Use mmap and cache the view buffer for get_view
This patch uses mmap if it is available and works. It also caches the view buffer for get_view. * configure.ac: Add AC_FUNC_MMAP. * config.in: Regenerated. * configure: Likewise. * plugin.c: Include <sys/mman.h>. (MAP_FAILED): New. Defined if not defined. (PROT_READ): Likewise. (MAP_PRIVATE): Likewise. (view_buffer_t): New. (plugin_input_file_t): Add view_buffer. (get_view): Try mmap and cache the view buffer. (plugin_maybe_claim): Initialize view_buffer.
This commit is contained in:
H.J. Lu
parent
d6c146e9ea
commit
2aec968d4d
5 changed files with 278 additions and 22 deletions
14
ld/ChangeLog
14
ld/ChangeLog
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@ -1,3 +1,17 @@
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2015-02-06 H.J. Lu <hongjiu.lu@intel.com>
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* configure.ac: Add AC_FUNC_MMAP.
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* config.in: Regenerated.
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* configure: Likewise.
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* plugin.c: Include <sys/mman.h>.
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(MAP_FAILED): New. Defined if not defined.
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(PROT_READ): Likewise.
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(MAP_PRIVATE): Likewise.
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(view_buffer_t): New.
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(plugin_input_file_t): Add view_buffer.
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(get_view): Try mmap and cache the view buffer.
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(plugin_maybe_claim): Initialize view_buffer.
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2015-02-05 H.J. Lu <hongjiu.lu@intel.com>
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* plugin.c (release_input_file): Set fd to -1 after closing it.
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@ -56,6 +56,9 @@
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/* Define to 1 if you have the <fcntl.h> header file. */
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#undef HAVE_FCNTL_H
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/* Define to 1 if you have the `getpagesize' function. */
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#undef HAVE_GETPAGESIZE
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/* Define to 1 if you have the `glob' function. */
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#undef HAVE_GLOB
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@ -83,6 +86,9 @@
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/* Define to 1 if you have the `mkstemp' function. */
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#undef HAVE_MKSTEMP
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/* Define to 1 if you have a working `mmap' system call. */
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#undef HAVE_MMAP
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/* Define to 1 if you have the <ndir.h> header file, and it defines `DIR'. */
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#undef HAVE_NDIR_H
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182
ld/configure
vendored
182
ld/configure
vendored
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@ -16549,6 +16549,188 @@ fi
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fi
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for ac_header in stdlib.h unistd.h
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do :
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as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
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ac_fn_c_check_header_mongrel "$LINENO" "$ac_header" "$as_ac_Header" "$ac_includes_default"
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eval as_val=\$$as_ac_Header
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if test "x$as_val" = x""yes; then :
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cat >>confdefs.h <<_ACEOF
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#define `$as_echo "HAVE_$ac_header" | $as_tr_cpp` 1
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_ACEOF
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fi
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done
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for ac_func in getpagesize
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do :
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ac_fn_c_check_func "$LINENO" "getpagesize" "ac_cv_func_getpagesize"
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if test "x$ac_cv_func_getpagesize" = x""yes; then :
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cat >>confdefs.h <<_ACEOF
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#define HAVE_GETPAGESIZE 1
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_ACEOF
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fi
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done
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{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for working mmap" >&5
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$as_echo_n "checking for working mmap... " >&6; }
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if test "${ac_cv_func_mmap_fixed_mapped+set}" = set; then :
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$as_echo_n "(cached) " >&6
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else
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if test "$cross_compiling" = yes; then :
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ac_cv_func_mmap_fixed_mapped=no
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else
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cat confdefs.h - <<_ACEOF >conftest.$ac_ext
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/* end confdefs.h. */
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$ac_includes_default
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/* malloc might have been renamed as rpl_malloc. */
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#undef malloc
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/* Thanks to Mike Haertel and Jim Avera for this test.
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Here is a matrix of mmap possibilities:
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mmap private not fixed
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mmap private fixed at somewhere currently unmapped
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mmap private fixed at somewhere already mapped
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mmap shared not fixed
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mmap shared fixed at somewhere currently unmapped
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mmap shared fixed at somewhere already mapped
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For private mappings, we should verify that changes cannot be read()
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back from the file, nor mmap's back from the file at a different
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address. (There have been systems where private was not correctly
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implemented like the infamous i386 svr4.0, and systems where the
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VM page cache was not coherent with the file system buffer cache
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like early versions of FreeBSD and possibly contemporary NetBSD.)
