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1 #include <stdio.h>
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2 #include <unistd.h>
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3 #include <stdlib.h>
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4 #include <string.h>
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5 #include <fcntl.h>
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6 #include <assert.h>
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7
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8 #define stat xv6_stat // avoid clash with host struct stat
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9 #include "types.h"
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10 #include "fs.h"
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11 #include "stat.h"
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12 #include "param.h"
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22
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13 #ifndef static_assert
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0
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14 #define static_assert(a, b) do { switch (0) case 0: case (a): ; } while (0)
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22
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15 #endif
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0
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16
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17 int nblocks = 985;
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18 int nlog = LOGSIZE;
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19 int ninodes = 200;
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20 int size = 1024;
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21
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22 int fsfd;
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23 struct superblock sb;
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24 char zeroes[512];
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25 uint freeblock;
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26 uint usedblocks;
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27 uint bitblocks;
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28 uint freeinode = 1;
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29
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30 void balloc(int);
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31 void wsect(uint, void*);
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32 void winode(uint, struct dinode*);
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33 void rinode(uint inum, struct dinode *ip);
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34 void rsect(uint sec, void *buf);
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35 uint ialloc(ushort type);
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36 void iappend(uint inum, void *p, int n);
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37
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38 // convert to intel byte order
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39 ushort
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40 xshort(ushort x)
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41 {
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42 ushort y;
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43 uchar *a = (uchar*)&y;
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44 a[0] = x;
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45 a[1] = x >> 8;
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46 return y;
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47 }
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48
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49 uint
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50 xint(uint x)
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51 {
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52 uint y;
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53 uchar *a = (uchar*)&y;
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54 a[0] = x;
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55 a[1] = x >> 8;
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56 a[2] = x >> 16;
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57 a[3] = x >> 24;
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58 return y;
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59 }
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60
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61 int
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62 main(int argc, char *argv[])
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63 {
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64 int i, cc, fd;
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65 uint rootino, inum, off;
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66 struct dirent de;
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67 char buf[512];
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68 struct dinode din;
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69
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70
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71 static_assert(sizeof(int) == 4, "Integers must be 4 bytes!");
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72
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73 if(argc < 2){
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74 fprintf(stderr, "Usage: mkfs fs.img files...\n");
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75 exit(1);
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76 }
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77
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78 assert((512 % sizeof(struct dinode)) == 0);
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79 assert((512 % sizeof(struct dirent)) == 0);
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80
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81 fsfd = open(argv[1], O_RDWR|O_CREAT|O_TRUNC, 0666);
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82 if(fsfd < 0){
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83 perror(argv[1]);
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84 exit(1);
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85 }
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86
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87 sb.size = xint(size);
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88 sb.nblocks = xint(nblocks); // so whole disk is size sectors
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89 sb.ninodes = xint(ninodes);
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90 sb.nlog = xint(nlog);
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91
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92 bitblocks = size/(512*8) + 1;
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93 usedblocks = ninodes / IPB + 3 + bitblocks;
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94 freeblock = usedblocks;
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95
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96 printf("used %d (bit %d ninode %zu) free %u log %u total %d\n", usedblocks,
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97 bitblocks, ninodes/IPB + 1, freeblock, nlog, nblocks+usedblocks+nlog);
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98
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99 assert(nblocks + usedblocks + nlog == size);
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100
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101 for(i = 0; i < nblocks + usedblocks + nlog; i++)
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102 wsect(i, zeroes);
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103
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104 memset(buf, 0, sizeof(buf));
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105 memmove(buf, &sb, sizeof(sb));
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106 wsect(1, buf);
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107
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108 rootino = ialloc(T_DIR);
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109 assert(rootino == ROOTINO);
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110
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111 bzero(&de, sizeof(de));
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112 de.inum = xshort(rootino);
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113 strcpy(de.name, ".");
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114 iappend(rootino, &de, sizeof(de));
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115
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116 bzero(&de, sizeof(de));
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117 de.inum = xshort(rootino);
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118 strcpy(de.name, "..");
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119 iappend(rootino, &de, sizeof(de));
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120
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121 for(i = 2; i < argc; i++){
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122 assert(index(argv[i], '/') == 0);
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123
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124 if((fd = open(argv[i], 0)) < 0){
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125 perror(argv[i]);
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126 exit(1);
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127 }
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128
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129 // Skip leading _ in name when writing to file system.
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130 // The binaries are named _rm, _cat, etc. to keep the
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131 // build operating system from trying to execute them
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132 // in place of system binaries like rm and cat.
