source: MondoRescue/branches/3.2/mindi-busybox/applets/applet_tables.c

/* vi: set sw=4 ts=4: */
/*
 * Applet table generator.
 * Runs on host and produces include/applet_tables.h
 *
 * Copyright (C) 2007 Denys Vlasenko <vda.linux@googlemail.com>
 *
 * Licensed under GPLv2, see file LICENSE in this source tree.
 */
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>

#undef ARRAY_SIZE
#define ARRAY_SIZE(x) ((unsigned)(sizeof(x) / sizeof((x)[0])))

#include "../include/autoconf.h"
#include "../include/applet_metadata.h"

struct bb_applet {
    const char *name;
    const char *main;
    enum bb_install_loc_t install_loc;
    enum bb_suid_t need_suid;
    /* true if instead of fork(); exec("applet"); waitpid();
     * one can do fork(); exit(applet_main(argc,argv)); waitpid(); */
    unsigned char noexec;
    /* Even nicer */
    /* true if instead of fork(); exec("applet"); waitpid();
     * one can simply call applet_main(argc,argv); */
    unsigned char nofork;
};

/* Define struct bb_applet applets[] */
#include "../include/applets.h"

enum { NUM_APPLETS = ARRAY_SIZE(applets) };

static int offset[NUM_APPLETS];

static int cmp_name(const void *a, const void *b)
{
    const struct bb_applet *aa = a;
    const struct bb_applet *bb = b;
    return strcmp(aa->name, bb->name);
}

int main(int argc, char **argv)
{
    int i;
    int ofs;
    unsigned MAX_APPLET_NAME_LEN = 1;

    qsort(applets, NUM_APPLETS, sizeof(applets[0]), cmp_name);

    ofs = 0;
    for (i = 0; i < NUM_APPLETS; i++) {
        offset[i] = ofs;
        ofs += strlen(applets[i].name) + 1;
    }
    /* We reuse 4 high-order bits of offset array for other purposes,
     * so if they are indeed needed, refuse to proceed */
    if (ofs > 0xfff)
        return 1;
    if (!argv[1])
        return 1;

    i = open(argv[1], O_WRONLY | O_TRUNC | O_CREAT, 0666);
    if (i < 0)
        return 1;
    dup2(i, 1);

    /* Keep in sync with include/busybox.h! */

    printf("/* This is a generated file, don't edit */\n\n");

    printf("#define NUM_APPLETS %u\n", NUM_APPLETS);
    if (NUM_APPLETS == 1) {
        printf("#define SINGLE_APPLET_STR \"%s\"\n", applets[0].name);
        printf("#define SINGLE_APPLET_MAIN %s_main\n", applets[0].main);
    }
    printf("\n");

    //printf("#ifndef SKIP_definitions\n");
    printf("const char applet_names[] ALIGN1 = \"\"\n");
    for (i = 0; i < NUM_APPLETS; i++) {
        printf("\"%s\" \"\\0\"\n", applets[i].name);
        if (MAX_APPLET_NAME_LEN < strlen(applets[i].name))
            MAX_APPLET_NAME_LEN = strlen(applets[i].name);
    }
    printf(";\n\n");

    printf("#ifndef SKIP_applet_main\n");
    printf("int (*const applet_main[])(int argc, char **argv) = {\n");
    for (i = 0; i < NUM_APPLETS; i++) {
        printf("%s_main,\n", applets[i].main);
    }
    printf("};\n");
    printf("#endif\n\n");

    printf("const uint16_t applet_nameofs[] ALIGN2 = {\n");
    for (i = 0; i < NUM_APPLETS; i++) {
        printf("0x%04x,\n",
            offset[i]
#if ENABLE_FEATURE_PREFER_APPLETS
            + (applets[i].nofork << 12)
            + (applets[i].noexec << 13)
#endif
#if ENABLE_FEATURE_SUID
            + (applets[i].need_suid << 14) /* 2 bits */
#endif
        );
    }
    printf("};\n\n");

#if ENABLE_FEATURE_INSTALLER
    printf("const uint8_t applet_install_loc[] ALIGN1 = {\n");
    i = 0;
    while (i < NUM_APPLETS) {
        int v = applets[i].install_loc; /* 3 bits */
        if (++i < NUM_APPLETS)
            v |= applets[i].install_loc << 4; /* 3 bits */
        printf("0x%02x,\n", v);
        i++;
    }
    printf("};\n");
#endif
    //printf("#endif /* SKIP_definitions */\n");
    printf("\n");
    printf("#define MAX_APPLET_NAME_LEN %u\n", MAX_APPLET_NAME_LEN);

    if (argv[2]) {
        char line_old[80];
        char line_new[80];
        FILE *fp;

        line_old[0] = 0;
        fp = fopen(argv[2], "r");
        if (fp) {
            fgets(line_old, sizeof(line_old), fp);
            fclose(fp);
        }
        sprintf(line_new, "#define NUM_APPLETS %u\n", NUM_APPLETS);
        if (strcmp(line_old, line_new) != 0) {
            fp = fopen(argv[2], "w");
            if (!fp)
                return 1;
            fputs(line_new, fp);
        }
    }

    return 0;
}