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For shared mappings, we should conversely verify that changes get
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propagated back to all the places they're supposed to be.
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Grep wants private fixed already mapped.
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The main things grep needs to know about mmap are:
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* does it exist and is it safe to write into the mmap'd area
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* how to use it (BSD variants) */
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#include <fcntl.h>
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#include <sys/mman.h>
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#if !defined STDC_HEADERS && !defined HAVE_STDLIB_H
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char *malloc ();
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#endif
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/* This mess was copied from the GNU getpagesize.h. */
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#ifndef HAVE_GETPAGESIZE
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/* Assume that all systems that can run configure have sys/param.h. */
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# ifndef HAVE_SYS_PARAM_H
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# define HAVE_SYS_PARAM_H 1
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# endif
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# ifdef _SC_PAGESIZE
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# define getpagesize() sysconf(_SC_PAGESIZE)
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# else /* no _SC_PAGESIZE */
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# ifdef HAVE_SYS_PARAM_H
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# include <sys/param.h>
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# ifdef EXEC_PAGESIZE
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# define getpagesize() EXEC_PAGESIZE
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# else /* no EXEC_PAGESIZE */
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# ifdef NBPG
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# define getpagesize() NBPG * CLSIZE
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# ifndef CLSIZE
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# define CLSIZE 1
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# endif /* no CLSIZE */
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# else /* no NBPG */
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# ifdef NBPC
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# define getpagesize() NBPC
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# else /* no NBPC */
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# ifdef PAGESIZE
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# define getpagesize() PAGESIZE
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# endif /* PAGESIZE */
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# endif /* no NBPC */
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# endif /* no NBPG */
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# endif /* no EXEC_PAGESIZE */
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# else /* no HAVE_SYS_PARAM_H */
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# define getpagesize() 8192 /* punt totally */
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# endif /* no HAVE_SYS_PARAM_H */
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# endif /* no _SC_PAGESIZE */
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#endif /* no HAVE_GETPAGESIZE */
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int
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main ()
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{
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char *data, *data2, *data3;
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int i, pagesize;
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int fd;
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pagesize = getpagesize ();
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/* First, make a file with some known garbage in it. */
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data = (char *) malloc (pagesize);
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if (!data)
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return 1;
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for (i = 0; i < pagesize; ++i)
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*(data + i) = rand ();
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umask (0);
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fd = creat ("conftest.mmap", 0600);
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if (fd < 0)
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return 1;
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if (write (fd, data, pagesize) != pagesize)
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return 1;
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close (fd);
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/* Next, try to mmap the file at a fixed address which already has
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something else allocated at it. If we can, also make sure that
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we see the same garbage. */
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fd = open ("conftest.mmap", O_RDWR);
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if (fd < 0)
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return 1;
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data2 = (char *) malloc (2 * pagesize);
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if (!data2)
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return 1;
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data2 += (pagesize - ((long int) data2 & (pagesize - 1))) & (pagesize - 1);
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if (data2 != mmap (data2, pagesize, PROT_READ | PROT_WRITE,
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MAP_PRIVATE | MAP_FIXED, fd, 0L))
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return 1;
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for (i = 0; i < pagesize; ++i)
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if (*(data + i) != *(data2 + i))
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return 1;
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/* Finally, make sure that changes to the mapped area do not
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percolate back to the file as seen by read(). (This is a bug on
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some variants of i386 svr4.0.) */
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for (i = 0; i < pagesize; ++i)
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*(data2 + i) = *(data2 + i) + 1;
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data3 = (char *) malloc (pagesize);
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if (!data3)
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return 1;
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if (read (fd, data3, pagesize) != pagesize)
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return 1;
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for (i = 0; i < pagesize; ++i)
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if (*(data + i) != *(data3 + i))
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return 1;
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close (fd);
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return 0;
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}
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_ACEOF
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if ac_fn_c_try_run "$LINENO"; then :
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ac_cv_func_mmap_fixed_mapped=yes
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else
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ac_cv_func_mmap_fixed_mapped=no
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fi
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rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \
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conftest.$ac_objext conftest.beam conftest.$ac_ext
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fi
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fi
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{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_func_mmap_fixed_mapped" >&5
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$as_echo "$ac_cv_func_mmap_fixed_mapped" >&6; }
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if test $ac_cv_func_mmap_fixed_mapped = yes; then
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$as_echo "#define HAVE_MMAP 1" >>confdefs.h
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fi
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rm -f conftest.mmap
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{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for library containing dlopen" >&5
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$as_echo_n "checking for library containing dlopen... " >&6; }
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if test "${ac_cv_search_dlopen+set}" = set; then :
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@ -195,6 +195,9 @@ AC_CHECK_FUNCS(glob mkstemp realpath sbrk setlocale waitpid)
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AC_CHECK_FUNCS(open lseek close)
