GNU bug report logs - #64954
GNU 'uptime' on OpenBSD always prints "0 users"

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Bruno Haible <bruno <at> clisp.org>
To: bug-coreutils <at> gnu.org
Subject: GNU 'uptime' on OpenBSD always prints "0 users"
Date: Sun, 30 Jul 2023 16:44:25 +0200

[Message part 1 (text/plain, inline)]

Hi,

GNU coreutils-9.3 'uptime', on OpenBSD 7.2, prints

 16:24:53  up 14 days 13:33,  0 users,  load average: 0.04, 0.44, 0.59

whereas the OpenBSD /usr/bin/uptime prints

 4:24PM  up 14 days, 13:33, 1 user, load averages: 0.04, 0.44, 0.59

The utmp file contain these entries:

    Time (GMT)           User          PID     Term Exit Boot User Process
------------------- --------------- ---------- ---- ---- ---- ------------
1970-01-01 00:00:00                          0   0    0            
1970-01-01 00:00:00                          0   0    0            
2023-07-16 00:52:00 bruno                    0   0    0            

The readutmp.h code, in particular the IS_USER_PROCESS macro, works fine.
(UT_TYPE_USER_PROCESS (U) expands to 0, and UT_TYPE_NOT_DEFINED expands to 1.)

The problem is that the readutmp code is entirely disabled on this platform.
Which is not appropriate.

When I revert the coreutils commit 2984e47c789ebc39f55a3b1cb20b943de88eeedc,
the coreutils 'uptime' program prints "1 user", as expected.

The rationale of that commit was wrong:
"Following gnulib commit 9041103 HAVE_UTMP_H will always be defined."
No, what that gnulib commit did is to create an <utmp.h> replacement
if the package imports the 'login_tty' module. But the HAVE_UTMP_H
is *still* only defined if the platform provides it.
Proof: On FreeBSD 13.2, which does not have <utmp.h> (it has <utmpx.h>
instead), configuring coreutils-9.3 produces the attached config.h,
which has

#define HAVE_UTMPX_H 1
/* #undef HAVE_UTMP_H */

So, find attached the fix of the bug.

[freebsd-13.2-config.h (text/x-chdr, attachment)]

[0001-uptime-Print-the-correct-number-of-users-on-OpenBSD.patch (text/x-patch, attachment)]

Message #8 received at 64954 <at> debbugs.gnu.org (full text, mbox):

From: Pádraig Brady <P <at> draigBrady.com>
To: Bruno Haible <bruno <at> clisp.org>, 64954 <at> debbugs.gnu.org
Subject: Re: bug#64954: GNU 'uptime' on OpenBSD always prints "0 users"
Date: Sun, 30 Jul 2023 19:41:12 +0100

On 30/07/2023 15:44, Bruno Haible wrote:
> Hi,
> 
> GNU coreutils-9.3 'uptime', on OpenBSD 7.2, prints
> 
>   16:24:53  up 14 days 13:33,  0 users,  load average: 0.04, 0.44, 0.59
> 
> whereas the OpenBSD /usr/bin/uptime prints
> 
>   4:24PM  up 14 days, 13:33, 1 user, load averages: 0.04, 0.44, 0.59
> 
> The utmp file contain these entries:
> 
>      Time (GMT)           User          PID     Term Exit Boot User Process
> ------------------- --------------- ---------- ---- ---- ---- ------------
> 1970-01-01 00:00:00                          0   0    0
> 1970-01-01 00:00:00                          0   0    0
> 2023-07-16 00:52:00 bruno                    0   0    0
> 
> The readutmp.h code, in particular the IS_USER_PROCESS macro, works fine.
> (UT_TYPE_USER_PROCESS (U) expands to 0, and UT_TYPE_NOT_DEFINED expands to 1.)
> 
> The problem is that the readutmp code is entirely disabled on this platform.
> Which is not appropriate.
> 
> When I revert the coreutils commit 2984e47c789ebc39f55a3b1cb20b943de88eeedc,
> the coreutils 'uptime' program prints "1 user", as expected.
> 
> The rationale of that commit was wrong:
> "Following gnulib commit 9041103 HAVE_UTMP_H will always be defined."
> No, what that gnulib commit did is to create an <utmp.h> replacement
> if the package imports the 'login_tty' module. But the HAVE_UTMP_H
> is *still* only defined if the platform provides it.
> Proof: On FreeBSD 13.2, which does not have <utmp.h> (it has <utmpx.h>
> instead), configuring coreutils-9.3 produces the attached config.h,
> which has
> 
> #define HAVE_UTMPX_H 1
> /* #undef HAVE_UTMP_H */
> 
> So, find attached the fix of the bug.

