ffi: provide mmap through carray.

* configure: configure test for mmap depositing HAVE_MMAP into
config.h.

* ffi.c (struct carray): Subject to HAVE_MMAP, new mm_len
member which keeps track of the size of an underlying mapping
so that we can unmap it, as well as peform operations like
msync on it.
(make_carray): Initialize mm_len to 0.
(MAP_GROWSDOWN, MAP_LOCKED, MAP_NORESERVE, MAP_POPULATE,
MAP_NONBLOCK, MAP_STACK, MAP_HUGETLB, MAP_SHARED, MAP_PRIVATE,
MAP_FIXED, MAP_ANON, MAP_HUGE_SHIFT, MAP_HUGE_MASK, PROT_READ,
PROT_WRITE, PROT_EXEC, PROT_NONE, PROT_GROWSDOWN,
PROT_GROWSUP, MADV_NORMAL, MADV_RANDOM, MADV_SEQUENTIAL,
MADV_WILLNEED, MADV_DONTNEED, MADV_FREE, MADV_REMOVE,
MADV_DONTFORK, MADV_DOFORK, MADV_MERGEABLE, MADV_UNMERGEABLE,
MADV_HUGEPAGE, MADV_NOHUGEPAGE, MADV_DONTDUMP, MADV_DODUMP,
MADV_WIPEONFORK, MADV_KEEPONFORK, MADV_HWPOISON, MS_ASYNC,
MS_SYNC, MS_INVALIDATE): #define as 0 if missing.

(carray_munmap_op): New static function.
(carray_mmap_ops): New static structure.
(mmap_wrap, munmap_wrap): New functions.
(mmap_op): New static function.
(mprotect_wrap, madvise_wrap, msync_wrap): New functions.
(ffi_init): Register mmap, munmap, mprotect, madvise and msync
as well as numerous integer variables: map-growsdown,
map-locked, map-noreserve, map-populate, map-nonblock,
map-stack, map-hugetlb, map-shared, map-private, map-fixed,
map-anon, map-huge-shift, map-huge-mask, prot-read,
prot-write, prot-exec, prot-none, prot-growsdown,
prot-growsup, madv-normal, madv-random, madv-sequential,
madv-willneed, madv-dontneed, madv-free, madv-remove,
madv-dontfork, madv-dofork, madv-mergeable, madv-unmergeable,
madv-hugepage, madv-nohugepage, madv-dontdump, madv-dodump,
madv-wipeonfork, madv-keeponfork, madv-hwpoison, ms-async,
ms-sync, ms-invalidate, page-size.

* ffi.h (mmap_wrap, munmap_wrap, mprotect_wrap madvise_wrap,
msync_wrap): Declared.

* tests/017/mmap.tl: New file.

* txr.1: Documented.

* stdlib/doc-syms.tl: Updated.

1 files changed, 29 insertions, 0 deletions

diff --git a/configure b/configure
index c710b778..0008f764 100755
--- a/configure
+++ b/configure
@@ -3781,6 +3781,35 @@ else
   printf "no\n"
 fi
 
+printf "Checking for mmap ... "
+cat > conftest.c <<!
+#include <sys/mman.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+int main(void)
+{
+  size_t pgsz = sysconf(_SC_PAGE_SIZE);
+  void *addr = mmap(0, pgsz, PROT_READ | PROT_WRITE | PROT_EXEC,
+                    MAP_PRIVATE | MAP_SHARED, -1, 0);
+  if (addr == MAP_FAILED)
+    return EXIT_FAILURE;
+  mprotect(addr, pgsz, PROT_WRITE);
+  madvise(addr, pgsz, MADV_SEQUENTIAL);
+  msync(addr, pgsz, MS_SYNC);
+  munmap(addr, pgsz);
+  return 0;
+}
+!
+
+if conftest ; then
+  printf "yes\n"
+  printf "#define HAVE_MMAP 1\n" >> config.h
+else
+  printf "no\n"
+fi
+
+
 #
 # Dependent variables
 #