1// SPDX-License-Identifier: GPL-2.0+ 2/* 3 * taken from gdb/remote.c 4 * 5 * I am only interested in the write to memory stuff - everything else 6 * has been ripped out 7 * 8 * all the copyright notices etc have been left in 9 */ 10 11/* enough so that it will compile */ 12#include <stdio.h> 13#include <stdlib.h> 14#include <string.h> 15#include <errno.h> 16 17/*nicked from gcc..*/ 18 19#ifndef alloca 20#ifdef __GNUC__ 21#define alloca __builtin_alloca 22#else /* not GNU C. */ 23#if (!defined (__STDC__) && defined (sparc)) || defined (__sparc__) || defined (__sparc) || defined (__sgi) 24#include <alloca.h> 25#else /* not sparc */ 26#if defined (MSDOS) && !defined (__TURBOC__) 27#include <malloc.h> 28#else /* not MSDOS, or __TURBOC__ */ 29#if defined(_AIX) 30#include <malloc.h> 31 #pragma alloca 32#else /* not MSDOS, __TURBOC__, or _AIX */ 33#ifdef __hpux 34#endif /* __hpux */ 35#endif /* not _AIX */ 36#endif /* not MSDOS, or __TURBOC__ */ 37#endif /* not sparc. */ 38#endif /* not GNU C. */ 39#ifdef __cplusplus 40extern "C" { 41#endif 42 void* alloca(size_t); 43#ifdef __cplusplus 44} 45#endif 46#endif /* alloca not defined. */ 47 48 49#include "serial.h" 50#include "error.h" 51#include "remote.h" 52#define REGISTER_BYTES 0 53#define fprintf_unfiltered fprintf 54#define fprintf_filtered fprintf 55#define fputs_unfiltered fputs 56#define fputs_filtered fputs 57#define fputc_unfiltered fputc 58#define fputc_filtered fputc 59#define printf_unfiltered printf 60#define printf_filtered printf 61#define puts_unfiltered puts 62#define puts_filtered puts 63#define putchar_unfiltered putchar 64#define putchar_filtered putchar 65#define fputstr_unfiltered(a,b,c) fputs((a), (c)) 66#define gdb_stdlog stderr 67#define SERIAL_READCHAR(fd,timo) serialreadchar((fd), (timo)) 68#define SERIAL_WRITE(fd, addr, len) serialwrite((fd), (addr), (len)) 69#define error Error 70#define perror_with_name Perror 71#define gdb_flush fflush 72#define max(a,b) (((a)>(b))?(a):(b)) 73#define min(a,b) (((a)<(b))?(a):(b)) 74#define target_mourn_inferior() {} 75#define ULONGEST unsigned long 76#define CORE_ADDR unsigned long 77 78static int putpkt (char *); 79static int putpkt_binary(char *, int); 80static void getpkt (char *, int); 81 82static int remote_debug = 0, remote_register_buf_size = 0, watchdog = 0; 83 84int remote_desc = -1, remote_timeout = 10; 85 86static void 87fputstrn_unfiltered(char *s, int n, int x, FILE *fp) 88{ 89 while (n-- > 0) 90 fputc(*s++, fp); 91} 92 93void 94remote_reset(void) 95{ 96 SERIAL_WRITE(remote_desc, "+", 1); 97} 98 99void 100remote_continue(void) 101{ 102 putpkt("c"); 103} 104 105/* Remote target communications for serial-line targets in custom GDB protocol 106 Copyright 1988, 91, 92, 93, 94, 95, 96, 97, 98, 1999 107 Free Software Foundation, Inc. 108 109 This file is part of GDB. 110 */ 111/* *INDENT-OFF* */ 112/* Remote communication protocol. 113 114 A debug packet whose contents are <data> 115 is encapsulated for transmission in the form: 116 117 $ <data> # CSUM1 CSUM2 118 119 <data> must be ASCII alphanumeric and cannot include characters 120 '$' or '#'. If <data> starts with two characters followed by 121 ':', then the existing stubs interpret this as a sequence number. 122 123 CSUM1 and CSUM2 are ascii hex representation of an 8-bit 124 checksum of <data>, the most significant nibble is sent first. 