FreeBSD/Linux Kernel Cross Reference
sys/gdb/gdb_packet.c
1 /*-
2 * Copyright (c) 2004 Marcel Moolenaar
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD: releng/11.2/sys/gdb/gdb_packet.c 271173 2014-09-05 16:40:47Z benno $");
29
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/ctype.h>
33 #include <sys/kdb.h>
34 #include <sys/libkern.h>
35 #include <sys/ttydefaults.h>
36
37 #include <machine/gdb_machdep.h>
38 #include <machine/kdb.h>
39
40 #include <gdb/gdb.h>
41 #include <gdb/gdb_int.h>
42
43 static char gdb_rxbuf[GDB_BUFSZ];
44 char *gdb_rxp = NULL;
45 size_t gdb_rxsz = 0;
46 static char gdb_txbuf[GDB_BUFSZ];
47 char *gdb_txp = NULL; /* Used in inline functions. */
48
49 #define C2N(c) (((c) < 'A') ? (c) - '' : \
50 10 + (((c) < 'a') ? (c) - 'A' : (c) - 'a'))
51 #define N2C(n) (((n) < 10) ? (n) + '' : (n) + 'a' - 10)
52
53 /*
54 * Get a single character
55 */
56
57 static int
58 gdb_getc(void)
59 {
60 int c;
61
62 do
63 c = gdb_cur->gdb_getc();
64 while (c == -1);
65
66 if (c == CTRL('C')) {
67 printf("Received ^C; trying to switch back to ddb.\n");
68
69 if (kdb_dbbe_select("ddb") != 0)
70 printf("The ddb backend could not be selected.\n");
71 else {
72 printf("using longjmp, hope it works!\n");
73 kdb_reenter();
74 }
75 }
76 return (c);
77 }
78
79 /*
80 * Functions to receive and extract from a packet.
81 */
82
83 int
84 gdb_rx_begin(void)
85 {
86 int c, cksum;
87
88 gdb_rxp = NULL;
89 do {
90 /*
91 * Wait for the start character, ignore all others.
92 * XXX needs a timeout.
93 */
94 while ((c = gdb_getc()) != '$')
95 ;
96
97 /* Read until a # or end of buffer is found. */
98 cksum = 0;
99 gdb_rxsz = 0;
100 while (gdb_rxsz < sizeof(gdb_rxbuf) - 1) {
101 c = gdb_getc();
102 if (c == '#')
103 break;
104 gdb_rxbuf[gdb_rxsz++] = c;
105 cksum += c;
106 }
107 gdb_rxbuf[gdb_rxsz] = 0;
108 cksum &= 0xff;
109
110 /* Bail out on a buffer overflow. */
111 if (c != '#') {
112 gdb_cur->gdb_putc('-');
113 return (ENOSPC);
114 }
115
116 c = gdb_getc();
117 cksum -= (C2N(c) << 4) & 0xf0;
118 c = gdb_getc();
119 cksum -= C2N(c) & 0x0f;
120 gdb_cur->gdb_putc((cksum == 0) ? '+' : '-');
121 if (cksum != 0)
122 printf("GDB: packet `%s' has invalid checksum\n",
123 gdb_rxbuf);
124 } while (cksum != 0);
125
126 gdb_rxp = gdb_rxbuf;
127 return (0);
128 }
129
130 int
131 gdb_rx_equal(const char *str)
132 {
133 int len;
134
135 len = strlen(str);
136 if (len > gdb_rxsz || strncmp(str, gdb_rxp, len) != 0)
137 return (0);
138 gdb_rxp += len;
139 gdb_rxsz -= len;
140 return (1);
141 }
142
143 int
144 gdb_rx_mem(unsigned char *addr, size_t size)
145 {
146 unsigned char *p;
147 void *prev;
148 jmp_buf jb;
149 size_t cnt;
150 int ret;
151 unsigned char c;
152
153 if (size * 2 != gdb_rxsz)
154 return (-1);
155
156 prev = kdb_jmpbuf(jb);
157 ret = setjmp(jb);
158 if (ret == 0) {
159 p = addr;
160 cnt = size;
161 while (cnt-- > 0) {
162 c = (C2N(gdb_rxp[0]) << 4) & 0xf0;
163 c |= C2N(gdb_rxp[1]) & 0x0f;
164 *p++ = c;
165 gdb_rxsz -= 2;
166 gdb_rxp += 2;
167 }
168 kdb_cpu_sync_icache(addr, size);
169 }
170 (void)kdb_jmpbuf(prev);
171 return ((ret == 0) ? 1 : 0);
172 }
173
174 int
175 gdb_rx_varhex(uintmax_t *vp)
176 {
177 uintmax_t v;
178 int c, neg;
179
180 c = gdb_rx_char();
181 neg = (c == '-') ? 1 : 0;
182 if (neg == 1)
183 c = gdb_rx_char();
184 if (!isxdigit(c)) {
185 gdb_rxp -= ((c == -1) ? 0 : 1) + neg;
186 gdb_rxsz += ((c == -1) ? 0 : 1) + neg;
187 return (-1);
188 }
189 v = 0;
190 do {
191 v <<= 4;
192 v += C2N(c);
193 c = gdb_rx_char();
194 } while (isxdigit(c));
195 if (c != -1) {
196 gdb_rxp--;
197 gdb_rxsz++;
198 }
199 *vp = (neg) ? -v : v;
200 return (0);
201 }
202
203 /*
204 * Function to build and send a package.
205 */
206
207 void
208 gdb_tx_begin(char tp)
209 {
210
211 gdb_txp = gdb_txbuf;
212 if (tp != '\0')
213 gdb_tx_char(tp);
214 }
215
216 int
217 gdb_tx_end(void)
218 {
219 const char *p;
220 int runlen;
221 unsigned char c, cksum;
222
223 do {
224 gdb_cur->gdb_putc('$');
225
226 cksum = 0;
227 p = gdb_txbuf;
228 while (p < gdb_txp) {
229 /* Send a character and start run-length encoding. */
230 c = *p++;
231 gdb_cur->gdb_putc(c);
232 cksum += c;
233 runlen = 0;
234 /* Determine run-length and update checksum. */
235 while (p < gdb_txp && *p == c) {
236 runlen++;
237 p++;
238 }
239 /* Emit the run-length encoded string. */
240 while (runlen >= 97) {
241 gdb_cur->gdb_putc('*');
242 cksum += '*';
243 gdb_cur->gdb_putc(97+29);
244 cksum += 97+29;
245 runlen -= 97;
246 if (runlen > 0) {
247 gdb_cur->gdb_putc(c);
248 cksum += c;
249 runlen--;
250 }
251 }
252 if (runlen == 1) {
253 gdb_cur->gdb_putc(c);
254 cksum += c;
255 runlen--;
256 }
257 if (runlen == 0)
258 continue;
259 /* Don't emit '$', '#', '+' or '-'. */
260 if (runlen == 7) {
261 gdb_cur->gdb_putc(c);
262 cksum += c;
263 runlen--;
264 }
265 if (runlen == 6 || runlen == 14 || runlen == 16) {
266 gdb_cur->gdb_putc(c);
267 cksum += c;
268 runlen--;
269 }
270 gdb_cur->gdb_putc('*');
271 cksum += '*';
272 gdb_cur->gdb_putc(runlen+29);
273 cksum += runlen+29;
274 }
275
276 gdb_cur->gdb_putc('#');
277 c = cksum >> 4;
278 gdb_cur->gdb_putc(N2C(c));
279 c = cksum & 0x0f;
280 gdb_cur->gdb_putc(N2C(c));
281
282 c = gdb_getc();
283 } while (c != '+');
284
285 return (0);
286 }
287
288 int
289 gdb_tx_mem(const unsigned char *addr, size_t size)
290 {
291 void *prev;
292 jmp_buf jb;
293 int ret;
294
295 prev = kdb_jmpbuf(jb);
296 ret = setjmp(jb);
297 if (ret == 0) {
298 while (size-- > 0) {
299 *gdb_txp++ = N2C(*addr >> 4);
300 *gdb_txp++ = N2C(*addr & 0x0f);
301 addr++;
302 }
303 }
304 (void)kdb_jmpbuf(prev);
305 return ((ret == 0) ? 1 : 0);
306 }
307
308 void
309 gdb_tx_reg(int regnum)
310 {
311 unsigned char *regp;
312 size_t regsz;
313
314 regp = gdb_cpu_getreg(regnum, ®sz);
315 if (regp == NULL) {
316 /* Register unavailable. */
317 while (regsz--) {
318 gdb_tx_char('x');
319 gdb_tx_char('x');
320 }
321 } else
322 gdb_tx_mem(regp, regsz);
323 }
324
325 /* Read binary data up until the end of the packet or until we have datalen decoded bytes */
326 int
327 gdb_rx_bindata(unsigned char *data, size_t datalen, size_t *amt)
328 {
329 int c;
330
331 *amt = 0;
332
333 while (*amt < datalen) {
334 c = gdb_rx_char();
335 /* End of packet? */
336 if (c == -1)
337 break;
338 /* Escaped character up next */
339 if (c == '}') {
340 /* Truncated packet? Bail out */
341 if ((c = gdb_rx_char()) == -1)
342 return (1);
343 c ^= 0x20;
344 }
345 *(data++) = c & 0xff;
346 (*amt)++;
347 }
348
349 return (0);
350 }
351
352 int
353 gdb_search_mem(const unsigned char *addr, size_t size, const unsigned char *pat, size_t patlen, const unsigned char **found)
354 {
355 void *prev;
356 jmp_buf jb;
357 int ret;
358
359 prev = kdb_jmpbuf(jb);
360 ret = setjmp(jb);
361 if (ret == 0)
362 *found = memmem(addr, size, pat, patlen);
363
364 (void)kdb_jmpbuf(prev);
365 return ((ret == 0) ? 1 : 0);
366 }
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