usr/gen_init_cpio.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <sys/types.h>
   4 #include <sys/stat.h>
   5 #include <string.h>
   6 #include <unistd.h>
   7 #include <time.h>
   8
   9 static unsigned int offset;
  10 static unsigned int ino = 721;
  11
  12 static void push_rest(const char *name)
  13 {
  14         unsigned int name_len = strlen(name) + 1;
  15         unsigned int tmp_ofs;
  16
  17         fputs(name, stdout);
  18         putchar(0);
  19         offset += name_len;
  20
  21         tmp_ofs = name_len + 110;
  22         while (tmp_ofs & 3) {
  23                 putchar(0);
  24                 offset++;
  25                 tmp_ofs++;
  26         }
  27 }
  28
  29 static void push_hdr(const char *s)
  30 {
  31         fputs(s, stdout);
  32         offset += 110;
  33 }
  34
  35 static void cpio_trailer(void)
  36 {
  37         char s[256];
  38         const char *name = "TRAILER!!!";
  39
  40         sprintf(s, "%s%08X%08X%08lX%08lX%08X%08lX"
  41                "%08X%08X%08X%08X%08X%08X%08X",
  42                 "070701",               /* magic */
  43                 0,                      /* ino */
  44                 0,                      /* mode */
  45                 (long) 0,               /* uid */
  46                 (long) 0,               /* gid */
  47                 1,                      /* nlink */
  48                 (long) 0,               /* mtime */
  49                 0,                      /* filesize */
  50                 0,                      /* major */
  51                 0,                      /* minor */
  52                 0,                      /* rmajor */
  53                 0,                      /* rminor */
  54                 strlen(name) + 1,       /* namesize */
  55                 0);                     /* chksum */
  56         push_hdr(s);
  57         push_rest(name);
  58
  59         while (offset % 512) {
  60                 putchar(0);
  61                 offset++;
  62         }
  63 }
  64
  65 static void cpio_mkdir(const char *name, unsigned int mode,
  66                        uid_t uid, gid_t gid)
  67 {
  68         char s[256];
  69         time_t mtime = time(NULL);
  70
  71         sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
  72                "%08X%08X%08X%08X%08X%08X%08X",
  73                 "070701",               /* magic */
  74                 ino++,                  /* ino */
  75                 S_IFDIR | mode,         /* mode */
  76                 (long) uid,             /* uid */
  77                 (long) gid,             /* gid */
  78                 2,                      /* nlink */
  79                 (long) mtime,           /* mtime */
  80                 0,                      /* filesize */
  81                 3,                      /* major */
  82                 1,                      /* minor */
  83                 0,                      /* rmajor */
  84                 0,                      /* rminor */
  85                 strlen(name) + 1,       /* namesize */
  86                 0);                     /* chksum */
  87         push_hdr(s);
  88         push_rest(name);
  89 }
  90
  91 static void cpio_mknod(const char *name, unsigned int mode,
  92                        uid_t uid, gid_t gid, int dev_type,
  93                        unsigned int maj, unsigned int min)
  94 {
  95         char s[256];
  96         time_t mtime = time(NULL);
  97
  98         if (dev_type == 'b')
  99                 mode |= S_IFBLK;
 100         else
 101                 mode |= S_IFCHR;
 102
 103         sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
 104                "%08X%08X%08X%08X%08X%08X%08X",
 105                 "070701",               /* magic */
 106                 ino++,                  /* ino */
 107                 mode,                   /* mode */
 108                 (long) uid,             /* uid */
 109                 (long) gid,             /* gid */
 110                 1,                      /* nlink */
 111                 (long) mtime,           /* mtime */
 112                 0,                      /* filesize */
 113                 3,                      /* major */
 114                 1,                      /* minor */
 115                 maj,                    /* rmajor */
 116                 min,                    /* rminor */
 117                 strlen(name) + 1,       /* namesize */
 118                 0);                     /* chksum */
 119         push_hdr(s);
 120         push_rest(name);
 121 }
 122
 123 int main (int argc, char *argv[])
 124 {
 125         cpio_mkdir("/dev", 0700, 0, 0);
 126         cpio_mknod("/dev/console", 0600, 0, 0, 'c', 5, 1);
 127         cpio_mkdir("/root", 0700, 0, 0);
 128         cpio_trailer();
 129
 130         exit(0);
 131
 132         /* silence compiler warnings */
 133         return 0;
 134         (void) argc;
 135         (void) argv;
 136 }
 137