125 the hex digits 0-9,a-f are used. 126 127 Receiver responds with: 128 129 + - if CSUM is correct and ready for next packet 130 - - if CSUM is incorrect 131 132 <data> is as follows: 133 Most values are encoded in ascii hex digits. Signal numbers are according 134 to the numbering in target.h. 135 136 Request Packet 137 138 set thread Hct... Set thread for subsequent operations. 139 c = 'c' for thread used in step and 140 continue; t... can be -1 for all 141 threads. 142 c = 'g' for thread used in other 143 operations. If zero, pick a thread, 144 any thread. 145 reply OK for success 146 ENN for an error. 147 148 read registers g 149 reply XX....X Each byte of register data 150 is described by two hex digits. 151 Registers are in the internal order 152 for GDB, and the bytes in a register 153 are in the same order the machine uses. 154 or ENN for an error. 155 156 write regs GXX..XX Each byte of register data 157 is described by two hex digits. 158 reply OK for success 159 ENN for an error 160 161 write reg Pn...=r... Write register n... with value r..., 162 which contains two hex digits for each 163 byte in the register (target byte 164 order). 165 reply OK for success 166 ENN for an error 167 (not supported by all stubs). 168 169 read mem mAA..AA,LLLL AA..AA is address, LLLL is length. 170 reply XX..XX XX..XX is mem contents 171 Can be fewer bytes than requested 172 if able to read only part of the data. 173 or ENN NN is errno 174 175 write mem MAA..AA,LLLL:XX..XX 176 AA..AA is address, 177 LLLL is number of bytes, 178 XX..XX is data 179 reply OK for success 180 ENN for an error (this includes the case 181 where only part of the data was 182 written). 183 184 write mem XAA..AA,LLLL:XX..XX 185 (binary) AA..AA is address, 186 LLLL is number of bytes, 187 XX..XX is binary data 188 reply OK for success 189 ENN for an error 190 191 continue cAA..AA AA..AA is address to resume 192 If AA..AA is omitted, 193 resume at same address. 194 195 step sAA..AA AA..AA is address to resume 196 If AA..AA is omitted, 197 resume at same address. 198 199 continue with Csig;AA..AA Continue with signal sig (hex signal 200 signal number). If ;AA..AA is omitted, 201 resume at same address. 202 203 step with Ssig;AA..AA Like 'C' but step not continue. 204 signal 205 206 last signal ? Reply the current reason for stopping. 207 This is the same reply as is generated 208 for step or cont : SAA where AA is the 209 signal number. 210 211 detach D Reply OK. 212 213 There is no immediate reply to step or cont. 214 The reply comes when the machine stops. 215 It is SAA AA is the signal number. 216 217 or... TAAn...:r...;n...:r...;n...:r...; 218 AA = signal number 219 n... = register number (hex) 220 r... = register contents 221 n... = `thread' 222 r... = thread process ID. This is 223 a hex integer. 224 n... = other string not starting 225 with valid hex digit. 226 gdb should ignore this n,r pair 227 and go on to the next. This way 228 we can extend the protocol. 229 or... WAA The process exited, and AA is 230 the exit status. This is only 231 applicable for certains sorts of 232 targets. 233 or... XAA The process terminated with signal 234 AA. 235 or (obsolete) NAA;tttttttt;dddddddd;bbbbbbbb 236 AA = signal number 237 tttttttt = address of symbol "_start" 238 dddddddd = base of data section 239 bbbbbbbb = base of bss section. 240 Note: only used by Cisco Systems 241 targets. The difference between this 242 reply and the "qOffsets" query is that 243 the 'N' packet may arrive spontaneously 244 whereas the 'qOffsets' is a query 245 initiated by the host debugger. 