Re: [PATCH] getentropy, getrandom: new modules

[Bruno Haible]

The getrandom module produces a Continuous Integration failure,
see https://gitlab.com/gnulib/gnulib-ci/-/jobs/574033012 . Namely:

  In file included from getentropy.c:24:0:
  ./sys/random.h:8:9: error: conflicting types for 'getrandom'
   ssize_t getrandom (void *, size_t, unsigned int);
           ^~~~~~~~~
  In file included from getentropy.c:21:0:
  ./unistd.h:1512:1: note: previous declaration of 'getrandom' was here
   _GL_FUNCDECL_SYS (getrandom, int, (void *buffer, size_t length,
   ^
  Makefile:8195: recipe for target 'getentropy.o' failed
  make[4]: *** [getentropy.o] Error 1

Namely, there is a declaration in <sys/random.h> with return type 'ssize_t'
and another declaration in <unistd.h> with return type 'int'.

Since
1) The documentation of this function on glibc systems has return type 'ssize_t'
   https://www.gnu.org/software/libc/manual/html_node/Unpredictable-Bytes.html
   https://www.man7.org/linux/man-pages/man2/getrandom.2.html
2) No known system declares the function in <unistd.h> (Solaris 11 has it in
   <sys/random.h>).

I conclude that gnulib does not need to offer this function in <unistd.h>.


2020-05-30  Bruno Haible  <bruno@clisp.org>

        unistd: Remove conflicting declaration of getrandom().
        * lib/unistd.in.h (getrandom): Remove declaration.
        * m4/unistd_h.m4 (gl_UNISTD_H): Don't test whether getrandom is
        declared.
        (gl_UNISTD_H_DEFAULTS): Don't initialize GNULIB_GETRANDOM,
        HAVE_GETRANDOM.
        * modules/unistd (Makefile.am): Don't substitute GNULIB_GETRANDOM,
        HAVE_GETRANDOM.

diff --git a/lib/unistd.in.h b/lib/unistd.in.h
index 4a0d665..906f806 100644
--- a/lib/unistd.in.h
+++ b/lib/unistd.in.h
@@ -1030,24 +1030,6 @@ _GL_WARN_ON_USE (getpass, "getpass is unportable - "
 #endif
 
