
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debug_printf_env("reusing startup env for '%s'\n", str);
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strcpy(cur->varstr, str);
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goto free_and_exp;
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}
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@ -2221,7 +2228,7 @@ static int set_local_var(char *str, unsigned flags)
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goto set_str_and_exp;
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}
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/* Not found - create new variable struct */
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/* Not found or shadowed - create new variable struct */
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cur = xzalloc(sizeof(*cur));
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cur->var_nest_level = local_lvl;
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cur->next = *cur_pp;
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@ -2250,7 +2257,7 @@ static int set_local_var(char *str, unsigned flags)
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/* unsetenv was already done */
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} else {
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int i;
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debug_printf_env("%s: putenv '%s'\n", __func__, cur->varstr);
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debug_printf_env("%s: putenv '%s'/%u\n", __func__, cur->varstr, cur->var_nest_level);
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i = putenv(cur->varstr);
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/* only now we can free old exported malloced string */
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free(free_me);
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@ -2313,21 +2320,6 @@ static int unset_local_var(const char *name)
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}
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#endif
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static void unset_vars(char **strings)
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{
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char **v;
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if (!strings)
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return;
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v = strings;
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while (*v) {
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const char *eq = strchrnul(*v, '=');
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unset_local_var_len(*v, (int)(eq - *v));
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v++;
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}
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free(strings);
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}
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#if BASH_HOSTNAME_VAR || ENABLE_FEATURE_SH_MATH || ENABLE_HUSH_READ || ENABLE_HUSH_GETOPTS
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static void FAST_FUNC set_local_var_from_halves(const char *name, const char *val)
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{
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@ -2349,15 +2341,20 @@ static void add_vars(struct variable *var)
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var->next = G.top_var;
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G.top_var = var;
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if (var->flg_export) {
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debug_printf_env("%s: restoring exported '%s'\n", __func__, var->varstr);
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debug_printf_env("%s: restoring exported '%s'/%u\n", __func__, var->varstr, var->var_nest_level);
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putenv(var->varstr);
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} else {
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debug_printf_env("%s: restoring variable '%s'\n", __func__, var->varstr);
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debug_printf_env("%s: restoring variable '%s'/%u\n", __func__, var->varstr, var->var_nest_level);
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}
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var = next;
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}
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}
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/* We put strings[i] into variable table and possibly putenv them.
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* If variable is read only, we can free the strings[i]
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* which attempts to overwrite it.
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* The strings[] vector itself is freed.
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*/
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static struct variable *set_vars_and_save_old(char **strings)
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{
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char **s;
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@ -2365,6 +2362,7 @@ static struct variable *set_vars_and_save_old(char **strings)
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if (!strings)
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return old;
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s = strings;
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while (*s) {
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struct variable *var_p;
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@ -2398,11 +2396,15 @@ static struct variable *set_vars_and_save_old(char **strings)
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var_p->next = old;
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old = var_p;
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}
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set_local_var(*s, SETFLAG_EXPORT);
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//bb_error_msg("G.var_nest_level:%d", G.var_nest_level);
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set_local_var(*s, (G.var_nest_level << SETFLAG_VARLVL_SHIFT) | SETFLAG_EXPORT);
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} else if (HUSH_DEBUG) {
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bb_error_msg_and_die("BUG in varexp4");
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}
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s++;
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next: ;
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}
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free(strings);
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return old;
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}
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@ -6339,7 +6341,7 @@ static char **expand_strvec_to_strvec_singleword_noglob(char **argv)
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#endif
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/* Used for expansion of right hand of assignments,
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* $((...)), heredocs, variable espansion parts.
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* $((...)), heredocs, variable expansion parts.
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*
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* NB: should NOT do globbing!
