72 lines
1.6 KiB
Text
72 lines
1.6 KiB
Text
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dnl See whether strncmp reads past the end of its string parameters.
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dnl On some versions of SunOS4 at least, strncmp reads a word at a time
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dnl but erroneously reads past the end of strings. This can cause
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dnl a SEGV in some cases.
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AC_DEFUN(libiberty_AC_FUNC_STRNCMP,
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[AC_REQUIRE([AC_FUNC_MMAP])
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AC_CACHE_CHECK([for working strncmp], ac_cv_func_strncmp_works,
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[AC_TRY_RUN([
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/* Test by Jim Wilson and Kaveh Ghazi.
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Check whether strncmp reads past the end of its string parameters. */
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#include <sys/types.h>
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#ifdef HAVE_FCNTL_H
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#include <fcntl.h>
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#endif
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#ifdef HAVE_SYS_MMAN_H
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#include <sys/mman.h>
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#endif
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#ifndef MAP_ANON
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#ifdef MAP_ANONYMOUS
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#define MAP_ANON MAP_ANONYMOUS
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#else
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#define MAP_ANON MAP_FILE
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#endif
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#endif
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#ifndef MAP_FILE
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#define MAP_FILE 0
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#endif
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#ifndef O_RDONLY
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#define O_RDONLY 0
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#endif
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#define MAP_LEN 0x10000
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main ()
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{
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#if defined(HAVE_MMAP) || defined(HAVE_MMAP_ANYWHERE)
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char *p;
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int dev_zero;
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dev_zero = open ("/dev/zero", O_RDONLY);
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if (dev_zero < 0)
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exit (1);
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p = (char *) mmap (0, MAP_LEN, PROT_READ|PROT_WRITE,
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MAP_ANON|MAP_PRIVATE, dev_zero, 0);
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if (p == (char *)-1)
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exit (2);
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else
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{
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char *string = "__si_type_info";
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char *q = (char *) p + MAP_LEN - strlen (string) - 2;
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char *r = (char *) p + 0xe;
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strcpy (q, string);
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strcpy (r, string);
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strncmp (r, q, 14);
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}
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#endif /* HAVE_MMAP || HAVE_MMAP_ANYWHERE */
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exit (0);
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}
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], ac_cv_func_strncmp_works=yes, ac_cv_func_strncmp_works=no,
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ac_cv_func_strncmp_works=no)
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rm -f core core.* *.core])
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if test $ac_cv_func_strncmp_works = no ; then
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LIBOBJS="$LIBOBJS strncmp.o"
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fi
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])
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