added mmap_anon to osdep lib. Used in loader for now

git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@21203 b3059339-0415-0410-9bf9-f77b7e298cf2

3 files changed, 76 insertions, 0 deletions

diff --git a/osdep/Makefile b/osdep/Makefile
index a5ee59201e..abd38716b1 100644
--- a/osdep/Makefile
+++ b/osdep/Makefile
@@ -12,6 +12,7 @@ SRCS= shmem.c \
       fseeko.c \
       swab.c \
       setenv.c \
+      mmap_anon.c \
       # timer.c \
 
 getch = getch2.c
diff --git a/osdep/mmap_anon.c b/osdep/mmap_anon.c
new file mode 100644
index 0000000000..b6d0b7cf35
--- /dev/null
+++ b/osdep/mmap_anon.c
@@ -0,0 +1,67 @@
+ /**
+ * \file mmap_anon.c
+ * \brief Provide a compatible anonymous space mapping function
+ */
+
+#include <sys/mman.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#if defined(MAP_ANON) && !defined(MAP_ANONYMOUS)
+#define MAP_ANONYMOUS MAP_ANON
+#endif
+
+/*
+ * mmap() anonymous space, depending on the system's mmap() style. On systems
+ * that use the /dev/zero mapping idiom, zerofd will be set to the file descriptor
+ * of the opened /dev/zero. 
+ */
+ 
+ /**
+ * \brief mmap() anonymous space, depending on the system's mmap() style. On systems
+ * that use the /dev/zero mapping idiom, zerofd will be set to the file descriptor
+ * of the opened /dev/zero.
+ *
+ * \param addr address to map at.
+ * \param len number of bytes from addr to be mapped.
+ * \param prot protections (region accessibility).
+ * \param flags specifies the type of the mapped object.
+ * \param offset start mapping at byte offset.
+ * \param zerofd 
+ * \return a pointer to the mapped region upon successful completion, -1 otherwise.
+ */
+void *mmap_anon(void *addr, size_t len, int prot, int flags, int *zerofd, off_t offset)
+{
+    int fd;
+    void *result;
+
+     /* From loader/ext.c:
+      * "Linux EINVAL's on us if we don't pass MAP_PRIVATE to an anon mmap"
+      * Therefore we preserve the same behavior on all platforms, ie. no
+      * shared mappings of anon space (if the concepts are supported). */
+#if defined(MAP_SHARED) && defined(MAP_PRIVATE)
+     flags = (flags & ~MAP_SHARED) | MAP_PRIVATE;
+#endif /* defined(MAP_SHARED) && defined(MAP_PRIVATE) */
+
+#ifdef MAP_ANONYMOUS
+    /* BSD-style anonymous mapping */
+    fd = -1;
+    result = mmap(addr, len, prot, flags | MAP_ANONYMOUS, -1, offset);
+#else
+    /* SysV-style anonymous mapping */
+    fd = open("/dev/zero", O_RDWR);
+    if(fd < 0){
+        perror( "Cannot open /dev/zero for READ+WRITE. Check permissions! error: ");
+        return NULL;
+    }
+
+    result = mmap(addr, len, prot, flags, fd, offset);
+#endif /* MAP_ANONYMOUS */
+
+    if (zerofd)
+        *zerofd = fd;
+
+    return result;
+}
+
diff --git a/osdep/mmap_anon.h b/osdep/mmap_anon.h
new file mode 100644
index 0000000000..edb909bdc0
--- /dev/null
+++ b/osdep/mmap_anon.h
@@ -0,0 +1,8 @@
+#ifndef _OSDEP_MMAP_ANON_H_
+#define _OSDEP_MMAP_ANON_H_
+
+#include <sys/types.h>
+
+void *mmap_anon(void *, size_t, int, int, int *, off_t);
+
+#endif /* _OSDEP_MMAP_ANON_H_ */