246 or... OXX..XX XX..XX is hex encoding of ASCII data. This 247 can happen at any time while the 248 program is running and the debugger 249 should continue to wait for 250 'W', 'T', etc. 251 252 thread alive TXX Find out if the thread XX is alive. 253 reply OK thread is still alive 254 ENN thread is dead 255 256 remote restart RXX Restart the remote server 257 258 extended ops ! Use the extended remote protocol. 259 Sticky -- only needs to be set once. 260 261 kill request k 262 263 toggle debug d toggle debug flag (see 386 & 68k stubs) 264 reset r reset -- see sparc stub. 265 reserved <other> On other requests, the stub should 266 ignore the request and send an empty 267 response ($#<checksum>). This way 268 we can extend the protocol and GDB 269 can tell whether the stub it is 270 talking to uses the old or the new. 271 search tAA:PP,MM Search backwards starting at address 272 AA for a match with pattern PP and 273 mask MM. PP and MM are 4 bytes. 274 Not supported by all stubs. 275 276 general query qXXXX Request info about XXXX. 277 general set QXXXX=yyyy Set value of XXXX to yyyy. 278 query sect offs qOffsets Get section offsets. Reply is 279 Text=xxx;Data=yyy;Bss=zzz 280 281 Responses can be run-length encoded to save space. A '*' means that 282 the next character is an ASCII encoding giving a repeat count which 283 stands for that many repititions of the character preceding the '*'. 284 The encoding is n+29, yielding a printable character where n >=3 285 (which is where rle starts to win). Don't use an n > 126. 286 287 So 288 "0* " means the same as "0000". */ 289/* *INDENT-ON* */ 290 291/* This variable (available to the user via "set remotebinarydownload") 292 dictates whether downloads are sent in binary (via the 'X' packet). 293 We assume that the stub can, and attempt to do it. This will be cleared if 294 the stub does not understand it. This switch is still needed, though 295 in cases when the packet is supported in the stub, but the connection 296 does not allow it (i.e., 7-bit serial connection only). */ 297static int remote_binary_download = 1; 298 299/* Have we already checked whether binary downloads work? */ 300static int remote_binary_checked; 301 302/* Maximum number of bytes to read/write at once. The value here 303 is chosen to fill up a packet (the headers account for the 32). */ 304#define MAXBUFBYTES(N) (((N)-32)/2) 305 306/* Having this larger than 400 causes us to be incompatible with m68k-stub.c 307 and i386-stub.c. Normally, no one would notice because it only matters 308 for writing large chunks of memory (e.g. in downloads). Also, this needs 309 to be more than 400 if required to hold the registers (see below, where 310 we round it up based on REGISTER_BYTES). */ 311/* Round up PBUFSIZ to hold all the registers, at least. */ 312#define PBUFSIZ ((REGISTER_BYTES > MAXBUFBYTES (400)) \ 313 ? (REGISTER_BYTES * 2 + 32) \ 314 : 400) 315 316 317/* This variable sets the number of bytes to be written to the target 318 in a single packet. Normally PBUFSIZ is satisfactory, but some 319 targets need smaller values (perhaps because the receiving end 320 is slow). */ 321 322static int remote_write_size = 0x7fffffff; 323 324/* This variable sets the number of bits in an address that are to be 325 sent in a memory ("M" or "m") packet. Normally, after stripping 326 leading zeros, the entire address would be sent. This variable 327 restricts the address to REMOTE_ADDRESS_SIZE bits. HISTORY: The 328 initial implementation of remote.c restricted the address sent in 329 memory packets to ``host::sizeof