source: rtems/c/src/exec/libfs/src/imfs/imfs_load_tar.c @ 8670008c

4.104.114.84.95
Last change on this file since 8670008c was 8670008c, checked in by Joel Sherrill <joel.sherrill@…>, on 10/16/01 at 19:06:11

2001-10-16 Chris Johns <ccj@…>

  • imfs/imfs_load_tar.c: Changed the code around to remove an internal compiler error on the Coldfire target.
  • Property mode set to 100644
File size: 8.5 KB
Line 
1/*
2 * $Id$
3 */
4
5#if HAVE_CONFIG_H
6#include "config.h"
7#endif
8
9/**************************************************************************
10 * This file implements the "mount" procedure for tar-based IMFS
11 * extensions.  The TAR is not actually mounted under the IMFS.
12 * Directories from the TAR file are created as usual in the IMFS.
13 * File entries are created as IMFS_LINEAR_FILE nodes with their nods
14 * pointing to addresses in the TAR image.
15 *************************************************************************/
16
17#include <rtems.h>
18#include <rtems/libio_.h>
19#include <string.h>
20#include <chain.h>
21#include <imfs.h>
22
23
24/**************************************************************************
25 * TAR file format:
26 *
27 *   Offset   Length   Contents
28 *     0    100 bytes  File name ('\0' terminated, 99 maxmum length)
29 *   100      8 bytes  File mode (in octal ascii)
30 *   108      8 bytes  User ID (in octal ascii)
31 *   116      8 bytes  Group ID (in octal ascii)
32 *   124     12 bytes  File size (s) (in octal ascii)
33 *   136     12 bytes  Modify time (in octal ascii)
34 *   148      8 bytes  Header checksum (in octal ascii)
35 *   156      1 bytes  Link flag
36 *   157    100 bytes  Linkname ('\0' terminated, 99 maxmum length)
37 *   257      8 bytes  Magic ("ustar  \0")
38 *   265     32 bytes  User name ('\0' terminated, 31 maxmum length)
39 *   297     32 bytes  Group name ('\0' terminated, 31 maxmum length)
40 *   329      8 bytes  Major device ID (in octal ascii)
41 *   337      8 bytes  Minor device ID (in octal ascii)
42 *   345    167 bytes  Padding
43 *   512   (s+p)bytes  File contents (s+p) := (((s) + 511) & ~511),
44 *                     round up to 512 bytes
45 *
46 *   Checksum:
47 *   int i, sum;
48 *   char* header = tar_header_pointer;
49 *   sum = 0;
50 *   for(i = 0; i < 512; i++)
51 *       sum += 0xFF & header[i];
52 *************************************************************************/
53
54#define LF_OLDNORMAL  '\0'     /* Normal disk file, Unix compatible */
55#define LF_NORMAL     '0'      /* Normal disk file                  */
56#define LF_LINK       '1'      /* Link to previously dumped file    */
57#define LF_SYMLINK    '2'      /* Symbolic link                     */
58#define LF_CHR        '3'      /* Character special file            */
59#define LF_BLK        '4'      /* Block special file                */
60#define LF_DIR        '5'      /* Directory                         */
61#define LF_FIFO       '6'      /* FIFO special file                 */
62#define LF_CONFIG     '7'      /* Contiguous file                   */
63
64#define MAX_NAME_FIELD_SIZE      99
65
66#define MIN(a,b)   ((a)>(b)?(b):(a))
67
68static unsigned long octal2ulong(char *octascii, int len);
69static int compute_tar_header_checksum(char *bufr);
70
71/**************************************************************************
72 * rtems_tarfs_load
73 *
74 * Here we create the mountpoint directory and load the tarfs at
75 * that node.  Once the IMFS has been mounted, we work through the
76 * tar image and perform as follows:
77 *  - For directories, simply call mkdir().  The IMFS creates nodes as
78 *    needed.
79 *  - For files, we make our own calls to IMFS eval_for_make and
80 *    create_node.
81 *************************************************************************/
82int
83rtems_tarfs_load(char *mountpoint,
84                 unsigned char *tar_image,
85                 unsigned long tar_size)
86{
87   rtems_filesystem_location_info_t root_loc;
88   rtems_filesystem_location_info_t loc;
89   char            *hdr_ptr;
90   char            filename[100];
91   char            full_filename[256];
92   int             hdr_chksum;
93   unsigned char   linkflag;
94   unsigned long   file_size;
95   unsigned long   file_mode;
96   int             offset;
97   unsigned long   nblocks;
98   IMFS_jnode_t    *node;
99   int             status;
100
101
102   status = rtems_filesystem_evaluate_path(mountpoint, 0, &root_loc, 0);
103   if (status != 0)
104      return(-1);
105
106   if (root_loc.ops != &IMFS_ops)
107      return(-1);
108
109   /***********************************************************************
110    * Create an IMFS node structure pointing to tar image memory.
111    **********************************************************************/
112   offset = 0;
113   while (1)
114   {
115      if (offset + 512 > tar_size)
116         break;
