gdb_packet.c

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    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/10.0/sys/gdb/gdb_packet.c 218825 2011-02-18 22:25:11Z mdf $");
   29 
   30 #include <sys/param.h>
   31 #include <sys/systm.h>
   32 #include <sys/ctype.h>
   33 #include <sys/kdb.h>
   34 #include <sys/ttydefaults.h>
   35 
   36 #include <machine/gdb_machdep.h>
   37 #include <machine/kdb.h>
   38 
   39 #include <gdb/gdb.h>
   40 #include <gdb/gdb_int.h>
   41 
   42 static char gdb_rxbuf[GDB_BUFSZ];
   43 char *gdb_rxp = NULL;
   44 size_t gdb_rxsz = 0;
   45 static char gdb_txbuf[GDB_BUFSZ];
   46 char *gdb_txp = NULL;                   /* Used in inline functions. */
   47 
   48 #define C2N(c)  (((c) < 'A') ? (c) - '' : \
   49             10 + (((c) < 'a') ? (c) - 'A' : (c) - 'a'))
   50 #define N2C(n)  (((n) < 10) ? (n) + '' : (n) + 'a' - 10)
   51 
   52 /*
   53  * Get a single character
   54  */
   55 
   56 static int
   57 gdb_getc(void)
   58 {
   59         int c;
   60 
   61         do
   62                 c = gdb_cur->gdb_getc();
   63         while (c == -1);
   64 
   65         if (c == CTRL('C')) {
   66                 printf("Received ^C; trying to switch back to ddb.\n");
   67 
   68                 if (kdb_dbbe_select("ddb") != 0)
   69                         printf("The ddb backend could not be selected.\n");
   70                 else {
   71                         printf("using longjmp, hope it works!\n");
   72                         kdb_reenter();
   73                 }
   74         }
   75         return (c);
   76 }
   77 
   78 /*
   79  * Functions to receive and extract from a packet.
   80  */
   81 
   82 int
   83 gdb_rx_begin(void)
   84 {
   85         int c, cksum;
   86 
   87         gdb_rxp = NULL;
   88         do {
   89                 /*
   90                  * Wait for the start character, ignore all others.
   91                  * XXX needs a timeout.
   92                  */
   93                 while ((c = gdb_getc()) != '$')
   94                         ;
   95 
   96                 /* Read until a # or end of buffer is found. */
   97                 cksum = 0;
   98                 gdb_rxsz = 0;
   99                 while (gdb_rxsz < sizeof(gdb_rxbuf) - 1) {
  100                         c = gdb_getc();
  101                         if (c == '#')
  102                                 break;
  103                         gdb_rxbuf[gdb_rxsz++] = c;
  104                         cksum += c;
  105                 }
  106                 gdb_rxbuf[gdb_rxsz] = 0;
  107                 cksum &= 0xff;
  108 
  109                 /* Bail out on a buffer overflow. */
  110                 if (c != '#') {
  111                         gdb_cur->gdb_putc('-');
  112                         return (ENOSPC);
  113                 }
  114 
  115                 c = gdb_getc();
  116                 cksum -= (C2N(c) << 4) & 0xf0;
  117                 c = gdb_getc();
  118                 cksum -= C2N(c) & 0x0f;
  119                 gdb_cur->gdb_putc((cksum == 0) ? '+' : '-');
  120                 if (cksum != 0)
  121                         printf("GDB: packet `%s' has invalid checksum\n",
  122                             gdb_rxbuf);
  123         } while (cksum != 0);
  124 
  125         gdb_rxp = gdb_rxbuf;
  126         return (0);
  127 }
  128 
  129 int
  130 gdb_rx_equal(const char *str)
  131 {
  132         int len;
  133 
  134         len = strlen(str);
  135         if (len > gdb_rxsz || strncmp(str, gdb_rxp, len) != 0)
  136                 return (0);
  137         gdb_rxp += len;
  138         gdb_rxsz -= len;
  139         return (1);
  140 }
  141 
  142 int
  143 gdb_rx_mem(unsigned char *addr, size_t size)
  144 {
  145         unsigned char *p;
  146         void *prev;
  147         jmp_buf jb;
  148         size_t cnt;
  149         int ret;
  150         unsigned char c;
  151 
  152         if (size * 2 != gdb_rxsz)
  153                 return (-1);
  154 
  155         prev = kdb_jmpbuf(jb);
  156         ret = setjmp(jb);
  157         if (ret == 0) {
  158                 p = addr;
  159                 cnt = size;
  160                 while (cnt-- > 0) {
  161                         c = (C2N(gdb_rxp[0]) << 4) & 0xf0;
  162                         c |= C2N(gdb_rxp[1]) & 0x0f;
  163                         *p++ = c;
  164                         gdb_rxsz -= 2;
  165                         gdb_rxp += 2;
  166                 }
  167                 kdb_cpu_sync_icache(addr, size);
  168         }
  169         (void)kdb_jmpbuf(prev);
  170         return ((ret == 0) ? 1 : 0);
  171 }
  172 
  173 int
  174 gdb_rx_varhex(uintmax_t *vp)
  175 {
  176         uintmax_t v;
  177         int c, neg;
  178 
  179         c = gdb_rx_char();
  180         neg = (c == '-') ? 1 : 0;
  181         if (neg == 1)
  182                 c = gdb_rx_char();
  183         if (!isxdigit(c)) {
  184                 gdb_rxp -= ((c == -1) ? 0 : 1) + neg;
  185                 gdb_rxsz += ((c == -1) ? 0 : 1) + neg;
  186                 return (-1);
  187         }
  188         v = 0;
  189         do {
  190                 v <<= 4;
  191                 v += C2N(c);
  192                 c = gdb_rx_char();
  193         } while (isxdigit(c));
  194         if (c != -1) {
  195                 gdb_rxp--;
  196                 gdb_rxsz++;
  197         }
  198         *vp = (neg) ? -v : v;
  199         return (0);
  200 }
  201 
  202 /*
  203  * Function to build and send a package.
