Extend the file handle cache entries to include symbol tables as well. An
index is used to implement binary search by symbol value. Lookups by
name are comparatively rare and are thus still implemented with a linear
search, but support for a binary search by name would be straightforward
to add if needed.
When looking up an object by name, allow prefix matches if no direct match
is found. This allows one to, for example, match libc entry probes with:
# dtrace -n 'pid$target:libc.so::entry' -c ./foo
instead of requiring "libc.so.7" or a glob.
Also remove proc_obj2map() as it currently just duplicates the
functionality of proc_name2map(). It's supposed to take a Solaris
link-map ID as a paramter, but support for this isn't implemented and
isn't required to support DTrace's pid provider.
libproc previously created a new handle for each symbol lookup, which
gives rather egregious performance for DTrace's ustack() action. With
this change libproc will cache the libelf descriptor upon access, making
lookups much faster in the common case.
As of r278658 libproc looks for debug files under /usr/lib/debug and will
use them if available. This change fleshes out that support a bit further:
- Check for a .gnu_debuglink section and use the file name specified
there if one is present.
- Validate external debug files with the CRC in the .gnu_debuglink
section so as to avoid using stale or corrupt debug files.
- Search for debug files in the directory containing the referencing
object or in the .debug subdirectory, as GDB does.
This allows librtld_db to fetch the PID from a handle without calling into
libproc. Together with r303531, this means that librtld_db no longer
references symbols from libproc.
modifications to libproc to support fetching the CTF info for a given file.
With this change, dtrace(1) is able to resolve type info for function and
USDT probe arguments, and function return values. In particular, the args[n]
syntax should now work for referencing arguments of userland probes,
provided that the requisite CTF info is available.
The uctf tests pass if the test programs are compiled with CTF info. The
current infrastructure around the DTrace test suite doesn't support this
yet.
Differential Revision: https://reviews.freebsd.org/D891
MFC after: 1 month
Relnotes: yes
Sponsored by: EMC / Isilon Storage Division
erroneously skip symbols that were not mangled at all. Fix this by
moving the return into the preceding if block.
While here, simplify the code by letting __cxa_demangle() allocate the
needed space for the demangled symbol. This also fixes a memory leak,
which would occur whenever __cxa_demangle() failed.
Reported by: pgj
MFC after: 3 days
* Don't print any error messages to stderr unless DEBUG is defined.
* Add a DPRINTFX macro for use when errno isn't set.
* Print the error string from libelf when appropriate.
o return the correct status in proc_wstatus()
o proc_read takes a void *
o correctly allocate the objs structure array
Sponsored by: The FreeBSD Foundation
* breakpoint setup support
* register query
* symbol to address mapping and vice-versa
* more misc utility functions based on their Solaris counterpart
Also, I've written some test cases.
Sponsored by: The FreeBSD Foundation
These will be fleshed out as part of the DTrace userland tracing
development.
For now, the kernel tracing part of DTrace requires minimal functionality
for this library.
The API for this library is deliberately different from the libproc in
OpenSolaris due to licensing restrictions.
