posix_spawn_file_actions_add* functions on musl libc

[Bruno Haible]

The gnulib configure test in m4/posix_spawn.m4, when run on Alpine Linux 3.7,
determines that the posix_spawn_file_actions_add* functions do not fail as
expected for an out-of-range file descriptor.

Let me document this in gnulib and update the cross-compilation guess
accordingly.

Rich, FYI: These are the test programs:

#include <spawn.h>
int main ()
{
  posix_spawn_file_actions_t actions;
  if (posix_spawn_file_actions_init (&actions) != 0)
    return 1;
  if (posix_spawn_file_actions_addclose (&actions, 10000000) == 0)
    return 2;
  return 0;
}

#include <spawn.h>
int main ()
{
  posix_spawn_file_actions_t actions;
  if (posix_spawn_file_actions_init (&actions) != 0)
    return 1;
  if (posix_spawn_file_actions_adddup2 (&actions, 10000000, 2) == 0)
    return 2;
  return 0;
}

#include <spawn.h>
#include <fcntl.h>
int main ()
{
  posix_spawn_file_actions_t actions;
  if (posix_spawn_file_actions_init (&actions) != 0)
    return 1;
  if (posix_spawn_file_actions_addopen (&actions, 10000000, "foo", 0, O_RDONLY)
      == 0)
    return 2;
  return 0;
}


2019-03-23  Bruno Haible  <address@hidden>

        posix_spawn_file_actions_*: Document musl libc bugs.
        * doc/posix-functions/posix_spawn_file_actions_addclose.texi: Mention
        the bug.
        * doc/posix-functions/posix_spawn_file_actions_adddup2.texi: Likewise.
        * doc/posix-functions/posix_spawn_file_actions_addopen.texi: Likewise.
        * m4/posix_spawn.m4 (gl_FUNC_POSIX_SPAWN_FILE_ACTIONS_ADDCLOSE): When
        cross-compiling to a musl system, guess no.
        (gl_FUNC_POSIX_SPAWN_FILE_ACTIONS_ADDDUP2): Likewise.
        (gl_FUNC_POSIX_SPAWN_FILE_ACTIONS_ADDOPEN): Likewise.

diff --git a/doc/posix-functions/posix_spawn_file_actions_addclose.texi 
b/doc/posix-functions/posix_spawn_file_actions_addclose.texi
index 199daa1..80418db 100644
--- a/doc/posix-functions/posix_spawn_file_actions_addclose.texi
+++ b/doc/posix-functions/posix_spawn_file_actions_addclose.texi
@@ -13,7 +13,7 @@ This function is missing on some platforms:
 Mac OS X 10.4, FreeBSD 6.0, NetBSD 5.0, OpenBSD 3.8, Minix 3.1.8, AIX 5.1, 
HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 9, Cygwin, mingw, MSVC 14, Interix 3.5, 
BeOS, Android 8.1.
 @item
 This function does not reject a too large file descriptor on some platforms:
-Solaris 11.4.
+musl libc, Solaris 11.4.
 @end itemize
 
 Portability problems not fixed by Gnulib:
diff --git a/doc/posix-functions/posix_spawn_file_actions_adddup2.texi 
b/doc/posix-functions/posix_spawn_file_actions_adddup2.texi
index e515715..985d6bc 100644
--- a/doc/posix-functions/posix_spawn_file_actions_adddup2.texi
+++ b/doc/posix-functions/posix_spawn_file_actions_adddup2.texi
@@ -13,7 +13,7 @@ This function is missing on some platforms:
 Mac OS X 10.4, FreeBSD 6.0, NetBSD 5.0, OpenBSD 3.8, Minix 3.1.8, AIX 5.1, 
HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 9, Cygwin, mingw, MSVC 14, Interix 3.5, 
BeOS, Android 8.1.
 @item
 This function does not reject a too large file descriptor on some platforms:
-Solaris 11.4.
+musl libc, Solaris 11.4.
 @end itemize
 
 Portability problems not fixed by Gnulib:
diff --git a/doc/posix-functions/posix_spawn_file_actions_addopen.texi 
b/doc/posix-functions/posix_spawn_file_actions_addopen.texi
index a7809cf..eea56e3 100644
--- a/doc/posix-functions/posix_spawn_file_actions_addopen.texi
+++ b/doc/posix-functions/posix_spawn_file_actions_addopen.texi
@@ -13,7 +13,7 @@ This function is missing on some platforms:
 Mac OS X 10.4, FreeBSD 6.0, NetBSD 5.0, OpenBSD 3.8, Minix 3.1.8, AIX 5.1, 
HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 9, Cygwin, mingw, MSVC 14, Interix 3.5, 
BeOS, Android 8.1.
 @item
 This function does not reject a too large file descriptor on some platforms:
-Solaris 11.4.
+musl libc, Solaris 11.4.
 @end itemize
 
