/* Remote target communications for serial-line targets in custom GDB protocol Copyright 1988, 1991, 1992, 1993, 1994 Free Software Foundation, Inc. This file is part of GDB. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ /* Remote communication protocol. A debug packet whose contents are is encapsulated for transmission in the form: $ # CSUM1 CSUM2 must be ASCII alphanumeric and cannot include characters '$' or '#' CSUM1 and CSUM2 are ascii hex representation of an 8-bit checksum of , the most significant nibble is sent first. the hex digits 0-9,a-f are used. Receiver responds with: + - if CSUM is correct and ready for next packet - - if CSUM is incorrect is as follows: All values are encoded in ascii hex digits. Request Packet read registers g reply XX....X Each byte of register data is described by two hex digits. Registers are in the internal order for GDB, and the bytes in a register are in the same order the machine uses. or ENN for an error. write regs GXX..XX Each byte of register data is described by two hex digits. reply OK for success ENN for an error read mem mAA..AA,LLLL AA..AA is address, LLLL is length. reply XX..XX XX..XX is mem contents Can be fewer bytes than requested if able to read only part of the data. or ENN NN is errno write mem MAA..AA,LLLL:XX..XX AA..AA is address, LLLL is number of bytes, XX..XX is data reply OK for success ENN for an error (this includes the case where only part of the data was written). cont cAA..AA AA..AA is address to resume If AA..AA is omitted, resume at same address. step sAA..AA AA..AA is address to resume If AA..AA is omitted, resume at same address. last signal ? Reply the current reason for stopping. This is the same reply as is generated for step or cont : SAA where AA is the signal number. There is no immediate reply to step or cont. The reply comes when the machine stops. It is SAA AA is the "signal number" or... TAAn...:r...;n:r...;n...:r...; AA = signal number n... = register number r... = register contents or... WAA The process exited, and AA is the exit status. This is only applicable for certains sorts of targets. kill request k toggle debug d toggle debug flag (see 386 & 68k stubs) reset r reset -- see sparc stub. reserved On other requests, the stub should ignore the request and send an empty response ($#). This way we can extend the protocol and GDB can tell whether the stub it is talking to uses the old or the new. <<<<<<< remote.c search tAA:PP,MM Search backwards starting at address ||||||| 1.81 search tAA:PP,MM Search backword starting at address ======= search tAA:PP,MM Search backward starting at address >>>>>>> 1.82 AA for a match with pattern PP and mask MM. PP and MM are 4 bytes. Not supported by all stubs. <<<<<<< remote.c general query qXXXX Request info about XXXX. general set QXXXX=yyyy Set value of XXXX to yyyy. query sect offs qOffsets Get section offsets. Reply is Text=xxx;Data=yyy;Bss=zzz */ ||||||| 1.81 ======= Responses can be run-length encoded to save space. A '*' means that the next two characters are hex digits giving a repeat count which stands for that many repititions of the character preceding the '*'. Note that this means that responses cannot contain '*'. Example: "0*03" means the same as "0000". */ >>>>>>> 1.82 #include "defs.h" #include #include #include "frame.h" #include "inferior.h" #include "bfd.h" #include "symfile.h" #include "target.h" #include "wait.h" #include "terminal.h" #include "gdbcmd.h" #include "objfiles.h" #include "gdb-stabs.h" #include "dcache.h" #if !defined(DONT_USE_REMOTE) #ifdef USG #include #endif #include #include "serial.h" /* Prototypes for local functions */ static int remote_write_bytes PARAMS ((CORE_ADDR memaddr, unsigned char *myaddr, int len)); static int remote_read_bytes