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Diffstat (limited to 'gdb/remote.c')
| -rw-r--r-- | gdb/remote.c | 829 |
1 files changed, 829 insertions, 0 deletions
diff --git a/gdb/remote.c b/gdb/remote.c new file mode 100644 index 0000000..9ff5650 --- /dev/null +++ b/gdb/remote.c @@ -0,0 +1,829 @@ +/* Memory-access and commands for inferior process, for GDB. + Copyright (C) 1988-1991 Free Software Foundation, Inc. + +This file is part of GDB. + +GDB 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 1, or (at your option) +any later version. + +GDB 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 GDB; see the file COPYING. If not, write to +the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ + +/* Remote communication protocol. + 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 + 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 + + 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" + + kill req k +*/ + +#include <stdio.h> +#include <string.h> +#include <fcntl.h> +#include "defs.h" +#include "param.h" +#include "frame.h" +#include "inferior.h" +#include "target.h" +#include "wait.h" +#include "terminal.h" + +#ifdef USG +#include <sys/types.h> +#endif + +#include <signal.h> + +extern int memory_insert_breakpoint (); +extern int memory_remove_breakpoint (); +extern void add_syms_addr_command (); +extern struct value *call_function_by_hand(); +extern void start_remote (); + +extern struct target_ops remote_ops; /* Forward decl */ + +static int kiodebug; +static int timeout = 5; + +#if 0 +int icache; +#endif + +/* Descriptor for I/O to remote machine. Initialize it to -1 so that + remote_open knows that we don't have a file open when the program + starts. */ +int remote_desc = -1; + +#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) + +static void remote_send (); +static void putpkt (); +static void getpkt (); +#if 0 +static void dcache_flush (); +#endif + + +/* Called when SIGALRM signal sent due to alarm() timeout. */ +#ifndef HAVE_TERMIO +void +remote_timer () +{ + if (kiodebug) + printf ("remote_timer called\n"); + + alarm (timeout); +} +#endif + +/* Initialize remote connection */ + +void +remote_start() +{ +} + +/* Clean up connection to a remote debugger. */ + +void +remote_close (quitting) + int quitting; +{ + if (remote_desc >= 0) + close (remote_desc); + remote_desc = -1; +} + +/* Open a connection to a remote debugger. + NAME is the filename used for communication. */ + +void +remote_open (name, from_tty) + char *name; + int from_tty; +{ + TERMINAL sg; + + 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)."); + + remote_close (0); + +#if 0 + dcache_init (); +#endif + + remote_desc = open (name, O_RDWR); + if (remote_desc < 0) + perror_with_name (name); + + ioctl (remote_desc, TIOCGETP, &sg); +#ifdef HAVE_TERMIO + sg.c_cc[VMIN] = 0; /* read with timeout. */ + sg.c_cc[VTIME] = timeout * 10; + sg.c_lflag &= ~(ICANON | ECHO); +#else + sg.sg_flags = RAW; +#endif + ioctl (remote_desc, TIOCSETP, &sg); + + if (from_tty) + printf ("Remote debugging using %s\n", name); + push_target (&remote_ops); /* Switch to using remote target now */ + start_remote (); /* Initialize gdb process mechanisms */ + +#ifndef HAVE_TERMIO +#ifndef NO_SIGINTERRUPT + /* Cause SIGALRM's to make reads fail. */ + if (siginterrupt (SIGALRM, 1) != 0) + perror ("remote_open: error in siginterrupt"); +#endif + + /* Set up read timeout timer. */ + if ((void (*)) signal (SIGALRM, remote_timer) == (void (*)) -1) + perror ("remote_open: error in signal"); +#endif + + putpkt ("?"); /* initiate a query from remote machine */ +} + +/* 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) + printf ("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. */ + +void +remote_resume (step, siggnal) + int step, siggnal; +{ + char buf[PBUFSIZ]; + + if (siggnal) + error ("Can't send signals to a remote system."); + +#if 0 + dcache_flush (); +#endif + + strcpy (buf, step ? "s": "c"); + + putpkt (buf); +} + +/* Wait until the remote machine stops, then return, + storing status in STATUS just as `wait' would. */ + +int +remote_wait (status) + WAITTYPE *status; +{ + unsigned char buf[PBUFSIZ]; + + WSETEXIT ((*status), 0); + getpkt (buf); + if (buf[0] == 'E') + error ("Remote failure reply: %s", buf); + if (buf[0] != 'S') + error ("Invalid remote reply: %s", buf); + WSETSTOP ((*status), (((fromhex (buf[1])) << 4) + (fromhex (buf[2])))); +} + +/* Read the remote registers into the block REGS. */ + +int +remote_fetch_registers (regno) + int regno; +{ + char buf[PBUFSIZ]; + int i; + char *p; + char regs[REGISTER_BYTES]; + + sprintf (buf, "g"); + remote_send (buf); + + /* 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 || p[1] == 0) + error ("Remote reply is too short: %s", buf); + regs[i] = fromhex (p[0]) * 16 + fromhex (p[1]); + p += 2; + } + for (i = 0; i < NUM_REGS; i++) + supply_register (i, ®s[REGISTER_BYTE(i)]); + return 0; +} + +/* Prepare to store registers. Since we send them all, we have to + read out the ones we don't want to change first. */ + +void +remote_prepare_to_store () +{ + remote_fetch_registers (-1); +} + +/* Store the remote registers from the contents of the block REGISTERS. + FIXME, eventually just store one register if that's all that is needed. */ + +int +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; + for (i = 0; i < REGISTER_BYTES; i++) + { + *p++ = tohex ((registers[i] >> 4) & 0xf); + *p++ = tohex (registers[i] & 0xf); + } + *p = '\0'; + + remote_send (buf); + return 0; +} + +#if 0 +/* Read a word from remote address ADDR and return it. + This goes through the data cache. */ + +int +remote_fetch_word (addr) + CORE_ADDR addr; +{ + 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; + } + } + return dcache_fetch (addr); +} + +/* Write a word WORD into remote address ADDR. + This goes through the data cache. */ + +void +remote_store_word (addr, word) + CORE_ADDR addr; + int word; +{ + dcache_poke (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. */ + +void +remote_write_bytes (memaddr, myaddr, len) + CORE_ADDR memaddr; + char *myaddr; + int len; +{ + char buf[PBUFSIZ]; + int i; + char *p; + + if (len > PBUFSIZ / 2 - 20) + abort (); + + sprintf (buf, "M%x,%x:", memaddr, len); + + /* Command describes registers byte by byte, + 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'; + + remote_send (buf); +} + +/* 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. */ + +void +remote_read_bytes (memaddr, myaddr, len) + CORE_ADDR memaddr; + char *myaddr; + int len; +{ + char buf[PBUFSIZ]; + int i; + char *p; + + if (len > PBUFSIZ / 2 - 1) + abort (); + + sprintf (buf, "m%x,%x", memaddr, len); + remote_send (buf); + + /* Reply describes registers 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) + error ("Remote reply is too short: %s", buf); + myaddr[i] = fromhex (p[0]) * 16 + fromhex (p[1]); + p += 2; + } +} + +/* Read or write LEN bytes from inferior memory at MEMADDR, transferring + to or from debugger address MYADDR. Write to inferior if WRITE is + nonzero. Returns length of data written or read; 0 for error. */ + +int +remote_xfer_inferior_memory(memaddr, myaddr, len, write) + CORE_ADDR memaddr; + char *myaddr; + int len; + int write; +{ + int origlen = len; + int xfersize; + while (len > 0) + { + if (len > MAXBUFBYTES) + xfersize = MAXBUFBYTES; + else + xfersize = len; + + if (write) + remote_write_bytes(memaddr, myaddr, xfersize); + else + remote_read_bytes (memaddr, myaddr, xfersize); + memaddr += xfersize; + myaddr += xfersize; + len -= xfersize; + } + return origlen; /* no error possible */ +} + +void +remote_files_info () +{ + printf ("remote files info missing here. FIXME.