 Portability problems not fixed by Gnulib:
diff --git a/m4/posix_spawn.m4 b/m4/posix_spawn.m4
index 1e2533c..d50dcc9 100644
--- a/m4/posix_spawn.m4
+++ b/m4/posix_spawn.m4
@@ -1,4 +1,4 @@
-# posix_spawn.m4 serial 15
+# posix_spawn.m4 serial 16
 dnl Copyright (C) 2008-2019 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -422,8 +422,8 @@ AC_DEFUN([gl_FUNC_POSIX_SPAWN_FILE_ACTIONS_ADDCLOSE],
   if test $REPLACE_POSIX_SPAWN = 1; then
     REPLACE_POSIX_SPAWN_FILE_ACTIONS_ADDCLOSE=1
   else
-    dnl On Solaris 11.0, posix_spawn_file_actions_addclose succeeds even
-    dnl if the fd argument is out of range.
+    dnl On musl libc and Solaris 11.0, posix_spawn_file_actions_addclose
+    dnl succeeds even if the fd argument is out of range.
     AC_CACHE_CHECK([whether posix_spawn_file_actions_addclose works],
       [gl_cv_func_posix_spawn_file_actions_addclose_works],
       [AC_RUN_IFELSE(
@@ -440,8 +440,9 @@ int main ()
 }]])],
          [gl_cv_func_posix_spawn_file_actions_addclose_works=yes],
          [gl_cv_func_posix_spawn_file_actions_addclose_works=no],
-         [# Guess no on Solaris, yes otherwise.
+         [# Guess no on musl libc and Solaris, yes otherwise.
           case "$host_os" in
+            *-musl*)  
gl_cv_func_posix_spawn_file_actions_addclose_works="guessing no" ;;
             solaris*) 
gl_cv_func_posix_spawn_file_actions_addclose_works="guessing no" ;;
                       # Guess no on native Windows.
             mingw*)   
gl_cv_func_posix_spawn_file_actions_addclose_works="guessing no" ;;
@@ -465,8 +466,8 @@ AC_DEFUN([gl_FUNC_POSIX_SPAWN_FILE_ACTIONS_ADDDUP2],
   if test $REPLACE_POSIX_SPAWN = 1; then
     REPLACE_POSIX_SPAWN_FILE_ACTIONS_ADDDUP2=1
   else
-    dnl On Solaris 11.0, posix_spawn_file_actions_adddup2 succeeds even
-    dnl if the fd argument is out of range.
+    dnl On musl libc and Solaris 11.0, posix_spawn_file_actions_adddup2
+    dnl succeeds even if the fd argument is out of range.
     AC_CACHE_CHECK([whether posix_spawn_file_actions_adddup2 works],
       [gl_cv_func_posix_spawn_file_actions_adddup2_works],
       [AC_RUN_IFELSE(
@@ -483,8 +484,9 @@ int main ()
 }]])],
          [gl_cv_func_posix_spawn_file_actions_adddup2_works=yes],
          [gl_cv_func_posix_spawn_file_actions_adddup2_works=no],
-         [# Guess no on Solaris, yes otherwise.
+         [# Guess no on musl libc and Solaris, yes otherwise.
           case "$host_os" in
+            *-musl*)  
gl_cv_func_posix_spawn_file_actions_adddup2_works="guessing no";;
             solaris*) 
gl_cv_func_posix_spawn_file_actions_adddup2_works="guessing no";;
                       # Guess no on native Windows.
             mingw*)   
gl_cv_func_posix_spawn_file_actions_adddup2_works="guessing no" ;;
@@ -508,8 +510,8 @@ AC_DEFUN([gl_FUNC_POSIX_SPAWN_FILE_ACTIONS_ADDOPEN],
   if test $REPLACE_POSIX_SPAWN = 1; then
     REPLACE_POSIX_SPAWN_FILE_ACTIONS_ADDOPEN=1
   else
-    dnl On Solaris 11.0, posix_spawn_file_actions_addopen succeeds even
-    dnl if the fd argument is out of range.
+    dnl On musl libc and Solaris 11.0, posix_spawn_file_actions_addopen
+    dnl succeeds even if the fd argument is out of range.
     AC_CACHE_CHECK([whether posix_spawn_file_actions_addopen works],
       [gl_cv_func_posix_spawn_file_actions_addopen_works],
       [AC_RUN_IFELSE(
@@ -528,8 +530,9 @@ int main ()
 }]])],
          [gl_cv_func_posix_spawn_file_actions_addopen_works=yes],
          [gl_cv_func_posix_spawn_file_actions_addopen_works=no],
-         [# Guess no on Solaris, yes otherwise.
+         [# Guess no on musl libc and Solaris, yes otherwise.
           case "$host_os" in
+            *-musl*)  
gl_cv_func_posix_spawn_file_actions_addopen_works="guessing no";;
             solaris*) 
gl_cv_func_posix_spawn_file_actions_addopen_works="guessing no";;
                       # Guess no on native Windows.
             mingw*)   
gl_cv_func_posix_spawn_file_actions_addopen_works="guessing no" ;;