[Bug libc/11040] New: getopt mistakenly allows '-;' as short option

[Bug libc/11040] New: getopt mistakenly allows '-;' as short option

[ebb9 at byu dot net]

getopt_long is documented as accepting an optstring of "W;" as an extension that
parses '-W longopt=value' the same as '--longopt=value'.  However, using this
extension also makes apps mistakenly accept '-;' as a valid short option.

In practice, encountering '-;' as a short option will be rare (since it requires
shell quoting).  Furthermore, if ';' appears in optstring outside of the
documented "W;" extension, there is no reason to forbid it from being a valid
short option as an extension permitted by POSIX.  However, if the only ';' in
optstring immediately follows 'W', it makes more sense to reject ';', the same
way that ':' is rejected.  And coding-wise, it is easier to forbid all use of
';', rather than making the code more complicated to determine whether ';' in
optstring immediately follows 'W'.

$ cat foo.c
#include <unistd.h>
#include <stdio.h>
#include <getopt.h>

static const struct option opts[] =
  {
    { "alpha",    no_argument,       NULL, 'a' },
    { "beta",     required_argument, NULL, 'b' },
    { NULL,       0,                 NULL, 0 }
  };

int
main (int argc, char **argv)
{
  int c = getopt_long (argc, argv, "ab:W;", opts, NULL);
  if (c == -1)
    puts ("got -1");
  else
    printf ("got %c\n", c);
  c = getopt_long (argc, argv, "ab:W;", opts, NULL);
  if (c == -1)
    puts ("got -1");
  else
    printf ("got %c\n", c);
  return 0;
}
$ ./foo '-a;'
got a
got ;
$ ./foo2 '-a:'
got a
./foo2: invalid option -- :
got ?

Workaround: code using the "W;" extension must be prepared to deal with a return
value of ';' and manually handle it as an invalid option.

Expected results: '-a;' should have errored out like '-a:'.

-- 
           Summary: getopt mistakenly allows '-;' as short option
           Product: glibc
           Version: 2.11
            Status: NEW
          Severity: normal
          Priority: P2
         Component: libc
        AssignedTo: drepper at redhat dot com
        ReportedBy: ebb9 at byu dot net
                CC: glibc-bugs at sources dot redhat dot com


http://sourceware.org/bugzilla/show_bug.cgi?id=11040

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[Bug libc/11040] getopt mistakenly allows '-;' as short option

[ebb9 at byu dot net]

------- Additional Comments From ebb9 at byu dot net  2009-12-01 16:54 -------
Created an attachment (id=4436)
 --> (http://sourceware.org/bugzilla/attachment.cgi?id=4436&action=view)
patch

2009-12-01  Eric Blake	<ebb9@byu.net>

	* posix/getopt.c (_getopt_internal_r): Reject '-;' as short
	option, since it conflicts with "W;" optstring extension.


-- 


http://sourceware.org/bugzilla/show_bug.cgi?id=11040

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[Bug libc/11040] getopt mistakenly allows '-;' as short option

[drepper at redhat dot com]

------- Additional Comments From drepper at redhat dot com  2010-04-08 00:31 -------
Fixed in git.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED


http://sourceware.org/bugzilla/show_bug.cgi?id=11040

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