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C/C++ Source or Header | 1995-02-02 | 40.7 KB | 1,601 lines

/* 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 <data> is encapsulated for transmission in the form: $ <data> # CSUM1 CSUM2 <data> must be ASCII alphanumeric and cannot include characters '$' or '#'. If <data> starts with two characters followed by ':', then the existing stubs interpret this as a sequence number. CSUM1 and CSUM2 are ascii hex representation of an 8-bit checksum of <data>, 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 <data> is as follows: Most values are encoded in ascii hex digits. Signal numbers are according to the numbering in target.h. Request Packet set thread Hct... Set thread for subsequent operations. c = 'c' for thread used in step and continue; t... can be -1 for all threads. c = 'g' for thread used in other operations. If zero, pick a thread, any thread. reply OK for success ENN for an error. 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 write reg Pn...=r... Write register n... with value r..., which contains two hex digits for each byte in the register (target byte order). reply OK for success ENN for an error (not supported by all stubs). 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). continue 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. continue with Csig;AA Continue with signal sig (hex signal signal number). step with Ssig;AA Like 'C' but step not continue. signal 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 (hex) r... = register contents n... = `thread' r... = thread process ID. This is a hex integer. n... = other string not starting with valid hex digit. gdb should ignore this n,r pair and go on to the next. This way we can extend the protocol. or... WAA The process exited, and AA is the exit status. This is only applicable for certains sorts of targets. or... XAA The process terminated with signal AA. or... Otext Send text to stdout. This can happen at any time while the program is running and the debugger should continue to wait for 'W', 'T', etc. kill request k toggle debug d toggle debug flag (see 386 & 68k stubs) reset r reset -- see sparc stub. reserved <other> On other requests, the stub should ignore the request and send an empty response ($#<checksum>). This way we can extend the protocol and GDB can tell whether the stub it is talking to uses the old or the new. search tAA:PP,MM Search backwards starting at address AA for a match with pattern PP and mask MM. PP and MM are 4 bytes. Not supported by all stubs. 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 Responses can be run-length encoded to save space. A '*' means that the next character is an ASCII encoding giving a repeat count which stands for that many repititions of the character preceding the '*'. The encoding is n+29, yielding a printable character where n >=3 (which is where rle starts to win). Don't use an n > 126. So "0* " means the same as "0000". */ #include "defs.h" #include <string.h> #include <fcntl.h> #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 "thread.h" #include "dcache.h" #ifdef USG #include <sys/types.h> #endif #include <signal.h> #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 int putpkt PARAMS ((char *buf)); static void remote_send PARAMS ((char *buf)); static int readchar PARAMS ((int timeout)); 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 remote_timeout = 2; /* 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. */ /* The blank line after the #if seems to be required to work around a bug in HP's PA compiler. */ #if REGISTER_BYTES > MAXBUFBYTES #undef PBUFSIZ #define PBUFSIZ (REGISTER_BYTES * 2 + 32) #endif /* Should we try the 'P' request? If this is set to one when the stub doesn't support 'P', the only consequence is some unnecessary traffic. */ static int stub_supports_P = 1; /* These are the threads which we last sent to the remote system. -1 for all or -2 for not sent yet. */ int general_thread; int cont_thread; static void set_thread (th, gen) int th; int gen; { char buf[PBUFSIZ]; int state = gen ? general_thread : cont_thread; if (state == th) return; buf[0] = 'H'; buf[1] = gen ? 