PARAMS ((CORE_ADDR memaddr, unsigned char *myaddr, int len)); static void remote_files_info PARAMS ((struct target_ops *ignore)); static int remote_xfer_memory PARAMS ((CORE_ADDR memaddr, char *myaddr, int len, int should_write, struct target_ops *target)); static void remote_prepare_to_store PARAMS ((void)); static void remote_fetch_registers PARAMS ((int regno)); static void remote_resume PARAMS ((int pid, int step, enum target_signal siggnal)); static int remote_start_remote PARAMS ((char *dummy)); static void remote_open PARAMS ((char *name, int from_tty)); static void remote_close PARAMS ((int quitting)); static void remote_store_registers PARAMS ((int regno)); static void getpkt PARAMS ((char *buf, int forever)); static void putpkt PARAMS ((char *buf)); static void remote_send PARAMS ((char *buf)); static int readchar PARAMS ((void)); static int remote_wait PARAMS ((int pid, struct target_waitstatus *status)); static int tohex PARAMS ((int nib)); static int fromhex PARAMS ((int a)); static void remote_detach PARAMS ((char *args, int from_tty)); static void remote_interrupt PARAMS ((int signo)); static void remote_interrupt_twice PARAMS ((int signo)); static void interrupt_query PARAMS ((void)); extern struct target_ops remote_ops; /* Forward decl */ /* This was 5 seconds, which is a long time to sit and wait. Unless this is going though some terminal server or multiplexer or other form of hairy serial connection, I would think 2 seconds would be plenty. */ static int timeout = 2; #if 0 int icache; #endif /* Descriptor for I/O to remote machine. Initialize it to NULL so that remote_open knows that we don't have a file open when the program starts. */ serial_t remote_desc = NULL; /* Having this larger than 400 causes us to be incompatible with m68k-stub.c and i386-stub.c. Normally, no one would notice because it only matters for writing large chunks of memory (e.g. in downloads). Also, this needs to be more than 400 if required to hold the registers (see below, where we round it up based on REGISTER_BYTES). */ #define PBUFSIZ 400 /* Maximum number of bytes to read/write at once. The value here is chosen to fill up a packet (the headers account for the 32). */ #define MAXBUFBYTES ((PBUFSIZ-32)/2) /* Round up PBUFSIZ to hold all the registers, at least. */ #if REGISTER_BYTES > MAXBUFBYTES #undef PBUFSIZ #define PBUFSIZ (REGISTER_BYTES * 2 + 32) #endif /* Clean up connection to a remote debugger. */ /* ARGSUSED */ static void remote_close (quitting) int quitting; { if (remote_desc) SERIAL_CLOSE (remote_desc); remote_desc = NULL; } /* Query the remote side for the text, data and bss offsets. */ static void get_offsets () { unsigned char buf [PBUFSIZ]; int nvals; CORE_ADDR text_addr, data_addr, bss_addr; struct section_offsets *offs; putpkt ("qOffsets"); getpkt (buf, 1); if (buf[0] == 'E') { warning ("Remote failure reply: %s", buf); return; } nvals = sscanf (buf, "Text=%lx;Data=%lx;Bss=%lx", &text_addr, &data_addr, &bss_addr); if (nvals != 3) error ("Malformed response to offset query, %s", buf); if (symfile_objfile == NULL) return; offs = (struct section_offsets *) alloca (sizeof (struct section_offsets) + symfile_objfile->num_sections * sizeof (offs->offsets)); memcpy (offs, symfile_objfile->section_offsets, sizeof (struct section_offsets) + symfile_objfile->num_sections * sizeof (offs->offsets)); ANOFFSET (offs, SECT_OFF_TEXT) = text_addr; ANOFFSET (offs, SECT_OFF_DATA) = data_addr; ANOFFSET (offs, SECT_OFF_BSS) = bss_addr; objfile_relocate (symfile_objfile, offs); } /* Stub for catch_errors. */ static int remote_start_remote (dummy) char *dummy; { immediate_quit = 1; /* Allow user to interrupt it */ /* Ack any packet which the remote side has already sent. */ SERIAL_WRITE (remote_desc, "+", 1); get_offsets (); /* Get text, data & bss offsets */ putpkt ("?"); /* initiate a query from remote machine */ immediate_quit = 0; start_remote (); /* Initialize gdb process mechanisms */ return 1; } /* Open a connection to a remote debugger. NAME is the filename used for communication. */ static DCACHE *remote_dcache; static void remote_open (name, from_tty) char *name; int from_tty; { if (name == 0) error ( "To open a remote debug connection, you need to specify what serial\n\ device is attached to the remote system (e.g. /dev/ttya)."); target_preopen (from_tty); unpush_target (&remote_ops); remote_dcache = dcache_init (remote_read_bytes, remote_write_bytes); remote_desc = SERIAL_OPEN (name); if (!remote_desc) perror_with_name (name); if (baud_rate != -1) { if (SERIAL_SETBAUDRATE (remote_desc, baud_rate)) { SERIAL_CLOSE (remote_desc); perror_with_name (name); } } SERIAL_RAW (remote_desc); /* If there is something sitting in the buffer we might take it as a response to a command, which would be bad. */ SERIAL_FLUSH_INPUT (remote_desc); if (from_tty) { puts_filtered ("Remote debugging using "); puts_filtered (name); puts_filtered ("\n"); } push_target (&remote_ops); /* Switch to using remote target now */ /* Start the remote connection; if error (0), discard this target. In particular, if the user quits, be sure to discard it (we'd be in an inconsistent state otherwise). */ if (!catch_errors (remote_start_remote, (char *)0, "Couldn't establish connection to remote target\n", RETURN_MASK_ALL)) pop_target(); } /* remote_detach() takes a program previously attached to and detaches it. We better not have left any breakpoints in the program or it'll die when it hits one. Close the open connection to the remote debugger. Use this when you want to detach and do something else with your gdb. */ static void remote_detach (args, from_tty) char *args; int from_tty; { if (args) error ("Argument given to \"detach\" when remotely debugging."); pop_target (); if (from_tty) puts_filtered ("Ending remote debugging.\n"); } /* Convert hex digit A to a number. */ static int fromhex (a) int a; { if (a >= '0' && a <= '9') return a - '0'; else if (a >= 'a' && a <= 'f') return a - 'a' + 10; else error ("Reply contains invalid hex digit"); return -1; } /* Convert number NIB to a hex digit. */ static int tohex (nib) int nib; { if (nib < 10) return '0'+nib; else return 'a'+nib-10; } /* Tell the remote machine to resume. */ static void remote_resume (pid, step, siggnal) int pid, step; enum target_signal siggnal; { char buf[PBUFSIZ]; if (siggnal) { char *name; target_terminal_ours_for_output (); printf_filtered ("Can't send signals to a remote system. %s not sent.\n", target_signal_to_name (siggnal)); target_terminal_inferior (); } dcache_flush (remote_dcache); strcpy (buf, step ? "s": "c"); putpkt (buf); } /* Send ^C to target to halt it. Target will respond, and send us a packet. */ static void remote_interrupt (signo) int signo; { /* If this doesn't work, try more severe steps. */ signal (signo, remote_interrupt_twice); if (remote_debug) printf_unfiltered ("remote_interrupt called\n"); SERIAL_WRITE (remote_desc, "\003", 1); /* Send a ^C */ } static void (*ofunc)(); /* The user typed ^C twice. */ static void remote_interrupt_twice (signo) int signo; { signal (signo, ofunc); interrupt_query (); signal (signo, remote_interrupt); } /* Ask the user what to do when an interrupt is received. */ static void interrupt_query () { target_terminal_ours (); if (query ("Interrupted while waiting for the program.