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929a41d57

Denys Vlasenko
Denys Vlasenko
2018-04-05
SUCCESS Duration: 140s

Subject

hush: less mind-bending set_vars_and_save_old()

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Architecture & Compiler Flags

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

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Build Log

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Commit Diff GitHub →

shell/hush.c +101 -71
shell/hush.c+101 -71
@@ -2140,19 +2140,10 @@ static int set_local_var(char *str, unsigned flags)
unsigned local_lvl = (flags >> SETFLAG_VARLVL_SHIFT);
eq_sign = strchr(str, '=');
- if (!eq_sign) { /* not expected to ever happen? */
- free(str);
- return -1;
- }
+ if (HUSH_DEBUG && !eq_sign)
+ bb_error_msg_and_die("BUG in setvar");
name_len = eq_sign - str + 1; /* including '=' */
-#if ENABLE_HUSH_LINENO_VAR
- if (G.lineno_var) {
- if (name_len == 7 && strncmp("LINENO", str, 6) == 0)
- G.lineno_var = NULL;
- }
-#endif
-
cur_pp = &G.top_var;
while ((cur = *cur_pp) != NULL) {
if (strncmp(cur->varstr, str, name_len) != 0) {
@@ -2175,19 +2166,6 @@ static int set_local_var(char *str, unsigned flags)
*eq_sign = '=';
}
if (cur->var_nest_level < local_lvl) {
- /* New variable is local ("local VAR=VAL" or
- * "VAR=VAL cmd")
- * and existing one is global, or local
- * on a lower level that new one.
- * Remove and save old one:
- */
- debug_printf_env("shadowing %s'%s'/%u by '%s'/%u\n",
- cur->flg_export ? "exported " : "",
- cur->varstr, cur->var_nest_level, str, local_lvl
- );
- *cur_pp = cur->next;
- cur->next = *G.shadowed_vars_pp;
- *G.shadowed_vars_pp = cur;
/* bash 3.2.33(1) and exported vars:
* # export z=z
* # f() { local z=a; env | grep ^z; }
@@ -2198,6 +2176,31 @@ static int set_local_var(char *str, unsigned flags)
*/
if (cur->flg_export)
flags |= SETFLAG_EXPORT;
+ /* New variable is local ("local VAR=VAL" or
+ * "VAR=VAL cmd")
+ * and existing one is global, or local
+ * on a lower level that new one.
+ * Remove it from global variable list:
+ */
+ *cur_pp = cur->next;
+ if (G.shadowed_vars_pp) {
+ /* Save in "shadowed" list */
+ debug_printf_env("shadowing %s'%s'/%u by '%s'/%u\n",
+ cur->flg_export ? "exported " : "",
+ cur->varstr, cur->var_nest_level, str, local_lvl
+ );
+ cur->next = *G.shadowed_vars_pp;
+ *G.shadowed_vars_pp = cur;
+ } else {
+ /* Came from pseudo_exec_argv(), no need to save: delete it */
+ debug_printf_env("shadow-deleting %s'%s'/%u by '%s'/%u\n",
+ cur->flg_export ? "exported " : "",
+ cur->varstr, cur->var_nest_level, str, local_lvl
+ );
+ if (cur->max_len == 0) /* allocated "VAR=VAL"? */
+ free_me = cur->varstr; /* then free it later */
+ free(cur);
+ }
break;
}
@@ -2207,8 +2210,10 @@ static int set_local_var(char *str, unsigned flags)
free(str);
goto exp;
}
+
+ /* Replace the value in the found "struct variable" */
if (cur->max_len != 0) {
- if (cur->max_len >= strlen(str)) {
+ if (cur->max_len >= strnlen(str, cur->max_len + 1)) {
/* This one is from startup env, reuse space */
debug_printf_env("reusing startup env for '%s'\n", str);
strcpy(cur->varstr, str);
@@ -2244,13 +2249,6 @@ static int set_local_var(char *str, unsigned flags)
#endif
if (flags & SETFLAG_EXPORT)
cur->flg_export = 1;
- if (name_len == 4 && cur->varstr[0] == 'P' && cur->varstr[1] == 'S')
- cmdedit_update_prompt();
-#if ENABLE_HUSH_GETOPTS
- /* defoptindvar is a "OPTIND=..." constant string */
- if (strncmp(cur->varstr, defoptindvar, 7) == 0)
- G.getopt_count = 0;
-#endif
if (cur->flg_export) {
if (flags & SETFLAG_UNEXPORT) {
cur->flg_export = 0;
@@ -2265,6 +2263,23 @@ static int set_local_var(char *str, unsigned flags)
}
}
free(free_me);