'g' : 'c'; if (th == 42000) { buf[2] = '0'; buf[3] = '\0'; } else if (th < 0) sprintf (&buf[2], "-%x", -th); else sprintf (&buf[2], "%x", th); putpkt (buf); getpkt (buf, 0); if (gen) general_thread = th; else cont_thread = th; } /* 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 () { char buf[PBUFSIZ]; int nvals; CORE_ADDR text_addr, data_addr, bss_addr; struct section_offsets *offs; putpkt ("qOffsets"); getpkt (buf, 0); if (buf[0] == '\000') return; /* Return silently. Stub doesn't support this command. */ 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)); /* FIXME: This code assumes gdb-stabs.h is being used; it's broken for xcoff, dwarf, sdb-coff, etc. But there is no simple canonical representation for this stuff. (Just what does "text" as seen by the stub mean, anyway? I think it means all sections with SEC_CODE set, but we currently have no way to deal with that). */ ANOFFSET (offs, SECT_OFF_TEXT) = text_addr; /* This is a temporary kludge to force data and bss to use the same offsets because that's what nlmconv does now. The real solution requires changes to the stub and remote.c that I don't have time to do right now. */ ANOFFSET (offs, SECT_OFF_DATA) = data_addr; ANOFFSET (offs, SECT_OFF_BSS) = data_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); /* Let the stub know that we want it to return the thread. */ set_thread (-1, 0); 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 out by trying the 'P' request to set registers. We set this each time that we open a new target so that if the user switches from one stub to another, we can (if the target is closed and reopened) cope. */ stub_supports_P = 1; general_thread = -2; cont_thread = -2; /* Without this, some commands which require an active target (such as kill) won't work. This variable serves (at least) double duty as both the pid of the target process (if it has such), and as a flag indicating that a target is active. These functions should be split out into seperate variables, especially since GDB will someday have a notion of debugging several processes. */ inferior_pid = 42000; /* 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 %d", a); } /* 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 enum target_signal last_sent_signal = TARGET_SIGNAL_0; int last_sent_step; static void remote_resume (pid, step, siggnal) int pid, step; enum target_signal siggnal; { char buf[PBUFSIZ]; if (pid == -1) set_thread (inferior_pid, 0); else set_thread (pid, 0); dcache_flush (remote_dcache); last_sent_signal = siggnal; last_sent_step = step; if (siggnal != TARGET_SIGNAL_0) { buf[0] = step ? 'S' : 'C'; buf[1] = tohex (((int)siggnal >> 4) & 0xf); buf[2] = tohex ((int)siggnal & 0xf); buf[3] = '\0'; } else 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 (); } /* If nonzero, ignore the next kill. */ int kill_kludge; /* 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]; int thread_num = -1; 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); switch (buf[0]) { case 'E': /* Error of some sort */ warning ("Remote failure reply: %s", buf); continue; case 'T': /* Status with PC, SP, FP, ... */ { 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) { p1 = (unsigned char *) strchr (p, ':'); if (p1 == NULL) warning ("Malformed packet (missing colon): %s\n\ Packet: '%s'\n", p, buf); if (strncmp (p, "thread", p1 - p) == 0) { thread_num = strtol (++p1, &p, 16); } } else { p = p1; if (*p++ != ':') warning ("Malformed packet (missing colon): %s\n\ Packet: '%s'\n", p, buf); if (regno >= NUM_REGS) warning ("Remote sent bad register number %d: %s\n\ Packet: '%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; } supply_register (regno, regs); } if (*p++ != ';') warning ("Remote register badly formatted: %s", buf); } } /* fall through */ case 'S': /* Old style status, just signal only */ status->kind = TARGET_WAITKIND_STOPPED; status->value.sig = (enum target_signal) (((fromhex (buf[1])) << 4) + (fromhex (buf[2]))); goto got_status; case 'W': /* Target exited */ { /* The remote process exited. */ status->kind = TARGET_WAITKIND_EXITED; status->value.integer = (fromhex (buf[1]) << 4) + fromhex (buf[2]); goto got_status; } case 'X': status->kind = TARGET_WAITKIND_SIGNALLED; status->value.sig = (enum target_signal) (((fromhex (buf[1])) << 4) + (fromhex (buf[2]))); kill_kludge = 1; goto got_status; case 'O': /* Console output */ fputs_filtered ((char *)(buf + 1), gdb_stdout); continue; case '\0': if (last_sent_signal != TARGET_SIGNAL_0) { /* Zero length reply means that we tried 'S' or 'C' and the remote system doesn't support it. */ target_terminal_ours_for_output (); printf_filtered ("Can't send signals to this remote system. %s not sent.