libguile/objcodes.c

   1 /* Copyright (C) 2001, 2009, 2010, 2011 Free Software Foundation, Inc.
   2  *
   3  * This library is free software; you can redistribute it and/or
   4  * modify it under the terms of the GNU Lesser General Public License
   5  * as published by the Free Software Foundation; either version 3 of
   6  * the License, or (at your option) any later version.
   7  *
   8  * This library is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * Lesser General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU Lesser General Public
  14  * License along with this library; if not, write to the Free Software
  15  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  16  * 02110-1301 USA
  17  */
  18
  19 #if HAVE_CONFIG_H
  20 #  include <config.h>
  21 #endif
  22
  23 #include <string.h>
  24 #include <fcntl.h>
  25 #include <unistd.h>
  26 #include <sys/mman.h>
  27 #include <sys/stat.h>
  28 #include <sys/types.h>
  29 #include <assert.h>
  30 #include <alignof.h>
  31
  32 #include "_scm.h"
  33 #include "programs.h"
  34 #include "objcodes.h"
  35
  36 /* SCM_OBJCODE_COOKIE, defined in _scm.h, is a magic value prepended
  37    to objcode on disk but not in memory.
  38
  39    The length of the header must be a multiple of 8 bytes.  */
  40 verify (((sizeof (SCM_OBJCODE_COOKIE) - 1) & 7) == 0);
  41
  42 \f
  43 /*
  44  * Objcode type
  45  */
  46
  47 /* The words in an objcode SCM object are as follows:
  48      - scm_tc7_objcode | the flags for this objcode
  49      - the struct scm_objcode C object
  50      - the parent of this objcode, if this is a slice, or #f if none
  51      - the file descriptor this objcode came from if this was mmaped,
  52        or 0 if none
  53  */
  54
  55 static SCM
  56 make_objcode_by_mmap (int fd)
  57 #define FUNC_NAME "make_objcode_by_mmap"
  58 {
  59   int ret;
  60   char *addr;
  61   struct stat st;
  62   SCM sret = SCM_BOOL_F;
  63   struct scm_objcode *data;
  64
  65   ret = fstat (fd, &st);
  66   if (ret < 0)
  67     SCM_SYSERROR;
  68
  69   if (st.st_size <= sizeof (struct scm_objcode) + strlen (SCM_OBJCODE_COOKIE))
  70     scm_misc_error (FUNC_NAME, "object file too small (~a bytes)",
  71                     scm_list_1 (SCM_I_MAKINUM (st.st_size)));
  72
  73   addr = mmap (0, st.st_size, PROT_READ, MAP_SHARED, fd, 0);
  74   if (addr == MAP_FAILED)
  75     {
  76       (void) close (fd);
  77       SCM_SYSERROR;
  78     }
  79
  80   if (memcmp (addr, SCM_OBJCODE_COOKIE, strlen (SCM_OBJCODE_COOKIE)))
  81     {
  82       SCM args = scm_list_1 (scm_from_latin1_stringn
  83                              (addr, strlen (SCM_OBJCODE_COOKIE)));
  84       (void) close (fd);
  85       (void) munmap (addr, st.st_size);
  86       scm_misc_error (FUNC_NAME, "bad header on object file: ~s", args);
  87     }
  88
  89   data = (struct scm_objcode*)(addr + strlen (SCM_OBJCODE_COOKIE));
  90
  91   if (data->len + data->metalen != (st.st_size - sizeof (*data) - strlen (SCM_OBJCODE_COOKIE)))
  92     {
  93       (void) close (fd);
  94       (void) munmap (addr, st.st_size);
  95       scm_misc_error (FUNC_NAME, "bad length header (~a, ~a)",
  96                       scm_list_2 (scm_from_size_t (st.st_size),
  97                                   scm_from_uint32 (sizeof (*data) + data->len
  98                                                    + data->metalen)));
