| 1 | /* Low-level RSP routines for GDB, the GNU debugger. |
| 2 | |
| 3 | Copyright (C) 1988-2020 Free Software Foundation, Inc. |
| 4 | |
| 5 | This file is part of GDB. |
| 6 | |
| 7 | This program is free software; you can redistribute it and/or modify |
| 8 | it under the terms of the GNU General Public License as published by |
| 9 | the Free Software Foundation; either version 3 of the License, or |
| 10 | (at your option) any later version. |
| 11 | |
| 12 | This program is distributed in the hope that it will be useful, |
| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | GNU General Public License for more details. |
| 16 | |
| 17 | You should have received a copy of the GNU General Public License |
| 18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 19 | |
| 20 | #include "common-defs.h" |
| 21 | #include "rsp-low.h" |
| 22 | |
| 23 | /* See rsp-low.h. */ |
| 24 | |
| 25 | int |
| 26 | fromhex (int a) |
| 27 | { |
| 28 | if (a >= '0' && a <= '9') |
| 29 | return a - '0'; |
| 30 | else if (a >= 'a' && a <= 'f') |
| 31 | return a - 'a' + 10; |
| 32 | else if (a >= 'A' && a <= 'F') |
| 33 | return a - 'A' + 10; |
| 34 | else |
| 35 | error (_("Reply contains invalid hex digit %d"), a); |
| 36 | } |
| 37 | |
| 38 | /* See rsp-low.h. */ |
| 39 | |
| 40 | int |
| 41 | tohex (int nib) |
| 42 | { |
| 43 | if (nib < 10) |
| 44 | return '0' + nib; |
| 45 | else |
| 46 | return 'a' + nib - 10; |
| 47 | } |
| 48 | |
| 49 | /* Encode 64 bits in 16 chars of hex. */ |
| 50 | |
| 51 | static const char hexchars[] = "0123456789abcdef"; |
| 52 | |
| 53 | static int |
| 54 | ishex (int ch, int *val) |
| 55 | { |
| 56 | if ((ch >= 'a') && (ch <= 'f')) |
| 57 | { |
| 58 | *val = ch - 'a' + 10; |
| 59 | return 1; |
| 60 | } |
| 61 | if ((ch >= 'A') && (ch <= 'F')) |
| 62 | { |
| 63 | *val = ch - 'A' + 10; |
| 64 | return 1; |
| 65 | } |
| 66 | if ((ch >= '0') && (ch <= '9')) |
| 67 | { |
| 68 | *val = ch - '0'; |
| 69 | return 1; |
| 70 | } |
| 71 | return 0; |
| 72 | } |
| 73 | |
| 74 | /* See rsp-low.h. */ |
| 75 | |
| 76 | char * |
| 77 | pack_nibble (char *buf, int nibble) |
| 78 | { |
| 79 | *buf++ = hexchars[(nibble & 0x0f)]; |
| 80 | return buf; |
| 81 | } |
| 82 | |
| 83 | /* See rsp-low.h. */ |
| 84 | |
| 85 | char * |
| 86 | pack_hex_byte (char *pkt, int byte) |
| 87 | { |
| 88 | *pkt++ = hexchars[(byte >> 4) & 0xf]; |
| 89 | *pkt++ = hexchars[(byte & 0xf)]; |
| 90 | return pkt; |
| 91 | } |
| 92 | |
| 93 | /* See rsp-low.h. */ |
| 94 | |
| 95 | const char * |
| 96 | unpack_varlen_hex (const char *buff, /* packet to parse */ |
| 97 | ULONGEST *result) |
| 98 | { |
| 99 | int nibble; |
| 100 | ULONGEST retval = 0; |
| 101 | |
| 102 | while (ishex (*buff, &nibble)) |
| 103 | { |
| 104 | buff++; |
| 105 | retval = retval << 4; |
| 106 | retval |= nibble & 0x0f; |
| 107 | } |
| 108 | *result = retval; |
| 109 | return buff; |
| 110 | } |
| 111 | |
| 112 | /* See rsp-low.h. */ |
| 113 | |
| 114 | int |
| 115 | hex2bin (const char *hex, gdb_byte *bin, int count) |
| 116 | { |
| 117 | int i; |
| 118 | |
| 119 | for (i = 0; i < count; i++) |
| 120 | { |
| 121 | if (hex[0] == 0 || hex[1] == 0) |
| 122 | { |
| 123 | /* Hex string is short, or of uneven length. |
| 124 | Return the count that has been converted so far. */ |
| 125 | return i; |
| 126 | } |
| 127 | *bin++ = fromhex (hex[0]) * 16 + fromhex (hex[1]); |
| 128 | hex += 2; |
| 129 | } |
| 130 | return i; |
| 131 | } |
| 132 | |
| 133 | /* See rsp-low.h. */ |
| 134 | |
| 135 | gdb::byte_vector |
| 136 | hex2bin (const char *hex) |
| 137 | { |
| 138 | size_t bin_len = strlen (hex) / 2; |
| 139 | gdb::byte_vector bin (bin_len); |
| 140 | |
| 141 | hex2bin (hex, bin.data (), bin_len); |
| 142 | |
| 143 | return bin; |
| 144 | } |
| 145 | |
| 146 | /* See rsp-low.h. */ |
| 147 | |
| 148 | std::string |
| 149 | hex2str (const char *hex) |
| 150 | { |
| 151 | return hex2str (hex, strlen (hex)); |
| 152 | } |
| 153 | |
| 154 | /* See rsp-low.h. */ |
| 155 | |
| 156 | std::string |
| 157 | hex2str (const char *hex, int count) |
| 158 | { |
| 159 | std::string ret; |
| 160 | |
| 161 | ret.reserve (count); |
| 162 | for (size_t i = 0; i < count; ++i) |
| 163 | { |
