nasmlib/file: move memory-mapping functions out of file.c

Move memory-mapping functions from file.c into a separate mmap.c.
This will be cleaner especially once (if) we end up doing a Windows
implementation, which is likely to look entirely different.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

3 files changed, 241 insertions, 158 deletions

diff --git a/nasmlib/file.c b/nasmlib/file.c
index 1f1e63bc..a6e7d565 100644
--- a/nasmlib/file.c
+++ b/nasmlib/file.c
@@ -31,69 +31,7 @@
  *
  * ----------------------------------------------------------------------- */
 
-#include "compiler.h"
-#include "nasmlib.h"
-
-#include <errno.h>
-
-#ifdef HAVE_FCNTL_H
-# include <fcntl.h>
-#endif
-#ifdef HAVE_SYS_STAT_H
-# include <sys/stat.h>
-#endif
-#ifdef HAVE_IO_H
-# include <io.h>
-#endif
-#ifdef HAVE_UNISTD_H
-# include <unistd.h>
-#endif
-#ifdef HAVE_SYS_MMAN_H
-# include <sys/mman.h>
-#endif
-
-#if !defined(HAVE_FILENO) && defined(HAVE__FILENO)
-# define HAVE_FILENO 1
-# define fileno _fileno
-#endif
-
-#if !defined(HAVE_ACCESS) && defined(HAVE__ACCESS)
-# define HAVE_ACCESS 1
-# define access _access
-#endif
-#ifndef R_OK
-# define R_OK 4                 /* Classic Unix constant, same on Windows */
-#endif
-
-/* Can we adjust the file size without actually writing all the bytes? */
-#ifdef HAVE_FILENO		/* Useless without fileno() */
-# ifdef HAVE__CHSIZE_S
-#  define nasm_ftruncate(fd,size) _chsize_s(fd,size)
-# elif defined(HAVE__CHSIZE)
-#  define nasm_ftruncate(fd,size) _chsize(fd,size)
-# elif defined(HAVE_FTRUNCATE)
-#  define nasm_ftruncate(fd,size) ftruncate(fd,size)
-# endif
-#endif
-
-/*
- * On Win32, stat has a 32-bit file size but _stati64 has a 64-bit file
- * size.  However, as "stat" is already a macro, don't confuse the situation
- * further by redefining it, instead we create our own.
- */
-#ifdef HAVE__STATI64
-# define nasm_stat _stati64
-#elif defined(HAVE_STAT)
-# define nasm_stat stat
-#endif
-
-#ifdef HAVE_FILENO
-# ifdef HAVE__FSTATI64
-#  define nasm_fstat _fstati64
-# elif defined(HAVE_FSTAT)
-#  define nasm_fstat fstat
-# endif
-#endif
+#include "file.h"
 