+
+ /* Handle special names */
+ if (name_len == 4 && cur->varstr[0] == 'P' && cur->varstr[1] == 'S')
+ cmdedit_update_prompt();
+ else
+ if ((ENABLE_HUSH_LINENO_VAR || ENABLE_HUSH_GETOPTS) && name_len == 7) {
+#if ENABLE_HUSH_LINENO_VAR
+ if (G.lineno_var && strncmp(cur->varstr, "LINENO", 6) == 0)
+ G.lineno_var = NULL;
+#endif
+#if ENABLE_HUSH_GETOPTS
+ /* defoptindvar is a "OPTIND=..." constant string */
+ if (strncmp(cur->varstr, defoptindvar, 7) == 0)
+ G.getopt_count = 0;
+#endif
+ }
+
return 0;
}
@@ -2282,14 +2297,16 @@ static int unset_local_var_len(const char *name, int name_len)
if (!name)
return EXIT_SUCCESS;
+ if ((ENABLE_HUSH_LINENO_VAR || ENABLE_HUSH_GETOPTS) && name_len == 6) {
#if ENABLE_HUSH_GETOPTS
- if (name_len == 6 && strncmp(name, "OPTIND", 6) == 0)
- G.getopt_count = 0;
+ if (strncmp(name, "OPTIND", 6) == 0)
+ G.getopt_count = 0;
#endif
#if ENABLE_HUSH_LINENO_VAR
- if (name_len == 6 && G.lineno_var && strncmp(name, "LINENO", 6) == 0)
- G.lineno_var = NULL;
+ if (G.lineno_var && strncmp(name, "LINENO", 6) == 0)
+ G.lineno_var = NULL;
#endif
+ }
cur_pp = &G.top_var;
while ((cur = *cur_pp) != NULL) {
@@ -2355,13 +2372,12 @@ static void add_vars(struct variable *var)
* which attempts to overwrite it.
* The strings[] vector itself is freed.
*/
-static struct variable *set_vars_and_save_old(char **strings)
+static void set_vars_and_save_old(char **strings)
{
char **s;
- struct variable *old = NULL;
if (!strings)
- return old;
+ return;
s = strings;
while (*s) {
@@ -2389,12 +2405,10 @@ static struct variable *set_vars_and_save_old(char **strings)
do { *p = p[1]; p++; } while (*p);
goto next;
}
- /* Remove variable from global linked list */
- debug_printf_env("%s: removing '%s'\n", __func__, var_p->varstr);
- *var_pp = var_p->next;
- /* Add it to returned list */
- var_p->next = old;
- old = var_p;
+ /* below, set_local_var() with nest level will
+ * "shadow" (remove) this variable from
+ * global linked list.
+ */
}
//bb_error_msg("G.var_nest_level:%d", G.var_nest_level);
set_local_var(*s, (G.var_nest_level << SETFLAG_VARLVL_SHIFT) | SETFLAG_EXPORT);
@@ -2405,7 +2419,6 @@ static struct variable *set_vars_and_save_old(char **strings)
next: ;
}
free(strings);
- return old;
}
@@ -7598,6 +7611,7 @@ static NOINLINE void pseudo_exec_argv(nommu_save_t *nommu_save,
char **argv_expanded)
{
const struct built_in_command *x;
+ struct variable **sv_shadowed;
char **new_env;
IF_HUSH_COMMAND(char opt_vV = 0;)
IF_HUSH_FUNCTIONS(const struct function *funcp;)
@@ -7614,13 +7628,14 @@ static NOINLINE void pseudo_exec_argv(nommu_save_t *nommu_save,
_exit(EXIT_SUCCESS);
}
+ sv_shadowed = G.shadowed_vars_pp;
#if BB_MMU
- set_vars_and_save_old(new_env);
- /* we can destroy set_vars_and_save_old's return value,
- * to save memory */
+ G.shadowed_vars_pp = NULL; /* "don't save, free them instead" */
#else
- nommu_save->old_vars = set_vars_and_save_old(new_env);
+ G.shadowed_vars_pp = &nommu_save->old_vars;
#endif
+ set_vars_and_save_old(new_env);
+ G.shadowed_vars_pp = sv_shadowed;
if (argv_expanded) {
argv = argv_expanded;
@@ -8181,7 +8196,6 @@ static int checkjobs_and_fg_shell(struct pipe *fg_pipe)
redirect_and_varexp_helper(old_vars_p, command, squirrel)
#endif
static int redirect_and_varexp_helper(
- struct variable **old_vars_p,
struct command *command,
struct squirrel **sqp,
char **argv_expanded)
@@ -8196,7 +8210,7 @@ static int redirect_and_varexp_helper(
dump_cmd_in_x_mode(new_env);
dump_cmd_in_x_mode(argv_expanded);
/* this takes ownership of new_env[i] elements, and frees new_env: */
- *old_vars_p = set_vars_and_save_old(new_env);
+ set_vars_and_save_old(new_env);
}
return rcode;
}