\n\ Give up (and stop debugging it)? ")) { target_mourn_inferior (); return_to_top_level (RETURN_QUIT); } target_terminal_inferior (); } /* Wait until the remote machine stops, then return, storing status in STATUS just as `wait' would. Returns "pid" (though it's not clear what, if anything, that means in the case of this target). */ static int remote_wait (pid, status) int pid; struct target_waitstatus *status; { unsigned char buf[PBUFSIZ]; status->kind = TARGET_WAITKIND_EXITED; status->value.integer = 0; while (1) { unsigned char *p; ofunc = (void (*)()) signal (SIGINT, remote_interrupt); getpkt ((char *) buf, 1); signal (SIGINT, ofunc); if (buf[0] == 'E') warning ("Remote failure reply: %s", buf); else if (buf[0] == 'T') { int i; long regno; char regs[MAX_REGISTER_RAW_SIZE]; /* Expedited reply, containing Signal, {regno, reg} repeat */ /* format is: 'Tssn...:r...;n...:r...;n...:r...;#cc', where ss = signal number n... = register number r... = register contents */ p = &buf[3]; /* after Txx */ while (*p) { unsigned char *p1; regno = strtol (p, &p1, 16); /* Read the register number */ if (p1 == p) warning ("Remote sent badly formed register number: %s\nPacket: '%s'\n", p1, buf); p = p1; if (*p++ != ':') warning ("Malformed packet (missing colon): %s\nPacket: '%s'\n", p, buf); if (regno >= NUM_REGS) warning ("Remote sent bad register number %d: %s\nPacket: '%s'\n", regno, p, buf); for (i = 0; i < REGISTER_RAW_SIZE (regno); i++) { if (p[0] == 0 || p[1] == 0) warning ("Remote reply is too short: %s", buf); regs[i] = fromhex (p[0]) * 16 + fromhex (p[1]); p += 2; } if (*p++ != ';') warning ("Remote register badly formatted: %s", buf); supply_register (regno, regs); } break; } else if (buf[0] == 'W') { /* The remote process exited. */ status->kind = TARGET_WAITKIND_EXITED; status->value.integer = (fromhex (buf[1]) << 4) + fromhex (buf[2]); return 0; } else if (buf[0] == 'S') break; else warning ("Invalid remote reply: %s", buf); } status->kind = TARGET_WAITKIND_STOPPED; status->value.sig = (enum target_signal) (((fromhex (buf[1])) << 4) + (fromhex (buf[2]))); return 0; } /* Number of bytes of registers this stub implements. */ static int register_bytes_found; /* Read the remote registers into the block REGS. */ /* Currently we just read all the registers, so we don't use regno. */ /* ARGSUSED */ static void remote_fetch_registers (regno) int regno; { char buf[PBUFSIZ]; int i; char *p; char regs[REGISTER_BYTES]; sprintf (buf, "g"); remote_send (buf); /* Unimplemented registers read as all bits zero. */ memset (regs, 0, REGISTER_BYTES); /* We can get out of synch in various cases. If the first character in the buffer is not a hex character, assume that has happened and try to fetch another packet to read. */ while ((buf[0] < '0' || buf[0] > '9') && (buf[0] < 'a' || buf[0] > 'f')) { if (remote_debug) printf_unfiltered ("Bad register packet; fetching a new packet\n"); getpkt (buf, 0); } /* Reply describes registers byte by byte, each byte encoded as two hex characters. Suck them all up, then supply them to the register cacheing/storage mechanism. */ p = buf; for (i = 0; i < REGISTER_BYTES; i++) { if (p[0] == 0) break; if (p[1] == 0) { warning ("Remote reply is of odd length: %s", buf); /* Don't change register_bytes_found in this case, and don't print a second warning. */ goto supply_them; } regs[i] = fromhex (p[0]) * 16 + fromhex (p[1]); p += 2; } if (i != register_bytes_found) { register_bytes_found = i; #ifdef REGISTER_BYTES_OK if (!REGISTER_BYTES_OK (i)) warning ("Remote reply is too short: %s", buf); #endif } supply_them: for (i = 0; i < NUM_REGS; i++) supply_register (i, ®s[REGISTER_BYTE(i)]); } /* Prepare to store registers. Since we send them all, we have to read out the ones we don't want to change first. */ static void remote_prepare_to_store () { /* Make sure the entire registers array is valid. */ read_register_bytes (0, (char *)NULL, REGISTER_BYTES); } /* Store the remote registers from the contents of the block REGISTERS. FIXME, eventually just