From: Jan Kratochvil Date: Wed, 6 Apr 2016 15:13:12 +0000 (+0200) Subject: Workaround gdbserver<7.7 for setfs X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=319cb5d0cf7ba3bc0e77ab420cfcf75568d722b4;p=binutils-gdb.git Workaround gdbserver<7.7 for setfs With current FSF GDB HEAD and old FSF gdbserver I expected I could do: gdb -ex 'file target:/root/redhat/threadit' -ex 'target remote :1234' (supplying that unsupported qXfer:exec-file:read by "file") But that does not work because: Sending packet: $vFile:setfs:0#bf...Packet received: OK Packet vFile:setfs (hostio-setfs) is supported ... Sending packet: $vFile:setfs:104#24...Packet received: OK "target:/root/redhat/threadit": could not open as an executable file: Invalid argument GDB documentation says: The valid responses to Host I/O packets are: An empty response indicates that this operation is not recognized. This "empty response" vs. "OK" was a bug in gdbserver < 7.7. It was fixed by: commit e7f0d979dd5cc4f8b658df892e93db69d6d660b7 Author: Yao Qi Date: Tue Dec 10 21:59:20 2013 +0800 Fix a bug in matching notifications. Message-ID: <1386684626-11415-1-git-send-email-yao@codesourcery.com> https://sourceware.org/ml/gdb-patches/2013-12/msg00373.html 2013-12-10 Yao Qi * notif.c (handle_notif_ack): Return 0 if no notification matches. with unpatched old FSF gdbserver and patched FSF GDB HEAD: gdb -ex 'file target:/root/redhat/threadit' -ex 'target remote :1234' Sending packet: $vFile:setfs:0#bf...Packet received: OK Packet vFile:setfs (hostio-setfs) is NOT supported ... (gdb) info sharedlibrary From To Syms Read Shared Object Library 0x00007ffff7ddbae0 0x00007ffff7df627a Yes (*) target:/lib64/ld-linux-x86-64.so.2 0x00007ffff7bc48a0 0x00007ffff7bcf514 Yes (*) target:/lib64/libpthread.so.0 gdb/ChangeLog 2016-04-06 Jan Kratochvil * remote.c (struct remote_state): New field unknown_v_replies_ok. (packet_config_support): Read it. (remote_start_remote): Set it. --- diff --git a/gdb/ChangeLog b/gdb/ChangeLog index e362360981c..e3848ec9513 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,9 @@ +2016-04-06 Jan Kratochvil + + * remote.c (struct remote_state): New field unknown_v_replies_ok. + (packet_config_support): Read it. + (remote_start_remote): Set it. + 2016-04-06 Jan Kratochvil * remote.c: Revert check-in by a mistake in the previous commit. diff --git a/gdb/remote.c b/gdb/remote.c index 5c407b6bb9c..ea7f5b8fb1f 100644 --- a/gdb/remote.c +++ b/gdb/remote.c @@ -426,6 +426,15 @@ struct remote_state request/reply nature of the RSP. We only cache data for a single file descriptor at a time. */ struct readahead_cache readahead_cache; + + /* gdbserver < 7.7 (before its fix from 2013-12-11) did reply to any + unknown 'v' packet with string "OK". "OK" gets interpreted by GDB + as a reply to known packet. For packet "vFile:setfs:" it is an + invalid reply and GDB would return error in + remote_hostio_set_filesystem, making remote files access impossible. + If this variable is non-zero it means the remote gdbserver is buggy + and any not yet detected packets are assumed as unsupported. */ + int unknown_v_replies_ok; }; /* Private data that we'll store in (struct thread_info)->private. */ @@ -1519,6 +1528,13 @@ packet_config_support (struct packet_config *config) case AUTO_BOOLEAN_FALSE: return PACKET_DISABLE; case AUTO_BOOLEAN_AUTO: + { + struct remote_state *rs = get_remote_state (); + + if (rs->unknown_v_replies_ok && config->name != NULL + && config->name[0] == 'v') + return PACKET_DISABLE; + } return config->support; default: gdb_assert_not_reached (_("bad switch")); @@ -4023,6 +4039,21 @@ remote_start_remote (int from_tty, struct target_ops *target, int extended_p) if (packet_support (PACKET_QAllow) != PACKET_DISABLE) remote_set_permissions (target); + /* See unknown_v_replies_ok description. */ + { + const char v_mustreplyempty[] = "vMustReplyEmpty"; + + putpkt (v_mustreplyempty); + getpkt (&rs->buf, &rs->buf_size, 0); + if (strcmp (rs->buf, "OK") == 0) + rs->unknown_v_replies_ok = 1; + else if (strcmp (rs->buf, "") == 0) + rs->unknown_v_replies_ok = 0; + else + error (_("Remote replied unexpectedly to '%s': %s"), v_mustreplyempty, + rs->buf); + } + /* Next, we possibly activate noack mode. If the QStartNoAckMode packet configuration is set to AUTO,