Linux Kernel  3.7.1
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initrd.c
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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 static 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  if (area == NULL)
41  return 0;
42 
43  if (load_initrd(initrd, area, size) == -1)
44  return 0;
45 
46  initrd_start = (unsigned long) area;
48  return 0;
49 }
50 
51 __uml_postsetup(read_initrd);
52 
53 static int __init uml_initrd_setup(char *line, int *add)
54 {
55  initrd = line;
56  return 0;
57 }
58 
59 __uml_setup("initrd=", uml_initrd_setup,
60 "initrd=<initrd image>\n"
61 " This is used to boot UML from an initrd image. The argument is the\n"
62 " name of the file containing the image.\n\n"
63 );
64 
65 static int load_initrd(char *filename, void *buf, int size)
66 {
67  int fd, n;
68 
69  fd = os_open_file(filename, of_read(OPENFLAGS()), 0);
70  if (fd < 0) {
71  printk(KERN_ERR "Opening '%s' failed - err = %d\n", filename,
72  -fd);
73  return -1;
74  }
75  n = os_read_file(fd, buf, size);
76  if (n != size) {
77  printk(KERN_ERR "Read of %d bytes from '%s' failed, "
78  "err = %d\n", size,
79  filename, -n);
80  return -1;
81  }
82 
83  os_close_file(fd);
84  return 0;
85 }