store one register if that's all that is needed. */ /* ARGSUSED */ static void remote_store_registers (regno) int regno; { char buf[PBUFSIZ]; int i; char *p; buf[0] = 'G'; /* Command describes registers byte by byte, each byte encoded as two hex characters. */ p = buf + 1; /* remote_prepare_to_store insures that register_bytes_found gets set. */ for (i = 0; i < register_bytes_found; i++) { *p++ = tohex ((registers[i] >> 4) & 0xf); *p++ = tohex (registers[i] & 0xf); } *p = '\0'; remote_send (buf); } #if 0 /* Use of the data cache is disabled because it loses for looking at and changing hardware I/O ports and the like. Accepting `volatile' would perhaps be one way to fix it, but a better way which would win for more cases would be to use the executable file for the text segment, like the `icache' code below but done cleanly (in some target-independent place, perhaps in target_xfer_memory, perhaps based on assigning each target a speed or perhaps by some simpler mechanism). */ /* Read a word from remote address ADDR and return it. This goes through the data cache. */ static int remote_fetch_word (addr) CORE_ADDR addr; { #if 0 if (icache) { extern CORE_ADDR text_start, text_end; if (addr >= text_start && addr < text_end) { int buffer; xfer_core_file (addr, &buffer, sizeof (int)); return buffer; } } #endif return dcache_fetch (remote_dcache, addr); } /* Write a word WORD into remote address ADDR. This goes through the data cache. */ static void remote_store_word (addr, word) CORE_ADDR addr; int word; { dcache_poke (remote_dcache, addr, word); } #endif /* 0 */ /* Write memory data directly to the remote machine. This does not inform the data cache; the data cache uses this. MEMADDR is the address in the remote memory space. MYADDR is the address of the buffer in our space. LEN is the number of bytes. Returns number of bytes transferred, or 0 for error. */ static int remote_write_bytes (memaddr, myaddr, len) CORE_ADDR memaddr; unsigned char *myaddr; int len; { char buf[PBUFSIZ]; int i; char *p; sprintf (buf, "M%x,%x:", memaddr, len); /* We send target system values byte by byte, in increasing byte addresses, each byte encoded as two hex characters. */ p = buf + strlen (buf); for (i = 0; i < len; i++) { *p++ = tohex ((myaddr[i] >> 4) & 0xf); *p++ = tohex (myaddr[i] & 0xf); } *p = '\0'; putpkt (buf); getpkt (buf, 0); if (buf[0] == 'E') { /* There is no correspondance between what the remote protocol uses for errors and errno codes. We would like a cleaner way of representing errors (big enough to include errno codes, bfd_error codes, and others). But for now just return EIO. */ errno = EIO; return 0; } return len; } /* Read memory data directly from the remote machine. This does not use the data cache; the data cache uses this. MEMADDR is the address in the remote memory space. MYADDR is the address of the buffer in our space. LEN is the number of bytes. Returns number of bytes transferred, or 0 for error. */ static int remote_read_bytes (memaddr, myaddr, len) CORE_ADDR memaddr; unsigned char *myaddr; int len; { char buf[PBUFSIZ]; int i; char *p; if (len > PBUFSIZ / 2 - 1) abort (); sprintf (buf, "m%x,%x", memaddr, len); putpkt (buf); getpkt (buf, 0); if (buf[0] == 'E') { /* There is no correspondance between what the remote protocol uses for errors and errno codes. We would like a cleaner way of representing errors (big enough to include errno codes, bfd_error codes, and others). But for now just return EIO. */ errno = EIO; return 0; } /* Reply describes memory byte by byte, each byte encoded as two hex characters. */ p = buf; for (i = 0; i < len; i++) { if (p[0] == 0 || p[1] == 0) /* Reply is short. This means that we were able to read only part of what we wanted to. */ break; myaddr[i] = fromhex (p[0]) * 16 + fromhex (p[1]); p += 2; } return i; } /* Read or write LEN bytes from inferior memory at MEMADDR, transferring to or from debugger address MYADDR. Write to inferior if SHOULD_WRITE is nonzero. Returns length of data written or read; 0 for error. */ /* ARGSUSED */ static int remote_xfer_memory(memaddr, myaddr, len, should_write, target) CORE_ADDR memaddr; char *myaddr; int len; int should_write; struct target_ops *target; /* ignored */ { int xfersize; int bytes_xferred; int total_xferred = 0; while (len > 0) { if (len > MAXBUFBYTES) xfersize = MAXBUFBYTES; else xfersize = len; if (should_write) bytes_xferred = remote_write_bytes (memaddr, (unsigned char *)myaddr, xfersize); else bytes_xferred = remote_read_bytes (memaddr, (unsigned char *)myaddr, xfersize); /* If we get an error, we are done xferring. */ if (bytes_xferred == 0) break; memaddr += bytes_xferred; myaddr += bytes_xferred; len -= bytes_xferred; total_xferred += bytes_xferred; } return total_xferred; } #if 0 /* Enable after 4.12. */ void remote_search (len, data, mask, startaddr, increment, lorange, hirange addr_found, data_found) int len; char *data; char *mask; CORE_ADDR startaddr; int increment; CORE_ADDR lorange; CORE_ADDR hirange; CORE_ADDR *addr_found; char *data_found; { if (increment == -4 && len == 4) { long mask_long, data_long; long data_found_long; CORE_ADDR addr_we_found; char buf[PBUFSIZ]; long returned_long[2]; char *p; mask_long = extract_unsigned_integer (mask, len); data_long = extract_unsigned_integer (data, len); sprintf (buf, "t%x:%x,%x", startaddr, data_long, mask_long); putpkt (buf); getpkt (buf, 0); if (buf[0] == '\0') { /* The stub doesn't support the 't' request. We might want to remember this fact, but on the other hand the stub could be switched on us. Maybe we should remember it only until the next "target remote". */ generic_search (len, data, mask, startaddr, increment, lorange, hirange, addr_found, data_found); return; } if (buf[0] == 'E') /* There is no correspondance between what the remote protocol uses for errors and errno codes. We would like a cleaner way of representing errors (big enough to include errno codes, bfd_error codes, and others). But for now just use EIO. */ memory_error (EIO, startaddr); p = buf; addr_we_found = 0; while (*p != '\0' && *p != ',') addr_we_found = (addr_we_found << 4) + fromhex (*p++); if (*p == '\0') error ("Protocol error: short return for search"); data_found_long = 0; while (*p != '\0' && *p != ',') data_found_long = (data_found_long << 4) + fromhex (*p++); /* Ignore anything after this comma, for future extensions. */ if (addr_we_found < lorange || addr_we_found >= hirange) { *addr_found = 0; return; } *addr_found = addr_we_found; *data_found = store_unsigned_integer (data_we_found, len); return; } generic_search (len, data, mask, startaddr, increment, lorange, hirange, addr_found, data_found); } #endif /* 0 */ static void remote_files_info (ignore) struct target_ops *ignore; { puts_filtered ("Debugging a target over a serial line.\n"); } /* Stuff for dealing with the packets which are part of this protocol. See comment at top of file for details. */ /* Read a single character from the remote end, masking it down to 7 bits. */ static int readchar () { int ch; ch = SERIAL_READCHAR (remote_desc, timeout); if (ch < 0) return ch; return ch & 0x7f; } /* Send the command in BUF to the remote machine, and read the reply into BUF. Report an error if we get an error reply. */ static void remote_send (buf) char *buf; { putpkt (buf); getpkt (buf, 0); if (buf[0] == 'E') error ("Remote failure reply: %s", buf); } /* Send a packet to the remote machine, with error checking. The data of the packet is in BUF. */ static void putpkt (buf) char *buf; { int i; unsigned char csum = 0; char