Add a mandatory debuginfod_begin()/_end() call pair to manage a client
object that represents persistent but non-global state.  From libdwfl,
dlopen the debuginfod.so client library early on.  This hopefully
makes sure that the code (and the libcurl.so dependency) is loaded
before the program goes into multi-threaded mode.

Signed-off-by: Mark Wielaard <mark@klomp.org>

Signed-off-by: Frank Ch. Eigler <fche@redhat.com>
Signed-off-by: Mark Wielaard <mark@klomp.org>
Signed-off-by: Aaron Merey <amerey@redhat.com>

This webapi extensions allows admins to hook up debuginfod to a
prometheus-compatible monitoring system for general situational
statistics.  The metrics are simple enough that local curl requests
can give a user a sense of what's going on.  The metrics are
documented as unstable with respect to future versions.

In order to support file/rpm archives that are organized via symlink
trees, add an "-L" option to debuginfod, meaning about the same as for
find(1) or ls(1): to traverse rather than ignore symlinks.

For interactive clients such as gdb, interruptibility is important for
usability during longer downloads.  This patchset adds a
download-progress callback function to the debuginfod client library,
with which a caller app can interrupt a download as well as be
notified of its quantitative progress.

Add the server to the debuginfod/ subdirectory.  This is a highly
multithreaded c++11 program (still buildable on rhel7's gcc 4.8,
which is only partly c++11 compliant).  Includes an initial suite
of tests, man pages, and a sample systemd service.

Signed-off-by: Frank Ch. Eigler <fche@redhat.com>
Signed-off-by: Aaron Merey <amerey@redhat.com>

Introduce the debuginfod/ subdirectory, containing the client for a
new debuginfo-over-http service, in shared-library and command-line
forms.  Two functions in libdwfl make calls into the client library to
fetch elf/dwarf files by buildid, as a fallback.  Instead of normal
dynamic linking (thus pulling in a variety of curl dependencies),
the libdwfl hooks use dlopen/dlsym.  Server & tests coming in patch 2.

Signed-off-by: Aaron Merey <amerey@redhat.com>
Signed-off-by: Frank Ch. Eigler <fche@redhat.com>

Add a missing bounds check, fix an off-by-one bounds check and replace
asserts with error messages.

https://sourceware.org/bugzilla/show_bug.cgi?id=25068

Signed-off-by: Mark Wielaard <mark@klomp.org>

If the sh_entsize of the symver section was bogus (bigger than necessary)
then some bogus data would be written out (except that then fails because
pwrite would probably fail). Fix that by ignoring the bogus sh_entsize
and use the actual symver data size.

https://sourceware.org/bugzilla/show_bug.cgi?id=25077

Signed-off-by: Mark Wielaard <mark@klomp.org>