parser.c revision ed8a7d84428ec945c48b6b53dc5a3a18fabaf683 
1#include <stdio.h>
2#include <stdlib.h>
3#include <unistd.h>
4#include <fcntl.h>
5#include <stdarg.h>
6#include <string.h>
7#include <stddef.h>
8#include <ctype.h>
9
10#include "init.h"
11#include "property_service.h"
12#include "parser.h"
13#include "util.h"
14#include "list.h"
15#include "log.h"
16
17#include <cutils/iosched_policy.h>
18
19#define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
20#include <sys/_system_properties.h>
21
22static list_declare(service_list);
23static list_declare(action_list);
24static list_declare(action_queue);
25
26#define RAW(x...) log_write(6, x)
27
28void DUMP(void)
29{
30#if 0
31    struct service *svc;
32    struct action *act;
33    struct command *cmd;
34    struct listnode *node;
35    struct listnode *node2;
36    struct socketinfo *si;
37    int n;
38
39    list_for_each(node, &service_list) {
40        svc = node_to_item(node, struct service, slist);
41        RAW("service %s\n", svc->name);
42        RAW("  class '%s'\n", svc->classname);
43        RAW("  exec");
44        for (n = 0; n < svc->nargs; n++) {
45            RAW(" '%s'", svc->args[n]);
46        }
47        RAW("\n");
48        for (si = svc->sockets; si; si = si->next) {
49            RAW("  socket %s %s 0%o\n", si->name, si->type, si->perm);
50        }
51    }
52
53    list_for_each(node, &action_list) {
54        act = node_to_item(node, struct action, alist);
55        RAW("on %s\n", act->name);
56        list_for_each(node2, &act->commands) {
57            cmd = node_to_item(node2, struct command, clist);
58            RAW("  %p", cmd->func);
59            for (n = 0; n < cmd->nargs; n++) {
60                RAW(" %s", cmd->args[n]);
61            }
62            RAW("\n");
63        }
64        RAW("\n");
65    }
66#endif
67}
68
69#define T_EOF 0
70#define T_TEXT 1
71#define T_NEWLINE 2
72
73struct parse_state
74{
75    char *ptr;
76    char *text;
77    int line;
78    int nexttoken;
79    void *context;
80    void (*parse_line)(struct parse_state *state, int nargs, char **args);
81    const char *filename;
82};
83
84static void *parse_service(struct parse_state *state, int nargs, char **args);
85static void parse_line_service(struct parse_state *state, int nargs, char **args);
86
87static void *parse_action(struct parse_state *state, int nargs, char **args);
88static void parse_line_action(struct parse_state *state, int nargs, char **args);
89
90void parse_error(struct parse_state *state, const char *fmt, ...)
91{
92    va_list ap;
93    char buf[128];
94    int off;
95
96    snprintf(buf, 128, "%s: %d: ", state->filename, state->line);
97    buf[127] = 0;
98    off = strlen(buf);
99
100    va_start(ap, fmt);
101    vsnprintf(buf + off, 128 - off, fmt, ap);
102    va_end(ap);
103    buf[127] = 0;
104    ERROR("%s", buf);
105}
106
107#define SECTION 0x01
108#define COMMAND 0x02
109#define OPTION  0x04
110
111#include "keywords.h"
112
113#define KEYWORD(symbol, flags, nargs, func) \
114    [ K_##symbol ] = { #symbol, func, nargs + 1, flags, },
115
116struct {
117    const char *name;
118    int (*func)(int nargs, char **args);
119    unsigned char nargs;
120    unsigned char flags;
121} keyword_info[KEYWORD_COUNT] = {
122    [ K_UNKNOWN ] = { "unknown", 0, 0, 0 },
123#include "keywords.h"
124};
125#undef KEYWORD
126
127#define kw_is(kw, type) (keyword_info[kw].flags & (type))
128#define kw_name(kw) (keyword_info[kw].name)
129#define kw_func(kw) (keyword_info[kw].func)
130#define kw_nargs(kw) (keyword_info[kw].nargs)
131
132int lookup_keyword(const char *s)
133{
134    switch (*s++) {
135    case 'c':
136	if (!strcmp(s, "opy")) return K_copy;
137        if (!strcmp(s, "apability")) return K_capability;
138        if (!strcmp(s, "hdir")) return K_chdir;
139        if (!strcmp(s, "hroot")) return K_chroot;
140        if (!strcmp(s, "lass")) return K_class;
141        if (!strcmp(s, "lass_start")) return K_class_start;
142        if (!strcmp(s, "lass_stop")) return K_class_stop;
143        if (!strcmp(s, "onsole")) return K_console;
144        if (!strcmp(s, "hown")) return K_chown;
145        if (!strcmp(s, "hmod")) return K_chmod;
146        if (!strcmp(s, "ritical")) return K_critical;
147        break;
148    case 'd':
