[PATCH 1/1] Fix segfault in DTC

On Tue, Sep 25, 2012 at 10:58:09AM -0700, Markus Mayer wrote:

Prior to this change, an empty input file would cause a segfault, because
yylloc had never been initialized. There was never any characters for the
lexer to match, so YY_USER_ACTION was never executed before the parse error
was detected.

When the parser printed the error message, it tried to include the name of
the file, but the structure holding the file name (yylloc.file, referenced
as pos->file) had never been initialized.

Without the fix:

$ ./dtc /dev/null
DTC: dts->dts  on file "/dev/null"
Segmentation fault (core dumped)

$ gdb dtc core
Program terminated with signal 11, Segmentation fault.
    at scripts/dtc/srcpos.c:194
194			fname = pos->file->name;
(gdb) bt
    at scripts/dtc/srcpos.c:194
    fmt=0x40d769 "%s", va=0x7fffbf027148) at scripts/dtc/srcpos.c:220
    at scripts/dtc/dtc-parser.tab.c:1920
    at scripts/dtc/treesource.c:38
    at scripts/dtc/dtc.c:203
(gdb) p *pos
$1 = {first_line = 0, first_column = 0, last_line = 0, last_column = 0,
  file = 0x0}

Which dtc version did you observe this with?  I'm unable to reproduce
the SEGV with current git.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson