package/screen/0002-no-memcpy-fallback.patch

   1 From: Maarten ter Huurne <maarten@treewalker.org>
   2 Date: Sat, 13 Sep 2014 11:37:59 +0200
   3 Subject: Do not use memcpy as an alternative for bcopy/memmove
   4
   5 The configure script runs a small test program to check whether
   6 memcpy can handle overlapping memory areas. However, it is not valid
   7 to conclude that if a single case of overlapping memory is handled
   8 correctly, all cases will be handled correctly.
   9
  10 Since screen already has its own bcopy implementation as a fallback
  11 for the case that bcopy and memmove are unusable, removing the memcpy
  12 option should not break any systems.
  13
  14 Signed-off-by: Maarten ter Huurne <maarten@treewalker.org>
  15 ---
  16  acconfig.h   |  3 +--
  17  configure.in | 18 +-----------------
  18  os.h         |  8 ++------
  19  osdef.h.in   | 10 +---------
  20  4 files changed, 5 insertions(+), 34 deletions(-)
  21
  22 diff --git a/acconfig.h b/acconfig.h
  23 index 2e46985..9b0b9d4 100644
  24 --- a/acconfig.h
  25 +++ b/acconfig.h
  26 @@ -476,7 +476,7 @@
  27  #undef GETTTYENT
  28
  29  /*
  30 - * Define USEBCOPY if the bcopy/memcpy from your system's C library
  31 + * Define USEBCOPY if the bcopy from your system's C library
  32   * supports the overlapping of source and destination blocks.  When
  33   * undefined, screen uses its own (probably slower) version of bcopy().
  34   *
  35 @@ -487,7 +487,6 @@
  36   * Their memove fails the test in the configure script. Sigh. (Juergen)
  37   */
  38  #undef USEBCOPY
  39 -#undef USEMEMCPY
  40  #undef USEMEMMOVE
  41
  42  /*
  43 diff --git a/configure.in b/configure.in
  44 index 572c2a3..ff9606d 100644
  45 --- a/configure.in
  46 +++ b/configure.in
  47 @@ -1144,7 +1144,7 @@ AC_TRY_LINK(,[getttyent();], AC_DEFINE(GETTTYENT))
  48  AC_CHECKING(fdwalk)
  49  AC_TRY_LINK([#include <stdlib.h>], [fdwalk(NULL, NULL);],AC_DEFINE(HAVE_FDWALK))
  50
  51 -AC_CHECKING(whether memcpy/memmove/bcopy handles overlapping arguments)
  52 +AC_CHECKING(whether memmove/bcopy handles overlapping arguments)
  53  AC_TRY_RUN([
  54  main() {
  55    char buf[10];
  56 @@ -1174,22 +1174,6 @@ main() {
  57    exit(0); /* libc version works properly.  */
  58  }], AC_DEFINE(USEMEMMOVE))
  59
  60 -
  61 -AC_TRY_RUN([
  62 -#define bcopy(s,d,l) memcpy(d,s,l)
  63 -main() {
  64 -  char buf[10];
  65 -  strcpy(buf, "abcdefghi");
  66 -  bcopy(buf, buf + 2, 3);
  67 -  if (strncmp(buf, "ababcf", 6))
  68 -    exit(1);
  69 -  strcpy(buf, "abcdefghi");
  70 -  bcopy(buf + 2, buf, 3);
  71 -  if (strncmp(buf, "cdedef", 6))
  72 -    exit(1);
  73 -  exit(0); /* libc version works properly.  */
  74 -}], AC_DEFINE(USEMEMCPY))
  75 -
  76  AC_SYS_LONG_FILE_NAMES
  77
  78  AC_MSG_CHECKING(for vsprintf)
  79 diff --git a/os.h b/os.h
  80 index 55de249..6838ec0 100644
  81 --- a/os.h
  82 +++ b/os.h
  83 @@ -142,12 +142,8 @@ extern int errno;
  84  # ifdef USEMEMMOVE
  85  #  define bcopy(s,d,len) memmove(d,s,len)
  86  # else
  87 -#  ifdef USEMEMCPY
  88 -#   define bcopy(s,d,len) memcpy(d,s,len)
  89 -#  else
  90 -#   define NEED_OWN_BCOPY
  91 -#   define bcopy xbcopy
  92 -#  endif
  93 +#  define NEED_OWN_BCOPY
  94 +#  define bcopy xbcopy
  95  # endif
  96  #endif
  97
  98 diff --git a/osdef.h.in b/osdef.h.in
  99 index 8687b60..e4057a0 100644
 100 --- a/osdef.h.in
 101 +++ b/osdef.h.in
 102 @@ -58,16 +58,8 @@ extern int   bcmp __P((char *, char *, int));
 103  extern int   killpg __P((int, int));
 104  #endif
 105
 106 -#ifndef USEBCOPY
 107 -# ifdef USEMEMCPY
 108 -extern void  memcpy __P((char *, char *, int));
 109 -# else
 110 -#  ifdef USEMEMMOVE
 111 +#if defined(USEMEMMOVE) && !defined(USEBCOPY)
 112  extern void  memmove __P((char *, char *, int));
 113 -#  else
 114 -extern void  bcopy __P((char *, char *, int));
 115 -#  endif
 116 -# endif
 117  #else
 118  extern void  bcopy __P((char *, char *, int));
 119  #endif
 120 --
 121 1.8.4.5
 122