149        if (!strcmp(s, "isabled")) return K_disabled;
150        if (!strcmp(s, "omainname")) return K_domainname;
151        if (!strcmp(s, "evice")) return K_device;
152        break;
153    case 'e':
154        if (!strcmp(s, "xec")) return K_exec;
155        if (!strcmp(s, "xport")) return K_export;
156        break;
157    case 'g':
158        if (!strcmp(s, "roup")) return K_group;
159        break;
160    case 'h':
161        if (!strcmp(s, "ostname")) return K_hostname;
162        break;
163    case 'i':
164        if (!strcmp(s, "oprio")) return K_ioprio;
165        if (!strcmp(s, "fup")) return K_ifup;
166        if (!strcmp(s, "nsmod")) return K_insmod;
167        if (!strcmp(s, "mport")) return K_import;
168        break;
169    case 'k':
170        if (!strcmp(s, "eycodes")) return K_keycodes;
171        break;
172    case 'l':
173        if (!strcmp(s, "oglevel")) return K_loglevel;
174        break;
175    case 'm':
176        if (!strcmp(s, "kdir")) return K_mkdir;
177        if (!strcmp(s, "ount")) return K_mount;
178        break;
179    case 'o':
180        if (!strcmp(s, "n")) return K_on;
181        if (!strcmp(s, "neshot")) return K_oneshot;
182        if (!strcmp(s, "nrestart")) return K_onrestart;
183        break;
184    case 'r':
185        if (!strcmp(s, "estart")) return K_restart;
186        break;
187    case 's':
188        if (!strcmp(s, "ervice")) return K_service;
189        if (!strcmp(s, "etenv")) return K_setenv;
190        if (!strcmp(s, "etkey")) return K_setkey;
191        if (!strcmp(s, "etprop")) return K_setprop;
192        if (!strcmp(s, "etrlimit")) return K_setrlimit;
193        if (!strcmp(s, "ocket")) return K_socket;
194        if (!strcmp(s, "tart")) return K_start;
195        if (!strcmp(s, "top")) return K_stop;
196        if (!strcmp(s, "ymlink")) return K_symlink;
197        if (!strcmp(s, "ysclktz")) return K_sysclktz;
198        break;
199    case 't':
200        if (!strcmp(s, "rigger")) return K_trigger;
201        break;
202    case 'u':
203        if (!strcmp(s, "ser")) return K_user;
204        break;
205    case 'w':
206        if (!strcmp(s, "rite")) return K_write;
207        break;
208    }
209    return K_UNKNOWN;
210}
211
212void parse_line_no_op(struct parse_state *state, int nargs, char **args)
213{
214}
215
216int next_token(struct parse_state *state)
217{
218    char *x = state->ptr;
219    char *s;
220
221    if (state->nexttoken) {
222        int t = state->nexttoken;
223        state->nexttoken = 0;
224        return t;
225    }
226
227    for (;;) {
228        switch (*x) {
229        case 0:
230            state->ptr = x;
231            return T_EOF;
232        case '\n':
233            state->line++;
234            x++;
235            state->ptr = x;
236            return T_NEWLINE;
237        case ' ':
238        case '\t':
239        case '\r':
240            x++;
241            continue;
242        case '#':
243            while (*x && (*x != '\n')) x++;
244            state->line++;
245            state->ptr = x;
246            return T_NEWLINE;
247        default:
248            goto text;
249        }
250    }
251
252textdone:
253    state->ptr = x;
254    *s = 0;
255    return T_TEXT;
256text:
257    state->text = s = x;
258textresume:
259    for (;;) {
260        switch (*x) {
261        case 0:
262            goto textdone;
263        case ' ':
264        case '\t':
265        case '\r':
266            x++;
267            goto textdone;
268        case '\n':
269            state->nexttoken = T_NEWLINE;
270            x++;
271            goto textdone;
272        case '"':
273            x++;
274            for (;;) {
275                switch (*x) {
276                case 0:
277                        /* unterminated quoted thing */
278                    state->ptr = x;
279                    return T_EOF;
280                case '"':
281                    x++;
282                    goto textresume;
283                default:
284                    *s++ = *x++;
285                }
286            }
287            break;
288        case '\\':
289            x++;
290            switch (*x) {
291            case 0:
292                goto textdone;
293            case 'n':
294                *s++ = '\n';
295                break;