 
-#if @GNULIB_GETRANDOM@
-/* Fill a buffer with random bytes.  */
-# if !@HAVE_GETRANDOM@
-_GL_FUNCDECL_SYS (getrandom, int, (void *buffer, size_t length,
-                                   unsigned int flags));
-# endif
-_GL_CXXALIAS_SYS (getrandom, int, (void *buffer, size_t length,
-                                   unsigned int flags));
-_GL_CXXALIASWARN (getrandom);
-#elif defined GNULIB_POSIXCHECK
-# undef getrandom
-# if HAVE_RAW_DECL_GETRANDOM
-_GL_WARN_ON_USE (getrandom, "getrandom is unportable - "
-                 "use gnulib module getrandom for portability");
-# endif
-#endif
-
-
 #if @GNULIB_GETUSERSHELL@
 /* Return the next valid login shell on the system, or NULL when the end of
    the list has been reached.  */
diff --git a/m4/unistd_h.m4 b/m4/unistd_h.m4
index 1f39d53..a3b4633 100644
--- a/m4/unistd_h.m4
+++ b/m4/unistd_h.m4
@@ -1,4 +1,4 @@
-# unistd_h.m4 serial 78
+# unistd_h.m4 serial 79
 dnl Copyright (C) 2006-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -44,7 +44,7 @@ AC_DEFUN([gl_UNISTD_H],
     ]], [access chdir chown dup dup2 dup3 environ euidaccess faccessat fchdir
     fchownat fdatasync fsync ftruncate getcwd getdomainname getdtablesize
     getentropy getgroups gethostname getlogin getlogin_r getpagesize getpass
-    getrandom getusershell setusershell endusershell
+    getusershell setusershell endusershell
     group_member isatty lchown link linkat lseek pipe pipe2 pread pwrite
     readlink readlinkat rmdir sethostname sleep symlink symlinkat
     truncate ttyname_r unlink unlinkat usleep])
@@ -90,7 +90,6 @@ AC_DEFUN([gl_UNISTD_H_DEFAULTS],
   GNULIB_GETOPT_POSIX=0;         AC_SUBST([GNULIB_GETOPT_POSIX])
   GNULIB_GETPAGESIZE=0;          AC_SUBST([GNULIB_GETPAGESIZE])
   GNULIB_GETPASS=0;              AC_SUBST([GNULIB_GETPASS])
-  GNULIB_GETRANDOM=0;            AC_SUBST([GNULIB_GETRANDOM])
   GNULIB_GETUSERSHELL=0;         AC_SUBST([GNULIB_GETUSERSHELL])
   GNULIB_GROUP_MEMBER=0;         AC_SUBST([GNULIB_GROUP_MEMBER])
   GNULIB_ISATTY=0;               AC_SUBST([GNULIB_ISATTY])
@@ -137,7 +136,6 @@ AC_DEFUN([gl_UNISTD_H_DEFAULTS],
   HAVE_GETLOGIN=1;        AC_SUBST([HAVE_GETLOGIN])
   HAVE_GETPAGESIZE=1;     AC_SUBST([HAVE_GETPAGESIZE])
   HAVE_GETPASS=1;         AC_SUBST([HAVE_GETPASS])
-  HAVE_GETRANDOM=1;       AC_SUBST([HAVE_GETRANDOM])
   HAVE_GROUP_MEMBER=1;    AC_SUBST([HAVE_GROUP_MEMBER])
   HAVE_LCHOWN=1;          AC_SUBST([HAVE_LCHOWN])
   HAVE_LINK=1;            AC_SUBST([HAVE_LINK])
diff --git a/modules/unistd b/modules/unistd
index dc32ce0..f075b78 100644
--- a/modules/unistd
+++ b/modules/unistd
@@ -63,7 +63,6 @@ unistd.h: unistd.in.h $(top_builddir)/config.status 
$(CXXDEFS_H) $(ARG_NONNULL_H
              -e 's/@''GNULIB_GETOPT_POSIX''@/$(GNULIB_GETOPT_POSIX)/g' \
              -e 's/@''GNULIB_GETPAGESIZE''@/$(GNULIB_GETPAGESIZE)/g' \
              -e 's/@''GNULIB_GETPASS''@/$(GNULIB_GETPASS)/g' \
-             -e 's/@''GNULIB_GETRANDOM''@/$(GNULIB_GETRANDOM)/g' \
              -e 's/@''GNULIB_GETUSERSHELL''@/$(GNULIB_GETUSERSHELL)/g' \
              -e 's/@''GNULIB_GROUP_MEMBER''@/$(GNULIB_GROUP_MEMBER)/g' \
              -e 's/@''GNULIB_ISATTY''@/$(GNULIB_ISATTY)/g' \
@@ -110,7 +109,6 @@ unistd.h: unistd.in.h $(top_builddir)/config.status 
$(CXXDEFS_H) $(ARG_NONNULL_H
              -e 's|@''HAVE_GETHOSTNAME''@|$(HAVE_GETHOSTNAME)|g' \
              -e 's|@''HAVE_GETPAGESIZE''@|$(HAVE_GETPAGESIZE)|g' \
              -e 's|@''HAVE_GETPASS''@|$(HAVE_GETPASS)|g' \
-             -e 's|@''HAVE_GETRANDOM''@|$(HAVE_GETRANDOM)|g' \
              -e 's|@''HAVE_GROUP_MEMBER''@|$(HAVE_GROUP_MEMBER)|g' \
              -e 's|@''HAVE_LCHOWN''@|$(HAVE_LCHOWN)|g' \
              -e 's|@''HAVE_LINK''@|$(HAVE_LINK)|g' \