I really like to use the x command in crash, as in:
crash-4.0.9> x/256xg 0xffff8801aa9c8000
0xffff8801aa9c8000: 0xffff8800c61541c0 0xffff880145a194c0
0xffff8801aa9c8010: 0xffff88016fa481c0 0xffff88016c7980c0
...
I like it better than the rd command (because of prior familiarity
perhaps?):
crash-4.0.9> rd -x -64 0xffff8801aa9c8000 256
ffff8801aa9c8000: ffff8800c61541c0 ffff880145a194c0
ffff8801aa9c8010: ffff88016fa481c0 ffff88016c7980c0
...
But I *really* like crash's ability to pipe and redirect commands, but
that doesn't work with the x command:
crash-4.0.9> x/256xg 0xffff8801aa9c8000 | grep ffff880145a194c0
crash-4.0.9>
But it works with rd:
crash-4.0.9> rd -x -64 0xffff8801aa9c8000 256 | grep ffff880145a194c0
ffff8801aa9c8000: ffff8800c61541c0 ffff880145a194c0
crash-4.0.9>
Another fun one:
crash-4.0.9> x/256xg 0xffff8801aa9c8000 | head
Argument to arithmetic operation not a number or boolean.
If you redirect the output of x, you get a file containing an error
message:
crash-4.0.9> x/256xg 0xffff8801aa9c8000 >xold.out
crash-4.0.9> !sh
sh-3.2$ cat xold.out
No symbol "xold" in current context.
sh-3.2$
The problem is that the setup of gdb commands in is_gdb_command() with
merge_orig_args set puts the "| thing" or "> thing" back onto the
command it is building to be passed through to gdb.
I first thought that cmd_gdb() passing a NULL, instead of the fp with
the redirection set up, into gdb_pass_through was part of the problem
also, but that seems to be dealt with later in gdb_interface.
There might some other reason for the strange behavior of
merge_orig_args that my testing has not found. But otherwise, the
attached patch will allow my favorite x command to be sent through pipes
and redirected to files.
Thanks,
Bob Montgomery
--- gdb_interface.c.orig 2009-09-14 15:23:58.000000000 -0600
+++ gdb_interface.c 2009-09-14 17:12:28.000000000 -0600
@@ -619,9 +619,11 @@ is_gdb_command(int merge_orig_args, ulon
FREEBUF(req);
if (retval && merge_orig_args) {
- argcnt = 2;
+ int i;
+ for (i = argcnt; i; i--)
+ args[i] = args[i-1];
args[0] = "gdb";
- args[1] = pc->orig_line;
+ argcnt++;
}
return retval;
--
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