  99     }
 100
 101   sret = scm_double_cell (SCM_MAKE_OBJCODE_TAG (SCM_OBJCODE_TYPE_MMAP, 0),
 102                           (scm_t_bits)(addr + strlen (SCM_OBJCODE_COOKIE)),
 103                           SCM_UNPACK (SCM_BOOL_F),
 104                           (scm_t_bits)fd);
 105
 106   /* FIXME: we leak ourselves and the file descriptor. but then again so does
 107      dlopen(). */
 108   return scm_permanent_object (sret);
 109 }
 110 #undef FUNC_NAME
 111
 112 SCM
 113 scm_c_make_objcode_slice (SCM parent, const scm_t_uint8 *ptr)
 114 #define FUNC_NAME "make-objcode-slice"
 115 {
 116   const struct scm_objcode *data, *parent_data;
 117   const scm_t_uint8 *parent_base;
 118
 119   SCM_VALIDATE_OBJCODE (1, parent);
 120   parent_data = SCM_OBJCODE_DATA (parent);
 121   parent_base = SCM_C_OBJCODE_BASE (parent_data);
 122
 123   if (ptr < parent_base
 124       || ptr >= (parent_base + parent_data->len + parent_data->metalen
 125                  - sizeof (struct scm_objcode)))
 126     scm_misc_error
 127       (FUNC_NAME, "offset out of bounds (~a vs ~a + ~a + ~a)",
 128        scm_list_4 (scm_from_unsigned_integer ((scm_t_bits) ptr),
 129                    scm_from_unsigned_integer ((scm_t_bits) parent_base),
 130                    scm_from_uint32 (parent_data->len),
 131                    scm_from_uint32 (parent_data->metalen)));
 132
 133   /* Make sure bytecode for the objcode-meta is suitable aligned.  Failing to
 134      do so leads to SIGBUS/SIGSEGV on some arches (e.g., SPARC).  */
 135   assert ((((scm_t_bits) ptr) &
 136            (alignof_type (struct scm_objcode) - 1UL)) == 0);
 137
 138   data = (struct scm_objcode*) ptr;
 139   assert (SCM_C_OBJCODE_BASE (data) + data->len + data->metalen
 140           <= parent_base + parent_data->len + parent_data->metalen);
 141
 142   return scm_double_cell (SCM_MAKE_OBJCODE_TAG (SCM_OBJCODE_TYPE_SLICE, 0),
 143                           (scm_t_bits)data, SCM_UNPACK (parent), 0);
 144 }
 145 #undef FUNC_NAME
 146
 147 \f
 148 /*
 149  * Scheme interface
 150  */
 151
 152 SCM_DEFINE (scm_objcode_p, "objcode?", 1, 0, 0,
 153             (SCM obj),
 154             "")
 155 #define FUNC_NAME s_scm_objcode_p
 156 {
 157   return scm_from_bool (SCM_OBJCODE_P (obj));
 158 }
 159 #undef FUNC_NAME
 160
 161 SCM_DEFINE (scm_objcode_meta, "objcode-meta", 1, 0, 0,
 162             (SCM objcode),
 163             "")
 164 #define FUNC_NAME s_scm_objcode_meta
 165 {
 166   SCM_VALIDATE_OBJCODE (1, objcode);
 167
 168   if (SCM_OBJCODE_META_LEN (objcode) == 0)
 169     return SCM_BOOL_F;
 170   else
 171     return scm_c_make_objcode_slice (objcode, (SCM_OBJCODE_BASE (objcode)
 172                                                + SCM_OBJCODE_LEN (objcode)));
 173 }
 174 #undef FUNC_NAME
 175
 176 SCM_DEFINE (scm_bytecode_to_objcode, "bytecode->objcode", 1, 0, 0,
 177             (SCM bytecode),
 178             "")
 179 #define FUNC_NAME s_scm_bytecode_to_objcode
 180 {
 181   size_t size;
 182   const scm_t_uint8 *c_bytecode;
 183   struct scm_objcode *data;
 184
 185   if (!scm_is_bytevector (bytecode))
 186     scm_wrong_type_arg (FUNC_NAME, 1, bytecode);
 187
 188   size = SCM_BYTEVECTOR_LENGTH (bytecode);
 189   c_bytecode = (const scm_t_uint8*)SCM_BYTEVECTOR_CONTENTS (bytecode);
 190
 191   SCM_ASSERT_RANGE (0, bytecode, size >= sizeof(struct scm_objcode));