296            case 'r':
297                *s++ = '\r';
298                break;
299            case 't':
300                *s++ = '\t';
301                break;
302            case '\\':
303                *s++ = '\\';
304                break;
305            case '\r':
306                    /* \ <cr> <lf> -> line continuation */
307                if (x[1] != '\n') {
308                    x++;
309                    continue;
310                }
311            case '\n':
312                    /* \ <lf> -> line continuation */
313                state->line++;
314                x++;
315                    /* eat any extra whitespace */
316                while((*x == ' ') || (*x == '\t')) x++;
317                continue;
318            default:
319                    /* unknown escape -- just copy */
320                *s++ = *x++;
321            }
322            continue;
323        default:
324            *s++ = *x++;
325        }
326    }
327    return T_EOF;
328}
329
330void parse_line(int nargs, char **args)
331{
332    int n;
333    int id = lookup_keyword(args[0]);
334    printf("%s(%d)", args[0], id);
335    for (n = 1; n < nargs; n++) {
336        printf(" '%s'", args[n]);
337    }
338    printf("\n");
339}
340
341void parse_new_section(struct parse_state *state, int kw,
342                       int nargs, char **args)
343{
344    printf("[ %s %s ]\n", args[0],
345           nargs > 1 ? args[1] : "");
346    switch(kw) {
347    case K_service:
348        state->context = parse_service(state, nargs, args);
349        if (state->context) {
350            state->parse_line = parse_line_service;
351            return;
352        }
353        break;
354    case K_on:
355        state->context = parse_action(state, nargs, args);
356        if (state->context) {
357            state->parse_line = parse_line_action;
358            return;
359        }
360        break;
361    }
362    state->parse_line = parse_line_no_op;
363}
364
365static void parse_config(const char *fn, char *s)
366{
367    struct parse_state state;
368    char *args[SVC_MAXARGS];
369    int nargs;
370
371    nargs = 0;
372    state.filename = fn;
373    state.line = 1;
374    state.ptr = s;
375    state.nexttoken = 0;
376    state.parse_line = parse_line_no_op;
377    for (;;) {
378        switch (next_token(&state)) {
379        case T_EOF:
380            state.parse_line(&state, 0, 0);
381            return;
382        case T_NEWLINE:
383            if (nargs) {
384                int kw = lookup_keyword(args[0]);
385                if (kw_is(kw, SECTION)) {
386                    state.parse_line(&state, 0, 0);
387                    parse_new_section(&state, kw, nargs, args);
388                } else {
389                    state.parse_line(&state, nargs, args);
390                }
391                nargs = 0;
392            }
393            break;
394        case T_TEXT:
395            if (nargs < SVC_MAXARGS) {
396                args[nargs++] = state.text;
397            }
398            break;
399        }
400    }
401}
402
403int parse_config_file(const char *fn)
404{
405    char *data;
406    data = read_file(fn, 0);
407    if (!data) return -1;
408
409    parse_config(fn, data);
410    DUMP();
411    return 0;
412}
413
414static int valid_name(const char *name)
415{
416    if (strlen(name) > 16) {
417        return 0;
418    }
419    while (*name) {
420        if (!isalnum(*name) && (*name != '_') && (*name != '-')) {
421            return 0;
422        }
423        name++;
424    }
425    return 1;
426}
427
428struct service *service_find_by_name(const char *name)
429{
430    struct listnode *node;
431    struct service *svc;
432    list_for_each(node, &service_list) {
433        svc = node_to_item(node, struct service, slist);
434        if (!strcmp(svc->name, name)) {
435            return svc;
436        }
437    }
438    return 0;
439}
440
441struct service *service_find_by_pid(pid_t pid)
442{
443    struct listnode *node;
444    struct service *svc;
445    list_for_each(node, &service_list) {
446        svc = node_to_item(node, struct service, slist);
447        if (svc->pid == pid) {
448            return svc;
449        }
450    }
451    return 0;
452}
453
454struct service *service_find_by_keychord(int keychord_id)
