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("$FreeBSD$");
   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, &regsz);
  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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FreeBSD/Linux Kernel Cross Reference sys/gdb/gdb_packet.c

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