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 [Ricardo: rebase on top of 4.3.1]
  16 Signed-off-by: Ricardo Martincoski <ricardo.martincoski@gmail.com>
  17 ---
  18  acconfig.h   |  3 +--
  19  configure.ac | 18 +-----------------
  20  os.h         |  8 ++------
  21  osdef.h.in   | 10 +---------
  22  4 files changed, 5 insertions(+), 34 deletions(-)
  23
  24 diff --git a/acconfig.h b/acconfig.h
  25 index 2e46985..9b0b9d4 100644
  26 --- a/acconfig.h
  27 +++ b/acconfig.h
  28 @@ -476,7 +476,7 @@
  29  #undef GETTTYENT
  30
  31  /*
  32 - * Define USEBCOPY if the bcopy/memcpy from your system's C library
  33 + * Define USEBCOPY if the bcopy from your system's C library
  34   * supports the overlapping of source and destination blocks.  When
  35   * undefined, screen uses its own (probably slower) version of bcopy().
  36   *
  37 @@ -487,7 +487,6 @@
  38   * Their memove fails the test in the configure script. Sigh. (Juergen)
  39   */
  40  #undef USEBCOPY
  41 -#undef USEMEMCPY
  42  #undef USEMEMMOVE
  43
  44  /*
  45 diff --git a/configure.ac b/configure.ac
  46 index 27690a6..b8e3bec 100644
  47 --- a/configure.ac
  48 +++ b/configure.ac
  49 @@ -1145,7 +1145,7 @@ AC_TRY_LINK(,[getttyent();], AC_DEFINE(GETTTYENT))
  50  AC_CHECKING(fdwalk)
  51  AC_TRY_LINK([#include <stdlib.h>], [fdwalk(NULL, NULL);],AC_DEFINE(HAVE_FDWALK))
  52
  53 -AC_CHECKING(whether memcpy/memmove/bcopy handles overlapping arguments)
  54 +AC_CHECKING(whether memmove/bcopy handles overlapping arguments)
  55  AC_TRY_RUN([
  56  main() {
  57    char buf[10];
  58 @@ -1175,22 +1175,6 @@ main() {
  59    exit(0); /* libc version works properly.  */
  60  }], AC_DEFINE(USEMEMMOVE))
  61
  62 -
  63 -AC_TRY_RUN([
  64 -#define bcopy(s,d,l) memcpy(d,s,l)
  65 -main() {
  66 -  char buf[10];
  67 -  strcpy(buf, "abcdefghi");
  68 -  bcopy(buf, buf + 2, 3);
  69 -  if (strncmp(buf, "ababcf", 6))
  70 -    exit(1);
  71 -  strcpy(buf, "abcdefghi");
  72 -  bcopy(buf + 2, buf, 3);
  73 -  if (strncmp(buf, "cdedef", 6))
  74 -    exit(1);
  75 -  exit(0); /* libc version works properly.  */
  76 -}], AC_DEFINE(USEMEMCPY))
  77 -
  78  AC_SYS_LONG_FILE_NAMES
  79
  80  AC_MSG_CHECKING(for vsprintf)
  81 diff --git a/os.h b/os.h
  82 index e827ac9..0b41fb9 100644
  83 --- a/os.h
  84 +++ b/os.h
  85 @@ -142,12 +142,8 @@ extern int errno;
  86  # ifdef USEMEMMOVE
  87  #  define bcopy(s,d,len) memmove(d,s,len)
  88  # else
  89 -#  ifdef USEMEMCPY
  90 -#   define bcopy(s,d,len) memcpy(d,s,len)
  91 -#  else
  92 -#   define NEED_OWN_BCOPY
  93 -#   define bcopy xbcopy
  94 -#  endif
  95 +#  define NEED_OWN_BCOPY
  96 +#  define bcopy xbcopy
  97  # endif
  98  #endif
  99
 100 diff --git a/osdef.h.in b/osdef.h.in
 101 index 8687b60..e4057a0 100644
 102 --- a/osdef.h.in
 103 +++ b/osdef.h.in
 104 @@ -58,16 +58,8 @@ extern int   bcmp __P((char *, char *, int));
 105  extern int   killpg __P((int, int));
 106  #endif
 107
 108 -#ifndef USEBCOPY
 109 -# ifdef USEMEMCPY
 110 -extern void  memcpy __P((char *, char *, int));
 111 -# else
 112 -#  ifdef USEMEMMOVE
 113 +#if defined(USEMEMMOVE) && !defined(USEBCOPY)
 114  extern void  memmove __P((char *, char *, int));
 115 -#  else
 116 -extern void  bcopy __P((char *, char *, int));
 117 -#  endif
 118 -# endif
 119  #else
 120  extern void  bcopy __P((char *, char *, int));
 121  #endif
 122 --
 123 1.8.4.5
 124