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hush: add support for local builtin 

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2009-06-03 12:47:26 +02:00
parent 98f74034cd
commit 295fef80bc
6 changed files with 211 additions and 71 deletions
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7
shell/Config.in
View File

@ -232,6 +232,13 @@ config HUSH_FUNCTIONS
help
Enable support for shell functions in hush. +800 bytes.
config HUSH_LOCAL
bool "Support local builtin"
default n
depends on HUSH_FUNCTIONS
help
Enable support for local variables in functions.
config HUSH_EXPORT_N
bool "Support export '-n' option"
default n

246
shell/hush.c
View File

@ -394,6 +394,9 @@ struct parse_context {
struct variable {
struct variable *next;
char *varstr; /* points to "name=" portion */
#if ENABLE_HUSH_LOCAL
unsigned func_nest_level;
#endif
int max_len; /* if > 0, name is part of initial env; else name is malloced */
smallint flg_export; /* putenv should be done on this var */
smallint flg_read_only;
@ -488,6 +491,10 @@ struct globals {
struct variable shell_ver;
#if ENABLE_HUSH_FUNCTIONS
struct function *top_func;
# if ENABLE_HUSH_LOCAL
struct variable **shadowed_vars_pp;
unsigned func_nest_level;
# endif
#endif
/* Signal and trap handling */
#if ENABLE_HUSH_FAST
@ -529,6 +536,9 @@ static int builtin_jobs(char **argv);
#if ENABLE_HUSH_HELP
static int builtin_help(char **argv);
#endif
#if ENABLE_HUSH_LOCAL
static int builtin_local(char **argv);
#endif
#if HUSH_DEBUG
static int builtin_memleak(char **argv);
#endif
@ -599,6 +609,9 @@ static const struct built_in_command bltins[] = {
#if ENABLE_HUSH_JOB
BLTIN("jobs" , builtin_jobs , "List active jobs"),
#endif
#if ENABLE_HUSH_LOCAL
BLTIN("local" , builtin_local , "Set local variable"),
#endif
#if HUSH_DEBUG
BLTIN("memleak" , builtin_memleak , "Debug tool"),
#endif
@ -1261,12 +1274,21 @@ static const char *get_local_var_value(const char *name)
* -1: clear export flag and unsetenv the variable
* flg_read_only is set only when we handle -R var=val
*/
#if BB_MMU
#define set_local_var(str, flg_export, flg_read_only) \
#if !BB_MMU && ENABLE_HUSH_LOCAL
/* all params are used */
#elif BB_MMU && ENABLE_HUSH_LOCAL
#define set_local_var(str, flg_export, local_lvl, flg_read_only) \
set_local_var(str, flg_export, local_lvl)
#elif BB_MMU && !ENABLE_HUSH_LOCAL
#define set_local_var(str, flg_export, local_lvl, flg_read_only) \
set_local_var(str, flg_export)
#elif !BB_MMU && !ENABLE_HUSH_LOCAL
#define set_local_var(str, flg_export, local_lvl, flg_read_only) \
set_local_var(str, flg_export, flg_read_only)
#endif
static int set_local_var(char *str, int flg_export, int flg_read_only)
static int set_local_var(char *str, int flg_export, int local_lvl, int flg_read_only)
{
struct variable **var_pp;
struct variable *cur;
char *eq_sign;
int name_len;
@ -1278,15 +1300,10 @@ static int set_local_var(char *str, int flg_export, int flg_read_only)
}
name_len = eq_sign - str + 1; /* including '=' */
cur = G.top_var; /* cannot be NULL (we have HUSH_VERSION and it's RO) */
while (1) {
var_pp = &G.top_var;
while ((cur = *var_pp) != NULL) {
if (strncmp(cur->varstr, str, name_len) != 0) {
if (!cur->next) {
/* Bail out. Note that now cur points
* to the last var in the linked list */
break;
}
cur = cur->next;
var_pp = &cur->next;
continue;
}
/* We found an existing var with this name */
@ -1298,33 +1315,61 @@ static int set_local_var(char *str, int flg_export, int flg_read_only)
free(str);
return -1;
}
if (flg_export == -1) {
if (flg_export == -1) { // "&& cur->flg_export" ?
debug_printf_env("%s: unsetenv '%s'\n", __func__, str);
*eq_sign = '\0';
unsetenv(str);
*eq_sign = '=';
}
#if ENABLE_HUSH_LOCAL
if (cur->func_nest_level < local_lvl) {
/* New variable is declared as local,
* and existing one is global, or local
* from enclosing function.
* Remove and save old one: */
*var_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; }
* # f
* z=a
* # env | grep ^z
* z=z
*/
if (cur->flg_export)
flg_export = 1;
break;
}
