parser.c

Android 一些工具

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdarg.h>
#include <string.h>
#include <stddef.h>
#include <ctype.h>

#include "init.h"
#include "property_service.h"

#define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
#include <sys/_system_properties.h>

static list_declare(service_list);
static list_declare(action_list);
static list_declare(action_queue);

#define RAW(x...) log_write(6, x)

void DUMP(void)
{
#if 0
    struct service *svc;
    struct action *act;
    struct command *cmd;
    struct listnode *node;
    struct listnode *node2;
    struct socketinfo *si;
    int n;
    
    list_for_each(node, &service_list) {
        svc = node_to_item(node, struct service, slist);
        RAW("service %s\n", svc->name);
        RAW("  class '%s'\n", svc->classname);
        RAW("  exec");
        for (n = 0; n < svc->nargs; n++) {
            RAW(" '%s'", svc->args[n]);
        }
        RAW("\n");
        for (si = svc->sockets; si; si = si->next) {
            RAW("  socket %s %s 0%o\n", si->name, si->type, si->perm);
        }
    }

    list_for_each(node, &action_list) {
        act = node_to_item(node, struct action, alist);
        RAW("on %s\n", act->name);
        list_for_each(node2, &act->commands) {
            cmd = node_to_item(node2, struct command, clist);
            RAW("  %p", cmd->func);
            for (n = 0; n < cmd->nargs; n++) {
                RAW(" %s", cmd->args[n]);
            }
            RAW("\n");
        }
        RAW("\n");
    }
#endif       
}

#define MAXARGS 64

#define T_EOF 0
#define T_TEXT 1
#define T_NEWLINE 2

struct parse_state
{
    char *ptr;
    char *text;
    int line;
    int nexttoken;
    void *context;
    void (*parse_line)(struct parse_state *state, int nargs, char **args);
    const char *filename;
};

static void *parse_service(struct parse_state *state, int nargs, char **args);
static void parse_line_service(struct parse_state *state, int nargs, char **args);

static void *parse_action(struct parse_state *state, int nargs, char **args);
static void parse_line_action(struct parse_state *state, int nargs, char **args);

void parse_error(struct parse_state *state, const char *fmt, ...)
{
    va_list ap;
    char buf[128];
    int off;
    
    snprintf(buf, 128, "%s: %d: ", state->filename, state->line);
    buf[127] = 0;
    off = strlen(buf);

    va_start(ap, fmt);
    vsnprintf(buf + off, 128 - off, fmt, ap);
    va_end(ap);
    buf[127] = 0;
    ERROR("%s", buf);
}

#define SECTION 0x01
#define COMMAND 0x02
#define OPTION  0x04

#include "keywords.h"

#define KEYWORD(symbol, flags, nargs, func) \
    [ K_##symbol ] = { #symbol, func, nargs + 1, flags, },

struct {
    const char *name;
    int (*func)(int nargs, char **args);
    unsigned char nargs;
    unsigned char flags;
} keyword_info[KEYWORD_COUNT] = {
    [ K_UNKNOWN ] = { "unknown", 0, 0, 0 },
#include "keywords.h"    
};
#undef KEYWORD

#define kw_is(kw, type) (keyword_info[kw].flags & (type))
#define kw_name(kw) (keyword_info[kw].name)
#define kw_func(kw) (keyword_info[kw].func)
#define kw_nargs(kw) (keyword_info[kw].nargs)

int lookup_keyword(const char *s)
{
    switch (*s++) {
    case 'c':
        if (!strcmp(s, "apability")) return K_capability;
        if (!strcmp(s, "lass")) return K_class;
        if (!strcmp(s, "lass_start")) return K_class_start;
        if (!strcmp(s, "lass_stop")) return K_class_stop;
        if (!strcmp(s, "onsole")) return K_console;
        if (!strcmp(s, "hown")) return K_chown;
        if (!strcmp(s, "hmod")) return K_chmod;
        if (!strcmp(s, "ritical")) return K_critical;
        break;
    case 'd':
        if (!strcmp(s, "isabled")) return K_disabled;
        if (!strcmp(s, "omainname")) return K_domainname;
        if (!strcmp(s, "evice")) return K_device;
        break;
    case 'e':
        if (!strcmp(s, "xec")) return K_exec;
        if (!strcmp(s, "xport")) return K_export;
        break;
    case 'g':
        if (!strcmp(s, "roup")) return K_group;
        break;
    case 'h':
        if (!strcmp(s, "ostname")) return K_hostname;
        break;
    case 'i':
        if (!strcmp(s, "fup")) return K_ifup;
        if (!strcmp(s, "nsmod")) return K_insmod;
        if (!strcmp(s, "mport")) return K_import;
        break;
    case 'l':
        if (!strcmp(s, "oglevel")) return K_loglevel;
        break;
    case 'm':
        if (!strcmp(s, "kdir")) return K_mkdir;
        if (!strcmp(s, "ount")) return K_mount;
        break;
    case 'o':
        if (!strcmp(s, "n")) return K_on;
        if (!strcmp(s, "neshot")) return K_oneshot;
        if (!strcmp(s, "nrestart")) return K_onrestart;
        break;
    case 'r':
        if (!strcmp(s, "estart")) return K_restart;
        break;
    case 's':
        if (!strcmp(s, "ervice")) return K_service;
        if (!strcmp(s, "etenv")) return K_setenv;
        if (!strcmp(s, "etkey")) return K_setkey;
        if (!strcmp(s, "etprop")) return K_setprop;
        if (!strcmp(s, "etrlimit")) return K_setrlimit;
        if (!strcmp(s, "ocket")) return K_socket;
        if (!strcmp(s, "tart")) return K_start;
        if (!strcmp(s, "top")) return K_stop;
        if (!strcmp(s, "ymlink")) return K_symlink;
        break;
    case 't':
        if (!strcmp(s, "rigger")) return K_trigger;
        break;
    case 'u':
        if (!strcmp(s, "ser")) return K_user;
        break;
    case 'w':
        if (!strcmp(s, "rite")) return K_write;
        break;
    }
    return K_UNKNOWN;
}

