Re: SIGSEGV in dc, at bcode.c:277 (function reset_bmachine())

В Tue, 13 Apr 2010 09:53:50 +0400
Hizel Ildar <hizel_at_vyborg.ru> пишет:

> В Sat, 10 Apr 2010 17:14:54 -0700
> David Wolfskill <david_at_catwhisker.org> пишет:
> 
> > As these things go, this probably isn't as critical as most thinsg
> > disussed on this list, but I happened to notice it today, built a
> > debugging world and at least cornered the annoying little varmint.
> > 
> > Sorry; no patch at this time. :-(
> > 
> > Here's how to reproduce it: while running CURRENT, invoke dc(1)
> > using the command-line expression-soecification ("-e ..."), thus:
> > 
> > freebeast(9.0-C)[2] dc -e "6 2/p"
> > Segmentation fault (core dumped)
> > freebeast(9.0-C)[3] 
> > 
> > This was running:
> > 
> > FreeBSD freebeast.catwhisker.org 9.0-CURRENT FreeBSD 9.0-CURRENT #1
> > r206447: Sat Apr 10 14:49:56 PDT 2010
> > root_at_freebeast.catwhisker.org:/common/S1/obj/usr/src/sys/GENERIC
> > i386
> > 
> 
> Also, when using the option -f file must be core dump :(
> 
> foo# echo '6 2/p' > /tmp/test
> foo# dc -f /tmp/test
> Segmentation fault (core dumped)
> foo# gdb /usr/bin/dc dc.core 
> GNU gdb 6.1.1 [FreeBSD]
> Copyright 2004 Free Software Foundation, Inc.
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> details. This GDB was configured as "i386-marcel-freebsd"...
> Core was generated by `dc'.
> Program terminated with signal 11, Segmentation fault.
> Reading symbols from /lib/libcrypto.so.6...done.
> Loaded symbols for /lib/libcrypto.so.6
> Reading symbols from /lib/libc.so.7...done.
> Loaded symbols for /lib/libc.so.7
> Reading symbols from /libexec/ld-elf.so.1...done.
> Loaded symbols for /libexec/ld-elf.so.1
> #0  0x08049818 in reset_bmachine (src=0x804fc48)
> at /usr/src/usr.bin/dc/bcode.c:277 277
> bmachine.readstack[0] = *src; (gdb) bt
> #0  0x08049818 in reset_bmachine (src=0x804fc48)
> at /usr/src/usr.bin/dc/bcode.c:277 #1  0x0804947e in procfile
> (fname=0xbfbfea22 "/tmp/test") at /usr/src/usr.bin/dc/dc.c:75 #2
> 0x0804951f in main (argc=3, argv=0xbfbfe8fc)
> at /usr/src/usr.bin/dc/dc.c:96 (gdb) quit foo# uname -a
> FreeBSD foo.vyborg.ru 9.0-CURRENT FreeBSD 9.0-CURRENT #1: Sun Apr 11
> 21:00:05 MSD 2010
> root_at_foo.vyborg.ru:/usr/obj/usr/src/sys/GENERIC  i386
> 

My patch:

foo# diff -ruN dc.c.orig dc.c
--- dc.c.orig   2010-04-13 10:33:22.000000000 +0400
+++ dc.c        2010-04-13 11:44:18.000000000 +0400
_at__at_ -87,12 +87,16 _at__at_
        while ((ch = getopt_long(argc, argv, "e:f:Vx", long_options, NULL)) != -1) {
                switch (ch) {
                case 'e':
+                       if(!preproc_done)
+                              init_bmachine(extended_regs);
                        src_setstring(&src, optarg);
                        reset_bmachine(&src);
                        eval();
                        preproc_done = true;
                        break;
                case 'f':
+                       if(!preproc_done)
+                              init_bmachine(extended_regs);
                        procfile(optarg);
                        preproc_done = true;
                        break;
_at__at_ -114,7 +118,9 _at__at_
        argc -= optind;
        argv += optind;
 
-       init_bmachine(extended_regs);
+        if (!preproc_done)
+               init_bmachine(extended_regs);
+
        setlinebuf(stdout);
        setlinebuf(stderr);


test:

foo# dc -f /tmp/test
3
foo# dc -e "6 2/p"
3
foo# dc -e "6 2/p" -f /tmp/test
3
3
foo# dc -e "6 2/p" -f /tmp/test /tmp/test
3
3
3