| 1 | /* |
| 2 | * YAFFS: Yet Another Flash File System. A NAND-flash specific file system. |
| 3 | * |
| 4 | * Copyright (C) 2002-2010 Aleph One Ltd. |
| 5 | * for Toby Churchill Ltd and Brightstar Engineering |
| 6 | * |
| 7 | * Created by Charles Manning <charles@aleph1.co.uk> |
| 8 | * |
| 9 | * This program is free software; you can redistribute it and/or modify |
| 10 | * it under the terms of the GNU General Public License version 2 as |
| 11 | * published by the Free Software Foundation. |
| 12 | */ |
| 13 | |
| 14 | /* |
| 15 | * This simple implementation of a name-value store assumes a small number of values and fits |
| 16 | * into a small finite buffer. |
| 17 | * |
| 18 | * Each attribute is stored as a record: |
| 19 | * sizeof(int) bytes record size. |
| 20 | * strnlen+1 bytes name null terminated. |
| 21 | * nbytes value. |
| 22 | * ---------- |
| 23 | * total size stored in record size |
| 24 | * |
| 25 | * This code has not been tested with unicode yet. |
| 26 | */ |
| 27 | |
| 28 | |
| 29 | #include "yaffs_nameval.h" |
| 30 | |
| 31 | #include "yportenv.h" |
| 32 | |
| 33 | static int nval_find(const char *xb, int xb_size, const YCHAR *name, |
| 34 | int *exist_size) |
| 35 | { |
| 36 | int pos=0; |
| 37 | int size; |
| 38 | |
| 39 | memcpy(&size,xb,sizeof(int)); |
| 40 | while(size > 0 && (size < xb_size) && (pos + size < xb_size)){ |
| 41 | if(yaffs_strncmp((YCHAR *)(xb+pos+sizeof(int)),name,size) == 0){ |
| 42 | if(exist_size) |
| 43 | *exist_size = size; |
| 44 | return pos; |
| 45 | } |
| 46 | pos += size; |
| 47 | if(pos < xb_size -sizeof(int)) |
| 48 | memcpy(&size,xb + pos,sizeof(int)); |
| 49 | else |
| 50 | size = 0; |
| 51 | } |
| 52 | if(exist_size) |
| 53 | *exist_size = 0; |
| 54 | return -1; |
| 55 | } |
| 56 | |
| 57 | static int nval_used(const char *xb, int xb_size) |
| 58 | { |
| 59 | int pos=0; |
| 60 | int size; |
| 61 | |
| 62 | memcpy(&size,xb + pos,sizeof(int)); |
| 63 | while(size > 0 && (size < xb_size) && (pos + size < xb_size)){ |
| 64 | pos += size; |
| 65 | if(pos < xb_size -sizeof(int)) |
| 66 | memcpy(&size,xb + pos,sizeof(int)); |
| 67 | else |
| 68 | size = 0; |
| 69 | } |
| 70 | return pos; |
| 71 | } |
| 72 | |
| 73 | int nval_del(char *xb, int xb_size, const YCHAR *name) |
| 74 | { |
| 75 | int pos = nval_find(xb, xb_size, name, NULL); |
| 76 | int size; |
| 77 | |
| 78 | if(pos >= 0 && pos < xb_size){ |
| 79 | /* Find size, shift rest over this record, then zero out the rest of buffer */ |
| 80 | memcpy(&size,xb+pos,sizeof(int)); |
| 81 | memcpy(xb + pos, xb + pos + size, xb_size - (pos + size)); |
| 82 | memset(xb + (xb_size - size),0,size); |
| 83 | return 0; |
| 84 | } else |
| 85 | return -ENODATA; |
| 86 | } |
| 87 | |
| 88 | int nval_set(char *xb, int xb_size, const YCHAR *name, const char *buf, int bsize, int flags) |
| 89 | { |
| 90 | int pos; |
| 91 | int namelen = yaffs_strnlen(name,xb_size); |
| 92 | int reclen; |
| 93 | int size_exist = 0; |
| 94 | int space; |
| 95 | int start; |
| 96 | |
| 97 | pos = nval_find(xb,xb_size,name, &size_exist); |
| 98 | |
| 99 | if(flags & XATTR_CREATE && pos >= 0) |
| 100 | return -EEXIST; |
| 101 | if(flags & XATTR_REPLACE && pos < 0) |
| 102 | return -ENODATA; |
| 103 | |
| 104 | start = nval_used(xb,xb_size); |
| 105 | space = xb_size - start + size_exist; |
| 106 | |
| 107 | reclen = (sizeof(int) + namelen + 1 + bsize); |
| 108 | |
| 109 | if(reclen > space) |
| 110 | return -ENOSPC; |
| 111 | |
| 112 | if(pos >= 0){ |
| 113 | nval_del(xb,xb_size,name); |
| 114 | start = nval_used(xb, xb_size); |
| 115 | } |
| 116 | |
| 117 | pos = start; |
| 118 | |
| 119 | memcpy(xb + pos,&reclen,sizeof(int)); |
| 120 | pos +=sizeof(int); |
| 121 | yaffs_strncpy((YCHAR *)(xb + pos), name, reclen); |
| 122 | pos+= (namelen+1); |
| 123 | memcpy(xb + pos,buf,bsize); |
| 124 | return 0; |
| 125 | } |
| 126 | |
| 127 | int nval_get(const char *xb, int xb_size, const YCHAR *name, char *buf, int bsize) |
| 128 | { |
| 129 | int pos = nval_find(xb,xb_size,name,NULL); |
| 130 | int size; |
| 131 | |
| 132 | if(pos >= 0 && pos< xb_size){ |
| 133 | |
| 134 | memcpy(&size,xb +pos,sizeof(int)); |
| 135 | pos+=sizeof(int); /* advance past record length */ |
| 136 | size -= sizeof(int); |
| 137 | |
| 138 | /* Advance over name string */ |
| 139 | while(xb[pos] && size > 0 && pos < xb_size){ |
| 140 | pos++; |
| 141 | size--; |
| 142 | } |
| 143 | /*Advance over NUL */ |
| 144 | pos++; |
| 145 | size--; |
| 146 | |
| 147 | if(size <= bsize){ |
| 148 | memcpy(buf,xb + pos,size); |
| 149 | return size; |
| 150 | } |
| 151 | |
| 152 | } |
| 153 | if(pos >= 0) |
| 154 | return -ERANGE; |
| 155 | else |
| 156 | return -ENODATA; |
| 157 | } |
| 158 | |
| 159 | int nval_list(const char *xb, int xb_size, char *buf, int bsize) |
| 160 | { |
| 161 | int pos = 0; |
| 162 | int size; |
| 163 | int name_len; |
| 164 | int ncopied = 0; |
| 165 | int filled = 0; |
| 166 | |
| 167 | memcpy(&size,xb + pos,sizeof(int)); |
| 168 | while(size > sizeof(int) && size <= xb_size && (pos + size) < xb_size && !filled){ |
| 169 | pos+= sizeof(int); |
| 170 | size-=sizeof(int); |
| 171 | name_len = yaffs_strnlen((YCHAR *)(xb + pos), size); |
| 172 | if(ncopied + name_len + 1 < bsize){ |
| 173 | memcpy(buf,xb+pos,name_len * sizeof(YCHAR)); |
| 174 | buf+= name_len; |
| 175 | *buf = '\0'; |
| 176 | buf++; |
| 177 | if(sizeof(YCHAR) > 1){ |
| 178 | *buf = '\0'; |
| 179 | buf++; |
| 180 | } |
| 181 | ncopied += (name_len+1); |
| 182 | } else |
| 183 | filled = 1; |
| 184 | pos+=size; |
| 185 | if(pos < xb_size -sizeof(int)) |
| 186 | memcpy(&size,xb + pos,sizeof(int)); |
| 187 | else |
| 188 | size = 0; |
| 189 | } |
| 190 | return ncopied; |
| 191 | } |
| 192 | |
| 193 | |
| 194 | int nval_hasvalues(const char *xb, int xb_size) |
| 195 | { |
| 196 | return nval_used(xb, xb_size) > 0; |
| 197 | } |
| 198 | |
