build: handle enforced 64 bit offsets for controlled ABI break

git-svn-id: svn://scm.orgis.org/mpg123/trunk@5415 35dc7657-300d-0410-a2e5-dc2837fedb53

NEWS

@@ -1,3 +1,12 @@
+1.32.6
+------
+- build: Detect forced 64 bit offsets on a dual-mode system that used
+  to default to 32 bits and drop ambiguous suffix-less symbols in that
+  case. This avoids subtle ABI breakage (causing memory corruption)
+  with existing binaries and instead has them fail during runtime linking.
+  You trigger that when having -D_FILE_OFFSET_BITS=64 in your compiler
+  flags during mpg123 build.
+
 1.32.5
 ------
 

configure.ac

@@ -1355,8 +1355,13 @@ AC_COMPUTE_INT(switched_off_size, sizeof(off_t), [
 #include <sys/types.h>
 ])
 AC_MSG_RESULT([$switched_off_size])
-# If you have predefined _FILE_OFFSET_BITS, I will treat that as a system
-# property.
+AC_MSG_CHECKING([unswitched off_t size])
+AC_COMPUTE_INT(unswitched_off_size, sizeof(off_t), [
+#undef  _FILE_OFFSET_BITS
+#include <sys/types.h>
+])
+AC_MSG_RESULT([$unswitched_off_size])
+# Now the size without meddling, possibly enforced to 64 bits by system settings.
 AC_CHECK_SIZEOF(off_t, [], [
 #include <sys/types.h>
 ])
@@ -1381,6 +1386,15 @@ else
   lfs_sensitive=no
 fi
 
+forced_off_64=no
+if test "x$unswitched_off_size" != "x$ac_cv_sizeof_off_t"; then
+  if test "x$ac_cv_sizeof_off_t" = x8; then
+    AC_MSG_NOTICE([Detected system with enforced 64 bit offsets, dropping suffixless symbols for uncryptic ABI breakage.])
+    AC_DEFINE([FORCED_OFF_64], 1, [System setup enforces 64 bit offsets where 32 bit would be native.])
+    forced_off_64=yes
+  fi
+fi
+
 use_largefile=auto
 
 AC_MSG_CHECKING([if native off_t is already 64 bits])
@@ -2969,8 +2983,16 @@ fi
 echo "  largefile sensitive ..... $lfs_sensitive"
 echo "  default offsets ......... $default_offset_bits"
 echo "  explicit 64 bit offsets . $use_largefile"
+echo "  forced 64 bit offsets ... $forced_off_64"
 echo "  only portable API ....... $portable_api"
 
+if test "x$forced_off_64" = xyes; then
+  echo
+  echo "Note: Ensure that client programs are built with _FILE_OFFSET_BITS defined to 64, too."
+  echo "      Old binaries built for 32 bit off_t may fail missing symbols in mpg123 libraries."
+  echo
+fi
+
 echo "
   Core libmpg123 features:
   Layer I ................. $layer1

src/libmpg123/lfs_wrap.c

@@ -208,10 +208,13 @@ static struct wrap_data* wrap_get(mpg123_handle *mh, int force_alloc)
 /* After settling the data... start with some simple wrappers. */
 
 // The fist block of wrappers is always present, using the native off_t width.
+// (Exception: If explicitly disabled using FORCED_OFF_64.)
 // A second block mirrors that in case of sizeof(off_t)==4 with _32 suffix.
 // A third block follows if 64 bit off_t is available with _64 suffix, just aliasing
 // the int64_t functions.
 
+#ifndef FORCED_OFF_64
+
 #define OFF_CONV(value, variable, handle) \
   if((value) >= OFF_MIN && (value) <= OFF_MAX) \
      variable = (off_t)(value); \
@@ -399,6 +402,8 @@ int attribute_align_arg mpg123_position( mpg123_handle *mh, off_t INT123_frame_o
 	return MPG123_OK;
 }
 
+#endif // FORCED_OFF_64
+
 // _32 aliases only for native 32 bit off_t
 // Will compilers be smart enough to optimize away the extra function call?
 #if SIZEOF_OFF_T == 4
@@ -523,6 +528,10 @@ int attribute_align_arg mpg123_position_32( mpg123_handle *mh, off_t INT123_fram
 #define OFF64 off_t
 #endif
 
+#ifndef FORCED_OFF_64
+// When 64 bit offsets are enforced, libmpg123.c defines the _64 functions directly.
+// There is no actual wrapper work, anyway.
+
 int attribute_align_arg mpg123_open_64(mpg123_handle *mh, const char *path)
 {
 	return mpg123_open(mh, path);
@@ -543,6 +552,8 @@ int attribute_align_arg mpg123_open_handle_64(mpg123_handle *mh, void *iohandle)
 {
 	return mpg123_open_handle(mh, iohandle);
 }
+#endif
+
 
 int attribute_align_arg mpg123_framebyframe_decode_64(mpg123_handle *mh, OFF64 *num, unsigned char **audio, size_t *bytes)
 {
@@ -860,6 +871,13 @@ static mpg123_ssize_t fallback_read(int fd, void *buf, size_t count)
 	return read(fd, buf, count);
 }
 
