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authorJan Kratochvil <jan.kratochvil@redhat.com>2016-04-27 21:27:40 +0200
committerJan Kratochvil <jan.kratochvil@redhat.com>2016-04-27 21:27:40 +0200
commit57809e5e5a506664eb54433ded81ab0785168a83 (patch)
treeb182387a6aaa5528d584b75b36b60f730f9c77a5
parent91f8bf69a526912f86da81070407bba6a050e27f (diff)
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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 <yao@codesourcery.com> 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 <yao@codesourcery.com> * 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 2016-04-26 Jan Kratochvil <jan.kratochvil@redhat.com> * remote.c (remote_start_remote): Detect PACKET_vFile_setfs.support.
-rw-r--r--gdb/ChangeLog4
-rw-r--r--gdb/remote.c19
2 files changed, 23 insertions, 0 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 165c2a3..5cf8a5f 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,7 @@
+2016-04-27 Jan Kratochvil <jan.kratochvil@redhat.com>
+
+ * remote.c (remote_start_remote): Detect PACKET_vFile_setfs.support.
+
2016-04-27 Martin Galvan <martin.galvan@tallertechnologies.com>
* c-valprint.c (c_value_print): Always convert val back to reference
diff --git a/gdb/remote.c b/gdb/remote.c
index 4c18b4f..1f0d67c 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -4031,6 +4031,25 @@ remote_start_remote (int from_tty, struct target_ops *target, int extended_p)
if (packet_support (PACKET_QAllow) != PACKET_DISABLE)
remote_set_permissions (target);
+ /* 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.
+ Disable "vFile:setfs:" in such case. Do not disable other 'v' packets as
+ other "vFile" packets get correctly detected even on gdbserver < 7.7. */
+ {
+ const char v_mustreplyempty[] = "vMustReplyEmpty";
+
+ putpkt (v_mustreplyempty);
+ getpkt (&rs->buf, &rs->buf_size, 0);
+ if (strcmp (rs->buf, "OK") == 0)
+ remote_protocol_packets[PACKET_vFile_setfs].support = PACKET_DISABLE;
+ else if (strcmp (rs->buf, "") != 0)
+ 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,