Android系统file_contexts二进制与文本转换工具

#ifdef _WIN32
    #define __USE_MINGW_ANSI_STDIO 1
#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#ifdef HAS_STDINT_H
    #include <stdint.h>
#endif
#ifdef unix
    #include <unistd.h>
    #include <sys/types.h>
    #include <sys/stat.h>
#else
    #include <direct.h>
    #include <io.h>
#endif

#define MAGIC 0xF97CFF8A

#define S_IFMT      00170000
#define S_IFSOCK    0140000
#define S_IFLNK        0120000
#define S_IFREG        0100000
#define S_IFBLK        0060000
#define S_IFDIR        0040000
#define S_IFCHR        0020000
#define S_IFIFO        0010000
#define S_ISUID        0004000
#define S_ISGID        0002000
#define S_ISVTX        0001000

#define S_ISLNK(m)    (((m) & S_IFMT) == S_IFLNK)
#define S_ISREG(m)    (((m) & S_IFMT) == S_IFREG)
#define S_ISDIR(m)    (((m) & S_IFMT) == S_IFDIR)
#define S_ISCHR(m)    (((m) & S_IFMT) == S_IFCHR)
#define S_ISBLK(m)    (((m) & S_IFMT) == S_IFBLK)
#define S_ISFIFO(m)    (((m) & S_IFMT) == S_IFIFO)
#define S_ISSOCK(m)    (((m) & S_IFMT) == S_IFSOCK)

char *mode_to_string(unsigned int mode)
{
    if (S_ISBLK(mode))
        return "-b";
    else if (S_ISCHR(mode))
        return "-c";
    else if (S_ISDIR(mode))
        return "-d";
    else if (S_ISFIFO(mode))
        return "-p";
    else if (S_ISLNK(mode))
        return "-l";
    else if (S_ISSOCK(mode))
        return "-s";
    else if (S_ISREG(mode))
        return "--";
    else
        return "";
}

int main(int argc, char *argv[])
{
    unsigned int selinux_vers;
    unsigned int nothing;
    unsigned int i;
    unsigned int steams;
    unsigned int num_of_regex;

    char steam[256];
    char src[512];
    char context[512];

    FILE *fp = NULL;
    FILE *fpout = NULL;

    if (argc != 3) {
        printf("usage: %s BINARY_FILE OUTPUT_TEXT_FILE
", argv[0]);
        printf("e.g: %s file_contexts.bin file_contexts
", argv[0]);
        return 1;
    }

    if ((fp = fopen(argv[1], "rb")) == NULL) {
        printf("Unable to open %s : ", argv[1]);
        perror("");
        return 1;
    }
    fread(&nothing, 1, 4, fp);
    if (nothing != MAGIC) {
        printf("%s is not a binary!
", argv[1]);
        if (fp) fclose(fp);
        return 1;
    }

    fread(&nothing, 1, 4, fp);
  selinux_vers = nothing;
    fread(&nothing, 1, 4, fp);
    fseek(fp, (unsigned int)ftell(fp) + nothing, SEEK_SET);

    fread(&nothing, 1, 4, fp);
    //printf("num of steams: 0x%x
", nothing);

    for (i=0; i<nothing; ++i) {
        fread(&steams, 1, 4, fp);
      fread(steam, 1, steams+1, fp);
        //printf("%s
", steam);
    }

    fread(&num_of_regex, 1, 4, fp);
    //printf("num of regex: 0x%x
", num_of_regex);

    if ((fpout = fopen(argv[2], "wb")) == NULL) {
        printf("unable to open %s for write!
", argv[2]);
        if (fp) fclose(fp);
        return 1;
    }

  //printf("selinux version: %d
", selinux_vers);
  fprintf(fpout, "#context version %d
", selinux_vers);

    for (i=0; i<num_of_regex; ++i) {
        fread(&nothing, 1, 4, fp);
      fread(context, 1, nothing, fp);
    fread(&nothing, 1, 4, fp);
    fread(src, 1, nothing, fp);
        //printf("%s %s
", src, context);
        fread(&nothing, 1, 4, fp);
        fprintf(fpout, "%s	%s	%s
", src, mode_to_string(nothing), context);
      fseek(fp, (unsigned int)ftell(fp) + 12, SEEK_SET);
        fread(&nothing, 1, 4, fp);
    fseek(fp, (unsigned int)ftell(fp) + nothing, SEEK_SET);
        fread(&nothing, 1 , 4, fp);
    fread(&nothing, 1 , 4, fp);
    fseek(fp, (unsigned int)ftell(fp) + nothing - 4, SEEK_SET);
    }

    if (fp) fclose(fp);
    if (fpout) fclose(fpout);

    return 0;
}