long'' bytes - (typically 32 330 bits). Consequently, for 64 bit targets, the upper 32 bits of an 331 address was never sent. Since fixing this bug may cause a break in 332 some remote targets this variable is principly provided to 333 facilitate backward compatibility. */ 334 335static int remote_address_size; 336 337/* Convert hex digit A to a number. */ 338 339static int 340fromhex (int a) 341{ 342 if (a >= '0' && a <= '9') 343 return a - '0'; 344 else if (a >= 'a' && a <= 'f') 345 return a - 'a' + 10; 346 else if (a >= 'A' && a <= 'F') 347 return a - 'A' + 10; 348 else { 349 error ("Reply contains invalid hex digit %d", a); 350 return -1; 351 } 352} 353 354/* Convert number NIB to a hex digit. */ 355 356static int 357tohex (int nib) 358{ 359 if (nib < 10) 360 return '0' + nib; 361 else 362 return 'a' + nib - 10; 363} 364 365/* Return the number of hex digits in num. */ 366 367static int 368hexnumlen (ULONGEST num) 369{ 370 int i; 371 372 for (i = 0; num != 0; i++) 373 num >>= 4; 374 375 return max (i, 1); 376} 377 378/* Set BUF to the hex digits representing NUM. */ 379 380static int 381hexnumstr (char *buf, ULONGEST num) 382{ 383 int i; 384 int len = hexnumlen (num); 385 386 buf[len] = '\0'; 387 388 for (i = len - 1; i >= 0; i--) 389 { 390 buf[i] = "0123456789abcdef"[(num & 0xf)]; 391 num >>= 4; 392 } 393 394 return len; 395} 396 397/* Mask all but the least significant REMOTE_ADDRESS_SIZE bits. */ 398 399static CORE_ADDR 400remote_address_masked (CORE_ADDR addr) 401{ 402 if (remote_address_size > 0 403 && remote_address_size < (sizeof (ULONGEST) * 8)) 404 { 405 /* Only create a mask when that mask can safely be constructed 406 in a ULONGEST variable. */ 407 ULONGEST mask = 1; 408 mask = (mask << remote_address_size) - 1; 409 addr &= mask; 410 } 411 return addr; 412} 413 414/* Determine whether the remote target supports binary downloading. 415 This is accomplished by sending a no-op memory write of zero length 416 to the target at the specified address. It does not suffice to send 417 the whole packet, since many stubs strip the eighth bit and subsequently 418 compute a wrong checksum, which causes real havoc with remote_write_bytes. 419 420 NOTE: This can still lose if the serial line is not eight-bit clean. In 421 cases like this, the user should clear "remotebinarydownload". */ 422static void 423check_binary_download (CORE_ADDR addr) 424{ 425 if (remote_binary_download && !remote_binary_checked) 426 { 427 char *buf = alloca (PBUFSIZ); 428 char *p; 429 remote_binary_checked = 1; 430 431 p = buf; 432 *p++ = 'X'; 433 p += hexnumstr (p, (ULONGEST) addr); 434 *p++ = ','; 435 p += hexnumstr (p, (ULONGEST) 0); 436 *p++ = ':'; 437 *p = '\0'; 438 439 putpkt_binary (buf, (int) (p - buf)); 440 getpkt (buf, 0); 441 442 if (buf[0] == '\0') 443 remote_binary_download = 0; 444 } 445 446 if (remote_debug) 447 { 448 if (remote_binary_download) 449 fprintf_unfiltered (gdb_stdlog, 450 "binary downloading suppported by target\n"); 451 else 452 fprintf_unfiltered (gdb_stdlog, 453 "binary downloading NOT suppported by target\n"); 454 } 455} 456 457/* Write memory data directly to the remote machine. 458 This does not inform the data cache; the data cache uses this. 459 MEMADDR is the address in the remote memory space. 460 MYADDR is the address of the buffer in our space. 461 LEN is the number of bytes. 