#endif
if (strcmp(cur->varstr + name_len, eq_sign + 1) == 0) {
free_and_exp:
free(str);
goto exp;
}
if (cur->max_len >= strlen(str)) {
/* This one is from startup env, reuse space */
strcpy(cur->varstr, str);
goto free_and_exp;
}
/* max_len == 0 signifies "malloced" var, which we can
* (and has to) free */
if (!cur->max_len)
if (cur->max_len != 0) {
if (cur->max_len >= strlen(str)) {
/* This one is from startup env, reuse space */
strcpy(cur->varstr, str);
goto free_and_exp;
}
} else {
/* max_len == 0 signifies "malloced" var, which we can
* (and has to) free */
free(cur->varstr);
}
cur->max_len = 0;
goto set_str_and_exp;
}
/* Not found - create next variable struct */
cur->next = xzalloc(sizeof(*cur));
cur = cur->next;
/* Not found - create new variable struct */
cur = xzalloc(sizeof(*cur));
#if ENABLE_HUSH_LOCAL
cur->func_nest_level = local_lvl;
#endif
cur->next = *var_pp;
*var_pp = cur;
set_str_and_exp:
cur->varstr = str;
@ -1418,7 +1463,7 @@ static void arith_set_local_var(const char *name, const char *val, int flags)
{
/* arith code doesnt malloc space, so do it for it */
char *var = xasprintf("%s=%s", name, val);
set_local_var(var, flags, 0);
set_local_var(var, flags, /*lvl:*/ 0, /*ro:*/ 0);
}
#endif
@ -1438,7 +1483,7 @@ static void add_vars(struct variable *var)
debug_printf_env("%s: restoring exported '%s'\n", __func__, var->varstr);
putenv(var->varstr);
} else {
debug_printf_env("%s: restoring local '%s'\n", __func__, var->varstr);
debug_printf_env("%s: restoring variable '%s'\n", __func__, var->varstr);
}
var = next;
}
@ -1471,7 +1516,7 @@ static struct variable *set_vars_and_save_old(char **strings)
var_p->next = old;
old = var_p;
}
set_local_var(*s, 1, 0);
set_local_var(*s, /*exp:*/ 1, /*lvl:*/ 0, /*ro:*/ 0);
}
s++;
}
@ -2302,7 +2347,7 @@ static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask)
val = NULL;
} else {
char *new_var = xasprintf("%s=%s", var, val);
set_local_var(new_var, 0, 0);
set_local_var(new_var, /*exp:*/ 0, /*lvl:*/ 0, /*ro:*/ 0);
}
}
}
@ -3036,9 +3081,13 @@ static int run_function(const struct function *funcp, char **argv)
smallint sv_flg;
save_and_replace_G_args(&sv, argv);
/* "we are in function, ok to use return" */
sv_flg = G.flag_return_in_progress;
G.flag_return_in_progress = -1;
#if ENABLE_HUSH_LOCAL
G.func_nest_level++;
#endif
/* On MMU, funcp->body is always non-NULL */
# if !BB_MMU
@ -3052,7 +3101,32 @@ static int run_function(const struct function *funcp, char **argv)
rc = run_list(funcp->body);
}
#if ENABLE_HUSH_LOCAL
{
struct variable *var;
struct variable **var_pp;
var_pp = &G.top_var;
while ((var = *var_pp) != NULL) {
if (var->func_nest_level < G.func_nest_level) {
var_pp = &var->next;
continue;
}
/* Unexport */
if (var->flg_export)
bb_unsetenv(var->varstr);
/* Remove from global list */
*var_pp = var->next;
/* Free */
if (!var->max_len)
free(var->varstr);
free(var);
}
G.func_nest_level--;
}
#endif
G.flag_return_in_progress = sv_flg;
restore_G_args(&sv, argv);
return rc;
@ -3606,7 +3680,7 @@ static int run_pipe(struct pipe *pi)
p = expand_string_to_string(*argv);
debug_printf_exec("set shell var:'%s'->'%s'\n",
*argv, p);
set_local_var(p, 0, 0);
set_local_var(p, /*exp:*/ 0, /*lvl:*/ 0, /*ro:*/ 0);
argv++;
}
/* Do we need to flag set_local_var() errors?
@ -3651,9 +3725,17 @@ static int run_pipe(struct pipe *pi)
}
#if ENABLE_HUSH_FUNCTIONS
else {
# if ENABLE_HUSH_LOCAL
struct variable **sv;
sv = G.shadowed_vars_pp;
G.shadowed_vars_pp = &old_vars;
# endif
debug_printf_exec(": function '%s' '%s'...\n",
funcp->name, argv_expanded[1]);
rcode = run_function(funcp, argv_expanded) & 0xff;
# if ENABLE_HUSH_LOCAL
G.shadowed_vars_pp = sv;
# endif
}
#endif
}
@ -4050,7 +4132,7 @@ static int run_list(struct pipe *pi)
}
/* Insert next value from for_lcur */
/* note: *for_lcur already has quotes removed, $var expanded, etc */
set_local_var(xasprintf("%s=%s", pi->cmds[0].argv[0], *for_lcur++), 0, 0);
set_local_var(xasprintf("%s=%s", pi->cmds[0].argv[0], *for_lcur++), /*exp:*/ 0, /*lvl:*/ 0, /*ro:*/ 0);
