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support loading objcode even if mmap(2) is unavailable

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* configure.ac: Check for sys/mman.h.

* libguile/objcodes.c (verify_cookie): Factor cookie verification out to
  a helper function.
  (make_objcode_from_file): Rename from make_objcode_by_mmap.  If mmap
  is unavailable, just read(2) to a bytevector.
This commit is contained in:
Andy Wingo 2011-04-01 12:10:42 +02:00
parent 355dd8cb4b
commit 13a78b0fd7
2 changed files with 118 additions and 52 deletions
Download patch file Download diff file Expand all files Collapse all files

2
configure.ac
View file

@ -773,7 +773,7 @@ AC_CHECK_FUNCS([DINFINITY DQNAN cexp chsize clog clog10 ctermid fesetround ftime
# cuserid - on Tru64 5.1b the declaration is documented to be available
# only with `_XOPEN_SOURCE' or some such.
#
AC_CHECK_HEADERS([crypt.h netdb.h pthread.h sys/param.h sys/resource.h sys/file.h])
AC_CHECK_HEADERS([crypt.h netdb.h pthread.h sys/param.h sys/resource.h sys/file.h sys/mman.h])
AC_CHECK_FUNCS(chroot flock getlogin cuserid getpriority setpriority getpass sethostname gethostname)
AC_CHECK_DECLS([sethostname, hstrerror, cuserid])

