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 #include <fcntl.h>
   9
  10 static unsigned int offset;
  11 static unsigned int ino = 721;
  12
  13 static void push_string(const char *name)
  14 {
  15         unsigned int name_len = strlen(name) + 1;
  16
  17         fputs(name, stdout);
  18         putchar(0);
  19         offset += name_len;
  20 }
  21
  22 static void push_pad (void)
  23 {
  24         while (offset & 3) {
  25                 putchar(0);
  26                 offset++;
  27         }
  28 }
  29
  30 static void push_rest(const char *name)
  31 {
  32         unsigned int name_len = strlen(name) + 1;
  33         unsigned int tmp_ofs;
  34
  35         fputs(name, stdout);
  36         putchar(0);
  37         offset += name_len;
  38
  39         tmp_ofs = name_len + 110;
  40         while (tmp_ofs & 3) {
  41                 putchar(0);
  42                 offset++;
  43                 tmp_ofs++;
  44         }
  45 }
  46
  47 static void push_hdr(const char *s)
  48 {
  49         fputs(s, stdout);
  50         offset += 110;
  51 }
  52
  53 static void cpio_trailer(void)
  54 {
  55         char s[256];
  56         const char name[] = "TRAILER!!!";
  57
  58         sprintf(s, "%s%08X%08X%08lX%08lX%08X%08lX"
  59                "%08X%08X%08X%08X%08X%08X%08X",
  60                 "070701",               /* magic */
  61                 0,                      /* ino */
  62                 0,                      /* mode */
  63                 (long) 0,               /* uid */
  64                 (long) 0,               /* gid */
  65                 1,                      /* nlink */
  66                 (long) 0,               /* mtime */
  67                 0,                      /* filesize */
  68                 0,                      /* major */
  69                 0,                      /* minor */
  70                 0,                      /* rmajor */
  71                 0,                      /* rminor */
  72                 (unsigned)strlen(name) + 1, /* namesize */
  73                 0);                     /* chksum */
  74         push_hdr(s);
  75         push_rest(name);
  76
  77         while (offset % 512) {
  78                 putchar(0);
  79                 offset++;
  80         }
  81 }
  82
  83 static void cpio_mkdir(const char *name, unsigned int mode,
  84                        uid_t uid, gid_t gid)
  85 {
  86         char s[256];
  87         time_t mtime = time(NULL);
  88
  89         sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
  90                "%08X%08X%08X%08X%08X%08X%08X",
  91                 "070701",               /* magic */
  92                 ino++,                  /* ino */
  93                 S_IFDIR | mode,         /* mode */
  94                 (long) uid,             /* uid */
  95                 (long) gid,             /* gid */
  96                 2,                      /* nlink */
  97                 (long) mtime,           /* mtime */
  98                 0,                      /* filesize */
  99                 3,                      /* major */
 100                 1,                      /* minor */
 101                 0,                      /* rmajor */
 102                 0,                      /* rminor */
 103                 (unsigned)strlen(name) + 1,/* namesize */
 104                 0);                     /* chksum */
 105         push_hdr(s);
 106         push_rest(name);
 107 }
 108
 109 static void cpio_mknod(const char *name, unsigned int mode,
 110                        uid_t uid, gid_t gid, int dev_type,
 111                        unsigned int maj, unsigned int min)
 112 {
 113         char s[256];
 114         time_t mtime = time(NULL);
 115
 116         if (dev_type == 'b')
 117                 mode |= S_IFBLK;
 118         else
 119                 mode |= S_IFCHR;
 120
 121         sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
 122                "%08X%08X%08X%08X%08X%08X%08X",
 123                 "070701",               /* magic */
 124                 ino++,                  /* ino */
 125                 mode,                   /* mode */
 126                 (long) uid,             /* uid */
 127                 (long) gid,             /* gid */
 128                 1,                      /* nlink */
 129                 (long) mtime,           /* mtime */
 130                 0,                      /* filesize */
 131                 3,                      /* major */
 132                 1,                      /* minor */
 133                 maj,                    /* rmajor */
 134                 min,                    /* rminor */
 135                 (unsigned)strlen(name) + 1,/* namesize */
 136                 0);                     /* chksum */
 137         push_hdr(s);
 138         push_rest(name);
 139 }
 140
 141 /* Not marked static to keep the compiler quiet, as no one uses this yet... */
 142 void cpio_mkfile(const char *filename, const char *location,
 143                         unsigned int mode, uid_t uid, gid_t gid)
 144 {
 145         char s[256];
 146         char *filebuf;
 147         struct stat buf;
 148         int file;
 149         int retval;
 150         int i;
 151
 152         mode |= S_IFREG;
 153
 154         retval = stat (filename, &buf);
 155         if (retval) {
 156                 fprintf (stderr, "Filename %s could not be located\n", filename);
 157                 goto error;
 158         }
 159
 160         file = open (filename, O_RDONLY);
 161         if (file < 0) {
 162                 fprintf (stderr, "Filename %s could not be opened for reading\n", filename);
 163                 goto error;
 164         }
 165
 166         filebuf = malloc(buf.st_size);
 167         if (!filebuf) {
 168                 fprintf (stderr, "out of memory\n");
 169                 goto error_close;
 170         }
 171
 172         retval = read (file, filebuf, buf.st_size);
 173         if (retval < 0) {
 174                 fprintf (stderr, "Can not read %s file\n", filename);
 175                 goto error_free;
 176         }
 177
 178         sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
 179                "%08X%08X%08X%08X%08X%08X%08X",
 180                 "070701",               /* magic */
 181                 ino++,                  /* ino */
 182                 mode,                   /* mode */
 183                 (long) uid,             /* uid */
 184                 (long) gid,             /* gid */
 185                 1,                      /* nlink */
 186                 (long) buf.st_mtime,    /* mtime */
 187                 (int) buf.st_size,      /* filesize */
 188                 3,                      /* major */
 189                 1,                      /* minor */
 190                 0,                      /* rmajor */
 191                 0,                      /* rminor */
 192                 (unsigned)strlen(location) + 1,/* namesize */
 193                 0);                     /* chksum */
 194         push_hdr(s);
 195         push_string(location);
 196         push_pad();
 197
 198         for (i = 0; i < buf.st_size; ++i)
 199                 fputc(filebuf[i], stdout);
 200         offset += buf.st_size;
 201         close(file);
 202         free(filebuf);
 203         push_pad();
 204         return;
 205
 206 error_free:
 207         free(filebuf);
 208 error_close:
 209         close(file);
 210 error:
 211         exit(-1);
 212 }
 213
 214 int main (int argc, char *argv[])
 215 {
 216         cpio_mkdir("/dev", 0755, 0, 0);
 217         cpio_mknod("/dev/console", 0600, 0, 0, 'c', 5, 1);
 218         cpio_mkdir("/root", 0700, 0, 0);
 219         cpio_trailer();
 220
 221         exit(0);
 222
 223         /* silence compiler warnings */
 224         return 0;
 225         (void) argc;
 226         (void) argv;
 227 }
 228