From FEDORA_PATCHES Mon Sep 17 00:00:00 2001 From: Jan Kratochvil Date: Thu, 9 Aug 2018 17:11:09 +0200 Subject: gdb-rhbz1187581-power8-regs-3of7.patch ;; Add GDB support to access/display POWER8 registers (IBM, RH BZ 1187581). commit 3df3a985a475db004706d64f83d9085f99053611 Author: Pedro Franco de Carvalho Date: Mon Aug 6 16:24:55 2018 -0300 Use get_remote_packet_size in download_tracepoint This patch changes the remote target to use the remote packet size to build QTDP packets, and to check if there is enough room for the packet. I changed the function to raise an error if the packet is too small, instead of aborting gdb (through xsnprintf). It isn't clear if gdb will be in a consistent state with respect to the stub after this, since it's possible that some packets will be sent but not others, and there could be an incomplete tracepoint on the stub. The char array used to build the packets is changed to a gdb::char_vector and sized with the result from get_remote_packet_size. When checking if the buffer is large enough to hold the tracepoint condition agent expression, the length of the expression is multiplied by two, since it is encoded with two hex digits per expression byte. For simplicity, I assume that the result won't overflow, which can happen for very long condition expressions. gdb/ChangeLog: 2018-08-06 Pedro Franco de Carvalho * remote.c (remote_target::download_tracepoint): Remove BUF_SIZE. Replace array buf with gdb::char_vector buf, of size get_remote_packet_size (). Replace references to buf and BUF_SIZE to buf.data () and buf.size (). Replace strcpy, strcat and xsnprintf with snprintf. Raise errors if the buffer is too small. diff --git a/gdb/remote.c b/gdb/remote.c --- a/gdb/remote.c +++ b/gdb/remote.c @@ -12799,26 +12799,35 @@ remote_target::remote_download_command_source (int num, ULONGEST addr, void remote_target::download_tracepoint (struct bp_location *loc) { -#define BUF_SIZE 2048 - CORE_ADDR tpaddr; char addrbuf[40]; - char buf[BUF_SIZE]; std::vector tdp_actions; std::vector stepping_actions; char *pkt; struct breakpoint *b = loc->owner; struct tracepoint *t = (struct tracepoint *) b; struct remote_state *rs = get_remote_state (); + int ret; + char *err_msg = _("Tracepoint packet too large for target."); + size_t size_left; + + /* We use a buffer other than rs->buf because we'll build strings + across multiple statements, and other statements in between could + modify rs->buf. */ + gdb::char_vector buf (get_remote_packet_size ()); encode_actions_rsp (loc, &tdp_actions, &stepping_actions); tpaddr = loc->address; sprintf_vma (addrbuf, tpaddr); - xsnprintf (buf, BUF_SIZE, "QTDP:%x:%s:%c:%lx:%x", b->number, - addrbuf, /* address */ - (b->enable_state == bp_enabled ? 'E' : 'D'), - t->step_count, t->pass_count); + ret = snprintf (buf.data (), buf.size (), "QTDP:%x:%s:%c:%lx:%x", + b->number, addrbuf, /* address */ + (b->enable_state == bp_enabled ? 'E' : 'D'), + t->step_count, t->pass_count); + + if (ret < 0 || ret >= buf.size ()) + error (err_msg); + /* Fast tracepoints are mostly handled by the target, but we can tell the target how big of an instruction block should be moved around. */ @@ -12830,8 +12839,15 @@ remote_target::download_tracepoint (struct bp_location *loc) { if (gdbarch_fast_tracepoint_valid_at (loc->gdbarch, tpaddr, NULL)) - xsnprintf (buf + strlen (buf), BUF_SIZE - strlen (buf), ":F%x", - gdb_insn_length (loc->gdbarch, tpaddr)); + { + size_left = buf.size () - strlen (buf.data ()); + ret = snprintf (buf.data () + strlen (buf.data ()), + size_left, ":F%x", + gdb_insn_length (loc->gdbarch, tpaddr)); + + if (ret < 0 || ret >= size_left) + error (err_msg); + } else /* If it passed validation at definition but fails now, something is very wrong. */ @@ -12855,7 +12871,14 @@ remote_target::download_tracepoint (struct bp_location *loc) struct static_tracepoint_marker marker; if (target_static_tracepoint_marker_at (tpaddr, &marker)) - strcat (buf, ":S"); + { + size_left = buf.size () - strlen (buf.data ()); + ret = snprintf (buf.data () + strlen (buf.data ()), + size_left, ":S"); + + if (ret < 0 || ret >= size_left) + error (err_msg); + } else error (_("Static tracepoint not valid during download")); } @@ -12873,10 +12896,26 @@ remote_target::download_tracepoint (struct bp_location *loc) capabilities at definition time. */ if (remote_supports_cond_tracepoints ()) { - agent_expr_up aexpr = gen_eval_for_expr (tpaddr, loc->cond.get ()); - xsnprintf (buf + strlen (buf), BUF_SIZE - strlen (buf), ":X%x,", - aexpr->len); - pkt = buf + strlen (buf); + agent_expr_up aexpr = gen_eval_for_expr (tpaddr, + loc->cond.get ()); + + size_left = buf.size () - strlen (buf.data ()); + + ret = snprintf (buf.data () + strlen (buf.data ()), + size_left, ":X%x,", aexpr->len); + + if (ret < 0 || ret >= size_left) + error (err_msg); + + size_left = buf.size () - strlen (buf.data ()); + + /* Two bytes to encode each aexpr byte, plus the terminating + null byte. */ + if (aexpr->len * 2 + 1 > size_left) + error (err_msg); + + pkt = buf.data () + strlen (buf.data ()); + for (int ndx = 0; ndx < aexpr->len; ++ndx) pkt = pack_hex_byte (pkt, aexpr->buf[ndx]); *pkt = '\0'; @@ -12887,8 +12926,17 @@ remote_target::download_tracepoint (struct bp_location *loc) } if (b->commands || *default_collect) - strcat (buf, "-"); - putpkt (buf); + { + size_left = buf.size () - strlen (buf.data ()); + + ret = snprintf (buf.data () + strlen (buf.data ()), + size_left, "-"); + + if (ret < 0 || ret >= size_left) + error (err_msg); + } + + putpkt (buf.data ()); remote_get_noisy_reply (); if (strcmp (rs->buf, "OK")) error (_("Target does not support tracepoints.")); @@ -12902,11 +12950,15 @@ remote_target::download_tracepoint (struct bp_location *loc) bool has_more = ((action_it + 1) != tdp_actions.end () || !stepping_actions.empty ()); - xsnprintf (buf, BUF_SIZE, "QTDP:-%x:%s:%s%c", - b->number, addrbuf, /* address */ - action_it->c_str (), - has_more ? '-' : 0); - putpkt (buf); + ret = snprintf (buf.data (), buf.size (), "QTDP:-%x:%s:%s%c", + b->number, addrbuf, /* address */ + action_it->c_str (), + has_more ? '-' : 0); + + if (ret < 0 || ret >= buf.size ()) + error (err_msg); + + putpkt (buf.data ()); remote_get_noisy_reply (); if (strcmp (rs->buf, "OK")) error (_("Error on target while setting tracepoints.")); @@ -12920,12 +12972,16 @@ remote_target::download_tracepoint (struct bp_location *loc) bool is_first = action_it == stepping_actions.begin (); bool has_more = (action_it + 1) != stepping_actions.end (); - xsnprintf (buf, BUF_SIZE, "QTDP:-%x:%s:%s%s%s", - b->number, addrbuf, /* address */ - is_first ? "S" : "", - action_it->c_str (), - has_more ? "-" : ""); - putpkt (buf); + ret = snprintf (buf.data (), buf.size (), "QTDP:-%x:%s:%s%s%s", + b->number, addrbuf, /* address */ + is_first ? "S" : "", + action_it->c_str (), + has_more ? "-" : ""); + + if (ret < 0 || ret >= buf.size ()) + error (err_msg); + + putpkt (buf.data ()); remote_get_noisy_reply (); if (strcmp (rs->buf, "OK")) error (_("Error on target while setting tracepoints.")); @@ -12935,22 +12991,32 @@ remote_target::download_tracepoint (struct bp_location *loc) { if (b->location != NULL) { - strcpy (buf, "QTDPsrc:"); + ret = snprintf (buf.data (), buf.size (), "QTDPsrc:"); + + if (ret < 0 || ret >= buf.size ()) + error (err_msg); + encode_source_string (b->number, loc->address, "at", event_location_to_string (b->location.get ()), - buf + strlen (buf), 2048 - strlen (buf)); - putpkt (buf); + buf.data () + strlen (buf.data ()), + buf.size () - strlen (buf.data ())); + putpkt (buf.data ()); remote_get_noisy_reply (); if (strcmp (rs->buf, "OK")) warning (_("Target does not support source download.")); } if (b->cond_string) { - strcpy (buf, "QTDPsrc:"); + ret = snprintf (buf.data (), buf.size (), "QTDPsrc:"); + + if (ret < 0 || ret >= buf.size ()) + error (err_msg); + encode_source_string (b->number, loc->address, - "cond", b->cond_string, buf + strlen (buf), - 2048 - strlen (buf)); - putpkt (buf); + "cond", b->cond_string, + buf.data () + strlen (buf.data ()), + buf.size () - strlen (buf.data ())); + putpkt (buf.data ()); remote_get_noisy_reply (); if (strcmp (rs->buf, "OK")) warning (_("Target does not support source download."));