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* "export v=/bin/c*; env | grep ^v=" outputs "v=/bin/c*"
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@ -7385,6 +7387,7 @@ static void exec_function(char ***to_free,
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static void enter_var_nest_level(void)
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{
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G.var_nest_level++;
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debug_printf_env("var_nest_level++ %u\n", G.var_nest_level);
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/* Try: f() { echo -n .; f; }; f
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* struct variable::var_nest_level is uint16_t,
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@ -7408,17 +7411,22 @@ static void leave_var_nest_level(void)
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continue;
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}
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/* Unexport */
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if (cur->flg_export)
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if (cur->flg_export) {
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debug_printf_env("unexporting nested '%s'/%u\n", cur->varstr, cur->var_nest_level);
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bb_unsetenv(cur->varstr);
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}
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/* Remove from global list */
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*cur_pp = cur->next;
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/* Free */
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if (!cur->max_len)
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if (!cur->max_len) {
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debug_printf_env("freeing nested '%s'/%u\n", cur->varstr, cur->var_nest_level);
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free(cur->varstr);
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}
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free(cur);
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}
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G.var_nest_level--;
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debug_printf_env("var_nest_level-- %u\n", G.var_nest_level);
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if (HUSH_DEBUG && (int)G.var_nest_level < 0)
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bb_error_msg_and_die("BUG: nesting underflow");
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}
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@ -7431,11 +7439,12 @@ static int run_function(const struct function *funcp, char **argv)
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save_and_replace_G_args(&sv, argv);
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/* "we are in function, ok to use return" */
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/* "We are in function, ok to use return" */
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sv_flg = G_flag_return_in_progress;
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G_flag_return_in_progress = -1;
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enter_var_nest_level();
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/* Make "local" variables properly shadow previous ones */
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IF_HUSH_LOCAL(enter_var_nest_level();)
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IF_HUSH_LOCAL(G.func_nest_level++;)
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/* On MMU, funcp->body is always non-NULL */
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@ -7451,7 +7460,7 @@ static int run_function(const struct function *funcp, char **argv)
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}
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IF_HUSH_LOCAL(G.func_nest_level--;)
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leave_var_nest_level();
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IF_HUSH_LOCAL(leave_var_nest_level();)
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G_flag_return_in_progress = sv_flg;
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@ -7608,11 +7617,9 @@ static NOINLINE void pseudo_exec_argv(nommu_save_t *nommu_save,
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#if BB_MMU
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set_vars_and_save_old(new_env);
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free(new_env); /* optional */
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/* we can also destroy set_vars_and_save_old's return value,
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/* we can destroy set_vars_and_save_old's return value,
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* to save memory */
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#else
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nommu_save->new_env = new_env;
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nommu_save->old_vars = set_vars_and_save_old(new_env);
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#endif
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@ -8174,10 +8181,10 @@ static int checkjobs_and_fg_shell(struct pipe *fg_pipe)
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* subshell: ( list ) [&]
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*/
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#if !ENABLE_HUSH_MODE_X
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#define redirect_and_varexp_helper(new_env_p, old_vars_p, command, squirrel, argv_expanded) \
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redirect_and_varexp_helper(new_env_p, old_vars_p, command, squirrel)
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#define redirect_and_varexp_helper(old_vars_p, command, squirrel, argv_expanded) \
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redirect_and_varexp_helper(old_vars_p, command, squirrel)
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#endif
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static int redirect_and_varexp_helper(char ***new_env_p,
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static int redirect_and_varexp_helper(
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struct variable **old_vars_p,
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struct command *command,
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struct squirrel **sqp,
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@ -8190,10 +8197,9 @@ static int redirect_and_varexp_helper(char ***new_env_p,
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int rcode = setup_redirects(command, sqp);
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if (rcode == 0) {
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char **new_env = expand_assignments(command->argv, command->assignment_cnt);
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*new_env_p = new_env;
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dump_cmd_in_x_mode(new_env);
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dump_cmd_in_x_mode(argv_expanded);
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if (old_vars_p)
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/* this takes ownership of new_env[i] elements, and frees new_env: */
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*old_vars_p = set_vars_and_save_old(new_env);
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}
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return rcode;
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@ -8284,13 +8290,9 @@ static NOINLINE int run_pipe(struct pipe *pi)
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argv = command->argv ? command->argv : (char **) &null_ptr;
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{
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const struct built_in_command *x;
