Bug in 4.{2,3}BSD 'vi'
Head UNIX Hacquer
Description:
Running 'ex' on Encore UMAX 4.2, the '%' and '#' constructs
fail in '!' escapes.
The problem is that when a '%' or '#' is expanded, the 'QUOTE'
attribute (the 0x80 bit) is set in each character for
pretty-printing purposes. This string (with high bits on for most
characters) is passed to the shell unchanged and havoc ensuses.
This does not fail on 4.2 or 4.3 (or ports) because the kernel
strips out the 0x80 bit when doing pathname tranlation in namei().
The UMAX file system code is NOT a direct port of the 4.2
code, having the 0x80 bit set causes an error. In fact, the shell
does some other strangeness with this string, so it never
reaches the kernel.
Repeat-By:
Edit a file with 'ex' under UMAX 4.2 and do ":!ls -l %' - something
will go wrong.
Fix:
One fix would be to change the kernel, but my sensibilities
say that UMAX is doing the right thing in rejecting path names with
high bits set, and that 'ex' is doing the wrong thing by passing them.
So here is my fix to 'ex' to remove the QUOTE bit from the unix
command buffer.
*** ex_unix.r.1.0.c Mon Sep 21 14:13:04 1987
--- ex_unix.c Mon Sep 21 12:01:04 1987
***************
*** 122,127
putnl();
flush();
}
}
/*
--- 122,133 -----
putnl();
flush();
}
+ /*
+ * Remove QUOTE bit from uxb - works fine for printing,
+ * works lousy for everybody else
+ */
+ for (up = uxb; *up; up++)
+ *up = *up & ~QUOTE;
}
/*
--
Shouter-To-Dead-Parrots @ Univ. of Texas Computation Center; Austin, Texas
cl...@ngp.utexas.edu; ...!ut-sally!ut-ngp!clyde
"It's a sort of a threat, you see. I've never been very good at them
myself, but I've told they can be very effective."