bug in CSH (history)

[chris]

There are a couple of bugs in the 'history' command of /bin/csh (and
offspring, such as newcsh):

1) The maximum number of arguments to the history command is set to 2.

2) The validity of the flags is not checked and since the argument pointer
is only incremented when a valid flag is found, using a wrong flag throws
the Cshell in a loop.

				-------------

To duplicate, type:
	csh
	set history = 100
	history -h -r 5
	history -x

				-------------

To fix:

1) In sh.init.c, change the following line:
	"history",	dohist,		0,	2,
to:
	"history",	dohist,		0,	4,

2) in sh.hist.c, change the following lines in dohist():
	vp++;
	while (*vp && *vp[0] == '-') {
		if (*vp && eq(*vp, "-h")) {
			hflg++;
			vp++;
		}
		if (*vp && eq(*vp, "-r")) {
			rflg++;
			vp++;
		}
	}
to:
	while (*++vp && **vp == '-') {
		while(*++*vp)
			switch(**vp) {
			case 'h':
				hflg++; break;
			case 'r':
				rflg++; break;
			case '-': /* ignore multiple '-'s */
				break;
			default:
				printf("Unknown flag: -%c\n", **vp);
				error("Usage: history [-rh] [# of events]");
			}
	}
		-----------------------------------------
-- 

 Chris Bertin            :         (617) 657-8720 x2318
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