462 463 Returns number of bytes transferred, or 0 for error. */ 464 465int 466remote_write_bytes (memaddr, myaddr, len) 467 CORE_ADDR memaddr; 468 char *myaddr; 469 int len; 470{ 471 unsigned char *buf = alloca (PBUFSIZ); 472 int max_buf_size; /* Max size of packet output buffer */ 473 int origlen; 474 extern int verbose; 475 476 /* Verify that the target can support a binary download */ 477 check_binary_download (memaddr); 478 479 /* Chop the transfer down if necessary */ 480 481 max_buf_size = min (remote_write_size, PBUFSIZ); 482 if (remote_register_buf_size != 0) 483 max_buf_size = min (max_buf_size, remote_register_buf_size); 484 485 /* Subtract header overhead from max payload size - $M<memaddr>,<len>:#nn */ 486 max_buf_size -= 2 + hexnumlen (memaddr + len - 1) + 1 + hexnumlen (len) + 4; 487 488 origlen = len; 489 while (len > 0) 490 { 491 unsigned char *p, *plen; 492 int todo; 493 int i; 494 495 /* construct "M"<memaddr>","<len>":" */ 496 /* sprintf (buf, "M%lx,%x:", (unsigned long) memaddr, todo); */ 497 memaddr = remote_address_masked (memaddr); 498 p = buf; 499 if (remote_binary_download) 500 { 501 *p++ = 'X'; 502 todo = min (len, max_buf_size); 503 } 504 else 505 { 506 *p++ = 'M'; 507 todo = min (len, max_buf_size / 2); /* num bytes that will fit */ 508 } 509 510 p += hexnumstr ((char *)p, (ULONGEST) memaddr); 511 *p++ = ','; 512 513 plen = p; /* remember where len field goes */ 514 p += hexnumstr ((char *)p, (ULONGEST) todo); 515 *p++ = ':'; 516 *p = '\0'; 517 518 /* We send target system values byte by byte, in increasing byte 519 addresses, each byte encoded as two hex characters (or one 520 binary character). */ 521 if (remote_binary_download) 522 { 523 int escaped = 0; 524 for (i = 0; 525 (i < todo) && (i + escaped) < (max_buf_size - 2); 526 i++) 527 { 528 switch (myaddr[i] & 0xff) 529 { 530 case '$': 531 case '#': 532 case 0x7d: 533 /* These must be escaped */ 534 escaped++; 535 *p++ = 0x7d; 536 *p++ = (myaddr[i] & 0xff) ^ 0x20; 537 break; 538 default: 539 *p++ = myaddr[i] & 0xff; 540 break; 541 } 542 } 543 544 if (i < todo) 545 { 546 /* Escape chars have filled up the buffer prematurely, 547 and we have actually sent fewer bytes than planned. 548 Fix-up the length field of the packet. */ 549 550 /* FIXME: will fail if new len is a shorter string than 551 old len. */ 552 553 plen += hexnumstr ((char *)plen, (ULONGEST) i); 554 *plen++ = ':'; 555 } 556 } 557 else 558 { 559 for (i = 0; i < todo; i++) 560 { 561 *p++ = tohex ((myaddr[i] >> 4) & 0xf); 562 *p++ = tohex (myaddr[i] & 0xf); 563 } 564 *p = '\0'; 565 } 566 567 putpkt_binary ((char *)buf, (int) (p - buf)); 568 getpkt ((char *)buf, 0); 569 570 if (buf[0] == 'E') 571 { 572 /* There is no correspondance between what the remote protocol uses 573 for errors and errno codes. We would like a cleaner way of 574 representing errors (big enough to include errno codes, bfd_error 575 codes, and others). But for now just return EIO. */ 576 errno = EIO; 577 return 0; 578 } 579 580 /* Increment by i, not by todo, in case escape chars 581 caused us to send fewer bytes than we'd planned. */ 582 myaddr += i; 583 memaddr += i; 584 len -= i; 585 586 if (verbose) 587 putc('.', stderr); 588 } 589 return origlen; 590} 591 592/* Stuff for dealing with the packets which are part of this protocol. 