hubert@entropy.UUCP (Steve Hubert) (10/28/86)
Subject: getusershell() is buggy
Index: lib/libc/gen/getusershell.c 4.3BSD
Description:
Getusershell(3) does not handle comments correctly. Setusershell(3)
does not work at all.
Repeat-By:
Run the following program with the default version of /etc/shells.
Notice that the first shell printed out is /passwd. This comes
from one of the leading comments in the file /etc/shells. Also notice
that setusershell() does not rewind the shells file so nothing is
printed out in the second loop.
main() {
char *cp, *getusershell();
for (cp = getusershell(); cp; cp = getusershell())
printf("%s\n", cp);
setusershell();
for (cp = getusershell(); cp; cp = getusershell())
printf("%s\n", cp);
}
Fix:
There was a fix posted as 4573@brl-smoke.ARPA to netnews.
That fix (as received at my site) was obviously incorrect since
it didn't work and it contained a line of code that looked like:
while (!isspace(*cp) != '/' && *cp != '\0')
Here is a context diff (to the original getusershell.c) to fix
the problem.
*** getusershell.c.old Mon Oct 27 17:17:05 1986
--- getusershell.c.new Mon Oct 27 17:17:05 1986
***************
*** 58,64 ****
setusershell()
{
! shells = initshells();
}
static char **
--- 58,64 ----
setusershell()
{
! endusershell();
}
static char **
***************
*** 96,101 ****
--- 96,103 ----
sp = shells;
cp = strings;
while (fgets(cp, MAXPATHLEN + 1, fp) != NULL) {
+ if (*cp == '#')
+ continue;
while (*cp != '/' && *cp != '\0')
cp++;
if (*cp == '\0')