I'm fine with the change, but we'll also need to adjust
the sc_prohibit_always_true_header_tests syntax check in gnulib
as that will fail since gnulib/lib/utmp.in.h is present
and thus use of HAVE_UTMP_H is disallowed.

cheers,
Pádraig

Message #11 received at 64954 <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Pádraig Brady <P <at> draigBrady.com>
Cc: Bruno Haible <bruno <at> clisp.org>, 64954 <at> debbugs.gnu.org
Subject: Re: bug#64954: GNU 'uptime' on OpenBSD always prints "0 users"
Date: Sun, 30 Jul 2023 12:43:31 -0700

[Message part 1 (text/plain, inline)]

On 2023-07-30 11:41, Pádraig Brady wrote:
> I'm fine with the change, but we'll also need to adjust
> the sc_prohibit_always_true_header_tests syntax check in gnulib

I looked into that but it's such a hassle that I came up with the 
attached simpler patch to Coreutils. How about installing it instead? No 
Gnulib change should be needed.

[0001-uptime-output-correct-user-count-on-OpenBSD.patch (text/x-patch, attachment)]

Message #14 received at 64954 <at> debbugs.gnu.org (full text, mbox):

From: Pádraig Brady <P <at> draigBrady.com>
To: Paul Eggert <eggert <at> cs.ucla.edu>
Cc: Bruno Haible <bruno <at> clisp.org>, 64954 <at> debbugs.gnu.org
Subject: Re: bug#64954: GNU 'uptime' on OpenBSD always prints "0 users"
Date: Mon, 31 Jul 2023 09:38:01 +0100

On 30/07/2023 20:43, Paul Eggert wrote:
> On 2023-07-30 11:41, Pádraig Brady wrote:
>> I'm fine with the change, but we'll also need to adjust
>> the sc_prohibit_always_true_header_tests syntax check in gnulib
> 
> I looked into that but it's such a hassle that I came up with the
> attached simpler patch to Coreutils. How about installing it instead? No
> Gnulib change should be needed.

Maybe, though I notice that gnulib docs
state the following platforms have neither getutent or getutxent,
and so might have issues with this?

OpenBSD 6.7, Minix 3.1.8, mingw, MSVC 14

Message #17 received at 64954 <at> debbugs.gnu.org (full text, mbox):

From: Bruno Haible <bruno <at> clisp.org>
To: Pádraig Brady <P <at> draigbrady.com>,
 Paul Eggert <eggert <at> cs.ucla.edu>
Cc: 64954 <at> debbugs.gnu.org
Subject: Re: bug#64954: GNU 'uptime' on OpenBSD always prints "0 users"
Date: Mon, 31 Jul 2023 11:05:36 +0200

Paul Eggert wrote:
> > I'm fine with the change, but we'll also need to adjust
> > the sc_prohibit_always_true_header_tests syntax check in gnulib
> 
> I looked into that but it's such a hassle that I came up with the 
> attached simpler patch to Coreutils. How about installing it instead?

Yes, that's better than what I proposed, on two accounts:
  - Gnulib modules should better provide .h files that can be #included
    on any platform. Thus, it's Gnulib's task to provide a readutmp.h
    and a read_utmp() function that can also be used on native Windows.
  - It gets rid of the horrible hack to pass the values of two uninitialized
    variables down to a function.