168
libguile/objcodes.c
View file

@ -23,12 +23,18 @@
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#ifdef HAVE_SYS_MMAN_H
#include <sys/mman.h>
#endif
#include <sys/stat.h>
#include <sys/types.h>
#include <assert.h>
#include <alignof.h>
#include <full-read.h>
#include "_scm.h"
#include "programs.h"
#include "objcodes.h"
@ -44,6 +50,52 @@ verify (((sizeof (SCM_OBJCODE_COOKIE) - 1) & 7) == 0);
* Objcode type
*/
static void
verify_cookie (char *cookie, struct stat *st, int map_fd, void *map_addr)
#define FUNC_NAME "make_objcode_from_file"
{
/* The cookie ends with a version of the form M.N, where M is the
major version and N is the minor version. For this Guile to be
able to load an objcode, M must be SCM_OBJCODE_MAJOR_VERSION, and N
must be less than or equal to SCM_OBJCODE_MINOR_VERSION. Since N
is the last character, we do a strict comparison on all but the
last, then a <= on the last one. */
if (memcmp (cookie, SCM_OBJCODE_COOKIE, strlen (SCM_OBJCODE_COOKIE) - 1))
{
SCM args = scm_list_1 (scm_from_latin1_stringn
(cookie, strlen (SCM_OBJCODE_COOKIE)));
if (map_fd >= 0)
{
(void) close (map_fd);
#ifdef HAVE_SYS_MMAN_H
(void) munmap (map_addr, st->st_size);
#endif
}
scm_misc_error (FUNC_NAME, "bad header on object file: ~s", args);
}
{
char minor_version = cookie[strlen (SCM_OBJCODE_COOKIE) - 1];
if (minor_version > SCM_OBJCODE_MINOR_VERSION_STRING[0])
{
if (map_fd >= 0)
{
(void) close (map_fd);
#ifdef HAVE_SYS_MMAN_H
(void) munmap (map_addr, st->st_size);
#endif
}
scm_misc_error (FUNC_NAME, "objcode minor version too new (~a > ~a)",
scm_list_2 (scm_from_latin1_stringn (&minor_version, 1),
scm_from_latin1_string
(SCM_OBJCODE_MINOR_VERSION_STRING)));
}
}
}
#undef FUNC_NAME
/* The words in an objcode SCM object are as follows:
- scm_tc7_objcode | type | flags
- the struct scm_objcode C object
@ -53,77 +105,91 @@ verify (((sizeof (SCM_OBJCODE_COOKIE) - 1) & 7) == 0);
*/
static SCM
make_objcode_by_mmap (int fd)
#define FUNC_NAME "make_objcode_by_mmap"
make_objcode_from_file (int fd)
#define FUNC_NAME "make_objcode_from_file"
{
int ret;
char *addr;
/* The SCM_OBJCODE_COOKIE is a string literal, and thus has an extra
trailing NUL, hence the - 1. */
char cookie[sizeof (SCM_OBJCODE_COOKIE) - 1];
struct stat st;
SCM sret = SCM_BOOL_F;
struct scm_objcode *data;
ret = fstat (fd, &st);
if (ret < 0)
SCM_SYSERROR;
if (st.st_size <= sizeof (struct scm_objcode) + strlen (SCM_OBJCODE_COOKIE))
if (st.st_size <= sizeof (struct scm_objcode) + sizeof cookie)
scm_misc_error (FUNC_NAME, "object file too small (~a bytes)",
scm_list_1 (SCM_I_MAKINUM (st.st_size)));
addr = mmap (0, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
if (addr == MAP_FAILED)
{
(void) close (fd);
SCM_SYSERROR;
}
/* The cookie ends with a version of the form M.N, where M is the
major version and N is the minor version. For this Guile to be
able to load an objcode, M must be SCM_OBJCODE_MAJOR_VERSION, and N
must be less than or equal to SCM_OBJCODE_MINOR_VERSION. Since N
is the last character, we do a strict comparison on all but the
last, then a <= on the last one. */
if (memcmp (addr, SCM_OBJCODE_COOKIE, strlen (SCM_OBJCODE_COOKIE) - 1))
{
SCM args = scm_list_1 (scm_from_latin1_stringn
(addr, strlen (SCM_OBJCODE_COOKIE)));
(void) close (fd);
(void) munmap (addr, st.st_size);
scm_misc_error (FUNC_NAME, "bad header on object file: ~s", args);
}
#ifdef HAVE_SYS_MMAN_H
{
char minor_version = addr[strlen (SCM_OBJCODE_COOKIE) - 1];
char *addr;
struct scm_objcode *data;
if (minor_version > SCM_OBJCODE_MINOR_VERSION_STRING[0])
scm_misc_error (FUNC_NAME, "objcode minor version too new (~a > ~a)",
scm_list_2 (scm_from_latin1_stringn (&minor_version, 1),
scm_from_latin1_string
(SCM_OBJCODE_MINOR_VERSION_STRING)));
addr = mmap (0, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
if (addr == MAP_FAILED)
{
int errno_save = errno;
(void) close (fd);
errno = errno_save;
SCM_SYSERROR;
}
else
{
memcpy (cookie, addr, sizeof cookie);
data = (struct scm_objcode *) (addr + sizeof cookie);
}
verify_cookie (cookie, &st, fd, addr);
if (data->len + data->metalen
!= (st.st_size - sizeof (*data) - sizeof cookie))
{
size_t total_len = sizeof (*data) + data->len + data->metalen;
(void) close (fd);
(void) munmap (addr, st.st_size);
scm_misc_error (FUNC_NAME, "bad length header (~a, ~a)",
scm_list_2 (scm_from_size_t (st.st_size),
scm_from_size_t (total_len)));
}
/* FIXME: we leak ourselves and the file descriptor. but then again so does
dlopen(). */
return scm_permanent_object
(scm_double_cell (SCM_MAKE_OBJCODE_TAG (SCM_OBJCODE_TYPE_MMAP, 0),
(scm_t_bits)(addr + strlen (SCM_OBJCODE_COOKIE)),
SCM_UNPACK (scm_from_int (fd)), 0));
}
#else
{
SCM bv = scm_c_make_bytevector (st.st_size - sizeof cookie);
data = (struct scm_objcode*)(addr + strlen (SCM_OBJCODE_COOKIE));
if (full_read (fd, cookie, sizeof cookie) != sizeof cookie
|| full_read (fd, SCM_BYTEVECTOR_CONTENTS (bv),
SCM_BYTEVECTOR_LENGTH (bv)) != SCM_BYTEVECTOR_LENGTH (bv))
{
int errno_save = errno;
(void) close (fd);
errno = errno_save;
SCM_SYSERROR;
}
if (data->len + data->metalen != (st.st_size - sizeof (*data) - strlen (SCM_OBJCODE_COOKIE)))
{
(void) close (fd);
(void) munmap (addr, st.st_size);
scm_misc_error (FUNC_NAME, "bad length header (~a, ~a)",
scm_list_2 (scm_from_size_t (st.st_size),
scm_from_uint32 (sizeof (*data) + data->len
+ data->metalen)));
}
(void) close (fd);
sret = scm_double_cell (SCM_MAKE_OBJCODE_TAG (SCM_OBJCODE_TYPE_MMAP, 0),
(scm_t_bits)(addr + strlen (SCM_OBJCODE_COOKIE)),
SCM_UNPACK (scm_from_int (fd)), 0);
verify_cookie (cookie, &st, -1, NULL);
/* FIXME: we leak ourselves and the file descriptor. but then again so does
dlopen(). */
return scm_permanent_object (sret);
return scm_bytecode_to_objcode (bv);
}
#endif
}
#undef FUNC_NAME
SCM
scm_c_make_objcode_slice (SCM parent, const scm_t_uint8 *ptr)
#define FUNC_NAME "make-objcode-slice"
@ -233,7 +299,7 @@ SCM_DEFINE (scm_load_objcode, "load-objcode", 1, 0, 0,
free (c_file);
if (fd < 0) SCM_SYSERROR;
return make_objcode_by_mmap (fd);
return make_objcode_from_file (fd);
}
#undef FUNC_NAME