this patch reduces the likelyhood of such events (without completly fixing them)
A+
--
Eric Pouech
Name: wd_gdb ChangeLog: fixed protocol packet handling when winedbg is too slow to answer License: X11 GenDate: 2003/01/06 21:41:01 UTC ModifiedFiles: programs/winedbg/gdbproxy.c AddedFiles: =================================================================== RCS file: /home/cvs/cvsroot/wine/wine/programs/winedbg/gdbproxy.c,v retrieving revision 1.3 diff -u -u -r1.3 gdbproxy.c --- programs/winedbg/gdbproxy.c 16 Dec 2002 22:10:34 -0000 1.3 +++ programs/winedbg/gdbproxy.c 6 Jan 2003 21:40:50 -0000 @@ -20,6 +20,10 @@ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ +/* Protocol specification can be found here: + * http://sources.redhat.com/gdb/onlinedocs/gdb_32.html + */ + #include "config.h" #include <assert.h> @@ -1788,6 +1792,7 @@ unsigned char in_cksum, loc_cksum; char* ptr; enum packet_return ret = packet_error; + int num_packet = 0; while ((ret & packet_last_f) == 0) { @@ -1814,49 +1819,68 @@ loc_cksum = checksum(gdbctx->in_buf + 1, plen); if (loc_cksum == in_cksum) { - int i; - - ret = packet_error; - - write(gdbctx->sock, "+", 1); - assert(plen); - - /* FIXME: should use bsearch if packet_entries was sorted */ - for (i = 0; i < sizeof(packet_entries)/sizeof(packet_entries[0]); i++) - { - if (packet_entries[i].key == gdbctx->in_buf[1]) break; - } - if (i == sizeof(packet_entries)/sizeof(packet_entries[0])) - { - if (gdbctx->trace & GDBPXY_TRC_PACKET) - fprintf(stderr, "Unknown packet request %*.*s\n", - plen, plen, &gdbctx->in_buf[1]); - } - else - { - gdbctx->in_packet = gdbctx->in_buf + 2; - gdbctx->in_packet_len = plen - 1; - if (gdbctx->trace & GDBPXY_TRC_PACKET) - fprintf(stderr, "Packet: %c%*.*s\n", - gdbctx->in_buf[1], - gdbctx->in_packet_len, gdbctx->in_packet_len, - gdbctx->in_packet); - ret = (packet_entries[i].handler)(gdbctx); + if (num_packet == 0) { + int i; + + ret = packet_error; + + write(gdbctx->sock, "+", 1); + assert(plen); + + /* FIXME: should use bsearch if packet_entries was sorted */ + for (i = 0; i < sizeof(packet_entries)/sizeof(packet_entries[0]); i++) + { + if (packet_entries[i].key == gdbctx->in_buf[1]) break; + } + if (i == sizeof(packet_entries)/sizeof(packet_entries[0])) + { + if (gdbctx->trace & GDBPXY_TRC_PACKET) + fprintf(stderr, "Unknown packet request %*.*s\n", + plen, plen, &gdbctx->in_buf[1]); + } + else + { + gdbctx->in_packet = gdbctx->in_buf + 2; + gdbctx->in_packet_len = plen - 1; + if (gdbctx->trace & GDBPXY_TRC_PACKET) + fprintf(stderr, "Packet: %c%*.*s\n", + gdbctx->in_buf[1], + gdbctx->in_packet_len, gdbctx->in_packet_len, + gdbctx->in_packet); + ret = (packet_entries[i].handler)(gdbctx); + } + switch (ret & ~packet_last_f) + { + case packet_error: packet_reply(gdbctx, "", 0); break; + case packet_ok: packet_reply(gdbctx, "OK", 2); break; + case packet_done: break; + } + if (gdbctx->trace & GDBPXY_TRC_LOWLEVEL) + fprintf(stderr, "reply-full: %*.*s\n", + gdbctx->out_len, gdbctx->out_len, gdbctx->out_buf); + i = write(gdbctx->sock, gdbctx->out_buf, gdbctx->out_len); + assert(i == gdbctx->out_len); + /* if this fails, we'll have to use POLLOUT... + */ + gdbctx->out_len = 0; + num_packet++; } - switch (ret & ~packet_last_f) + else { - case packet_error: packet_reply(gdbctx, "", 0); break; - case packet_ok: packet_reply(gdbctx, "OK", 2); break; - case packet_done: break; + /* FIXME: if we have in our input buffer more than one packet, + * it's very likely that we took too long to answer to a given packet + * and gdb is sending us again the same packet + * We simply drop the second packet. This will lower the risk of error, + * but there's still some race conditions here + * A better fix (yet not perfect) would be to have two threads: + * - one managing the packets for gdb + * - the second one managing the commands... + * This would allow us also the reply with the '+' character (Ack of + * the command) way sooner than what we do know + */ + if (gdbctx->trace & GDBPXY_TRC_LOWLEVEL) + fprintf(stderr, "dropping packet, I was too slow to respond\n"); } - if (gdbctx->trace & GDBPXY_TRC_LOWLEVEL) - fprintf(stderr, "reply-full: %*.*s\n", - gdbctx->out_len, gdbctx->out_len, gdbctx->out_buf); - i = write(gdbctx->sock, gdbctx->out_buf, gdbctx->out_len); - assert(i == gdbctx->out_len); - /* if this fails, we'll have to use POLLOUT... - */ - gdbctx->out_len = 0; } else {