void parse_line_no_op(struct parse_state *state, int nargs, char **args)
{
}

int next_token(struct parse_state *state)
{
    char *x = state->ptr;
    char *s;

    if (state->nexttoken) {
        int t = state->nexttoken;
        state->nexttoken = 0;
        return t;
    }

    for (;;) {
        switch (*x) {
        case 0:
            state->ptr = x;
            return T_EOF;
        case '\n':
            state->line++;
            x++;
            state->ptr = x;
            return T_NEWLINE;
        case ' ':
        case '\t':
        case '\r':
            x++;
            continue;
        case '#':
            while (*x && (*x != '\n')) x++;
            state->line++;
            state->ptr = x;
            return T_NEWLINE;
        default:
            goto text;
        }
    }

textdone:
    state->ptr = x;
    *s = 0;
    return T_TEXT;
text:
    state->text = s = x;
textresume:
    for (;;) {
        switch (*x) {
        case 0:
            goto textdone;
        case ' ':
        case '\t':
        case '\r':
            x++;
            goto textdone;
        case '\n':
            state->nexttoken = T_NEWLINE;
            x++;
            goto textdone;
        case '"':
            x++;
            for (;;) {
                switch (*x) {
                case 0:
                        /* unterminated quoted thing */
                    state->ptr = x;
                    return T_EOF;
                case '"':
                    x++;
                    goto textresume;
                default:
                    *s++ = *x++;
                }
            }
            break;
        case '\\':
            x++;
            switch (*x) {
            case 0:
                goto textdone;
            case 'n':
                *s++ = '\n';
                break;
            case 'r':
                *s++ = '\r';
                break;
            case 't':
                *s++ = '\t';
                break;
            case '\\':
                *s++ = '\\';
                break;
            case '\r':
                    /* \ <cr> <lf> -> line continuation */
                if (x[1] != '\n') {
                    x++;
                    continue;
                }
            case '\n':
                    /* \ <lf> -> line continuation */
                state->line++;
                x++;
                    /* eat any extra whitespace */
                while((*x == ' ') || (*x == '\t')) x++;
                continue;
            default:
                    /* unknown escape -- just copy */
                *s++ = *x++;
            }
            continue;
        default:
            *s++ = *x++;
        }
    }
    return T_EOF;
}

void parse_line(int nargs, char **args)
{
    int n;
    int id = lookup_keyword(args[0]);
    printf("%s(%d)", args[0], id);
    for (n = 1; n < nargs; n++) {
        printf(" '%s'", args[n]);
    }
    printf("\n");
}

void parse_new_section(struct parse_state *state, int kw,
                       int nargs, char **args)
{
    printf("[ %s %s ]\n", args[0],
           nargs > 1 ? args[1] : "");
    switch(kw) {
    case K_service:
        state->context = parse_service(state, nargs, args);
        if (state->context) {
            state->parse_line = parse_line_service;
            return;
        }
        break;
    case K_on:
        state->context = parse_action(state, nargs, args);
        if (state->context) {
            state->parse_line = parse_line_action;
            return;
        }
        break;
    }
    state->parse_line = parse_line_no_op;
}

static void parse_config(const char *fn, char *s)
{
    struct parse_state state;
    char *args[MAXARGS];
    int nargs;

    nargs = 0;
    state.filename = fn;
    state.line = 1;
    state.ptr = s;
    state.nexttoken = 0;
    state.parse_line = parse_line_no_op;
    for (;;) {
        switch (next_token(&state)) {
        case T_EOF:
            state.parse_line(&state, 0, 0);
            return;
        case T_NEWLINE:
            if (nargs) {
                int kw = lookup_keyword(args[0]);
                if (kw_is(kw, SECTION)) {
                    state.parse_line(&state, 0, 0);
                    parse_new_section(&state, kw, nargs, args);
                } else {
                    state.parse_line(&state, nargs, args);
                }