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hush: less mind-bending set_vars_and_save_old()

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function                                             old     new   delta
run_pipe                                            1651    1701     +50
set_local_var                                        510     557     +47
pseudo_exec_argv                                     544     581     +37
redirect_and_varexp_helper                            64      56      -8
set_vars_and_save_old                                164     149     -15
unset_local_var                                      274     256     -18
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 3/3 up/down: 134/-41)            Total: 93 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2018-04-05 14:09:14 +02:00
parent 4e1dc539e9
commit 929a41d577
1 changed files with 101 additions and 71 deletions
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172
shell/hush.c
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@ -2140,19 +2140,10 @@ static int set_local_var(char *str, unsigned flags)
unsigned local_lvl = (flags >> SETFLAG_VARLVL_SHIFT); unsigned local_lvl = (flags >> SETFLAG_VARLVL_SHIFT);
eq_sign = strchr(str, '='); eq_sign = strchr(str, '=');
if (!eq_sign) { /* not expected to ever happen? */ if (HUSH_DEBUG && !eq_sign)
free(str); bb_error_msg_and_die("BUG in setvar");
return -1;
}
name_len = eq_sign - str + 1; /* including '=' */ 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; cur_pp = &G.top_var;
while ((cur = *cur_pp) != NULL) { while ((cur = *cur_pp) != NULL) {
if (strncmp(cur->varstr, str, name_len) != 0) { if (strncmp(cur->varstr, str, name_len) != 0) {
@ -2175,19 +2166,6 @@ static int set_local_var(char *str, unsigned flags)
*eq_sign = '='; *eq_sign = '=';
} }
if (cur->var_nest_level < local_lvl) { 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: /* bash 3.2.33(1) and exported vars:
* # export z=z * # export z=z
* # f() { local z=a; env | grep ^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) if (cur->flg_export)
flags |= SETFLAG_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; break;
} }
@ -2207,8 +2210,10 @@ static int set_local_var(char *str, unsigned flags)
free(str); free(str);
goto exp; goto exp;
} }
/* Replace the value in the found "struct variable" */
if (cur->max_len != 0) { 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 */ /* This one is from startup env, reuse space */
debug_printf_env("reusing startup env for '%s'\n", str); debug_printf_env("reusing startup env for '%s'\n", str);
strcpy(cur->varstr, str); strcpy(cur->varstr, str);
@ -2244,13 +2249,6 @@ static int set_local_var(char *str, unsigned flags)
#endif #endif
if (flags & SETFLAG_EXPORT) if (flags & SETFLAG_EXPORT)
cur->flg_export = 1; 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 (cur->flg_export) {
if (flags & SETFLAG_UNEXPORT) { if (flags & SETFLAG_UNEXPORT) {
cur->flg_export = 0; cur->flg_export = 0;
@ -2265,6 +2263,23 @@ static int set_local_var(char *str, unsigned flags)
} }
} }
free(free_me); 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; return 0;
} }
@ -2282,14 +2297,16 @@ static int unset_local_var_len(const char *name, int name_len)
if (!name) if (!name)
return EXIT_SUCCESS; return EXIT_SUCCESS;
if ((ENABLE_HUSH_LINENO_VAR || ENABLE_HUSH_GETOPTS) && name_len == 6) {
#if ENABLE_HUSH_GETOPTS #if ENABLE_HUSH_GETOPTS
if (name_len == 6 && strncmp(name, "OPTIND", 6) == 0) if (strncmp(name, "OPTIND", 6) == 0)
G.getopt_count = 0; G.getopt_count = 0;
#endif #endif
#if ENABLE_HUSH_LINENO_VAR #if ENABLE_HUSH_LINENO_VAR
if (name_len == 6 && G.lineno_var && strncmp(name, "LINENO", 6) == 0) if (G.lineno_var && strncmp(name, "LINENO", 6) == 0)
G.lineno_var = NULL; G.lineno_var = NULL;
#endif #endif
}
cur_pp = &G.top_var; cur_pp = &G.top_var;
while ((cur = *cur_pp) != NULL) { while ((cur = *cur_pp) != NULL) {
@ -2355,13 +2372,12 @@ static void add_vars(struct variable *var)
* which attempts to overwrite it. * which attempts to overwrite it.
* The strings[] vector itself is freed. * 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; char **s;
struct variable *old = NULL;
if (!strings) if (!strings)
return old; return;
s = strings; s = strings;
while (*s) { while (*s) {
@ -2389,12 +2405,10 @@ static struct variable *set_vars_and_save_old(char **strings)
do { *p = p[1]; p++; } while (*p); do { *p = p[1]; p++; } while (*p);
goto next; goto next;
} }
/* Remove variable from global linked list */ /* below, set_local_var() with nest level will
debug_printf_env("%s: removing '%s'\n", __func__, var_p->varstr); * "shadow" (remove) this variable from
*var_pp = var_p->next; * global linked list.