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#if ENABLE_HUSH_FUNCTIONS
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const struct function *funcp;
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#else
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enum { funcp = 0 };
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#endif
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char **new_env = NULL;
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struct variable *old_vars = NULL;
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IF_HUSH_FUNCTIONS(const struct function *funcp;)
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IF_NOT_HUSH_FUNCTIONS(enum { funcp = 0 };)
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struct variable *old_vars;
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#if ENABLE_HUSH_LINENO_VAR
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if (G.lineno_var)
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@ -8303,28 +8305,6 @@ static NOINLINE int run_pipe(struct pipe *pi)
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* Try "a=t >file"
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*/
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G.expand_exitcode = 0;
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#if 0 /* A few cases in testsuite fail with this code. FIXME */
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rcode = redirect_and_varexp_helper(&new_env, /*old_vars:*/ NULL, command, &squirrel, /*argv_expanded:*/ NULL);
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/* Set shell variables */
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if (new_env) {
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argv = new_env;
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while (*argv) {
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if (set_local_var(*argv, /*flag:*/ 0)) {
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/* assignment to readonly var / putenv error? */
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rcode = 1;
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}
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argv++;
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}
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}
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/* Redirect error sets $? to 1. Otherwise,
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* if evaluating assignment value set $?, retain it.
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* Try "false; q=`exit 2`; echo $?" - should print 2: */
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if (rcode == 0)
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rcode = G.expand_exitcode;
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/* Exit, _skipping_ variable restoring code: */
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goto clean_up_and_ret0;
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#else /* Older, bigger, but more correct code */
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rcode = setup_redirects(command, &squirrel);
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restore_redirects(squirrel);
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@ -8358,7 +8338,6 @@ static NOINLINE int run_pipe(struct pipe *pi)
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debug_leave();
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debug_printf_exec("run_pipe: return %d\n", rcode);
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return rcode;
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#endif
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}
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/* Expand the rest into (possibly) many strings each */
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@ -8372,6 +8351,7 @@ static NOINLINE int run_pipe(struct pipe *pi)
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}
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/* if someone gives us an empty string: `cmd with empty output` */
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//TODO: what about: var=EXPR `` >FILE ? will var be set? Will FILE be created?
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if (!argv_expanded[0]) {
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free(argv_expanded);
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debug_leave();
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@ -8394,7 +8374,14 @@ static NOINLINE int run_pipe(struct pipe *pi)
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goto clean_up_and_ret1;
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}
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}
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rcode = redirect_and_varexp_helper(&new_env, &old_vars, command, &squirrel, argv_expanded);
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/* Without bumping var nesting level, this leaks
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* exported $a:
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* a=b true; env | grep ^a=
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*/
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enter_var_nest_level();
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rcode = redirect_and_varexp_helper(&old_vars, command, &squirrel, argv_expanded);
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if (rcode == 0) {
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if (!funcp) {
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debug_printf_exec(": builtin '%s' '%s'...\n",
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@ -8405,24 +8392,23 @@ static NOINLINE int run_pipe(struct pipe *pi)
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}
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#if ENABLE_HUSH_FUNCTIONS
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else {
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# if ENABLE_HUSH_LOCAL
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struct variable **sv;
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sv = G.shadowed_vars_pp;
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struct variable **sv = G.shadowed_vars_pp;
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/* Make "local" builtins in the called function
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* stash shadowed variables in old_vars list
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*/
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G.shadowed_vars_pp = &old_vars;
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# endif
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debug_printf_exec(": function '%s' '%s'...\n",
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funcp->name, argv_expanded[1]);
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rcode = run_function(funcp, argv_expanded) & 0xff;
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# if ENABLE_HUSH_LOCAL
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G.shadowed_vars_pp = sv;
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# endif
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}
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#endif
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}
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clean_up_and_ret:
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unset_vars(new_env);
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leave_var_nest_level();
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add_vars(old_vars);
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/* clean_up_and_ret0: */
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restore_redirects(squirrel);
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/*
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* Try "usleep 99999999" + ^C + "echo $?"
