Hi Frank,
On Fri, 2019-11-15 at 16:00 -0500, Frank Ch. Eigler wrote:
> > > + string popen_cmd = string("/usr/bin/rpm2cpio " +
> > > shell_escape(b_source0));
> >
> > Why the hardcoded path?
> > Could you check at startup if rpm2cpio is in the PATH?
>
> Hm, since this is run under popen(), so it'll do $PATH searching for
> us. Checking whether it is present at runtime ... hmmm ugh ... how
> about an autoconf test instead? The worst thing that happens with
> the
> current code is that on a non-rpm system, if it does find .rpm files,
> the code will print errors and otherwise ignore RPMs.
OK, I think how you did it on the branch, just remove the path, let the
shell find rpm2cpio, is fine for now.
> > > + // extract this file to a temporary file
> > > + char tmppath[PATH_MAX] = "/tmp/debuginfod.XXXXXX"; // XXX:
> > > $TMP_DIR etc.
> >
> > Some other code uses:
> > const char *tmpdir = getenv ("TMPDIR") ?: P_tmpdir;
> > static const char suffix[] = "/debuginfod.XXXXXX";
> > Also PATH_MAX?
>
> OK -- and yeah if we getenv() we might need PATH_MAX.
> Will try asprintf() here and the client instead.
It would be really nice if this code at least respected TMPDIR.
> > Also I prefer checking against NULL, it is slightly more obvious (0
> > returns often means success).
>
> ... the C++ tradition is 0 for null pointers, but if you insist...
No, if that is the C++ way then that is fine.
> > > + Dwarf_Off offset = 0;
> > > + Dwarf_Off old_offset;
> > > + size_t hsize;
> > > +
> > > + while (dwarf_nextcu (dbg, old_offset = offset, &offset, &hsize, NULL,
> > > NULL, NULL) == 0)
> >
> > These days I would prefer dwarf_get_units (). It is slightly higher
> > level and immediately gives you the cudie and unit_type.
>
> Will look into that later.
>
> > > + {
> > > + Dwarf_Die cudie_mem;
> > > + Dwarf_Die *cudie = dwarf_offdie (dbg, old_offset + hsize,
> > > &cudie_mem);
> > > +
> > > + if (cudie == NULL)
> > > + continue;
> > > + if (dwarf_tag (cudie) != DW_TAG_compile_unit)
> > > + continue;
> > > +
> > > + const char *cuname = dwarf_diename(cudie) ?: "unknown";
> > > +
> > > + Dwarf_Files *files;
> > > + size_t nfiles;
> > > + if (dwarf_getsrcfiles (cudie, &files, &nfiles) != 0)
> > > + continue;
> >
> > So you are really only interested in the file/line tables.
> > In that case you could also use dwarf_next_lines which iterates through
> > the debug line units directly, so you don't need to do the whole CU DIE
> > tree iteration yourself (and it handles CUless tables).
>
> Ditto.
I believe the code works as is, so it isn't urgent.
I just think it
would simplify things a bit.
> > > + string waldo;
> > > + if (hat[0] == '/') // absolute
> > > + waldo = (string (hat));
> > > + else // comp_dir relative
> > > + waldo = (string (comp_dir) + string("/") + string (hat));
> >
> > Do you have to think about/handle a comp_dir that ends with a / ?
> > Old debugedit truncated some strings by adding /// (to fill up the
> > spaces till the '\0'...) Yes, terrible :{
>
> It should just work(tm) if the debugger uses the documented convention
> and preserves those extra slashes (just as if it preserved ../ and
> such).
See also the other email/review. So, we always add an '/' between
comp_dir and the file. That should probably be explicitly documented
because I wouldn't be surprised if some code doesn't when comp_dir
already ends in a slash.
I just double checked that dwarf_getsrclines always (unconditionally)
adds a '/', so the use of dwarf_filesrc here does the right thing.
Thanks,
Mark
