There was an implicit request on the user-guile mailing list (20 Jul 2017) to
provide a scheme language call to mmap.
I am working on a prototype and will post when I get a simple case working.
Here is non-working code so far:
Currently I have this in a file “mmap.c” and #including into filesys.c.
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#ifdef HAVE_SYS_MMAN_H
# include <sys/mman.h>
#endif
#include "libguile/_scm.h"
#include "libguile/smob.h"
#include "libguile/fdes-finalizers.h"
#include "libguile/feature.h"
SCM_API SCM scm_mmap (SCM addr, SCM len, SCM prot, SCM flags, SCM fd,
SCM offset);
SCM_API SCM scm_munmap (SCM addr, SCM len);
#if defined(HAVE_SYS_MMAN_H) && defined(HAVE_MAP_ANONYMOUS)
// python mmap makes the last four args optional
// should use fd=-1 default on mac
SCM_DEFINE (scm_mmap, "mmap", 6, 0, 0,
(SCM addr, SCM len, SCM prot, SCM flags, SCM fd, SCM offset),
"See the man page. returns a foreign pointer which one would"
"ordinarily convert to bytevector using pointer->bytevector. "
"Note that the region returned by mmap is not (?) searched "
"by the garbage collector."
"@example\n(define reg\n (pointer->bytevector\n "
"(mmap %void-pointer #x10000 (logior PROT_READ PROT_WRITE) "
"MAP_ANON -1 0) #x1000))"
"@end example"
)
#define FUNC_NAME s_scm_mmap
{
void *c_mem, *c_addr;
size_t c_len;
int c_prot, c_flags, c_fd;
scm_t_off c_offset;
SCM ret;
SCM_VALIDATE_POINTER (1, addr);
c_addr = (void *) SCM_POINTER_VALUE (addr);
c_len = scm_to_size_t (len);
c_prot = scm_to_int (prot);
c_flags = scm_to_int (flags);
c_fd = scm_to_int (fd);
c_offset = SCM_UNBNDP (offset) ? 0: scm_to_off_t (offset);
c_mem = mmap(c_addr, c_len, c_prot, c_flags, c_fd, c_offset);
ret = scm_from_pointer (c_mem, NULL);
return ret;
}
#undef FUNC_NAME
SCM_DEFINE (scm_munmap, "munmap", 2, 0, 0,
(SCM addr, SCM len),
"See the man page. Given foreign pointer unmap."
)
#define FUNC_NAME s_scm_munmap
{
void *c_addr;
size_t c_len;
int c_res;
SCM res;
SCM_VALIDATE_POINTER (1, addr);
c_addr = (void *) SCM_POINTER_VALUE (addr);
c_len = scm_to_size_t (len);
c_res = munmap(c_addr, c_len);
res = scm_from_int (c_res);
return res;
}
#endif /* HAVE_SYS_MMAN_H */
#if defined(HAVE_SYS_MMAN_H) && defined(HAVE_MAP_ANONYMOUS)
#define MMAP_DEFS \
scm_c_define ("PROT_NONE", scm_from_int (PROT_NONE)); \
scm_c_define ("PROT_READ", scm_from_int (PROT_READ)); \
scm_c_define ("PROT_WRITE", scm_from_int (PROT_WRITE)); \
scm_c_define ("PROT_EXEC", scm_from_int (PROT_EXEC)); \
\
scm_c_define ("MAP_ANONYMOUS", scm_from_int (MAP_ANONYMOUS)); \
scm_c_define ("MAP_ANON", scm_from_int (MAP_ANON)); \
scm_c_define ("MAP_FILE", scm_from_int (MAP_FILE)); \
scm_c_define ("MAP_FIXED", scm_from_int (MAP_FIXED)); \
scm_c_define ("MAP_HASSEMAPHORE", scm_from_int (MAP_HASSEMAPHORE)); \
scm_c_define ("MAP_PRIVATE", scm_from_int (MAP_PRIVATE)); \
scm_c_define ("MAP_SHARED", scm_from_int (MAP_SHARED)); \
scm_c_define ("MAP_NOCACHE", scm_from_int (MAP_NOCACHE))
#else
#define MMAP_DEFS /* */
#endif /* HAVE_SYS_MMAN_H */