buf2[PBUFSIZ]; int cnt = strlen (buf); int ch; char *p; /* Copy the packet into buffer BUF2, encapsulating it and giving it a checksum. */ if (cnt > sizeof(buf2) - 5) /* Prosanity check */ abort(); p = buf2; *p++ = '$'; for (i = 0; i < cnt; i++) { csum += buf[i]; *p++ = buf[i]; } *p++ = '#'; *p++ = tohex ((csum >> 4) & 0xf); *p++ = tohex (csum & 0xf); /* Send it over and over until we get a positive ack. */ while (1) { if (remote_debug) { *p = '\0'; printf_unfiltered ("Sending packet: %s...", buf2); gdb_flush(gdb_stdout); } if (SERIAL_WRITE (remote_desc, buf2, p - buf2)) perror_with_name ("putpkt: write failed"); /* read until either a timeout occurs (-2) or '+' is read */ while (1) { ch = readchar (); switch (ch) { case '+': if (remote_debug) printf_unfiltered("Ack\n"); return; case SERIAL_TIMEOUT: break; /* Retransmit buffer */ case SERIAL_ERROR: perror_with_name ("putpkt: couldn't read ACK"); case SERIAL_EOF: error ("putpkt: EOF while trying to read ACK"); default: if (remote_debug) printf_unfiltered ("%02X %c ", ch&0xFF, ch); continue; } break; /* Here to retransmit */ } #if 0 /* This is wrong. If doing a long backtrace, the user should be able to get out next time we call QUIT, without anything as violent as interrupt_query. If we want to provide a way out of here without getting to the next QUIT, it should be based on hitting ^C twice as in remote_wait. */ if (quit_flag) { quit_flag = 0; interrupt_query (); } #endif } } /* Read a packet from the remote machine, with error checking, and store it in BUF. BUF is expected to be of size PBUFSIZ. If FOREVER, wait forever rather than timing out; this is used while the target is executing user code. */ static void getpkt (retbuf, forever) char *retbuf; int forever; { char *bp; unsigned char csum; int c = 0; unsigned char c1, c2; int retries = 0; char buf[PBUFSIZ]; #define MAX_RETRIES 10 while (1) { #if 0 /* This is wrong. If doing a long backtrace, the user should be able to get out time next we call QUIT, without anything as violent as interrupt_query. If we want to provide a way out of here without getting to the next QUIT, it should be based on hitting ^C twice as in remote_wait. */ if (quit_flag) { quit_flag = 0; interrupt_query (); } #endif /* This can loop forever if the remote side sends us characters continuously, but if it pauses, we'll get a zero from readchar because of timeout. Then we'll count that as a retry. */ c = readchar(); if (c > 0 && c != '$') continue; if (c == SERIAL_TIMEOUT) { if (forever) continue; if (++retries >= MAX_RETRIES) if (remote_debug) puts_filtered ("Timed out.\n"); goto out; } if (c == SERIAL_EOF) error ("Remote connection closed"); if (c == SERIAL_ERROR) perror_with_name ("Remote communication error"); /* Force csum to be zero here because of possible error retry. */ csum = 0; bp = buf; while (1) { c = readchar (); if (c == SERIAL_TIMEOUT) { if (remote_debug) puts_filtered ("Timeout in mid-packet, retrying\n"); goto whole; /* Start a new packet, count retries */ } if (c == '$') { if (remote_debug) puts_filtered ("Saw new packet start in middle of old one\n"); goto whole; /* Start a new packet, count retries */ } if (c == '#') break; if (bp >= buf+PBUFSIZ-1) { *bp = '\0'; puts_filtered ("Remote packet too long: "); puts_filtered (buf); puts_filtered ("\n"); goto whole; } *bp++ = c; csum += c; } *bp = 0; c1 = fromhex (readchar ()); c2 = fromhex (readchar ()); if ((csum & 0xff) == (c1 << 4) + c2) break; printf_filtered ("Bad checksum, sentsum=0x%x, csum=0x%x, buf=", (c1 << 4) + c2, csum & 0xff); puts_filtered (buf); puts_filtered ("\n"); /* Try the whole thing again. */ whole: if (++retries < MAX_RETRIES) { SERIAL_WRITE (remote_desc, "-", 1); } else { printf_unfiltered ("Ignoring packet error, continuing...