[PATCH] stdlib: work around MirBSD WEXITSTATUS bug

[Eric Blake]

* lib/stdlib.in.h (includes): Guarantee WEXITSTATUS.
* modules/stdlib (Depends-on): Add sys_wait.
* tests/test-sys_wait.c (main): Enhance test.
* tests/test-stdlib.c (main): Likewise.
* doc/posix-headers/stdlib.texi (stdlib.h): Document the bug.

Signed-off-by: Eric Blake <address@hidden>
---

While debating about whether to fix WEXITSTATUS(constant) for
MacOS, I disovered this POSIX-compliance bug in MirBSD.  Basically,
POSIX guarantees that the system() return value can be parsed
without having to manually drag in <sys/wait.h>.

 ChangeLog                     |    7 +++++++
 doc/posix-headers/stdlib.texi |    4 ++++
 lib/stdlib.in.h               |    5 +++++
 modules/stdlib                |    1 +
 tests/test-stdlib.c           |   32 ++++++++++++++++++++++++++------
 tests/test-sys_wait.c         |   23 ++++++++++++++++++++++-
 6 files changed, 65 insertions(+), 7 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index ffbb1c0..bacfce3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
 2010-09-15  Eric Blake  <address@hidden>

+       stdlib: work around MirBSD WEXITSTATUS bug
+       * lib/stdlib.in.h (includes): Guarantee WEXITSTATUS.
+       * modules/stdlib (Depends-on): Add sys_wait.
+       * tests/test-sys_wait.c (main): Enhance test.
+       * tests/test-stdlib.c (main): Likewise.
+       * doc/posix-headers/stdlib.texi (stdlib.h): Document the bug.
+
        docs: mention MacOS issue with WEXITSTATUS(constant)
        * doc/posix-headers/sys_wait.texi (sys/wait.h): Document the
        issue.
diff --git a/doc/posix-headers/stdlib.texi b/doc/posix-headers/stdlib.texi
index e1d6aba..f400f62 100644
--- a/doc/posix-headers/stdlib.texi
+++ b/doc/posix-headers/stdlib.texi
@@ -17,6 +17,10 @@ stdlib.h
 Some platforms provide a @code{NULL} macro that cannot be used in arbitrary
 expressions:
 NetBSD 5.0
+
address@hidden
+Some platforms fail to provide @code{WEXITSTATUS} and friends:
+MirBSD 10.
 @end itemize

 Portability problems not fixed by Gnulib:
diff --git a/lib/stdlib.in.h b/lib/stdlib.in.h
index d4ac469..0c1c165 100644
--- a/lib/stdlib.in.h
+++ b/lib/stdlib.in.h
@@ -38,6 +38,11 @@
 /* NetBSD 5.0 mis-defines NULL.  */
 #include <stddef.h>

+/* MirBSD 10 fails to define WEXITSTATUS.  */
+#ifndef WEXITSTATUS
+# include <sys/wait.h>
+#endif
+
 /* Solaris declares getloadavg() in <sys/loadavg.h>.  */
 #if (@GNULIB_GETLOADAVG@ || defined GNULIB_POSIXCHECK) && @HAVE_SYS_LOADAVG_H@
 # include <sys/loadavg.h>
diff --git a/modules/stdlib b/modules/stdlib
index 489f70a..f822aa3 100644
--- a/modules/stdlib
+++ b/modules/stdlib
@@ -11,6 +11,7 @@ c++defs
 include_next
 stddef
 stdint
+sys_wait
 unistd
 warn-on-use

diff --git a/tests/test-stdlib.c b/tests/test-stdlib.c
index 4bd8715..8066b05 100644
--- a/tests/test-stdlib.c
+++ b/tests/test-stdlib.c
@@ -22,7 +22,17 @@

 #include "verify.h"

-int exitcode;
+/* Check that EXIT_SUCCESS is 0, per POSIX.  */
+static int exitcode = EXIT_SUCCESS;
+#if EXIT_SUCCESS
+"oops"
+#endif
+
+/* Check for GNU value (not guaranteed by POSIX, but is guaranteed by
+   gnulib).  */
+#if EXIT_FAILURE != 1
+"oops"
+#endif

 /* Check that NULL can be passed through varargs as a pointer type,
    per POSIX 2008.  */
@@ -31,13 +41,23 @@ verify (sizeof NULL == sizeof (void *));
 int
 main (void)
 {
-  /* Check that some macros are defined and different integer constants.  */
-  switch (exitcode)
+  /* Check subset of <sys/wait.h> macros that must be visible here.
+     Note that some of these macros are only portable when operating
+     on an lvalue.  */
+  int i;
+  for (i = 0; i < 0x10000; i = (i ? i << 1 : 1))
+    if (!!WIFSIGNALED (i) + !!WIFEXITED (i) + !!WIFSTOPPED (i) != 1)
+      return 1;
+  i = WEXITSTATUS (i) + WSTOPSIG (i) + WTERMSIG (i);
+
+  switch (i)
     {
-    case EXIT_SUCCESS:
-    case EXIT_FAILURE:
+#if 0
+  /* Gnulib doesn't guarantee these, yet.  */
+    case WNOHANG:
+    case WUNTRACED:
+#endif
       break;
     }
-
   return 0;
 }
diff --git a/tests/test-sys_wait.c b/tests/test-sys_wait.c
index 8c0170e..557aae1 100644
--- a/tests/test-sys_wait.c
+++ b/tests/test-sys_wait.c
@@ -26,5 +26,26 @@ static pid_t a;
 int
 main (void)
 {
-  return a;
+  /* Check for existence of required macros.  Note that we document
+     that these are safe only on lvalues.  */
+  int i;
+  for (i = 0; i < 0x10000; i = (i ? i << 1 : 1))
+    if (!!WIFSIGNALED (i) + !!WIFEXITED (i) + !!WIFSTOPPED (i) != 1)
+      return 1;
+  i = WEXITSTATUS (i) + WSTOPSIG (i) + WTERMSIG (i);
+
+  switch (i)
+    {
+#if 0
+  /* Gnulib doesn't guarantee these, yet.  */
+    case WCONTINUED:
+    case WNOHANG:
+    case WUNTRACED:
+    case WEXITED:
+    case WNOWAIT:
+    case WSTOPPED:
+#endif
+      break;
+    }
+  return a ? i : 0;
 }
-- 
1.7.2.3