| 164 | if (hex[0] == '\0' || hex[1] == '\0') |
| 165 | { |
| 166 | /* Hex string is short, or of uneven length. Return what we |
| 167 | have so far. */ |
| 168 | return ret; |
| 169 | } |
| 170 | ret += fromhex (hex[0]) * 16 + fromhex (hex[1]); |
| 171 | hex += 2; |
| 172 | } |
| 173 | |
| 174 | return ret; |
| 175 | } |
| 176 | |
| 177 | /* See rsp-low.h. */ |
| 178 | |
| 179 | int |
| 180 | bin2hex (const gdb_byte *bin, char *hex, int count) |
| 181 | { |
| 182 | int i; |
| 183 | |
| 184 | for (i = 0; i < count; i++) |
| 185 | { |
| 186 | *hex++ = tohex ((*bin >> 4) & 0xf); |
| 187 | *hex++ = tohex (*bin++ & 0xf); |
| 188 | } |
| 189 | *hex = 0; |
| 190 | return i; |
| 191 | } |
| 192 | |
| 193 | /* See rsp-low.h. */ |
| 194 | |
| 195 | std::string |
| 196 | bin2hex (const gdb_byte *bin, int count) |
| 197 | { |
| 198 | std::string ret; |
| 199 | |
| 200 | ret.reserve (count * 2); |
| 201 | for (int i = 0; i < count; ++i) |
| 202 | { |
| 203 | ret += tohex ((*bin >> 4) & 0xf); |
| 204 | ret += tohex (*bin++ & 0xf); |
| 205 | } |
| 206 | |
| 207 | return ret; |
| 208 | } |
| 209 | |
| 210 | /* Return whether byte B needs escaping when sent as part of binary data. */ |
| 211 | |
| 212 | static int |
| 213 | needs_escaping (gdb_byte b) |
| 214 | { |
| 215 | return b == '$' || b == '#' || b == '}' || b == '*'; |
| 216 | } |
| 217 | |
| 218 | /* See rsp-low.h. */ |
| 219 | |
| 220 | int |
| 221 | remote_escape_output (const gdb_byte *buffer, int len_units, int unit_size, |
| 222 | gdb_byte *out_buf, int *out_len_units, |
| 223 | int out_maxlen_bytes) |
| 224 | { |
| 225 | int input_unit_index, output_byte_index = 0, byte_index_in_unit; |
| 226 | int number_escape_bytes_needed; |
| 227 | |
| 228 | /* Try to copy integral addressable memory units until |
| 229 | (1) we run out of space or |
| 230 | (2) we copied all of them. */ |
| 231 | for (input_unit_index = 0; |
| 232 | input_unit_index < len_units; |
| 233 | input_unit_index++) |
| 234 | { |
| 235 | /* Find out how many escape bytes we need for this unit. */ |
| 236 | number_escape_bytes_needed = 0; |
| 237 | for (byte_index_in_unit = 0; |
| 238 | byte_index_in_unit < unit_size; |
| 239 | byte_index_in_unit++) |
| 240 | { |
| 241 | int idx = input_unit_index * unit_size + byte_index_in_unit; |
| 242 | gdb_byte b = buffer[idx]; |
| 243 | if (needs_escaping (b)) |
| 244 | number_escape_bytes_needed++; |
| 245 | } |
| 246 | |
| 247 | /* Check if we have room to fit this escaped unit. */ |
| 248 | if (output_byte_index + unit_size + number_escape_bytes_needed > |
| 249 | out_maxlen_bytes) |
| 250 | break; |
| 251 | |
| 252 | /* Copy the unit byte per byte, adding escapes. */ |
| 253 | for (byte_index_in_unit = 0; |
| 254 | byte_index_in_unit < unit_size; |
| 255 | byte_index_in_unit++) |
| 256 | { |
| 257 | int idx = input_unit_index * unit_size + byte_index_in_unit; |
| 258 | gdb_byte b = buffer[idx]; |
| 259 | if (needs_escaping (b)) |
| 260 | { |
| 261 | out_buf[output_byte_index++] = '}'; |
| 262 | out_buf[output_byte_index++] = b ^ 0x20; |
| 263 | } |
| 264 | else |
| 265 | out_buf[output_byte_index++] = b; |
| 266 | } |
| 267 | } |
| 268 | |
| 269 | *out_len_units = input_unit_index; |
| 270 | return output_byte_index; |
| 271 | } |
| 272 | |
| 273 | /* See rsp-low.h. */ |
| 274 | |
| 275 | int |
| 276 | remote_unescape_input (const gdb_byte *buffer, int len, |
| 277 | gdb_byte *out_buf, int out_maxlen) |
| 278 | { |
| 279 | int input_index, output_index; |
| 280 | int escaped; |
| 281 | |
| 282 | output_index = 0; |
| 283 | escaped = 0; |
| 284 | for (input_index = 0; input_index < len; input_index++) |
| 285 | { |
| 286 | gdb_byte b = buffer[input_index]; |
| 287 | |
| 288 | if (output_index + 1 > out_maxlen) |
| 289 | error (_("Received too much data from the target.")); |
| 290 | |
| 291 | if (escaped) |
| 292 | { |
| 293 | out_buf[output_index++] = b ^ 0x20; |
| 294 | escaped = 0; |
| 295 | } |
| 296 | else if (b == '}') |
| 297 | escaped = 1; |
| 298 | else |
| 299 | out_buf[output_index++] = b; |
| 300 | } |
| 301 | |
| 302 | if (escaped) |
| 303 | error (_("Unmatched escape character in target response.")); |
| 304 | |
| 305 | return output_index; |
| 306 | } |
| 307 | |