@@ -8288,6 +8302,7 @@ static NOINLINE int run_pipe(struct pipe *pi)
const struct built_in_command *x;
IF_HUSH_FUNCTIONS(const struct function *funcp;)
IF_NOT_HUSH_FUNCTIONS(enum { funcp = 0 };)
+ struct variable **sv_shadowed;
struct variable *old_vars;
#if ENABLE_HUSH_LINENO_VAR
@@ -8338,13 +8353,11 @@ static NOINLINE int run_pipe(struct pipe *pi)
/* Expand the rest into (possibly) many strings each */
#if defined(CMD_SINGLEWORD_NOGLOB)
- if (command->cmd_type == CMD_SINGLEWORD_NOGLOB) {
+ if (command->cmd_type == CMD_SINGLEWORD_NOGLOB)
argv_expanded = expand_strvec_to_strvec_singleword_noglob(argv + command->assignment_cnt);
- } else
+ else
#endif
- {
argv_expanded = expand_strvec_to_strvec(argv + command->assignment_cnt);
- }
/* if someone gives us an empty string: `cmd with empty output` */
//TODO: what about: var=EXPR `` >FILE ? will var be set? Will FILE be created?
@@ -8354,17 +8367,19 @@ static NOINLINE int run_pipe(struct pipe *pi)
return G.last_exitcode;
}
-#if ENABLE_HUSH_FUNCTIONS
+ old_vars = NULL;
+ sv_shadowed = G.shadowed_vars_pp;
+
/* Check if argv[0] matches any functions (this goes before bltins) */
- funcp = find_function(argv_expanded[0]);
-#endif
- x = NULL;
- if (!funcp)
+ IF_HUSH_FUNCTIONS(funcp = find_function(argv_expanded[0]);)
+ IF_HUSH_FUNCTIONS(x = NULL;)
+ IF_HUSH_FUNCTIONS(if (!funcp))
x = find_builtin(argv_expanded[0]);
if (x || funcp) {
if (x && x->b_function == builtin_exec && argv_expanded[1] == NULL) {
debug_printf("exec with redirects only\n");
rcode = setup_redirects(command, NULL);
+//TODO: what about: var=EXPR exec >FILE ? will var be set?
/* rcode=1 can be if redir file can't be opened */
goto clean_up_and_ret1;
}
@@ -8373,9 +8388,22 @@ static NOINLINE int run_pipe(struct pipe *pi)
* a=b true; env | grep ^a=
*/
enter_var_nest_level();
- rcode = redirect_and_varexp_helper(&old_vars, command, &squirrel, argv_expanded);
+ /* Collect all variables "shadowed" by helper
+ * (IOW: old vars overridden by "var1=val1 var2=val2 cmd..." syntax)
+ * into old_vars list:
+ */
+ G.shadowed_vars_pp = &old_vars;
+ rcode = redirect_and_varexp_helper(command, &squirrel, argv_expanded);
if (rcode == 0) {
if (!funcp) {
+ /* Do not collect *to old_vars list* vars shadowed
+ * by e.g. "local VAR" builtin (collect them
+ * in the previously nested list instead):
+ * don't want them to be restored immediately
+ * after "local" completes.
+ */
+ G.shadowed_vars_pp = sv_shadowed;
+
debug_printf_exec(": builtin '%s' '%s'...\n",
x->b_cmd, argv_expanded[1]);
fflush_all();
@@ -8384,17 +8412,15 @@ static NOINLINE int run_pipe(struct pipe *pi)
}
#if ENABLE_HUSH_FUNCTIONS
else {
- struct variable **sv = G.shadowed_vars_pp;
- /* Make "local" builtins in the called function
- * stash shadowed variables in old_vars list
- */
- G.shadowed_vars_pp = &old_vars;
-
debug_printf_exec(": function '%s' '%s'...\n",
funcp->name, argv_expanded[1]);
rcode = run_function(funcp, argv_expanded) & 0xff;
-
- G.shadowed_vars_pp = sv;
+ /*
+ * But do collect *to old_vars list* vars shadowed
+ * within function execution. To that end, restore
+ * this pointer _after_ function run:
+ */
+ G.shadowed_vars_pp = sv_shadowed;
}
#endif
}
@@ -8405,7 +8431,11 @@ static NOINLINE int run_pipe(struct pipe *pi)
goto must_fork;
enter_var_nest_level();
- rcode = redirect_and_varexp_helper(&old_vars, command, &squirrel, argv_expanded);
+ /* Collect all variables "shadowed" by helper into old_vars list */
+ G.shadowed_vars_pp = &old_vars;
+ rcode = redirect_and_varexp_helper(command, &squirrel, argv_expanded);
+ G.shadowed_vars_pp = sv_shadowed;
+
if (rcode == 0) {
debug_printf_exec(": run_nofork_applet '%s' '%s'...\n",
argv_expanded[0], argv_expanded[1]);