Pádraig Brady wrote:
> gnulib docs
> state the following platforms have neither getutent or getutxent,
> and so might have issues with this?

OpenBSD 6.7, Minix 3.1.8, mingw, MSVC 14

On these platforms the #include "readutmp.h" would already provoke a
mass of syntax errors.

Btw, we don't test on Minix any longer (since Minix is dead),
and OpenBSD 6.x is end-of-life already [1].

Bruno

https://en.wikipedia.org/wiki/OpenBSD#Releases

Message #20 received at 64954 <at> debbugs.gnu.org (full text, mbox):

From: Bruno Haible <bruno <at> clisp.org>
To: Pádraig Brady <P <at> draigbrady.com>,
 Paul Eggert <eggert <at> cs.ucla.edu>
Cc: bug-gnulib <at> gnu.org, 64954 <at> debbugs.gnu.org
Subject: Re: bug#64954: GNU 'uptime' on OpenBSD always prints "0 users"
Date: Mon, 31 Jul 2023 16:17:13 +0200

I wrote in <https://debbugs.gnu.org/cgi/bugreport.cgi?bug=64954>:
>   - Gnulib modules should better provide .h files that can be #included
>     on any platform. Thus, it's Gnulib's task to provide a readutmp.h
>     and a read_utmp() function that can also be used on native Windows.

Done as follows:


2023-07-31  Bruno Haible  <bruno <at> clisp.org>

	readutmp: Make the header file and function usable on all platforms.
	* lib/readutmp.h (struct gl_utmp, UTMP_STRUCT_NAME, UT_TIME_MEMBER,
	UT_EXIT_E_TERMINATION, UT_EXIT_E_EXIT, UT_USER): Provide fallback
	definitions.
	(READ_UTMP_SUPPORTED): New macro.
	* lib/readutmp.c (read_utmp) [!READ_UTMP_SUPPORTED]: Provide a dummy
	definition.
	* modules/readutmp (Depends-on): Add sys_time.
	(configure.ac): Remove conditional.
	(Makefile.am): Compile readutmp.c on all platforms.
	(Include): Include readutmp.h on all platforms.
	* tests/test-readutmp.c: Include readutmp.h on all platforms.
	(main): Invoke read_utmp on all platforms.

diff --git a/lib/readutmp.c b/lib/readutmp.c
index acffe1000e..af43d1ad6b 100644
--- a/lib/readutmp.c
+++ b/lib/readutmp.c
@@ -61,6 +61,8 @@ extract_trimmed_name (const STRUCT_UTMP *ut)
   return trimmed_name;
 }
 
+#if READ_UTMP_SUPPORTED
+
 /* Is the utmp entry U desired by the user who asked for OPTIONS?  */
 
 static bool
@@ -77,12 +79,12 @@ desirable_utmp_entry (STRUCT_UTMP const *u, int options)
   return true;
 }
 
-#ifdef UTMP_NAME_FUNCTION
+# if defined UTMP_NAME_FUNCTION
 
 static void
 copy_utmp_entry (STRUCT_UTMP *dst, STRUCT_UTMP *src)
 {
-#if __GLIBC__ && _TIME_BITS == 64
+#  if __GLIBC__ && _TIME_BITS == 64
   /* Convert from external form in SRC to internal form in DST.
      It is OK to convert now, rather than earlier, before
      desirable_utmp_entry was invoked, because desirable_utmp_entry
@@ -119,9 +121,9 @@ copy_utmp_entry (STRUCT_UTMP *dst, STRUCT_UTMP *src)
   dst->ut_tv.tv_sec = s->ut_tv.tv_sec;
   dst->ut_tv.tv_usec = s->ut_tv.tv_usec;
   memcpy (&dst->ut_addr_v6, s->ut_addr_v6, sizeof dst->ut_addr_v6);
-#else
+#  else
   *dst = *src;
-#endif
+#  endif
 }
 
 int
@@ -158,7 +160,7 @@ read_utmp (char const *file, size_t *n_entries, STRUCT_UTMP **utmp_buf,
   return 0;
 }
 
