[Bug libc/6700] New: utmpname(3) returns interger but man page says void and doesnot returns with failure if file not found.

["halesh dot s at gmail dot com" <sourceware-bugzilla at sourceware dot org>]

Hi,

In glibc 2.7 I found, Man page of utmpname(3) says its prototype as...

            void utmpname(const char *file);

But if we check the source in login/utmpname.c
int
__utmpname (const char *file)
{
....
....
}

This is conflicting one, so man page needs to be fixed.

And utmpname(3) does not reports failure if the file that we pass and
it does not exists.

The testcase is...
$ ls -l utmp1
ls: utmp1: No such file or directory

$ cat test.c
#include <stdio.h>
#include <utmp.h>

int main()
{
     printf("%d\n", utmpname("./utmp1"));
}

$ gcc test.c -o test
$ ./test
0

This intern affecting the other commands like who (1).

$ who ./utmp1
$ echo $?
0

**Even utmp1 file not exists, its exit status is zero.

Fixing the issue in utmp will fix the other dependencies.

Patch to fix the issue
=======================

--- utmpname.c.old      2008-06-24 16:36:27.000000000 +0530
+++ utmpname.c  2008-06-24 16:37:12.000000000 +0530
@@ -21,6 +21,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <utmp.h>
+#include <sys/stat.h>

 #include "utmp-private.h"

@@ -39,6 +40,12 @@
 __utmpname (const char *file)
 {
  int result = -1;
+ struct stat buf;
+
+  if (stat(file, &buf) != 0)
+   {
+        return result;
+   }

 __libc_lock_lock (__libc_utmp_lock);


Thanks,
Halesh

-- 
           Summary: utmpname(3) returns interger but man page says void and
                    doesnot returns with failure if file not found.
           Product: glibc
           Version: unspecified
            Status: NEW
          Severity: minor
          Priority: P2
         Component: libc
        AssignedTo: drepper at redhat dot com
        ReportedBy: halesh dot s at gmail dot com
                CC: glibc-bugs at sources dot redhat dot com


http://sourceware.org/bugzilla/show_bug.cgi?id=6700

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