\n"); break; } } /* Deal with run-length encoding. */ { char *src = buf; char *dest = retbuf; int i; int repeat; do { if (*src == '*') { if (src[1] == '\0' || src[2] == '\0') { if (remote_debug) puts_filtered ("Packet too short, retrying\n"); goto whole; } repeat = (fromhex (src[1]) << 4) + fromhex (src[2]); for (i = 0; i < repeat; ++i) { *dest++ = src[-1]; } src += 2; } else { *dest++ = *src; } } while (*src++ != '\0'); } out: SERIAL_WRITE (remote_desc, "+", 1); if (remote_debug) fprintf_unfiltered (gdb_stderr,"Packet received: %s\n", buf); } static void remote_kill () { putpkt ("k"); /* Don't wait for it to die. I'm not really sure it matters whether we do or not. For the existing stubs, kill is a noop. */ target_mourn_inferior (); } static void remote_mourn () { unpush_target (&remote_ops); generic_mourn_inferior (); } #ifdef REMOTE_BREAKPOINT /* On some machines, e.g. 68k, we may use a different breakpoint instruction than other targets. */ static unsigned char break_insn[] = REMOTE_BREAKPOINT; /* Check that it fits in BREAKPOINT_MAX bytes. */ static unsigned char check_break_insn_size[BREAKPOINT_MAX] = REMOTE_BREAKPOINT; #else /* No REMOTE_BREAKPOINT. */ /* Same old breakpoint instruction. This code does nothing different than mem-break.c. */ static unsigned char break_insn[] = BREAKPOINT; #endif /* No REMOTE_BREAKPOINT. */ /* Insert a breakpoint on targets that don't have any better breakpoint support. We read the contents of the target location and stash it, then overwrite it with a breakpoint instruction. ADDR is the target location in the target machine. CONTENTS_CACHE is a pointer to memory allocated for saving the target contents. It is guaranteed by the caller to be long enough to save sizeof BREAKPOINT bytes (this is accomplished via BREAKPOINT_MAX). */ static int remote_insert_breakpoint (addr, contents_cache) CORE_ADDR addr; char *contents_cache; { int val; val = target_read_memory (addr, contents_cache, sizeof break_insn); if (val == 0) val = target_write_memory (addr, (char *)break_insn, sizeof break_insn); return val; } static int remote_remove_breakpoint (addr, contents_cache) CORE_ADDR addr; char *contents_cache; { return target_write_memory (addr, contents_cache, sizeof break_insn); } /* Define the target subroutine names */ struct target_ops remote_ops = { "remote", /* to_shortname */ "Remote serial target in gdb-specific protocol", /* to_longname */ "Use a remote computer via a serial line, using a gdb-specific protocol.\n\ Specify the serial device it is connected to (e.g. /dev/ttya).", /* to_doc */ remote_open, /* to_open */ remote_close, /* to_close */ NULL, /* to_attach */ remote_detach, /* to_detach */ remote_resume, /* to_resume */ remote_wait, /* to_wait */ remote_fetch_registers, /* to_fetch_registers */ remote_store_registers, /* to_store_registers */ remote_prepare_to_store, /* to_prepare_to_store */ remote_xfer_memory, /* to_xfer_memory */ remote_files_info, /* to_files_info */ remote_insert_breakpoint, /* to_insert_breakpoint */ remote_remove_breakpoint, /* to_remove_breakpoint */ NULL, /* to_terminal_init */ NULL, /* to_terminal_inferior */ NULL, /* to_terminal_ours_for_output */ NULL, /* to_terminal_ours */ NULL, /* to_terminal_info */ remote_kill, /* to_kill */ generic_load, /* to_load */ NULL, /* to_lookup_symbol */ NULL, /* to_create_inferior */ remote_mourn, /* to_mourn_inferior */ 0, /* to_can_run */ 0, /* to_notice_signals */ process_stratum, /* to_stratum */ NULL, /* to_next */ 1, /* to_has_all_memory */ 1, /* to_has_memory */ 1, /* to_has_stack */ 1, /* to_has_registers */ 1, /* to_has_execution */ NULL, /* sections */ NULL, /* sections_end */ OPS_MAGIC /* to_magic */ }; #endif /* Use remote. */ void _initialize_remote () { #if !defined(DONT_USE_REMOTE) add_target (&remote_ops); #endif }