/* Add it to returned list */ */
var_p->next = old;
old = var_p;
} }
//bb_error_msg("G.var_nest_level:%d", G.var_nest_level); //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); 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: ; next: ;
} }
free(strings); free(strings);
return old;
} }
@ -7598,6 +7611,7 @@ static NOINLINE void pseudo_exec_argv(nommu_save_t *nommu_save,
char **argv_expanded) char **argv_expanded)
{ {
const struct built_in_command *x; const struct built_in_command *x;
struct variable **sv_shadowed;
char **new_env; char **new_env;
IF_HUSH_COMMAND(char opt_vV = 0;) IF_HUSH_COMMAND(char opt_vV = 0;)
IF_HUSH_FUNCTIONS(const struct function *funcp;) 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); _exit(EXIT_SUCCESS);
} }
sv_shadowed = G.shadowed_vars_pp;
#if BB_MMU #if BB_MMU
set_vars_and_save_old(new_env); G.shadowed_vars_pp = NULL; /* "don't save, free them instead" */
/* we can destroy set_vars_and_save_old's return value,
* to save memory */
#else #else
nommu_save->old_vars = set_vars_and_save_old(new_env); G.shadowed_vars_pp = &nommu_save->old_vars;
#endif #endif
set_vars_and_save_old(new_env);
G.shadowed_vars_pp = sv_shadowed;
if (argv_expanded) { if (argv_expanded) {
argv = 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) redirect_and_varexp_helper(old_vars_p, command, squirrel)
#endif #endif
static int redirect_and_varexp_helper( static int redirect_and_varexp_helper(
struct variable **old_vars_p,
struct command *command, struct command *command,
struct squirrel **sqp, struct squirrel **sqp,
char **argv_expanded) 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(new_env);
dump_cmd_in_x_mode(argv_expanded); dump_cmd_in_x_mode(argv_expanded);
/* this takes ownership of new_env[i] elements, and frees new_env: */ /* 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; return rcode;
} }
@ -8288,6 +8302,7 @@ static NOINLINE int run_pipe(struct pipe *pi)
const struct built_in_command *x; const struct built_in_command *x;
IF_HUSH_FUNCTIONS(const struct function *funcp;) IF_HUSH_FUNCTIONS(const struct function *funcp;)
IF_NOT_HUSH_FUNCTIONS(enum { funcp = 0 };) IF_NOT_HUSH_FUNCTIONS(enum { funcp = 0 };)
struct variable **sv_shadowed;
struct variable *old_vars; struct variable *old_vars;
#if ENABLE_HUSH_LINENO_VAR #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 */ /* Expand the rest into (possibly) many strings each */
#if defined(CMD_SINGLEWORD_NOGLOB) #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); argv_expanded = expand_strvec_to_strvec_singleword_noglob(argv + command->assignment_cnt);
} else else
#endif #endif
{
argv_expanded = expand_strvec_to_strvec(argv + command->assignment_cnt); argv_expanded = expand_strvec_to_strvec(argv + command->assignment_cnt);
}
/* if someone gives us an empty string: `cmd with empty output` */ /* 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? //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; 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) */ /* Check if argv[0] matches any functions (this goes before bltins) */
funcp = find_function(argv_expanded[0]); IF_HUSH_FUNCTIONS(funcp = find_function(argv_expanded[0]);)
#endif IF_HUSH_FUNCTIONS(x = NULL;)
x = NULL; IF_HUSH_FUNCTIONS(if (!funcp))
if (!funcp)
x = find_builtin(argv_expanded[0]); x = find_builtin(argv_expanded[0]);
if (x || funcp) { if (x || funcp) {
if (x && x->b_function == builtin_exec && argv_expanded[1] == NULL) { if (x && x->b_function == builtin_exec && argv_expanded[1] == NULL) {
debug_printf("exec with redirects only\n"); debug_printf("exec with redirects only\n");
rcode = setup_redirects(command, NULL); 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 */ /* rcode=1 can be if redir file can't be opened */
goto clean_up_and_ret1; goto clean_up_and_ret1;
} }
@ -8373,9 +8388,22 @@ static NOINLINE int run_pipe(struct pipe *pi)
* a=b true; env | grep ^a= * a=b true; env | grep ^a=
*/ */
enter_var_nest_level(); 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 (rcode == 0) {
if (!funcp) { 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", debug_printf_exec(": builtin '%s' '%s'...\n",
x->b_cmd, argv_expanded[1]); x->b_cmd, argv_expanded[1]);
fflush_all(); fflush_all();
@ -8384,17 +8412,15 @@ static NOINLINE int run_pipe(struct pipe *pi)
} }
#if ENABLE_HUSH_FUNCTIONS #if ENABLE_HUSH_FUNCTIONS
else { 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", debug_printf_exec(": function '%s' '%s'...\n",
funcp->name, argv_expanded[1]); funcp->name, argv_expanded[1]);
rcode = run_function(funcp, argv_expanded) & 0xff; 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 #endif
} }
@ -8405,7 +8431,11 @@ static NOINLINE int run_pipe(struct pipe *pi)
goto must_fork; goto must_fork;
enter_var_nest_level(); 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) { if (rcode == 0) {
debug_printf_exec(": run_nofork_applet '%s' '%s'...\n", debug_printf_exec(": run_nofork_applet '%s' '%s'...\n",
argv_expanded[0], argv_expanded[1]); argv_expanded[0], argv_expanded[1]);