455{
456    struct listnode *node;
457    struct service *svc;
458    list_for_each(node, &service_list) {
459        svc = node_to_item(node, struct service, slist);
460        if (svc->keychord_id == keychord_id) {
461            return svc;
462        }
463    }
464    return 0;
465}
466
467void service_for_each(void (*func)(struct service *svc))
468{
469    struct listnode *node;
470    struct service *svc;
471    list_for_each(node, &service_list) {
472        svc = node_to_item(node, struct service, slist);
473        func(svc);
474    }
475}
476
477void service_for_each_class(const char *classname,
478                            void (*func)(struct service *svc))
479{
480    struct listnode *node;
481    struct service *svc;
482    list_for_each(node, &service_list) {
483        svc = node_to_item(node, struct service, slist);
484        if (!strcmp(svc->classname, classname)) {
485            func(svc);
486        }
487    }
488}
489
490void service_for_each_flags(unsigned matchflags,
491                            void (*func)(struct service *svc))
492{
493    struct listnode *node;
494    struct service *svc;
495    list_for_each(node, &service_list) {
496        svc = node_to_item(node, struct service, slist);
497        if (svc->flags & matchflags) {
498            func(svc);
499        }
500    }
501}
502
503void action_for_each_trigger(const char *trigger,
504                             void (*func)(struct action *act))
505{
506    struct listnode *node;
507    struct action *act;
508    list_for_each(node, &action_list) {
509        act = node_to_item(node, struct action, alist);
510        if (!strcmp(act->name, trigger)) {
511            func(act);
512        }
513    }
514}
515
516void queue_property_triggers(const char *name, const char *value)
517{
518    struct listnode *node;
519    struct action *act;
520    list_for_each(node, &action_list) {
521        act = node_to_item(node, struct action, alist);
522        if (!strncmp(act->name, "property:", strlen("property:"))) {
523            const char *test = act->name + strlen("property:");
524            int name_length = strlen(name);
525
526            if (!strncmp(name, test, name_length) &&
527                    test[name_length] == '=' &&
528                    !strcmp(test + name_length + 1, value)) {
529                action_add_queue_tail(act);
530            }
531        }
532    }
533}
534
535void queue_all_property_triggers()
536{
537    struct listnode *node;
538    struct action *act;
539    list_for_each(node, &action_list) {
540        act = node_to_item(node, struct action, alist);
541        if (!strncmp(act->name, "property:", strlen("property:"))) {
542            /* parse property name and value
543               syntax is property:<name>=<value> */
544            const char* name = act->name + strlen("property:");
545            const char* equals = strchr(name, '=');
546            if (equals) {
547                char prop_name[PROP_NAME_MAX + 1];
548                const char* value;
549                int length = equals - name;
550                if (length > PROP_NAME_MAX) {
551                    ERROR("property name too long in trigger %s", act->name);
552                } else {
553                    memcpy(prop_name, name, length);
554                    prop_name[length] = 0;
555
556                    /* does the property exist, and match the trigger value? */
557                    value = property_get(prop_name);
558                    if (value && !strcmp(equals + 1, value)) {
559                        action_add_queue_tail(act);
560                    }
561                }
562            }
563        }
564    }
565}
566
567void queue_builtin_action(int (*func)(int nargs, char **args), char *name)
568{
569    struct action *act;
570    struct command *cmd;
571
572    act = calloc(1, sizeof(*act));
573    act->name = name;
574    list_init(&act->commands);
575
576    cmd = calloc(1, sizeof(*cmd));
577    cmd->func = func;
578    cmd->args[0] = name;
579    list_add_tail(&act->commands, &cmd->clist);
580
581    list_add_tail(&action_list, &act->alist);
582    action_add_queue_tail(act);
583}
584
585void action_add_queue_tail(struct action *act)
586{