\n", target_signal_to_name (last_sent_signal)); last_sent_signal = TARGET_SIGNAL_0; target_terminal_inferior (); strcpy (buf, last_sent_step ? "s" : "c"); putpkt (buf); continue; } /* else fallthrough */ default: warning ("Invalid remote reply: %s", buf); continue; } } got_status: if (thread_num != -1) { /* Initial thread value can only be acquired via wait, so deal with this marker which is used before the first thread value is acquired. */ if (inferior_pid == 42000) { inferior_pid = thread_num; add_thread (inferior_pid); } return thread_num; } return inferior_pid; } /* 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]; set_thread (inferior_pid, 1); 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 may send them all (using a 'G' request), 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 register REGNO, or all registers if REGNO == -1, from the contents of REGISTERS. FIXME: ignores errors. */ static void remote_store_registers (regno) int regno; { char buf[PBUFSIZ]; int i; char *p; set_thread (inferior_pid, 1); if (regno >= 0 && stub_supports_P) { /* Try storing a single register. */ char *regp; sprintf (buf, "P%x=", regno); p = buf + strlen (buf); regp = ®isters[REGISTER_BYTE (regno)]; for (i = 0; i < REGISTER_RAW_SIZE (regno); ++i) { *p++ = tohex ((regp[i] >> 4) & 0xf); *p++ = tohex (regp[i] & 0xf); } *p = '\0'; remote_send (buf); if (buf[0] != '\0') { /* The stub understands the 'P' request. We are done. */ return; } /* The stub does not support the 'P' request. Use 'G' instead, and don't try using 'P' in the future (it will just waste our time). */ stub_supports_P = 0; } 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. Another idea would be to use the executable file for the text segment (for all SEC_CODE sections? For all SEC_READONLY sections?). This has problems if you want to actually see what the memory contains (e.g. self-modifying code, clobbered memory, user downloaded the wrong thing). */ /* 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; { 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; /* FIXME-32x64: Need a version of print_address_numeric which puts the result in a buffer like sprintf. */ sprintf (buf, "M%lx,%x:", (unsigned long) 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 (); /* FIXME-32x64: Need a version of print_address_numeric which puts the result in a buffer like sprintf. */ sprintf (buf, "m%lx,%x", (unsigned long) 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; set_thread (inferior_pid, 1); 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 (timeout) int timeout; { int ch; ch = SERIAL_READCHAR (remote_desc, timeout); switch (ch) { case SERIAL_EOF: error ("Remote connection closed"); case SERIAL_ERROR: perror_with_name ("Remote communication error"); case SERIAL_TIMEOUT: return ch; default: 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 int 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++ = '$'; for (i = 0; i < cnt; i++) { csum += buf[i]; *p++ = buf[i]; } *p++ = '#'; *p++ = tohex ((csum >> 4) & 0xf); *p++ = tohex (csum & 0xf); /* Send it over and over until we get a positive ack. */ while (1) { int started_error_output = 0; if (remote_debug) { *p = '\0'; printf_unfiltered ("Sending packet: %s...", buf2); gdb_flush(gdb_stdout); } if (SERIAL_WRITE (remote_desc, buf2, p - buf2)) perror_with_name ("putpkt: write failed"); /* read until either a timeout occurs (-2) or '+' is read */ while (1) { ch = readchar (remote_timeout); if (remote_debug) { switch (ch) { case '+': case SERIAL_TIMEOUT: case '$': if (started_error_output) { putc_unfiltered ('\n'); started_error_output = 0; } } } switch (ch) { case '+': if (remote_debug) printf_unfiltered("Ack\n"); return 1; case SERIAL_TIMEOUT: break; /* Retransmit buffer */ case '$': { char junkbuf[PBUFSIZ]; /* It's probably an old response, and we're out of sync. Just gobble up the packet and ignore it. */ getpkt (junkbuf, 0); continue; /* Now, go look for + */ } default: if (remote_debug) { if (!started_error_output) { started_error_output = 1; printf_unfiltered ("putpkt: Junk: "); } putc_unfiltered (ch & 0177); } continue; } break; /* Here to retransmit */ } #if 0 /* This is wrong. If doing a long backtrace, the user should be able to get out next time we call QUIT, without anything as violent as interrupt_query. If we want to provide a way out of here without getting to the next QUIT, it should be based on hitting ^C twice as in remote_wait. */ if (quit_flag) { quit_flag = 0; interrupt_query (); } #endif } } /* Come here after finding the start of the frame. Collect the rest into BUF, verifying the checksum, length, and handling run-length compression. Returns 0 on any error, 1 on success. */ static int read_frame (buf) char *buf; { unsigned char csum; char *bp; int c; csum = 0; bp = buf; while (1) { c = readchar (remote_timeout); switch (c) { case SERIAL_TIMEOUT: if (remote_debug) puts_filtered ("Timeout in mid-packet, retrying\n"); return 0; case '$': if (remote_debug) puts_filtered ("Saw new packet start in middle of old one\n"); return 0; /* Start a new packet, count retries */ case '#': { unsigned char pktcsum; *bp = '\000'; pktcsum = fromhex (readchar (remote_timeout)) << 4; pktcsum |= fromhex (readchar (remote_timeout)); if (csum == pktcsum) return 1; if (remote_debug) { printf_filtered ("Bad checksum, sentsum=0x%x, csum=0x%x, buf=", pktcsum, csum); puts_filtered (buf); puts_filtered ("\n"); } return 0; } case '*': /* Run length encoding */ csum += c; c = readchar (remote_timeout); csum += c; c = c - ' ' + 3; /* Compute repeat count */ if (c > 0 && c < 255 && bp + c - 1 < buf + PBUFSIZ - 1) { memset (bp, *(bp - 1), c); bp += c; continue; } *bp = '\0'; printf_filtered ("Repeat count %d too large for buffer: ", c); puts_filtered (buf); puts_filtered ("\n"); return 0; default: if (bp < buf + PBUFSIZ - 1) { *bp++ = c; csum += c; continue; } *bp = '\0'; puts_filtered ("Remote packet too long: "); puts_filtered (buf); puts_filtered ("\n"); return 0; } } } /* 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 (buf, forever) char *buf; int forever; { char *bp; int c; int tries; int timeout; int val; if (forever) timeout = -1; else timeout = remote_timeout; #define MAX_TRIES 10 for (tries = 1; tries <= MAX_TRIES; tries++) { /* 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. */ /* Note that we will only wait forever prior to the start of a packet. After that, we expect characters to arrive at a brisk pace. They should show up within remote_timeout intervals. */ do { c = readchar (timeout); if (c == SERIAL_TIMEOUT) { if (remote_debug) puts_filtered ("Timed out.\n"); goto retry; } } while (c != '$'); /* We've found the start of a packet, now collect the data. */ val = read_frame (buf); if (val == 1) { if (remote_debug) fprintf_unfiltered (gdb_stderr, "Packet received: %s\n", buf); SERIAL_WRITE (remote_desc, "+", 1); return; } /* Try the whole thing again. */ retry: SERIAL_WRITE (remote_desc, "-", 1); } /* We have tried hard enough, and just can't receive the packet. Give up. */ printf_unfiltered ("Ignoring packet error, continuing...\n"); SERIAL_WRITE (remote_desc, "+", 1); } static void remote_kill () { /* For some mysterious reason, wait_for_inferior calls kill instead of mourn after it gets TARGET_WAITKIND_SIGNALLED. Work around it. */ if (kill_kludge) { kill_kludge = 0; target_mourn_inferior (); return; } /* Use catch_errors so the user can quit from gdb even when we aren't on speaking terms with the remote system. */ catch_errors (putpkt, "k", "", RETURN_MASK_ERROR); /* 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 */ 0, /* to_stop */ 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 */ }; void _initialize_remote () { add_target (&remote_ops); }