continue;
}
if (rword == RES_IN) {
@ -6250,7 +6332,7 @@ int hush_main(int argc, char **argv)
break;
case 'R':
case 'V':
set_local_var(xstrdup(optarg), 0, opt == 'R');
set_local_var(xstrdup(optarg), /*exp:*/ 0, /*lvl:*/ 0, /*ro:*/ opt == 'R');
break;
# if ENABLE_HUSH_FUNCTIONS
case 'F': {
@ -6583,6 +6665,55 @@ static void print_escaped(const char *s)
} while (*s);
}
#if !ENABLE_HUSH_LOCAL
#define helper_export_local(argv, exp, lvl) \
helper_export_local(argv, exp)
#endif
static void helper_export_local(char **argv, int exp, int lvl)
{
do {
char *name = *argv;
/* So far we do not check that name is valid (TODO?) */
if (strchr(name, '=') == NULL) {
struct variable *var;
var = get_local_var(name);
if (exp == -1) { /* unexporting? */
/* export -n NAME (without =VALUE) */
if (var) {
var->flg_export = 0;
debug_printf_env("%s: unsetenv '%s'\n", __func__, name);
unsetenv(name);
} /* else: export -n NOT_EXISTING_VAR: no-op */
continue;
}
if (exp == 1) { /* exporting? */
/* export NAME (without =VALUE) */
if (var) {
var->flg_export = 1;
debug_printf_env("%s: putenv '%s'\n", __func__, var->varstr);
putenv(var->varstr);
continue;
}
}
/* Exporting non-existing variable.
* bash does not put it in environment,
* but remembers that it is exported,
* and does put it in env when it is set later.
* We just set it to "" and export. */
/* Or, it's "local NAME" (without =VALUE).
* bash sets the value to "". */
name = xasprintf("%s=", name);
} else {
/* (Un)exporting/making local NAME=VALUE */
name = xstrdup(name);
}
set_local_var(name, /*exp:*/ exp, /*lvl:*/ lvl, /*ro:*/ 0);
} while (*++argv);
}
static int builtin_export(char **argv)
{
unsigned opt_unexport;
@ -6625,50 +6756,23 @@ static int builtin_export(char **argv)
argv++;
#endif
do {
char *name = *argv;
/* So far we do not check that name is valid (TODO?) */
if (strchr(name, '=') == NULL) {
struct variable *var;
var = get_local_var(name);
if (opt_unexport) {
/* export -n NAME (without =VALUE) */
if (var) {
var->flg_export = 0;
debug_printf_env("%s: unsetenv '%s'\n", __func__, name);
unsetenv(name);
} /* else: export -n NOT_EXISTING_VAR: no-op */
continue;
}
/* export NAME (without =VALUE) */
if (var) {
var->flg_export = 1;
debug_printf_env("%s: putenv '%s'\n", __func__, var->varstr);
putenv(var->varstr);
continue;
}
/* Exporting non-existing variable.
* bash does not put it in environment,
* but remembers that it is exported,
* and does put it in env when it is set later.
* We just set it to "" and export. */
name = xasprintf("%s=", name);
} else {
/* (Un)exporting NAME=VALUE */
name = xstrdup(name);
}
set_local_var(name,
/*export:*/ (opt_unexport ? -1 : 1),
/*readonly:*/ 0
);
} while (*++argv);
helper_export_local(argv, (opt_unexport ? -1 : 1), 0);
return EXIT_SUCCESS;
}
#if ENABLE_HUSH_LOCAL
static int builtin_local(char **argv)
{
if (G.func_nest_level == 0) {
bb_error_msg("%s: not in a function", argv[0]);
return EXIT_FAILURE; /* bash compat */
}
helper_export_local(argv, 0, G.func_nest_level);
return EXIT_SUCCESS;
}
#endif
static int builtin_trap(char **argv)
{
int sig;
@ -6944,7 +7048,7 @@ static int builtin_read(char **argv)
//TODO: bash unbackslashes input, splits words and puts them in argv[i]
string = xmalloc_reads(STDIN_FILENO, xasprintf("%s=", name), NULL);
return set_local_var(string, 0, 0);
return set_local_var(string, /*exp:*/ 0, /*lvl:*/ 0, /*ro:*/ 0);
}
/* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#set

3
shell/hush_test/hush-misc/func_local1.right Normal file
View File

@ -0,0 +1,3 @@
z=a
z=z
Done

5
shell/hush_test/hush-misc/func_local1.tests Executable file
View File

@ -0,0 +1,5 @@
export z=z
f() { local z=a; env | grep ^z; }
f
env | grep ^z
echo Done

14
shell/hush_test/hush-misc/func_local2.right Normal file
View File

@ -0,0 +1,14 @@
1
2
1
2
1
1
2
2
3
2
2
3
1
Done

7
shell/hush_test/hush-misc/func_local2.tests Executable file
View File

@ -0,0 +1,7 @@
x=1
f() { echo $x; local x=$((x+1)); echo $x; }
g() { f; echo $x; f; local x=$((x+1)); f; echo $x; f; }
f
g
echo $x
echo Done