 void nasm_write(const void *ptr, size_t size, FILE *f)
 {
@@ -291,98 +229,3 @@ off_t nasm_file_size_by_path(const char *pathname)
     return len;
 #endif
 }
-
-/*
- * System page size
- *
- * Not needed unless we have mmap(), and can cause compile failures,
- * e.g. on MinGW32, so we #if around it.
- */
-#if defined(HAVE_FILENO) && defined(HAVE_MMAP)
-
-/* File scope since not all compilers like static data in inline functions */
-static size_t nasm_pagemask;
-
-static size_t get_pagemask(void)
-{
-    size_t ps = 0;
-
-# if defined(HAVE_SYSCONF) && defined(_SC_PAGESIZE)
-    ps = sysconf(_SC_PAGESIZE);
-# elif defined(HAVE_GETPAGESIZE)
-    ps = getpagesize();
-# endif
-
-    nasm_pagemask = ps = is_power2(ps) ? (ps - 1) : 0;
-    return ps;
-}
-
-static inline size_t pagemask(void)
-{
-    size_t pm = nasm_pagemask;
-
-    if (unlikely(!pm))
-        return get_pagemask();
-
-    return pm;
-}
-
-#endif
-
-/*
- * Try to map an input file into memory
- */
-const void *nasm_map_file(FILE *fp, off_t start, off_t len)
-{
-#if defined(HAVE_FILENO) && defined(HAVE_MMAP)
-   const char *p;
-    off_t  astart;              /* Aligned start */
-    size_t salign;              /* Amount of start adjustment */
-    size_t alen;                /* Aligned length */
-    const size_t page_mask = pagemask();
-
-    if (unlikely(!page_mask))
-        return NULL;            /* Page size undefined? */
-
-    if (unlikely(!len))
-        return NULL;            /* Mapping nothing... */
-
-    if (unlikely(len != (off_t)(size_t)len))
-        return NULL;            /* Address space insufficient */
-
-    astart = start & ~(off_t)page_mask;
-    salign = start - astart;
-    alen = (len + salign + page_mask) & ~page_mask;
-
-    p = mmap(NULL, alen, PROT_READ, MAP_SHARED, fileno(fp), astart);
-    return unlikely(p == MAP_FAILED) ? NULL : p + salign;
-#else
-    /* XXX: add Windows support? */
-    (void)fp; (void)start; (void)len;
-    return NULL;
-#endif
-}
-
-/*
- * Unmap an input file
- */
-void nasm_unmap_file(const void *p, size_t len)
-{
-#if defined(HAVE_FILENO) && defined(HAVE_MMAP)
-    const size_t page_mask = pagemask();
-    uintptr_t astart;
-    size_t salign;
-    size_t alen;
-
-    if (unlikely(!page_mask))
-        return;
-
-    astart = (uintptr_t)p & ~(uintptr_t)page_mask;
-    salign = (uintptr_t)p - astart;
-    alen = (len + salign + page_mask) & ~page_mask;
-
-    munmap((void *)astart, alen);
-#else
-    (void)p; (void)len;
-#endif
-}
diff --git a/nasmlib/file.h b/nasmlib/file.h
new file mode 100644
index 00000000..85957938
--- /dev/null
+++ b/nasmlib/file.h
@@ -0,0 +1,101 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 1996-2017 The NASM Authors - All Rights Reserved
+ *   See the file AUTHORS included with the NASM distribution for
+ *   the specific copyright holders.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following
+ *   conditions are met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above
+ *     copyright notice, this list of conditions and the following
+ *     disclaimer in the documentation and/or other materials provided
+ *     with the distribution.
+ *
+ *     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ *     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ *     INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ *     MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ *     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ *     CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ *     NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ *     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ *     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ *     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ *     OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+ *     EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * ----------------------------------------------------------------------- */
+
+#ifndef NASMLIB_FILE_H
+#define NASMLIB_FILE_H
+
+#include "compiler.h"
+#include "nasmlib.h"
+
+#include <errno.h>
+
+#ifdef HAVE_FCNTL_H
+# include <fcntl.h>
+#endif
+#ifdef HAVE_SYS_STAT_H
+# include <sys/stat.h>
+#endif
+#ifdef HAVE_IO_H
+# include <io.h>
+#endif
+#ifdef HAVE_UNISTD_H
+# include <unistd.h>
+#endif
+#ifdef HAVE_SYS_MMAN_H
+# include <sys/mman.h>
+#endif
+
+#if !defined(HAVE_FILENO) && defined(HAVE__FILENO)
+# define HAVE_FILENO 1
+# define fileno _fileno
+#endif
+
+#if !defined(HAVE_ACCESS) && defined(HAVE__ACCESS)
+# define HAVE_ACCESS 1
+# define access _access
+#endif
+#ifndef R_OK
+# define R_OK 4                 /* Classic Unix constant, same on Windows */
+#endif
+
+/* Can we adjust the file size without actually writing all the bytes? */
+#ifdef HAVE_FILENO		/* Useless without fileno() */
+# ifdef HAVE__CHSIZE_S
+#  define nasm_ftruncate(fd,size) _chsize_s(fd,size)
