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

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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>
This commit is contained in:
Denys Vlasenko 2018-04-09 19:05:11 +02:00
parent eb0de05d68
commit 9db344a0f4
1 changed files with 59 additions and 49 deletions
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108
shell/hush.c
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@ -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);