-#else
+# else
 
 int
 read_utmp (char const *file, size_t *n_entries, STRUCT_UTMP **utmp_buf,
@@ -198,4 +200,16 @@ read_utmp (char const *file, size_t *n_entries, STRUCT_UTMP **utmp_buf,
   return 0;
 }
 
+# endif
+
+#else /* dummy fallback */
+
+int
+read_utmp (char const *file, size_t *n_entries, STRUCT_UTMP **utmp_buf,
+           int options)
+{
+  errno = ENOSYS;
+  return -1;
+}
+
 #endif
diff --git a/lib/readutmp.h b/lib/readutmp.h
index 7d2a628135..d710699525 100644
--- a/lib/readutmp.h
+++ b/lib/readutmp.h
@@ -38,6 +38,7 @@
 # endif
 
 # if HAVE_UTMPX_H
+
 #  if HAVE_UTMP_H
     /* HPUX 10.20 needs utmp.h, for the definition of e.g., UTMP_FILE.  */
 #   include <utmp.h>
@@ -114,6 +115,24 @@
 #   endif
 #  endif
 
+# else
+
+/* Provide a dummy fallback.  */
+
+/* Get 'struct timeval'.  */
+#  include <sys/time.h>
+
+struct gl_utmp
+{
+  char ut_user[1];
+  char ut_line[1];
+  struct timeval ut_tv;
+};
+#  define UTMP_STRUCT_NAME gl_utmp
+#  define UT_TIME_MEMBER(UT_PTR) ((UT_PTR)->ut_tv.tv_sec)
+#  define UT_EXIT_E_TERMINATION(U) 0
+#  define UT_EXIT_E_EXIT(U) 0
+
 # endif
 
 /* Accessor macro for the member named ut_user or ut_name.  */
@@ -137,6 +156,10 @@
 #   define UT_USER(Utmp) ((Utmp)->ut_name)
 #  endif
 
+# else /* dummy fallback */
+
+#  define UT_USER(Utmp) ((Utmp)->ut_user)
+
 # endif
 
 # define HAVE_STRUCT_XTMP_UT_EXIT \
@@ -151,10 +174,14 @@
     (HAVE_STRUCT_UTMP_UT_PID \
      || HAVE_STRUCT_UTMPX_UT_PID)
 
+/* Type of entry returned by read_utmp().  */
 typedef struct UTMP_STRUCT_NAME STRUCT_UTMP;
 
+/* Size of the UT_USER (ut) member.  */
 enum { UT_USER_SIZE = sizeof UT_USER ((STRUCT_UTMP *) 0) };
 
+/* Definition of UTMP_FILE and WTMP_FILE.  */
+
 # if !defined UTMP_FILE && defined _PATH_UTMP
 #  define UTMP_FILE _PATH_UTMP
 # endif
@@ -181,12 +208,15 @@ enum { UT_USER_SIZE = sizeof UT_USER ((STRUCT_UTMP *) 0) };
 #  define WTMP_FILE "/etc/wtmp"
 # endif
 
+/* Accessor macro for the member named ut_pid.  */
 # if HAVE_STRUCT_XTMP_UT_PID
 #  define UT_PID(U) ((U)->ut_pid)
 # else
 #  define UT_PID(U) 0
 # endif
 
+/* Accessor macros for the member named ut_type.  */
+
 # if HAVE_STRUCT_UTMP_UT_TYPE || HAVE_STRUCT_UTMPX_UT_TYPE
 #  define UT_TYPE_EQ(U, V) ((U)->ut_type == (V))
 #  define UT_TYPE_NOT_DEFINED 0
@@ -207,11 +237,17 @@ enum { UT_USER_SIZE = sizeof UT_USER ((STRUCT_UTMP *) 0) };
 #  define UT_TYPE_USER_PROCESS(U) 0
 # endif
 