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133 if(argv[i][0] == '_')
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134 ++argv[i];
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135
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136 inum = ialloc(T_FILE);
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137
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138 bzero(&de, sizeof(de));
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139 de.inum = xshort(inum);
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140 strncpy(de.name, argv[i], DIRSIZ);
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141 iappend(rootino, &de, sizeof(de));
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142
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143 while((cc = read(fd, buf, sizeof(buf))) > 0)
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144 iappend(inum, buf, cc);
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145
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146 close(fd);
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147 }
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148
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149 // fix size of root inode dir
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150 rinode(rootino, &din);
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151 off = xint(din.size);
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152 off = ((off/BSIZE) + 1) * BSIZE;
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153 din.size = xint(off);
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154 winode(rootino, &din);
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155
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156 balloc(usedblocks);
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157
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158 exit(0);
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159 }
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160
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161 void
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162 wsect(uint sec, void *buf)
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163 {
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164 if(lseek(fsfd, sec * 512L, 0) != sec * 512L){
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165 perror("lseek");
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166 exit(1);
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167 }
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168 if(write(fsfd, buf, 512) != 512){
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169 perror("write");
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170 exit(1);
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171 }
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172 }
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173
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174 uint
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175 i2b(uint inum)
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176 {
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177 return (inum / IPB) + 2;
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178 }
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179
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180 void
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181 winode(uint inum, struct dinode *ip)
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182 {
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183 char buf[512];
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184 uint bn;
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185 struct dinode *dip;
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186
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187 bn = i2b(inum);
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188 rsect(bn, buf);
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189 dip = ((struct dinode*)buf) + (inum % IPB);
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190 *dip = *ip;
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191 wsect(bn, buf);
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192 }
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193
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194 void
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195 rinode(uint inum, struct dinode *ip)
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196 {
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197 char buf[512];
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198 uint bn;
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199 struct dinode *dip;
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200
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201 bn = i2b(inum);
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202 rsect(bn, buf);
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203 dip = ((struct dinode*)buf) + (inum % IPB);
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204 *ip = *dip;
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205 }
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206
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207 void
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208 rsect(uint sec, void *buf)
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209 {
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210 if(lseek(fsfd, sec * 512L, 0) != sec * 512L){
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211 perror("lseek");
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212 exit(1);
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213 }
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214 if(read(fsfd, buf, 512) != 512){
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215 perror("read");
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216 exit(1);
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217 }
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218 }
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219
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220 uint
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221 ialloc(ushort type)
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222 {
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223 uint inum = freeinode++;
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224 struct dinode din;
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225
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226 bzero(&din, sizeof(din));
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227 din.type = xshort(type);
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228 din.nlink = xshort(1);
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229 din.size = xint(0);
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230 winode(inum, &din);
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231 return inum;
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232 }
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233
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234 void
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235 balloc(int used)
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236 {
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237 uchar buf[512];
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238 int i;
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239
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240 printf("balloc: first %d blocks have been allocated\n", used);
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241 assert(used < 512*8);
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242 bzero(buf, 512);
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243 for(i = 0; i < used; i++){
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244 buf[i/8] = buf[i/8] | (0x1 << (i%8));
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245 }
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246 printf("balloc: write bitmap block at sector %zu\n", ninodes/IPB + 3);
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247 wsect(ninodes / IPB + 3, buf);
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248 }
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249
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250 #define min(a, b) ((a) < (b) ? (a) : (b))
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251
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252 void
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253 iappend(uint inum, void *xp, int n)
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254 {
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255 char *p = (char*)xp;
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256 uint fbn, off, n1;
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257 struct dinode din;
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258 char buf[512];
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259 uint indirect[NINDIRECT];
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260 uint x;
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261
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262 rinode(inum, &din);
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263
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264 off = xint(din.size);
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265 while(n > 0){
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266 fbn = off / 512;
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267 assert(fbn < MAXFILE);
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268 if(fbn < NDIRECT){
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269 if(xint(din.addrs[fbn]) == 0){
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270 din.addrs[fbn] = xint(freeblock++);
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271 usedblocks++;
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272 }
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273 x = xint(din.addrs[fbn]);
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274 } else {
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275 if(xint(din.addrs[NDIRECT]) == 0){
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276 // printf("allocate indirect block\n");
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277 din.addrs[NDIRECT] = xint(freeblock++);
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278 usedblocks++;
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279 }
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280 // printf("read indirect block\n");
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281 rsect(xint(din.addrs[NDIRECT]), (char*)indirect);
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282 if(indirect[fbn - NDIRECT] == 0){
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283 indirect[fbn - NDIRECT] = xint(freeblock++);
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284 usedblocks++;
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285 wsect(xint(din.addrs[NDIRECT]), (char*)indirect);
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286 }
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287 x = xint(indirect[fbn-NDIRECT]);
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288 }
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289 n1 = min(n, (fbn + 1) * 512 - off);
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290 rsect(x, buf);
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291 bcopy(p, buf + off - (fbn * 512), n1);
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292 wsect(x, buf);
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293 n -= n1;
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294 off += n1;
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295 p += n1;
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296 }
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297 din.size = xint(off);
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298 winode(inum, &din);
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299 }
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