MINOR: debug: add ability to dump loaded shared libraries
Many times core dumps reported by users who experience trouble are
difficult to exploit due to missing system libraries. Sometimes,
having just a list of loaded libraries and their respective addresses
can already provide some hints about some problems.
This patch makes a step in that direction by adding a new "show libs"
command that will try to enumerate the list of object files that are
loaded in memory, relying on the dynamic linker for this. It may also
be used to detect that some foreign code embarks other undesired libs
(e.g. some external Lua modules).
At the moment it's only supported on glibc when USE_DL is set, but it's
implemented in a way that ought to make it reasonably easy to be extended
to other platforms.
(cherry picked from commit 6ab7b21a1108c0f187d09196dfc20d40f654e6c9)
Signed-off-by: Willy Tarreau <w@1wt.eu>
(cherry picked from commit 04fb3620a17b9448c45be7213dbb1d1abc221017)
Signed-off-by: Willy Tarreau <w@1wt.eu>
diff --git a/doc/management.txt b/doc/management.txt
index 275e318..ae4aee8 100644
--- a/doc/management.txt
+++ b/doc/management.txt
@@ -2426,6 +2426,19 @@
$ echo "show info json" | socat /var/run/haproxy.sock stdio | \
python -m json.tool
+show libs
+ Dump the list of loaded shared dynamic libraries and object files, on systems
+ that support it. When available, for each shared object the range of virtual
+ addresses will be indicated, the size and the path to the object. This can be
+ used for example to try to estimate what library provides a function that
+ appears in a dump. Note that on many systems, addresses will change upon each
+ restart (address space randomization), so that this list would need to be
+ retrieved upon startup if it is expected to be used to analyse a core file.
+ This command may only be issued on sockets configured for levels "operator"
+ or "admin". Note that the output format may vary between operating systems,
+ architectures and even haproxy versions, and ought not to be relied on in
+ scripts.
+
show map [[@<ver>] <map>]
Dump info about map converters. Without argument, the list of all available
maps is returned. If a <map> is specified, its contents are dumped. <map> is