+/* Determines whether an entry *U corresponds to a user process.  */
 # define IS_USER_PROCESS(U)                                     \
    (UT_USER (U)[0]                                              \
     && (UT_TYPE_USER_PROCESS (U)                                \
         || (UT_TYPE_NOT_DEFINED && UT_TIME_MEMBER (U) != 0)))
 
+/* Define if read_utmp is not just a dummy.  */
+# if HAVE_UTMPX_H || HAVE_UTMP_H
+#  define READ_UTMP_SUPPORTED 1
+# endif
+
 /* Options for read_utmp.  */
 enum
   {
diff --git a/modules/readutmp b/modules/readutmp
index 7f84f189ea..4b2de331dc 100644
--- a/modules/readutmp
+++ b/modules/readutmp
@@ -11,23 +11,18 @@ extensions
 xalloc
 stdbool
 stdint
+sys_time
 fopen-gnu
 unlocked-io-internal
 
 configure.ac:
 gl_READUTMP
-gl_CONDITIONAL([GL_COND_OBJ_READUTMP],
-               [test $ac_cv_header_utmp_h = yes || test $ac_cv_header_utmpx_h = yes])
 
 Makefile.am:
-if GL_COND_OBJ_READUTMP
 lib_SOURCES += readutmp.c
-endif
 
 Include:
-#if HAVE_UTMPX_H || HAVE_UTMP_H
-#include "readutmp.h"
-#endif
+"readutmp.h"
 
 License:
 GPL
diff --git a/tests/test-readutmp.c b/tests/test-readutmp.c
index 1dbf70b351..933808b257 100644
--- a/tests/test-readutmp.c
+++ b/tests/test-readutmp.c
@@ -18,25 +18,23 @@
 
 #include <config.h>
 
-#if HAVE_UTMPX_H || HAVE_UTMP_H
+#include "readutmp.h"
 
-# include "readutmp.h"
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
 
-# include <stddef.h>
-# include <stdio.h>
-# include <stdlib.h>
-# include <string.h>
-# include <time.h>
+#include "xalloc.h"
 
-# include "xalloc.h"
+#define ELEMENT STRUCT_UTMP
+#define COMPARE(entry1, entry2) \
+  _GL_CMP (UT_TIME_MEMBER (entry1), UT_TIME_MEMBER (entry2))
+#define STATIC static
+#include "array-mergesort.h"
 
-# define ELEMENT STRUCT_UTMP
-# define COMPARE(entry1, entry2) \
-   _GL_CMP (UT_TIME_MEMBER (entry1), UT_TIME_MEMBER (entry2))
-# define STATIC static
-# include "array-mergesort.h"
-
-# include "macros.h"
+#include "macros.h"
 
 int
 main (int argc, char *argv[])
@@ -46,7 +44,11 @@ main (int argc, char *argv[])
 
   if (read_utmp (UTMP_FILE, &num_entries, &entries, 0) < 0)
     {
+      #if READ_UTMP_SUPPORTED
       fprintf (stderr, "Skipping test: cannot open %s\n", UTMP_FILE);
+      #else
+      fprintf (stderr, "Skipping test: neither <utmpx.h> nor <utmp.h> is available\n");
+      #endif
       return 77;
     }
 
@@ -99,16 +101,3 @@ main (int argc, char *argv[])
 
   return 0;
 }
-
-#else
-
-# include <stdio.h>
-
-int
-main ()
-{
-  fprintf (stderr, "Skipping test: neither <utmpx.h> nor <utmp.h> is available\n");
-  return 77;
-}
-
-#endif

Message #25 received at 64954-done <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Bruno Haible <bruno <at> clisp.org>, Pádraig Brady
 <P <at> draigbrady.com>
Cc: 64954-done <at> debbugs.gnu.org, bug-gnulib <at> gnu.org
Subject: Re: bug#64954: GNU 'uptime' on OpenBSD always prints "0 users"
Date: Mon, 31 Jul 2023 09:29:09 -0700

Thanks, I propagated that into Coreutils and installed the simplified 
patch I mentioned yesterday. Closing the coreutils bug report.

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