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@ -8453,7 +8439,8 @@ static NOINLINE int run_pipe(struct pipe *pi)
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if (ENABLE_FEATURE_SH_NOFORK && NUM_APPLETS > 1) {
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int n = find_applet_by_name(argv_expanded[0]);
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if (n >= 0 && APPLET_IS_NOFORK(n)) {
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rcode = redirect_and_varexp_helper(&new_env, &old_vars, command, &squirrel, argv_expanded);
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enter_var_nest_level();
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rcode = redirect_and_varexp_helper(&old_vars, command, &squirrel, argv_expanded);
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if (rcode == 0) {
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debug_printf_exec(": run_nofork_applet '%s' '%s'...\n",
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argv_expanded[0], argv_expanded[1]);
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@ -8487,7 +8474,6 @@ static NOINLINE int run_pipe(struct pipe *pi)
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struct fd_pair pipefds;
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#if !BB_MMU
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volatile nommu_save_t nommu_save;
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nommu_save.new_env = NULL;
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nommu_save.old_vars = NULL;
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nommu_save.argv = NULL;
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nommu_save.argv_from_re_execing = NULL;
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@ -8580,7 +8566,6 @@ static NOINLINE int run_pipe(struct pipe *pi)
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/* Clean up after vforked child */
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free(nommu_save.argv);
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free(nommu_save.argv_from_re_execing);
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unset_vars(nommu_save.new_env);
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add_vars(nommu_save.old_vars);
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#endif
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free(argv_expanded);
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@ -10066,7 +10051,11 @@ static int FAST_FUNC builtin_local(char **argv)
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return EXIT_FAILURE; /* bash compat */
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}
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argv++;
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return helper_export_local(argv, G.var_nest_level << SETFLAG_VARLVL_SHIFT);
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/* Since all builtins run in a nested variable level,
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* need to use level - 1 here. Or else the variable will be removed at once
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* after builtin returns.
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*/
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return helper_export_local(argv, (G.var_nest_level - 1) << SETFLAG_VARLVL_SHIFT);
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}
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#endif
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3
shell/hush_test/hush-vars/var_nested1.right
Normal file
3
shell/hush_test/hush-vars/var_nested1.right
Normal file
@ -0,0 +1,3 @@
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Expected:AB Actual:AB
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Expected:Ab Actual:Ab
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Expected:ab Actual:ab
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16
shell/hush_test/hush-vars/var_nested1.tests
Executable file
16
shell/hush_test/hush-vars/var_nested1.tests
Executable file
@ -0,0 +1,16 @@
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f() { a=A; b=B; }
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a=a
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b=b
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f
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echo Expected:AB Actual:$a$b
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a=a
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b=b
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b= f
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echo Expected:Ab Actual:$a$b
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a=a
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b=b
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a= b= f
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echo Expected:ab Actual:$a$b
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||||
1
shell/hush_test/hush-vars/var_nested2.right
Normal file
1
shell/hush_test/hush-vars/var_nested2.right
Normal file
@ -0,0 +1 @@
|
||||
aB
|
||||
2
shell/hush_test/hush-vars/var_nested2.tests
Executable file
2
shell/hush_test/hush-vars/var_nested2.tests
Executable file
@ -0,0 +1,2 @@
|
||||
# the bug was easier to trigger in one-liner form
|
||||
a=a; b=b; f() { a=A; b=B; }; a= f; echo $a$b
|
||||
Loading…
Reference in New Issue
Block a user