593 See comment at top of file for details. */ 594 595/* Read a single character from the remote end, masking it down to 7 bits. */ 596 597static int 598readchar (int timeout) 599{ 600 int ch; 601 602 ch = SERIAL_READCHAR (remote_desc, timeout); 603 604 switch (ch) 605 { 606 case SERIAL_EOF: 607 error ("Remote connection closed"); 608 case SERIAL_ERROR: 609 perror_with_name ("Remote communication error"); 610 case SERIAL_TIMEOUT: 611 return ch; 612 default: 613 return ch & 0x7f; 614 } 615} 616 617static int 618putpkt (buf) 619 char *buf; 620{ 621 return putpkt_binary (buf, strlen (buf)); 622} 623 624/* Send a packet to the remote machine, with error checking. The data 625 of the packet is in BUF. The string in BUF can be at most PBUFSIZ - 5 626 to account for the $, # and checksum, and for a possible /0 if we are 627 debugging (remote_debug) and want to print the sent packet as a string */ 628 629static int 630putpkt_binary (buf, cnt) 631 char *buf; 632 int cnt; 633{ 634 int i; 635 unsigned char csum = 0; 636 char *buf2 = alloca (PBUFSIZ); 637 char *junkbuf = alloca (PBUFSIZ); 638 639 int ch; 640 int tcount = 0; 641 char *p; 642 643 /* Copy the packet into buffer BUF2, encapsulating it 644 and giving it a checksum. */ 645 646 if (cnt > BUFSIZ - 5) /* Prosanity check */ 647 abort (); 648 649 p = buf2; 650 *p++ = '$'; 651 652 for (i = 0; i < cnt; i++) 653 { 654 csum += buf[i]; 655 *p++ = buf[i]; 656 } 657 *p++ = '#'; 658 *p++ = tohex ((csum >> 4) & 0xf); 659 *p++ = tohex (csum & 0xf); 660 661 /* Send it over and over until we get a positive ack. */ 662 663 while (1) 664 { 665 int started_error_output = 0; 666 667 if (remote_debug) 668 { 669 *p = '\0'; 670 fprintf_unfiltered (gdb_stdlog, "Sending packet: "); 671 fputstrn_unfiltered (buf2, p - buf2, 0, gdb_stdlog); 672 fprintf_unfiltered (gdb_stdlog, "..."); 673 gdb_flush (gdb_stdlog); 674 } 675 if (SERIAL_WRITE (remote_desc, buf2, p - buf2)) 676 perror_with_name ("putpkt: write failed"); 677 678 /* read until either a timeout occurs (-2) or '+' is read */ 679 while (1) 680 { 681 ch = readchar (remote_timeout); 682 683 if (remote_debug) 684 { 685 switch (ch) 686 { 687 case '+': 688 case SERIAL_TIMEOUT: 689 case '$': 690 if (started_error_output) 691 { 692 putchar_unfiltered ('\n'); 693 started_error_output = 0; 694 } 695 } 696 } 697 698 switch (ch) 699 { 700 case '+': 701 if (remote_debug) 702 fprintf_unfiltered (gdb_stdlog, "Ack\n"); 703 return 1; 704 case SERIAL_TIMEOUT: 705 tcount++; 706 if (tcount > 3) 707 return 0; 708 break; /* Retransmit buffer */ 709 case '$': 710 { 711 /* It's probably an old response, and we're out of sync. 712 Just gobble up the packet and ignore it. */ 713 getpkt (junkbuf, 0); 714 continue; /* Now, go look for + */ 715 } 716 default: 717 if (remote_debug) 718 { 719 if (!started_error_output) 720 { 721 started_error_output = 1; 722 fprintf_unfiltered (gdb_stdlog, "putpkt: Junk: "); 723 } 724 fputc_unfiltered (ch & 0177, gdb_stdlog); 725 } 726 continue; 727 } 728 break; /* Here to retransmit */ 729 } 730 731#if 0 732 /* This is wrong. If doing a long backtrace, the user should be 733 able to get out next time we call QUIT, without anything as 734 violent as interrupt_query. If we want to provide a way out of 735 here without getting to the next QUIT, it should be based on 736 hitting ^C twice as in remote_wait. */ 737 if (quit_flag) 738 { 739 quit_flag = 0; 740 interrupt_query (); 741 } 742#endif 743 } 744} 745 746/* Come here after finding the start of the frame. Collect the rest 747 into BUF, verifying the checksum, length, and handling run-length 748 compression. Returns 0 on any error, 1 on success. */ 749 750static int 751read_frame (char *buf) 752{ 753 unsigned char csum; 754 char *bp; 755 int c; 756 757 csum = 0; 758 bp = buf; 759 760 while (1) 761 { 762 c = readchar (remote_timeout); 763 764 switch (c) 765 { 766 case SERIAL_TIMEOUT: 