\n"); +} + +/* + +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 + '$' or '#' + + CSUM1 and CSUM2 are ascii hex representation of an 8-bit + checksum of <data>, the most significant nibble is sent first. + the hex digits 0-9,a-f are used. + +Receiver responds with: + + + - if CSUM is correct and ready for next packet + - - if CSUM is incorrect + +*/ + +static int +readchar () +{ + char buf; + + buf = '\0'; +#ifdef HAVE_TERMIO + /* termio does the timeout for us. */ + read (remote_desc, &buf, 1); +#else + alarm (timeout); + read (remote_desc, &buf, 1); + alarm (0); +#endif + + return buf & 0x7f; +} + +/* Send the command in BUF to the remote machine, + and read the reply into BUF. + Report an error if we get an error reply. */ + +static void +remote_send (buf) + char *buf; +{ + + putpkt (buf); + getpkt (buf); + + if (buf[0] == 'E') + error ("Remote failure reply: %s", buf); +} + +/* Send a packet to the remote machine, with error checking. + The data of the packet is in BUF. */ + +static void +putpkt (buf) + char *buf; +{ + int i; + unsigned char csum = 0; + char buf2[500]; + int cnt = strlen (buf); + char ch; + char *p; + + /* Copy the packet into buffer BUF2, encapsulating it + and giving it a checksum. */ + + p = buf2; + *p++ = '$'; + + 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. */ + + do { + if (kiodebug) + { + *p = '\0'; + printf ("Sending packet: %s (%s)\n", buf2, buf); + } + write (remote_desc, buf2, p - buf2); + + /* read until either a timeout occurs (\0) or '+' is read */ + do { + ch = readchar (); + } while ((ch != '+') && (ch != '\0')); + } while (ch != '+'); +} + +/* Read a packet from the remote machine, with error checking, + and store it in BUF. */ + +static void +getpkt (buf) + char *buf; +{ + char *bp; + unsigned char csum; + int c; + unsigned char c1, c2; + + /* allow immediate quit while reading from device, it could be hung */ + immediate_quit++; + + while (1) + { + /* Force csum to be zero here because of possible error retry. */ + csum = 0; + + while ((c = readchar()) != '$'); + + bp = buf; + while (1) + { + c = readchar (); + if (c == '#') + break; + *bp++ = c; + csum += c; + } + *bp = 0; + + c1 = fromhex (readchar ()); + c2 = fromhex (readchar ()); + if ((csum & 0xff) == (c1 << 4) + c2) + break; + printf ("Bad checksum, sentsum=0x%x, csum=0x%x, buf=%s\n", + (c1 << 4) + c2, csum & 0xff, buf); + write (remote_desc, "-", 1); + } + + immediate_quit--; + + write (remote_desc, "+", 1); + + if (kiodebug) + fprintf (stderr,"Packet received :%s\n", buf); +} + +/* The data cache leads to incorrect results because it doesn't know about + volatile variables, thus making it impossible to debug functions which + use hardware registers. Therefore it is #if 0'd out. Effect on + performance is some, for backtraces of functions with a few + arguments each. For functions with many arguments, the stack + frames don't fit in the cache blocks, which makes the cache less + helpful. Disabling the cache is a big performance win for fetching + large structures, because the cache code fetched data in 16-byte + chunks. */ +#if 0 +/* The data cache records all the data read from the remote machine + since the last time it stopped. + + Each cache block holds 16 bytes of data + starting at a multiple-of-16 address. */ + +#define DCACHE_SIZE 64 /* Number of cache blocks */ + +struct dcache_block { + struct dcache_block *next, *last; + unsigned int addr; /* Address for which data is recorded. */ + int data[4]; +}; + +struct dcache_block dcache_free, dcache_valid; + +/* Free all the data cache blocks, thus discarding all cached data. */ + +static void +dcache_flush () +{ + register struct dcache_block *db; + + while ((db = dcache_valid.next) != &dcache_valid) + { + remque (db); + insque (db, &dcache_free); + } +} + +/* + * If addr is present in the dcache, return the address of the block + * containing it. + */ + +struct dcache_block * +dcache_hit (addr) +{ + register struct dcache_block *db; + + if (addr & 3) + abort (); + + /* Search all cache blocks for one that is at this address. */ + db = dcache_valid.next; + while (db != &dcache_valid) + { + if ((addr & 0xfffffff0) == db->addr) + return db; + db = db->next; + } + return NULL; +} + +/* Return the int data at address ADDR in dcache block DC. */ + +int +dcache_value (db, addr) + struct dcache_block *db; + unsigned int addr; +{ + if (addr & 3) + abort (); + return (db->data[(addr>>2)&3]); +} + +/* Get a free cache block, put it on the valid list, + and return its address. The caller should store into the block + the address and data that it describes. */ + +struct dcache_block * +dcache_alloc () +{ + register struct dcache_block *db; + + if ((db = dcache_free.next) == &dcache_free) + /* If we can't get one from the free list, take last valid */ + db = dcache_valid.last; + + remque (db); + insque (db, &dcache_valid); + return (db); +} + +/* Return the contents of the word at address ADDR in the remote machine, + using the data cache. */ + +int +dcache_fetch (addr) + CORE_ADDR addr; +{ + register struct dcache_block *db; + + db = dcache_hit (addr); + if (db == 0) + { + db = dcache_alloc (); + remote_read_bytes (addr & ~0xf, db->data, 16); + db->addr = addr & ~0xf; + } + return (dcache_value (db, addr)); +} + +/* Write the word at ADDR both in the data cache and in the remote machine. */ + +dcache_poke (addr, data) + CORE_ADDR addr; + int data; +{ + register struct dcache_block *db; + + /* First make sure the word is IN the cache. DB is its cache block. */ + db = dcache_hit (addr); + if (db == 0) + { + db = dcache_alloc (); + remote_read_bytes (addr & ~0xf, db->data, 16); + db->addr = addr & ~0xf; + } + + /* Modify the word in the cache. */ + db->data[(addr>>2)&3] = data; + + /* Send the changed word. */ + remote_write_bytes (addr, &data, 4); +} + +/* Initialize the data cache. */ + +dcache_init () +{ + register i; + register struct dcache_block *db; + + db = (struct dcache_block *) xmalloc (sizeof (struct dcache_block) * + DCACHE_SIZE); + dcache_free.next = dcache_free.last = &dcache_free; + dcache_valid.next = dcache_valid.last = &dcache_valid; + for (i=0;i<DCACHE_SIZE;i++,db++) + insque (db, &dcache_free); +} +#endif /* 0 */ + +/* Define the target subroutine names */ + +struct target_ops remote_ops = { + "remote", "Remote serial target in gdb-specific protocol", + remote_open, remote_close, + 0, remote_detach, remote_resume, remote_wait, /* attach */ + remote_fetch_registers, remote_store_registers, + remote_prepare_to_store, 0, 0, /* conv_from, conv_to */ + remote_xfer_inferior_memory, remote_files_info, + 0, 0, /* insert_breakpoint, remove_breakpoint, */ + 0, 0, 0, 0, 0, /* Terminal crud */ + 0, /* kill */ + 0, add_syms_addr_command, /* load */ + call_function_by_hand, + 0, /* lookup_symbol */ + 0, 0, /* create_inferior FIXME, mourn_inferior FIXME */ + process_stratum, 0, /* next */ + 1, 1, 1, 1, 1, /* all mem, mem, stack, regs, exec */ + OPS_MAGIC, /* Always the last thing */ +}; + +void +_initialize_remote () +{ + add_target (&remote_ops); +} |