git.zerfleddert.de Git - rsbs2/blob - filesystem.c

   1 #include <sys/stat.h>
   2 #include <sys/types.h>
   3 #include <limits.h>
   4 #include <fcntl.h>
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <strings.h>
   8 #include <string.h>
   9 #include <unistd.h>
  10 #include <errno.h>
  11 #include <libgen.h>
  12 #include "rsb-lz.h"
  13 #include "filesystem.h"
  14
  15 struct file_entry* get_next_file(unsigned char *fw, int len)
  16 {
  17         static unsigned char *pos;
  18         static unsigned char *start;
  19         static unsigned char *end;
  20         static struct file_entry fent;
  21         int name_length;
  22
  23         if (fw != NULL && len != 0) {
  24                 pos = fw + 0x28;
  25
  26 #if 0
  27                 printf("Start of filesystem: 0x%08x\n", *((unsigned int*)pos));
  28 #endif
  29                 start = fw;
  30                 pos = fw + *((unsigned int*)pos);
  31                 end = fw + len;
  32         }
  33
  34         fent.unknown = *pos;
  35         pos++;
  36
  37         if (fent.unknown == 0x00) {
  38                 /* EOF */
  39                 int fill = (4 - ((pos - start) % 4)) % 4;
  40                 int i;
  41
  42                 for (i = 0; i < fill; i++) {
  43                         if (*pos != 0xff) {
  44                                 fprintf(stderr, "Wrong fill byte after EOF: 0x%02x, aborting!\n", *pos);
  45                                 exit(1);
  46                         }
  47                         pos++;
  48                 }
  49
  50                 if (pos != end) {
  51                         fprintf(stderr, "EOF marker not at end-of-file %p <-> %p, aborting!\n", pos, end);
  52                         exit(1);
  53                 }
  54
  55                 return NULL;
  56         }
  57
  58
  59         name_length = *((unsigned int*)pos);
  60         pos += 4;
  61
  62         fent.length = *((unsigned int*)pos);
  63         pos += 4;
  64
  65         if ((fent.length > (end - pos)) ||
  66             (name_length > (end - pos))) {
  67                 printf("EOF reached without hitting EOF marker, aborting "
  68                         "(unknown: 0x%02x, namelen: 0x%08x, contentlen: 0x%08x!\n",
  69                         fent.unknown, name_length, fent.length);
  70                 exit(1);
  71         }
  72
  73         fent.name = (char*)pos;
  74         pos += name_length;
  75
  76         fent.start = pos;
  77         pos += fent.length;
  78
  79         return &fent;
  80 }
  81
  82 void extract_files(unsigned char *fw, int len)
  83 {
  84         struct file_entry *fent;
  85
  86         fent = get_next_file(fw, len);
  87
  88         while (fent) {
  89                 printf("%s: unknown: 0x%02x, length: %d",
  90                         fent->name, fent->unknown, fent->length);
  91
  92                 if (fent->length > 0) {
  93                         write_file(fent->name, fent->start, fent->length);
  94                         if (*((unsigned int*)fent->start) == LZ_MAGIC) {
  95                                 char *lzname;
  96
  97                                 if ((lzname = strdup(fent->name)) == NULL) {
  98                                         perror("strdup");
  99                                         exit(1);
 100                                 }
 101
 102                                 if (!strcmp(lzname + strlen(lzname) - 4 , ".lz")) {
 103                                         fprintf(stderr, "Ugh, can't derive filename...\n");
 104                                         exit(1);
 105                                 }
 106                                 lzname[strlen(lzname) - 3] = 0x00;
 107
 108                                 printf("%s: packed file found", lzname);
 109
 110                                 extract_lz_file(fent->start, (unsigned char*)lzname);
 111                                 free(lzname);
 112                         } else if (!strcmp(fent->name, "firmware")) {
 113                                 unsigned char *lzpos;
 114                                 char lzname[128];
 115
 116                                 bzero(lzname, sizeof(lzname));
 117                                 strcpy(lzname, "firmware.");
 118
 119                                 lzpos = fent->start + *((unsigned int*)(fent->start + 0x20));
 120                                 memcpy(lzname + strlen(lzname), lzpos - 4, 4);
 121                                 lzpos += 4;
 122                                 if (*((unsigned int*)(lzpos)) == LZ_MAGIC) {
 123                                         printf("%s: compressed firmware part found", lzname);
 124                                         extract_lz_file(lzpos, (unsigned char*)lzname);
 125                                 }
 126                         }
 127                 } else {
 128                         printf(", ignoring...\n");
 129                 }
 130                 fent = get_next_file(NULL, 0);
 131         }
 132 }
 133
 134 void mkdir_p(char *dir)
 135 {
 136         char *copy, *parent;
 137
 138         if ((dir == NULL) || (!strcmp(dir, ".")))
 139                 return;
 140
 141         if ((copy = strdup(dir)) == NULL) {
 142                 perror("strdup");
 143                 exit(1);
 144         }
 145         parent = dirname(copy);
 146         mkdir_p(parent);
 147
 148         errno = 0;
 149         if (mkdir(dir, 0755) == -1) {
 150                 if (errno != EEXIST) {
 151                         fprintf(stderr, "%s: ", dir);
 152                         perror("mkdir");
 153                         exit(1);
 154                 }
 155         }
 156         free(copy);
 157 }
 158
 159 void write_file(char *fname, unsigned char *buf, int len)
 160 {
 161         char filename[PATH_MAX];
 162         char *filename_c, *dirn;
 163         int fd;
 164         int remaining;
 165         int ret;
 166
 167         strcpy(filename, "extracted/");
 168         strcat(filename, fname);
 169
 170         if ((filename_c = strdup(filename)) == NULL) {
 171                 perror("strdup");
 172                 exit(1);
 173         }
 174         dirn = dirname(filename_c);
 175         mkdir_p(dirn);
 176         free(filename_c);
 177
 178         if ((fd = open(filename, O_WRONLY|O_CREAT, 0644)) == -1) {
 179                 fprintf(stderr, "%s: ", filename);
 180                 perror("open");
 181                 exit(1);
 182         }
 183
 184         remaining = len;
 185
 186         while(remaining) {
 187                 ret = write(fd, buf + (len - remaining), remaining);
 188                 if (ret < 0) {
 189                         perror("write");
 190                         exit(1);
 191                 }
 192                 remaining -= ret;
 193         }
 194
 195         printf(", %s written.\n", filename);
 196
 197         close(fd);
 198 }