767 if (remote_debug) 768 fputs_filtered ("Timeout in mid-packet, retrying\n", gdb_stdlog); 769 return 0; 770 case '$': 771 if (remote_debug) 772 fputs_filtered ("Saw new packet start in middle of old one\n", 773 gdb_stdlog); 774 return 0; /* Start a new packet, count retries */ 775 case '#': 776 { 777 unsigned char pktcsum; 778 779 *bp = '\000'; 780 781 pktcsum = fromhex (readchar (remote_timeout)) << 4; 782 pktcsum |= fromhex (readchar (remote_timeout)); 783 784 if (csum == pktcsum) 785 { 786 return 1; 787 } 788 789 if (remote_debug) 790 { 791 fprintf_filtered (gdb_stdlog, 792 "Bad checksum, sentsum=0x%x, csum=0x%x, buf=", 793 pktcsum, csum); 794 fputs_filtered (buf, gdb_stdlog); 795 fputs_filtered ("\n", gdb_stdlog); 796 } 797 return 0; 798 } 799 case '*': /* Run length encoding */ 800 csum += c; 801 c = readchar (remote_timeout); 802 csum += c; 803 c = c - ' ' + 3; /* Compute repeat count */ 804 805 if (c > 0 && c < 255 && bp + c - 1 < buf + PBUFSIZ - 1) 806 { 807 memset (bp, *(bp - 1), c); 808 bp += c; 809 continue; 810 } 811 812 *bp = '\0'; 813 printf_filtered ("Repeat count %d too large for buffer: ", c); 814 puts_filtered (buf); 815 puts_filtered ("\n"); 816 return 0; 817 default: 818 if (bp < buf + PBUFSIZ - 1) 819 { 820 *bp++ = c; 821 csum += c; 822 continue; 823 } 824 825 *bp = '\0'; 826 puts_filtered ("Remote packet too long: "); 827 puts_filtered (buf); 828 puts_filtered ("\n"); 829 830 return 0; 831 } 832 } 833} 834 835/* Read a packet from the remote machine, with error checking, and 836 store it in BUF. BUF is expected to be of size PBUFSIZ. If 837 FOREVER, wait forever rather than timing out; this is used while 838 the target is executing user code. */ 839 840static void 841getpkt (buf, forever) 842 char *buf; 843 int forever; 844{ 845 int c; 846 int tries; 847 int timeout; 848 int val; 849 850 strcpy (buf, "timeout"); 851 852 if (forever) 853 { 854 timeout = watchdog > 0 ? watchdog : -1; 855 } 856 857 else 858 timeout = remote_timeout; 859 860#define MAX_TRIES 3 861 862 for (tries = 1; tries <= MAX_TRIES; tries++) 863 { 864 /* This can loop forever if the remote side sends us characters 865 continuously, but if it pauses, we'll get a zero from readchar 866 because of timeout. Then we'll count that as a retry. */ 867 868 /* Note that we will only wait forever prior to the start of a packet. 869 After that, we expect characters to arrive at a brisk pace. They 870 should show up within remote_timeout intervals. */ 871 872 do 873 { 874 c = readchar (timeout); 875 876 if (c == SERIAL_TIMEOUT) 877 { 878 if (forever) /* Watchdog went off. Kill the target. */ 879 { 880 target_mourn_inferior (); 881 error ("Watchdog has expired. Target detached.\n"); 882 } 883 if (remote_debug) 884 fputs_filtered ("Timed out.\n", gdb_stdlog); 885 goto retry; 886 } 887 } 888 while (c != '$'); 889 890 /* We've found the start of a packet, now collect the data. */ 891 892 val = read_frame (buf); 893 894 if (val == 1) 895 { 896 if (remote_debug) 897 { 898 fprintf_unfiltered (gdb_stdlog, "Packet received: "); 899 fputstr_unfiltered (buf, 0, gdb_stdlog); 900 fprintf_unfiltered (gdb_stdlog, "\n"); 901 } 902 SERIAL_WRITE (remote_desc, "+", 1); 903 return; 904 } 905 906 /* Try the whole thing again. */ 907 retry: 908 SERIAL_WRITE (remote_desc, "-", 1); 909 } 910 911 /* We have tried hard enough, and just can't receive the packet. Give up. */ 912 913 printf_unfiltered ("Ignoring packet error, continuing...\n"); 914 SERIAL_WRITE (remote_desc, "+", 1); 915} 916