source: azure_iot_hub/trunk/musl-1.1.18/src/mman/mmap.c@ 388

#include <unistd.h>
#include <sys/mman.h>
#include <errno.h>
#include <stdint.h>
#include <limits.h>
#include "syscall.h"
#include "libc.h"

#ifndef __c2__
static void dummy(void) { }
weak_alias(dummy, __vm_wait);
#else
extern void __vm_wait(void);
#endif

#define UNIT SYSCALL_MMAP2_UNIT
#define OFF_MASK ((-0x2000ULL << (8*sizeof(syscall_arg_t)-1)) | (UNIT-1))

void *__mmap(void *start, size_t len, int prot, int flags, int fd, off_t off)
{
        long ret;
        if (off & OFF_MASK) {
                errno = EINVAL;
                return MAP_FAILED;
        }
        if (len >= PTRDIFF_MAX) {
                errno = ENOMEM;
                return MAP_FAILED;
        }
        if (flags & MAP_FIXED) {
                __vm_wait();
        }
#ifdef SYS_mmap2
        ret = __syscall(SYS_mmap2, start, len, prot, flags, fd, off/UNIT);
#else
        ret = __syscall(SYS_mmap, start, len, prot, flags, fd, off);
#endif
        /* Fixup incorrect EPERM from kernel. */
        if (ret == -EPERM && !start && (flags&MAP_ANON) && !(flags&MAP_FIXED))
                ret = -ENOMEM;
        return (void *)__syscall_ret(ret);
}

#ifndef __c2__
weak_alias(__mmap, mmap);
#else
void *mmap(void *start, size_t len, int prot, int flags, int fd, off_t off)
{
        return __mmap(start, len, prot, flags, fd, off);
}
#endif

LFS64(mmap);