Re: top(1) segfaults if terminal window is too short

[christos%astron.com@localhost (Christos Zoulas)]

In article 
<2218b9af0812120910p50c6ad40yf5f78cfef04acdfd%mail.gmail.com@localhost>,
Stathis Kamperis <ekamperi%gmail.com@localhost> wrote:
>Greetings people.
>
>The following apply to netbsd-5 ( can anyone please test -current also? )
>
>top(1) segfaults if the terminal from which it is invoked has a height of
>less than 6 lines of height.
>
>[stathis@netbsd ~] top
>Segmentation fault (core dumped)
>
>If it has exactly 6 lines of height it dies with the following error:
>[stathis@netbsd ~] top
>top: can't allocate sufficient memory
>
>If it is 7 lines of height or more it works ok.
>Here is the backtrace I got:
>
>[stathis@netbsd /usr/src/external/bsd/top/dist] gdb ./top
>GNU gdb 6.5
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>---Type <return> to continue, or q <return> to quit---
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>---Type <return> to continue, or q <return> to quit---
>This GDB was configured as "i386--netbsdelf"...
>(gdb) r
>Starting program: /usr/src/external/bsd/top/dist/top
>
>Program received signal SIGSEGV, Segmentation fault.
>summary_format (x=-1, y=-1, numbers=0x8055ac0, names=0x0, cidx=0x0) at
>display.c:540
>540         while ((thisname = *names++) != NULL)
>(gdb) bt
>#0  summary_format (x=-1, y=-1, numbers=0x8055ac0, names=0x0,
>cidx=0x0) at display.c:540
>#1  0x0804cf3b in i_procstates (total=48, brkdn=0x8055ac0, threads=0)
>at display.c:1093
>#2  0x0804e7c8 in do_display (gstate=0xbb901080) at top.c:547
>#3  0x0804f3d6 in main (argc=1, argv=0xbfbfe858) at top.c:972
>(gdb)
>
>It seems as a null pointer dereference sorf of problem, since names=0x0 and 
>then
>the while loop does *names++.
>
>I looked at the source and i_procstates() does this:
>
>        /* format and print the process state summary */
>        summary_format(-1, -1, brkdn, procstate_names, NULL);
>
>At this particular point the `procstate_names' equals NULL and it is
>passed to summary_format()
>which attempts to dereference it. The problem is that the
>`procstate_names' is a global variable,
>and well I can track easily how it changes across the code.

Fixed in head.

christos