  204  */
  205 
  206 void
  207 gdb_tx_begin(char tp)
  208 {
  209 
  210         gdb_txp = gdb_txbuf;
  211         if (tp != '\0')
  212                 gdb_tx_char(tp);
  213 }
  214 
  215 int
  216 gdb_tx_end(void)
  217 {
  218         const char *p;
  219         int runlen;
  220         unsigned char c, cksum;
  221 
  222         do {
  223                 gdb_cur->gdb_putc('$');
  224 
  225                 cksum = 0;
  226                 p = gdb_txbuf;
  227                 while (p < gdb_txp) {
  228                         /* Send a character and start run-length encoding. */
  229                         c = *p++;
  230                         gdb_cur->gdb_putc(c);
  231                         cksum += c;
  232                         runlen = 0;
  233                         /* Determine run-length and update checksum. */
  234                         while (p < gdb_txp && *p == c) {
  235                                 runlen++;
  236                                 p++;
  237                         }
  238                         /* Emit the run-length encoded string. */
  239                         while (runlen >= 97) {
  240                                 gdb_cur->gdb_putc('*');
  241                                 cksum += '*';
  242                                 gdb_cur->gdb_putc(97+29);
  243                                 cksum += 97+29;
  244                                 runlen -= 97;
  245                                 if (runlen > 0) {
  246                                         gdb_cur->gdb_putc(c);
  247                                         cksum += c;
  248                                         runlen--;
  249                                 }
  250                         }
  251                         if (runlen == 1) {
  252                                 gdb_cur->gdb_putc(c);
  253                                 cksum += c;
  254                                 runlen--;
  255                         }
  256                         if (runlen == 0)
  257                                 continue;
  258                         /* Don't emit '$', '#', '+' or '-'. */
  259                         if (runlen == 7) {
  260                                 gdb_cur->gdb_putc(c);
  261                                 cksum += c;
  262                                 runlen--;
  263                         }
  264                         if (runlen == 6 || runlen == 14 || runlen == 16) {
  265                                 gdb_cur->gdb_putc(c);
  266                                 cksum += c;
  267                                 runlen--;
  268                         }
  269                         gdb_cur->gdb_putc('*');
  270                         cksum += '*';
  271                         gdb_cur->gdb_putc(runlen+29);
  272                         cksum += runlen+29;
  273                 }
  274 
  275                 gdb_cur->gdb_putc('#');
  276                 c = cksum >> 4;
  277                 gdb_cur->gdb_putc(N2C(c));
  278                 c = cksum & 0x0f;
  279                 gdb_cur->gdb_putc(N2C(c));
  280 
  281                 c = gdb_getc();
  282         } while (c != '+');
  283 
  284         return (0);
  285 }
  286 
  287 int
  288 gdb_tx_mem(const unsigned char *addr, size_t size)
  289 {
  290         void *prev;
  291         jmp_buf jb;
  292         int ret;
  293 
  294         prev = kdb_jmpbuf(jb);
  295         ret = setjmp(jb);
  296         if (ret == 0) {
  297                 while (size-- > 0) {
  298                         *gdb_txp++ = N2C(*addr >> 4);
  299                         *gdb_txp++ = N2C(*addr & 0x0f);
  300                         addr++;
  301                 }
  302         }
  303         (void)kdb_jmpbuf(prev);
  304         return ((ret == 0) ? 1 : 0);
  305 }
  306 
  307 void
  308 gdb_tx_reg(int regnum)
  309 {
  310         unsigned char *regp;
  311         size_t regsz;
  312 
  313         regp = gdb_cpu_getreg(regnum, &regsz);
  314         if (regp == NULL) {
  315                 /* Register unavailable. */
  316                 while (regsz--) {
  317                         gdb_tx_char('x');
  318                         gdb_tx_char('x');
  319                 }
  320         } else
  321                 gdb_tx_mem(regp, regsz);
  322 }
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FreeBSD/Linux Kernel Cross Reference sys/gdb/gdb_packet.c

FreeBSD/Linux Kernel Cross Reference
sys/gdb/gdb_packet.c