117
118      /******************************************************************
119       * Read a header.
120       ******************************************************************/
121      hdr_ptr = &tar_image[offset];
122      offset += 512;
123      if (strncmp(&hdr_ptr[257], "ustar  ", 7))
124         break;
125
126      strncpy(filename, hdr_ptr, MAX_NAME_FIELD_SIZE);
127      filename[MAX_NAME_FIELD_SIZE] = '\0';
128
129      linkflag   = hdr_ptr[156];
130      file_mode  = octal2ulong(&hdr_ptr[100], 8);
131      file_size  = octal2ulong(&hdr_ptr[124], 12);
132      hdr_chksum = (int)octal2ulong(&hdr_ptr[148], 8);
133
134      if (compute_tar_header_checksum(hdr_ptr) != hdr_chksum)
135         break;
136
137      /******************************************************************
138       * Generate an IMFS node depending on the file type.
139       * - For directories, just create directories as usual.  IMFS
140       *   will take care of the rest.
141       * - For files, create a file node with special tarfs properties.
142       *****************************************************************/
143      if (linkflag == LF_DIR)
144      {
145         strcpy(full_filename, mountpoint);
146         if (full_filename[strlen(full_filename)-1] != '/')
147            strcat(full_filename, "/");
148         strcat(full_filename, filename);
149         mkdir(full_filename, S_IRWXU | S_IRWXG | S_IRWXO);
150      }
151      /******************************************************************
152       * Create a LINEAR_FILE node if no user write permission.
153       *****************************************************************/
154      else if ((linkflag == LF_NORMAL) &&
155               ((file_mode & 0200) == 0000))
156      {
157         const char  *name;
158
159         loc = root_loc;
160         if (IMFS_evaluate_for_make(filename, &loc, &name) == 0)
161         {
162            node = IMFS_create_node(&loc,
163                                    IMFS_LINEAR_FILE, (char *)name,
164                                    (S_IRUSR | S_IRGRP | S_IROTH) | S_IFREG,
165                                    NULL);
166            node->info.linearfile.size   = file_size;
167            node->info.linearfile.direct = &tar_image[offset];
168         }
169
170         nblocks = (((file_size) + 511) & ~511) / 512;
171         offset += 512 * nblocks;
172      }
173      /******************************************************************
174       * Create a regular MEMORY_FILE if write permission exists.
175       *****************************************************************/
176      else if ((linkflag == LF_NORMAL) &&
177               ((file_mode & 0200) == 0200))
178      {
179         int fd;
180         int n, left, ptr;
181
182         strcpy(full_filename, mountpoint);
183         if (full_filename[strlen(full_filename)-1] != '/')
184            strcat(full_filename, "/");
185         strcat(full_filename, filename);
186
187         fd = creat(full_filename, S_IRUSR|S_IWUSR | S_IRGRP|S_IWGRP);
188         if (fd != -1)
189         {
190            left = file_size;
191            ptr  = offset;
192            while ((n = write(fd, &tar_image[ptr], left)) > 0)
193            {
194               left -= n;
195               ptr += n;
196            }
197            close(fd);
198         }
199
200         nblocks = (((file_size) + 511) & ~511) / 512;
201         offset += 512 * nblocks;
202      }
203   }
204
205   return(status);
206}
207
208/**************************************************************************
209 * This converts octal ASCII number representations into an
210 * unsigned long.  Only support 32-bit numbers for now.
211 *************************************************************************/
212static unsigned long
213octal2ulong(char *octascii, int len)
214{
215   int           i;
216   unsigned long num;
217   unsigned long mult;
218
219   num = 0;
220   mult = 1;
221   for (i=len-1; i>=0; i--)
222   {
223      if ((octascii[i] < '0') || (octascii[i] > '9'))
224         continue;
225
226      num  += mult*((unsigned long)(octascii[i] - '0'));
227      mult *= 8;
228   }
229   return(num);
230}
231
232
233/************************************************************************
234 * Compute the TAR checksum and check with the value in
235 * the archive.  The checksum is computed over the entire
236 * header, but the checksum field is substituted with blanks.
237 ************************************************************************/
238static int
239compute_tar_header_checksum(char *bufr)
240{
241   int  i, sum;
242
243
244   sum = 0;
245   for (i=0; i<512; i++)
246   {
247      if ((i >= 148) && (i < 156))
248         sum += 0xff & ' ';
249      else
250         sum += 0xff & bufr[i];
251   }
252   return(sum);
253}
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