+// In forced 64 bit offset mode, the only definitions of these are
+// the _64 ones.
+#ifdef FORCED_OFF_64
+#define mpg123_replace_reader mpg123_replace_reader_64
+#define mpg123_replace_reader_handle mpg123_replace_reader_handle_64
+#endif
+
 /* Reader replacement prepares the hidden handle storage for next mpg123_open_fd() or plain mpg123_open(). */
 int attribute_align_arg mpg123_replace_reader(mpg123_handle *mh, mpg123_ssize_t (*r_read) (int, void *, size_t), off_t (*r_lseek)(int, off_t, int) )
 {
@@ -978,6 +996,8 @@ int attribute_align_arg mpg123_replace_reader_handle_64(mpg123_handle *mh, mpg12
 
 #elif SIZEOF_OFF_T == 8
 
+// If 64 bit off_t is enforced, libmpg123.c already defines the _64 functions.
+#ifndef FORCED_OFF_64
 int attribute_align_arg mpg123_replace_reader_64(mpg123_handle *mh, mpg123_ssize_t (*r_read) (int, void *, size_t), off_t (*r_lseek)(int, off_t, int) )
 {
 	return mpg123_replace_reader(mh, r_read, r_lseek);
@@ -987,5 +1007,6 @@ int attribute_align_arg mpg123_replace_reader_handle_64(mpg123_handle *mh, mpg12
 {
 	return mpg123_replace_reader_handle(mh, r_read, r_lseek, cleanup);
 }
+#endif
 
 #endif

src/libmpg123/libmpg123.c

@@ -560,6 +560,15 @@ double attribute_align_arg mpg123_geteq2(mpg123_handle *mh, int channel, int ban
 }
 
 #ifndef PORTABLE_API
+
+#ifdef FORCED_OFF_64
+// Only _64 symbols for a system-wide enforced _FILE_OFFSET_BITS=64.
+#define mpg123_open mpg123_open_64
+#define mpg123_open_fixed mpg123_open_fixed_64
+#define mpg123_open_fd mpg123_open_fd_64
+#define mpg123_open_handle mpg123_open_handle_64
+#endif
+
 /* plain file access, no http! */
 int attribute_align_arg mpg123_open(mpg123_handle *mh, const char *path)
 {
@@ -579,7 +588,9 @@ int attribute_align_arg mpg123_open(mpg123_handle *mh, const char *path)
 // The convenience function mpg123_open_fixed() wraps over acual mpg123_open
 // and hence needs to have the exact same code in lfs_wrap.c. The flesh is
 // in INT123_open_fixed_pre() and INT123_open_fixed_post(), wich are only defined here.
-int INT123_open_fixed_pre(mpg123_handle *mh, int channels, int encoding)
+// Update: The open routines are just alias calls now, since the conversion to
+// int64_t internally.
+static int INT123_open_fixed_pre(mpg123_handle *mh, int channels, int encoding)
 {
 	if(!mh)
 		return MPG123_BAD_HANDLE;
@@ -590,7 +601,7 @@ int INT123_open_fixed_pre(mpg123_handle *mh, int channels, int encoding)
 	return err;
 }
 
-int INT123_open_fixed_post(mpg123_handle *mh, int channels, int encoding)
+static int INT123_open_fixed_post(mpg123_handle *mh, int channels, int encoding)
 {
 	if(!mh)
 		return MPG123_BAD_HANDLE;
@@ -637,7 +648,7 @@ int attribute_align_arg mpg123_open_fd(mpg123_handle *mh, int fd)
 		ret = INT123_open_stream_handle(mh, mh->wrapperdata);
 	return ret;
 }
-#endif
+#endif // PORTABLE_API
 
 int attribute_align_arg mpg123_open_handle(mpg123_handle *mh, void *iohandle)
 {

src/libmpg123/mpg123lib_intern.h

@@ -323,9 +323,6 @@ int64_t INT123_outblock_bytes(mpg123_handle *fr, int64_t s);
 /* Postprocessing format conversion of freshly decoded buffer. */
 void INT123_postprocess_buffer(mpg123_handle *fr);
 
-int INT123_open_fixed_pre(mpg123_handle *mh, int channels, int encoding);
-int INT123_open_fixed_post(mpg123_handle *mh, int channels, int encoding);
-
 /* If networking is enabled and we really mean internal networking, the timeout_read function is available. */
 #if defined (NETWORK) && !defined (WANT_WIN32_SOCKETS)
 /* Does not work with win32 */

src/libsyn123/resample.c

@@ -2038,8 +2038,10 @@ type attribute_align_arg name(long inrate, long outrate, type io) \
 }
 
 #if  SIZEOF_OFF_T == 8
+#ifndef FORCED_OFF_64
 resample_total_alias(off_t, syn123_resample_total, syn123_resample_total64)
 resample_total_alias(off_t, syn123_resample_intotal, syn123_resample_intotal64)
+#endif
 resample_total_alias(off_t, syn123_resample_total_64, syn123_resample_total64)
 resample_total_alias(off_t, syn123_resample_intotal_64, syn123_resample_intotal64)
 #elif SIZEOF_OFF_T == 4

src/version.h

@@ -16,7 +16,7 @@
 // only single spaces as separator to ease parsing by build scripts
 #define MPG123_MAJOR 1
 #define MPG123_MINOR 32
-#define MPG123_PATCH 5
+#define MPG123_PATCH 6
 // Don't get too wild with that to avoid confusing m4. No brackets.
 // Also, it should fit well into a sane file name for the tarball.
 #define MPG123_SUFFIX "-dev"