 192   data = (struct scm_objcode*)c_bytecode;
 193
 194   if (data->len + data->metalen != (size - sizeof (*data)))
 195     scm_misc_error (FUNC_NAME, "bad bytevector size (~a != ~a)",
 196                     scm_list_2 (scm_from_size_t (size),
 197                                 scm_from_uint32 (sizeof (*data) + data->len + data->metalen)));
 198
 199   /* foolishly, we assume that as long as bytecode is around, that c_bytecode
 200      will be of the same length; perhaps a bad assumption? */
 201   return scm_double_cell (SCM_MAKE_OBJCODE_TAG (SCM_OBJCODE_TYPE_BYTEVECTOR, 0),
 202                           (scm_t_bits)data, SCM_UNPACK (bytecode), 0);
 203 }
 204 #undef FUNC_NAME
 205
 206 SCM_DEFINE (scm_load_objcode, "load-objcode", 1, 0, 0,
 207             (SCM file),
 208             "")
 209 #define FUNC_NAME s_scm_load_objcode
 210 {
 211   int fd;
 212   char *c_file;
 213
 214   SCM_VALIDATE_STRING (1, file);
 215
 216   c_file = scm_to_locale_string (file);
 217   fd = open (c_file, O_RDONLY);
 218   free (c_file);
 219   if (fd < 0) SCM_SYSERROR;
 220
 221   return make_objcode_by_mmap (fd);
 222 }
 223 #undef FUNC_NAME
 224
 225 SCM_DEFINE (scm_objcode_to_bytecode, "objcode->bytecode", 1, 0, 0,
 226             (SCM objcode),
 227             "")
 228 #define FUNC_NAME s_scm_objcode_to_bytecode
 229 {
 230   scm_t_int8 *s8vector;
 231   scm_t_uint32 len;
 232
 233   SCM_VALIDATE_OBJCODE (1, objcode);
 234
 235   len = sizeof (struct scm_objcode) + SCM_OBJCODE_TOTAL_LEN (objcode);
 236
 237   s8vector = scm_malloc (len);
 238   memcpy (s8vector, SCM_OBJCODE_DATA (objcode), len);
 239
 240   return scm_c_take_bytevector (s8vector, len);
 241 }
 242 #undef FUNC_NAME
 243
 244 SCM_DEFINE (scm_write_objcode, "write-objcode", 2, 0, 0,
 245             (SCM objcode, SCM port),
 246             "")
 247 #define FUNC_NAME s_scm_write_objcode
 248 {
 249   SCM_VALIDATE_OBJCODE (1, objcode);
 250   SCM_VALIDATE_OUTPUT_PORT (2, port);
 251
 252   scm_c_write (port, SCM_OBJCODE_COOKIE, strlen (SCM_OBJCODE_COOKIE));
 253   scm_c_write (port, SCM_OBJCODE_DATA (objcode),
 254                sizeof (struct scm_objcode) + SCM_OBJCODE_TOTAL_LEN (objcode));
 255
 256   return SCM_UNSPECIFIED;
 257 }
 258 #undef FUNC_NAME
 259
 260 void
 261 scm_i_objcode_print (SCM objcode, SCM port, scm_print_state *pstate)
 262 {
 263   scm_puts ("#<objcode ", port);
 264   scm_uintprint ((scm_t_bits)SCM_OBJCODE_BASE (objcode), 16, port);
 265   scm_puts (">", port);
 266 }
 267
 268 \f
 269 void
 270 scm_bootstrap_objcodes (void)
 271 {
 272   scm_c_register_extension ("libguile-" SCM_EFFECTIVE_VERSION,
 273                             "scm_init_objcodes",
 274                             (scm_t_extension_init_func)scm_init_objcodes, NULL);
 275 }
 276
 277 /* Before, we used __BYTE_ORDER, but that is not defined on all
 278    systems. So punt and use automake, PDP endianness be damned. */
 279 #ifdef WORDS_BIGENDIAN
 280 #define SCM_BYTE_ORDER 4321
 281 #else
 282 #define SCM_BYTE_ORDER 1234
 283 #endif
 284
 285 void
 286 scm_init_objcodes (void)
 287 {
 288 #ifndef SCM_MAGIC_SNARFER
 289 #include "libguile/objcodes.x"
 290 #endif
 291
 292   scm_c_define ("word-size", scm_from_size_t (sizeof(SCM)));
 293   scm_c_define ("byte-order", scm_from_uint16 (SCM_BYTE_ORDER));
 294 }
 295
 296 /*
 297   Local Variables:
 298   c-file-style: "gnu"
 299   End:
 300 */