posix_spawn_file_actions_addchdir: New module.

Suggested by Eric Blake in
<https://lists.gnu.org/archive/html/bug-findutils/2018-09/msg00007.html>.

* lib/spawn.in.h (posix_spawn_file_actions_addchdir): New declaration.
* lib/spawn_int.h (struct __spawn_action): Add tag 'spawn_do_chdir' and
union member 'chdir_action'.
* lib/spawn_faction_addchdir.c: New file.
* lib/spawni.c (__spawni): Implement the spawn_do_chdir action.
* lib/spawn_faction_addclose.c: Test REPLACE_POSIX_SPAWN instead of
HAVE_WORKING_POSIX_SPAWN.
* lib/spawn_faction_adddup2.c: Likewise.
* lib/spawn_faction_addopen.c: Likewise.
* m4/posix_spawn_faction_addchdir.m4: New file.
* m4/posix_spawn.m4 (gl_POSIX_SPAWN_BODY): Test whether module
'posix_spawn_file_actions_addchdir' is present and whether
posix_spawn_file_actions_addchdir_np exists. Define REPLACE_POSIX_SPAWN
instead of HAVE_WORKING_POSIX_SPAWN.
* m4/spawn_h.m4 (gl_SPAWN_H): Test whether
posix_spawn_file_actions_addchdir is declared.
(gl_SPAWN_H_DEFAULTS): Initialize
GNULIB_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR,
HAVE_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR,
REPLACE_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR.
* modules/spawn (Makefile.am): Substitute
GNULIB_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR,
HAVE_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR,
REPLACE_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR.
* modules/posix_spawn_file_actions_addchdir: New file.
* modules/posix_spawn_file_actions_addclose (Depends-on,
configure.ac): Test also REPLACE_POSIX_SPAWN.
* modules/posix_spawn_file_actions_adddup2 (Depends-on,
configure.ac): Likewise.
* modules/posix_spawn_file_actions_addopen (Depends-on,
configure.ac): Likewise.
* tests/test-spawn-c++.cc (posix_spawn_file_actions_addchdir): Check
signature.
* doc/posix-functions/posix_spawn.texi: Mention the new module.
* doc/posix-functions/posix_spawnp.texi: Likewise.

1 files changed, 35 insertions, 0 deletions

diff --git a/lib/spawn.in.h b/lib/spawn.in.h
index a606176523..7460c651b6 100644
--- a/lib/spawn.in.h
+++ b/lib/spawn.in.h
@@ -878,6 +878,41 @@ _GL_WARN_ON_USE (posix_spawn_file_actions_adddup2,
 # endif
 #endif
 
+#if @GNULIB_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR@
+/* Add an action to FILE-ACTIONS which tells the implementation to call
+   'chdir' to the given directory during the 'spawn' call.  */
+# if @REPLACE_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   define posix_spawn_file_actions_addchdir rpl_posix_spawn_file_actions_addchdir
+#  endif
+_GL_FUNCDECL_RPL (posix_spawn_file_actions_addchdir, int,
+                  (posix_spawn_file_actions_t *_Restrict_ __file_actions,
+                   const char *_Restrict_ __path)
+                  __THROW _GL_ARG_NONNULL ((1, 2)));
+_GL_CXXALIAS_RPL (posix_spawn_file_actions_addchdir, int,
+                  (posix_spawn_file_actions_t *_Restrict_ __file_actions,
+                   const char *_Restrict_ __path));
+# else
+#  if !@HAVE_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR@
+_GL_FUNCDECL_SYS (posix_spawn_file_actions_addchdir, int,
+                  (posix_spawn_file_actions_t *_Restrict_ __file_actions,
+                   const char *_Restrict_ __path)
+                  __THROW _GL_ARG_NONNULL ((1, 2)));
+#  endif
+_GL_CXXALIAS_SYS (posix_spawn_file_actions_addchdir, int,
+                  (posix_spawn_file_actions_t *_Restrict_ __file_actions,
+                   const char *_Restrict_ __path));
+# endif
+_GL_CXXALIASWARN (posix_spawn_file_actions_addchdir);
+#elif defined GNULIB_POSIXCHECK
+# undef posix_spawn_file_actions_addchdir
+# if HAVE_RAW_DECL_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR
+_GL_WARN_ON_USE (posix_spawn_file_actions_addchdir,
+                 "posix_spawn_file_actions_addchdir is unportable - "
+                 "use gnulib module posix_spawn_file_actions_addchdir for portability");
+# endif
+#endif
+
 
 #endif /* _@GUARD_PREFIX@_SPAWN_H */
 #endif /* _@GUARD_PREFIX@_SPAWN_H */