+# elif defined(HAVE__CHSIZE)
+#  define nasm_ftruncate(fd,size) _chsize(fd,size)
+# elif defined(HAVE_FTRUNCATE)
+#  define nasm_ftruncate(fd,size) ftruncate(fd,size)
+# endif
+#endif
+
+/*
+ * On Win32, stat has a 32-bit file size but _stati64 has a 64-bit file
+ * size.  However, as "stat" is already a macro, don't confuse the situation
+ * further by redefining it, instead we create our own.
+ */
+#ifdef HAVE__STATI64
+# define nasm_stat _stati64
+#elif defined(HAVE_STAT)
+# define nasm_stat stat
+#endif
+
+#ifdef HAVE_FILENO
+# ifdef HAVE__FSTATI64
+#  define nasm_fstat _fstati64
+# elif defined(HAVE_FSTAT)
+#  define nasm_fstat fstat
+# endif
+#endif
+
+#endif /* NASMLIB_FILE_H */
diff --git a/nasmlib/mmap.c b/nasmlib/mmap.c
new file mode 100644
index 00000000..5fc5646f
--- /dev/null
+++ b/nasmlib/mmap.c
@@ -0,0 +1,139 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 1996-2017 The NASM Authors - All Rights Reserved
+ *   See the file AUTHORS included with the NASM distribution for
+ *   the specific copyright holders.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following
+ *   conditions are met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above
+ *     copyright notice, this list of conditions and the following
+ *     disclaimer in the documentation and/or other materials provided
+ *     with the distribution.
+ *
+ *     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ *     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ *     INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ *     MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ *     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ *     CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ *     NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ *     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ *     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ *     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ *     OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+ *     EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * ----------------------------------------------------------------------- */
+
+#include "file.h"
+
+/* ----------------------------------------------------------------------- *
+ *   Unix-style memory mapping, using mmap().
+ * ----------------------------------------------------------------------- */
+#if defined(HAVE_FILENO) && defined(HAVE_MMAP)
+
+/*
+ * System page size
+ */
+
+/* File scope since not all compilers like static data in inline functions */
+static size_t nasm_pagemask;
+
+static size_t get_pagemask(void)
+{
+    size_t ps = 0;
+
+# if defined(HAVE_SYSCONF) && defined(_SC_PAGESIZE)
+    ps = sysconf(_SC_PAGESIZE);
+# elif defined(HAVE_GETPAGESIZE)
+    ps = getpagesize();
+# elif defined(PAGE_SIZE)
+    ps = PAGE_SIZE;
+# endif
+
+    nasm_pagemask = ps = is_power2(ps) ? (ps - 1) : 0;
+    return ps;
+}
+
+static inline size_t pagemask(void)
+{
+    size_t pm = nasm_pagemask;
+
+    if (unlikely(!pm))
+        return get_pagemask();
+
+    return pm;
+}
+
+/*
+ * Try to map an input file into memory
+ */
+const void *nasm_map_file(FILE *fp, off_t start, off_t len)
+{
+    const char *p;
+    off_t  astart;              /* Aligned start */
+    size_t salign;              /* Amount of start adjustment */
+    size_t alen;                /* Aligned length */
+    const size_t page_mask = pagemask();
+
+    if (unlikely(!page_mask))
+        return NULL;            /* Page size undefined? */
+
+    if (unlikely(!len))
+        return NULL;            /* Mapping nothing... */
+
+    if (unlikely(len != (off_t)(size_t)len))
+        return NULL;            /* Address space insufficient */
+
+    astart = start & ~(off_t)page_mask;
+    salign = start - astart;
+    alen = (len + salign + page_mask) & ~page_mask;
+
+    p = mmap(NULL, alen, PROT_READ, MAP_SHARED, fileno(fp), astart);
+    return unlikely(p == MAP_FAILED) ? NULL : p + salign;
+}
+
+/*
+ * Unmap an input file
+ */
+void nasm_unmap_file(const void *p, size_t len)
+{
+    const size_t page_mask = pagemask();
+    uintptr_t astart;
+    size_t salign;
+    size_t alen;
+
+    if (unlikely(!page_mask))
+        return;
+
+    astart = (uintptr_t)p & ~(uintptr_t)page_mask;
+    salign = (uintptr_t)p - astart;
+    alen = (len + salign + page_mask) & ~page_mask;
+
+    munmap((void *)astart, alen);
+}
+
+/* ----------------------------------------------------------------------- *
+ *   No memory map support at all
+ *   XXX: Add a section with Windows support
+ * ----------------------------------------------------------------------- */
+#else
+
+const void *nasm_map_file(FILE *fp, off_t start, off_t len)
+{
+    (void)fp; (void)start; (void)len;
+    return NULL;
+}
+
+void nasm_unmap_file(const void *p, size_t len)
+{
+    (void)p; (void)len;
+}
+
+#endif