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AC_HEADER_DIRENT
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dnl AC_CHECK_HEADERS(sys/mman.h)
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AC_FUNC_MMAP
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AC_SEARCH_LIBS([dlopen], [dl])
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AM_CONDITIONAL([ENABLE_PLUGINS], [test x$plugins = xyes])
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95
ld/plugin.c
95
ld/plugin.c
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@ -32,6 +32,18 @@
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#include "plugin.h"
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#include "plugin-api.h"
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#include "elf-bfd.h"
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#if HAVE_MMAP
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# include <sys/mman.h>
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# ifndef MAP_FAILED
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# define MAP_FAILED ((void *) -1)
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# endif
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# ifndef PROT_READ
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# define PROT_READ 0
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# endif
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# ifndef MAP_PRIVATE
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# define MAP_PRIVATE 0
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# endif
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#endif
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#include <errno.h>
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#if !(defined(errno) || defined(_MSC_VER) && defined(_INC_ERRNO))
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extern int errno;
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@ -76,11 +88,19 @@ typedef struct plugin
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bfd_boolean cleanup_done;
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} plugin_t;
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typedef struct view_buffer
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{
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char *addr;
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size_t filesize;
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off_t offset;
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} view_buffer_t;
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/* The internal version of struct ld_plugin_input_file with a BFD
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pointer. */
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typedef struct plugin_input_file
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{
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bfd *abfd;
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view_buffer_t view_buffer;
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char *name;
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int fd;
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off_t offset;
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@ -475,35 +495,63 @@ get_input_file (const void *handle, struct ld_plugin_input_file *file)
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static enum ld_plugin_status
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get_view (const void *handle, const void **viewp)
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{
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const plugin_input_file_t *input = handle;
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plugin_input_file_t *input = (plugin_input_file_t *) handle;
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char *buffer;
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size_t size;
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size_t size = input->filesize;
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ASSERT (called_plugin);
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if (lseek (input->fd, input->offset, SEEK_SET) < 0)
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return LDPS_ERR;
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/* FIXME: einfo should support %lld. */
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if ((off_t) size != input->filesize)
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einfo (_("%P%F: unsupported input file size: %s (%ld bytes)\n"),
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input->name, (long) input->filesize);
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size = input->filesize;
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buffer = bfd_alloc (input->abfd, size);
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if (buffer == NULL)
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return LDPS_ERR;
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*viewp = buffer;
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do
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/* Check the cached view buffer. */
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if (input->view_buffer.addr != NULL
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&& input->view_buffer.filesize == size
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&& input->view_buffer.offset == input->offset)
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{
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ssize_t got = read (input->fd, buffer, size);
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if (got == 0)
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break;
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else if (got > 0)
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{
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buffer += got;
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size -= got;
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}
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else if (errno != EINTR)
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return LDPS_ERR;
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*viewp = input->view_buffer.addr;
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return LDPS_OK;
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}
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while (size > 0);
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input->view_buffer.filesize = size;
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input->view_buffer.offset = input->offset;
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#if HAVE_MMAP
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buffer = mmap (NULL, size, PROT_READ, MAP_PRIVATE, input->fd,
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input->offset);
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if (buffer == MAP_FAILED)
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#endif
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{
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char *p;
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if (lseek (input->fd, input->offset, SEEK_SET) < 0)
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return LDPS_ERR;
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buffer = bfd_alloc (input->abfd, size);
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if (buffer == NULL)
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return LDPS_ERR;
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p = buffer;
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do
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{
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ssize_t got = read (input->fd, p, size);
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if (got == 0)
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break;
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else if (got > 0)
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{
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p += got;
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size -= got;
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}
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else if (errno != EINTR)
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return LDPS_ERR;
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}
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while (size > 0);
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}
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input->view_buffer.addr = buffer;
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*viewp = buffer;
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return LDPS_OK;
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}
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@ -951,6 +999,9 @@ plugin_maybe_claim (struct ld_plugin_input_file *file,
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bfd_get_error ());
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input->abfd = abfd;
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input->view_buffer.addr = NULL;
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input->view_buffer.filesize = 0;
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input->view_buffer.offset = 0;
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input->fd = file->fd;
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input->offset = file->offset;
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input->filesize = file->filesize;
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