Date: Sun, 19 Nov 2000 18:51:26 -0500 (EST) From: Garance A Drosehn <gad@freefour.acs.rpi.edu> To: FreeBSD-gnats-submit@freebsd.org Cc: gad@eclipse.acs.rpi.edu, gad@freebsd.org Subject: bin/22965: [PATCH] fix for minor bug in libc/gen/getcap.c Message-ID: <200011192351.SAA30775@freefour.acs.rpi.edu>
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>Number: 22965
>Category: bin
>Synopsis: [PATCH] fix for minor bug in libc/gen/getcap.c
>Confidential: no
>Severity: non-critical
>Priority: medium
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Sun Nov 19 16:00:01 PST 2000
>Closed-Date:
>Last-Modified:
>Originator: Garance A Drosehn
>Release: FreeBSD 3.2-RELEASE i386
>Organization:
RPI ; Troy NY
>Environment:
While compiling FreeBSD's lpr/lpd for use on some other platforms,
I ran into a fairly nasty bug on redhat linux. As near as I can
tell, the bug has existed in FreeBSD's 'getcap' for several years
without it causing any known problems, but I do believe the code
is wrong and should be fixed anyway.
(while this send-pr is coming from a 3.2 system, the patch is
for the source in freebsd-current, ie, 5.x as of Nov 2000)
>Description:
You probably don't want to know what the problem is under linux...
However, the problem comes down to code which does:
(void)fclose(pfp);
if (ferror(pfp)) { ...do stuff... }
According to the "single unix spec", the behavior of calling
ANY "f-routine" on a closed stream is undefined. I take it to
mean that's a bad idea. Certainly on linux it can trigger some
major headaches.
Also, I don't see what is to be gained by calling ferror in the
above case. My change is just to USE the return code from fclose,
instead of throwing it away, and have error-processing key off
that instead of ferror.
>How-To-Repeat:
.na.
>Fix:
Here is the patch I propose. If no one objects to this, I can
commit this patch sometime after thanksgiving. Or I would be
more than happy if someone else wants to claim ownership of
getcap, and they generate their own patch for it... :-)
This also initializes global (static) variables to appropriate
values, although that probably doesn't effect anything.
Index: getcap.c
===================================================================
RCS file: /home/ncvs/src/lib/libc/gen/getcap.c,v
retrieving revision 1.12
diff -u -r1.12 getcap.c
--- getcap.c 2000/05/21 02:55:09 1.12
+++ getcap.c 2000/11/19 23:09:15
@@ -62,9 +62,9 @@
#define TCERR (char)1
#define SHADOW (char)2
-static size_t topreclen; /* toprec length */
-static char *toprec; /* Additional record specified by cgetset() */
-static int gottoprec; /* Flag indicating retrieval of toprecord */
+static size_t topreclen = 0; /* toprec length */
+static char *toprec = NULL; /* Additional record specified by cgetset() */
+static int gottoprec = 0; /* Flag indicating retrieval of toprecord */
static int cdbget __P((DB *, char **, char *));
static int getent __P((char **, u_int *, char **, int, char *, int, char *));
@@ -619,9 +619,9 @@
return (cgetnext(buf, db_array));
}
-static FILE *pfp;
-static int slash;
-static char **dbp;
+static FILE *pfp = NULL;
+static int slash = 0; /* on if last line read-in ended with a '/' */
+static char **dbp = NULL;
int
cgetclose()
@@ -647,7 +647,7 @@
char **db_array;
{
size_t len;
- int status, i, done;
+ int done, fcloseres, i, status;
char *cp, *line, *rp, *np, buf[BSIZE], nbuf[BSIZE];
u_int dummy;
@@ -665,8 +665,9 @@
} else {
line = fgetln(pfp, &len);
if (line == NULL && pfp) {
- (void)fclose(pfp);
- if (ferror(pfp)) {
+ fcloseres = fclose(pfp);
+ pfp = NULL;
+ if (fcloseres != 0) {
(void)cgetclose();
return (-1);
} else {
@@ -724,8 +725,9 @@
} else { /* name field extends beyond the line */
line = fgetln(pfp, &len);
if (line == NULL && pfp) {
- (void)fclose(pfp);
- if (ferror(pfp)) {
+ fcloseres = fclose(pfp);
+ pfp = NULL;
+ if (fcloseres != 0) {
(void)cgetclose();
return (-1);
}
>Release-Note:
>Audit-Trail:
>Unformatted:
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