587    list_add_tail(&action_queue, &act->qlist);
588}
589
590struct action *action_remove_queue_head(void)
591{
592    if (list_empty(&action_queue)) {
593        return 0;
594    } else {
595        struct listnode *node = list_head(&action_queue);
596        struct action *act = node_to_item(node, struct action, qlist);
597        list_remove(node);
598        return act;
599    }
600}
601
602int action_queue_empty()
603{
604    return list_empty(&action_queue);
605}
606
607static void *parse_service(struct parse_state *state, int nargs, char **args)
608{
609    struct service *svc;
610    if (nargs < 3) {
611        parse_error(state, "services must have a name and a program\n");
612        return 0;
613    }
614    if (!valid_name(args[1])) {
615        parse_error(state, "invalid service name '%s'\n", args[1]);
616        return 0;
617    }
618
619    svc = service_find_by_name(args[1]);
620    if (svc) {
621        parse_error(state, "ignored duplicate definition of service '%s'\n", args[1]);
622        return 0;
623    }
624
625    nargs -= 2;
626    svc = calloc(1, sizeof(*svc) + sizeof(char*) * nargs);
627    if (!svc) {
628        parse_error(state, "out of memory\n");
629        return 0;
630    }
631    svc->name = args[1];
632    svc->classname = "default";
633    memcpy(svc->args, args + 2, sizeof(char*) * nargs);
634    svc->args[nargs] = 0;
635    svc->nargs = nargs;
636    svc->onrestart.name = "onrestart";
637    list_init(&svc->onrestart.commands);
638    list_add_tail(&service_list, &svc->slist);
639    return svc;
640}
641
642static void parse_line_service(struct parse_state *state, int nargs, char **args)
643{
644    struct service *svc = state->context;
645    struct command *cmd;
646    int i, kw, kw_nargs;
647
648    if (nargs == 0) {
649        return;
650    }
651
652    svc->ioprio_class = IoSchedClass_NONE;
653
654    kw = lookup_keyword(args[0]);
655    switch (kw) {
656    case K_capability:
657        break;
658    case K_class:
659        if (nargs != 2) {
660            parse_error(state, "class option requires a classname\n");
661        } else {
662            svc->classname = args[1];
663        }
664        break;
665    case K_console:
666        svc->flags |= SVC_CONSOLE;
667        break;
668    case K_disabled:
669        svc->flags |= SVC_DISABLED;
670        break;
671    case K_ioprio:
672        if (nargs != 3) {
673            parse_error(state, "ioprio optin usage: ioprio <rt|be|idle> <ioprio 0-7>\n");
674        } else {
675            svc->ioprio_pri = strtoul(args[2], 0, 8);
676
677            if (svc->ioprio_pri < 0 || svc->ioprio_pri > 7) {
678                parse_error(state, "priority value must be range 0 - 7\n");
679                break;
680            }
681
682            if (!strcmp(args[1], "rt")) {
683                svc->ioprio_class = IoSchedClass_RT;
684            } else if (!strcmp(args[1], "be")) {
685                svc->ioprio_class = IoSchedClass_BE;
686            } else if (!strcmp(args[1], "idle")) {
687                svc->ioprio_class = IoSchedClass_IDLE;
688            } else {
689                parse_error(state, "ioprio option usage: ioprio <rt|be|idle> <0-7>\n");
690            }
691        }
692        break;
693    case K_group:
694        if (nargs < 2) {
695            parse_error(state, "group option requires a group id\n");
696        } else if (nargs > NR_SVC_SUPP_GIDS + 2) {
697            parse_error(state, "group option accepts at most %d supp. groups\n",
698                        NR_SVC_SUPP_GIDS);
699        } else {
700            int n;
701            svc->gid = decode_uid(args[1]);
702            for (n = 2; n < nargs; n++) {
703                svc->supp_gids[n-2] = decode_uid(args[n]);
704            }
705            svc->nr_supp_gids = n - 2;
706        }
707        break;
708    case K_keycodes:
709        if (nargs < 2) {
710            parse_error(state, "keycodes option requires atleast one keycode\n");
711        } else {
712            svc->keycodes = malloc((nargs - 1) * sizeof(svc->keycodes[0]));
713            if (!svc->keycodes) {
714                parse_error(state, "could not allocate keycodes\n");
715            } else {
716                svc->nkeycodes = nargs - 1;
717                for (i = 1; i < nargs; i++) {
