arch/um/kernel/initrd.c

   1 /*
   2  * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include <linux/init.h>
   7 #include <linux/bootmem.h>
   8 #include <linux/initrd.h>
   9 #include <asm/types.h>
  10 #include <init.h>
  11 #include <os.h>
  12
  13 /* Changed by uml_initrd_setup, which is a setup */
  14 static char *initrd __initdata = NULL;
  15 static int load_initrd(char *filename, void *buf, int size);
  16
  17 int __init read_initrd(void)
  18 {
  19         void *area;
  20         long long size;
  21         int err;
  22
  23         if (initrd == NULL)
  24                 return 0;
  25
  26         err = os_file_size(initrd, &size);
  27         if (err)
  28                 return 0;
  29
  30         /*
  31          * This is necessary because alloc_bootmem craps out if you
  32          * ask for no memory.
  33          */
  34         if (size == 0) {
  35                 printk(KERN_ERR "\"%s\" is a zero-size initrd\n", initrd);
  36                 return 0;
  37         }
  38
  39         area = alloc_bootmem(size);
  40
  41         if (load_initrd(initrd, area, size) == -1)
  42                 return 0;
  43
  44         initrd_start = (unsigned long) area;
  45         initrd_end = initrd_start + size;
  46         return 0;
  47 }
  48
  49 static int __init uml_initrd_setup(char *line, int *add)
  50 {
  51         initrd = line;
  52         return 0;
  53 }
  54
  55 __uml_setup("initrd=", uml_initrd_setup,
  56 "initrd=<initrd image>\n"
  57 "    This is used to boot UML from an initrd image.  The argument is the\n"
  58 "    name of the file containing the image.\n\n"
  59 );
  60
  61 static int load_initrd(char *filename, void *buf, int size)
  62 {
  63         int fd, n;
  64
  65         fd = os_open_file(filename, of_read(OPENFLAGS()), 0);
  66         if (fd < 0) {
  67                 printk(KERN_ERR "Opening '%s' failed - err = %d\n", filename,
  68                        -fd);
  69                 return -1;
  70         }
  71         n = os_read_file(fd, buf, size);
  72         if (n != size) {
  73                 printk(KERN_ERR "Read of %d bytes from '%s' failed, "
  74                        "err = %d\n", size,
  75                        filename, -n);
  76                 return -1;
  77         }
  78
  79         os_close_file(fd);
  80         return 0;
  81 }