1 /* ----------------------------------------------------------------------- *
2 *
3 * Copyright 2007-2008 H. Peter Anvin - All Rights Reserved
4 *
5 * Permission is hereby granted, free of charge, to any person
6 * obtaining a copy of this software and associated documentation
7 * files (the "Software"), to deal in the Software without
8 * restriction, including without limitation the rights to use,
9 * copy, modify, merge, publish, distribute, sublicense, and/or
10 * sell copies of the Software, and to permit persons to whom
11 * the Software is furnished to do so, subject to the following
12 * conditions:
13 *
14 * The above copyright notice and this permission notice shall
15 * be included in all copies or substantial portions of the Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
18 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
19 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
20 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
21 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
22 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
23 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
24 * OTHER DEALINGS IN THE SOFTWARE.
25 *
26 * ----------------------------------------------------------------------- */
27
28 /*
29 * initramfs_file.c
30 *
31 * Utility functions to add arbitrary files including cpio header
32 */
33
34 #include <stdlib.h>
35 #include <stdio.h>
36 #include <string.h>
37 #include <sys/stat.h>
38 #include <syslinux/linux.h>
39
40 #define CPIO_MAGIC "070701"
41 struct cpio_header {
42 char c_magic[6]; /* 070701 */
43 char c_ino[8]; /* Inode number */
44 char c_mode[8]; /* File mode and permissions */
45 char c_uid[8]; /* uid */
46 char c_gid[8]; /* gid */
47 char c_nlink[8]; /* Number of links */
48 char c_mtime[8]; /* Modification time */
49 char c_filesize[8]; /* Size of data field */
50 char c_maj[8]; /* File device major number */
51 char c_min[8]; /* File device minor number */
52 char c_rmaj[8]; /* Device node reference major number */
53 char c_rmin[8]; /* Device node reference minor number */
54 char c_namesize[8]; /* Length of filename including final \0 */
55 char c_chksum[8]; /* Checksum if c_magic ends in 2 */
56 };
57
58 static uint32_t next_ino = 1;
59
60 /* Create cpio headers for the directory entries leading up to a file.
61 Returns the number of bytes; doesn't touch the buffer if too small. */
initramfs_mkdirs(const char * filename,void * buffer,size_t buflen)62 static size_t initramfs_mkdirs(const char *filename, void *buffer,
63 size_t buflen)
64 {
65 const char *p = filename;
66 char *bp = buffer;
67 int len;
68 size_t bytes = 0, hdr_sz;
69 int pad;
70
71 while ((p = strchr(p, '/'))) {
72 if (p != filename && p[-1] != '/') {
73 len = p - filename;
74 bytes += ((sizeof(struct cpio_header) + len + 1) + 3) & ~3;
75 }
76 p++;
77 }
78
79 if (buflen >= bytes) {
80 p = filename;
81 while ((p = strchr(p, '/'))) {
82 if (p != filename && p[-1] != '/') {
83 len = p - filename;
84 hdr_sz = ((sizeof(struct cpio_header) + len + 1) + 3) & ~3;
85 bp += sprintf(bp, "070701%08x%08x%08x%08x%08x%08x%08x%08x%08x"
86 "%08x%08x%08x%08x", next_ino++, S_IFDIR | 0755,
87 0, 0, 1, 0, 0, 0, 1, 0, 1, len + 1, 0);
88 memcpy(bp, filename, len);
89 bp += len;
90 pad = hdr_sz - (sizeof(struct cpio_header) + len);
91 memset(bp, 0, pad);
92 bp += pad;
93 }
94 p++;
95 }
96 }
97
98 return bytes;
99 }
100
101 /*
102 * Create a file header (with optional parent directory entries)
103 * and add it to an initramfs chain
104 */
initramfs_mknod(struct initramfs * ihead,const char * filename,int do_mkdir,uint16_t mode,size_t len,uint32_t major,uint32_t minor)105 int initramfs_mknod(struct initramfs *ihead, const char *filename,
106 int do_mkdir,
107 uint16_t mode, size_t len, uint32_t major, uint32_t minor)
108 {
109 size_t bytes, hdr_sz;
110 int namelen = strlen(filename);
111 int pad;
112 char *buffer, *bp;
113
114 if (do_mkdir)
115 bytes = initramfs_mkdirs(filename, NULL, 0);
116 else
117 bytes = 0;
118
119 hdr_sz = ((sizeof(struct cpio_header) + namelen + 1) + 3) & ~3;
120 bytes += hdr_sz;
121
122 bp = buffer = malloc(bytes);
123 if (!buffer)
124 return -1;
125
126 if (do_mkdir)
127 bp += initramfs_mkdirs(filename, bp, bytes);
128
129 bp += sprintf(bp, "070701%08x%08x%08x%08x%08x%08x%08x%08x%08x"
130 "%08x%08x%08x%08x", next_ino++, mode,
131 0, 0, 1, 0, len, 0, 1, major, minor, namelen + 1, 0);
132 memcpy(bp, filename, namelen);
133 bp += namelen;
134 pad = hdr_sz - (sizeof(struct cpio_header) + namelen);
135 memset(bp, 0, pad);
136
137 if (initramfs_add_data(ihead, buffer, bytes, bytes, 4)) {
138 free(buffer);
139 return -1;
140 }
141
142 return 0;
143 }
144
145 /*
146 * Add a file given data in memory to an initramfs chain. This
147 * can be used to create nonfiles like symlinks by specifying an
148 * appropriate mode.
149 */
initramfs_add_file(struct initramfs * ihead,const void * data,size_t data_len,size_t len,const char * filename,int do_mkdir,uint32_t mode)150 int initramfs_add_file(struct initramfs *ihead, const void *data,
151 size_t data_len, size_t len,
152 const char *filename, int do_mkdir, uint32_t mode)
153 {
154 if (initramfs_mknod(ihead, filename, do_mkdir,
155 (mode & S_IFMT) ? mode : mode | S_IFREG, len, 0, 1))
156 return -1;
157
158 return initramfs_add_data(ihead, data, data_len, len, 4);
159 }
160
initramfs_add_trailer(struct initramfs * ihead)161 int initramfs_add_trailer(struct initramfs *ihead)
162 {
163 return initramfs_mknod(ihead, "TRAILER!!!", 0, 0, 0, 0, 0);
164 }
165