718                    svc->keycodes[i - 1] = atoi(args[i]);
719                }
720            }
721        }
722        break;
723    case K_oneshot:
724        svc->flags |= SVC_ONESHOT;
725        break;
726    case K_onrestart:
727        nargs--;
728        args++;
729        kw = lookup_keyword(args[0]);
730        if (!kw_is(kw, COMMAND)) {
731            parse_error(state, "invalid command '%s'\n", args[0]);
732            break;
733        }
734        kw_nargs = kw_nargs(kw);
735        if (nargs < kw_nargs) {
736            parse_error(state, "%s requires %d %s\n", args[0], kw_nargs - 1,
737                kw_nargs > 2 ? "arguments" : "argument");
738            break;
739        }
740
741        cmd = malloc(sizeof(*cmd) + sizeof(char*) * nargs);
742        cmd->func = kw_func(kw);
743        cmd->nargs = nargs;
744        memcpy(cmd->args, args, sizeof(char*) * nargs);
745        list_add_tail(&svc->onrestart.commands, &cmd->clist);
746        break;
747    case K_critical:
748        svc->flags |= SVC_CRITICAL;
749        break;
750    case K_setenv: { /* name value */
751        struct svcenvinfo *ei;
752        if (nargs < 2) {
753            parse_error(state, "setenv option requires name and value arguments\n");
754            break;
755        }
756        ei = calloc(1, sizeof(*ei));
757        if (!ei) {
758            parse_error(state, "out of memory\n");
759            break;
760        }
761        ei->name = args[1];
762        ei->value = args[2];
763        ei->next = svc->envvars;
764        svc->envvars = ei;
765        break;
766    }
767    case K_socket: {/* name type perm [ uid gid ] */
768        struct socketinfo *si;
769        if (nargs < 4) {
770            parse_error(state, "socket option requires name, type, perm arguments\n");
771            break;
772        }
773        if (strcmp(args[2],"dgram") && strcmp(args[2],"stream")) {
774            parse_error(state, "socket type must be 'dgram' or 'stream'\n");
775            break;
776        }
777        si = calloc(1, sizeof(*si));
778        if (!si) {
779            parse_error(state, "out of memory\n");
780            break;
781        }
782        si->name = args[1];
783        si->type = args[2];
784        si->perm = strtoul(args[3], 0, 8);
785        if (nargs > 4)
786            si->uid = decode_uid(args[4]);
787        if (nargs > 5)
788            si->gid = decode_uid(args[5]);
789        si->next = svc->sockets;
790        svc->sockets = si;
791        break;
792    }
793    case K_user:
794        if (nargs != 2) {
795            parse_error(state, "user option requires a user id\n");
796        } else {
797            svc->uid = decode_uid(args[1]);
798        }
799        break;
800    default:
801        parse_error(state, "invalid option '%s'\n", args[0]);
802    }
803}
804
805static void *parse_action(struct parse_state *state, int nargs, char **args)
806{
807    struct action *act;
808    if (nargs < 2) {
809        parse_error(state, "actions must have a trigger\n");
810        return 0;
811    }
812    if (nargs > 2) {
813        parse_error(state, "actions may not have extra parameters\n");
814        return 0;
815    }
816    act = calloc(1, sizeof(*act));
817    act->name = args[1];
818    list_init(&act->commands);
819    list_add_tail(&action_list, &act->alist);
820        /* XXX add to hash */
821    return act;
822}
823
824static void parse_line_action(struct parse_state* state, int nargs, char **args)
825{
826    struct command *cmd;
827    struct action *act = state->context;
828    int (*func)(int nargs, char **args);
829    int kw, n;
830
831    if (nargs == 0) {
832        return;
833    }
834
835    kw = lookup_keyword(args[0]);
836    if (!kw_is(kw, COMMAND)) {
837        parse_error(state, "invalid command '%s'\n", args[0]);
838        return;
839    }
840
841    n = kw_nargs(kw);
842    if (nargs < n) {
843        parse_error(state, "%s requires %d %s\n", args[0], n - 1,
844            n > 2 ? "arguments" : "argument");
845        return;
846    }
847    cmd = malloc(sizeof(*cmd) + sizeof(char*) * nargs);
848    cmd->func = kw_func(kw);
849    cmd->nargs = nargs;
850    memcpy(cmd->args, args, sizeof(char*) * nargs);
851    list_add_tail(&act->commands, &cmd->clist);
852}
853