From cedf009d3c798f6d06ca8c32ef4ef859f1ea244c Mon Sep 17 00:00:00 2001
From: Tomas Hajny <hajny@freepascal.org>
Date: Sun, 18 May 2014 20:37:40 +0000
Subject: [PATCH]   * fix for SIGSEGV in Exec without command line parameters
 revealed in discussion for #26160

git-svn-id: trunk@27804 -
---
 rtl/go32v2/dos.pp | 3 +--
 rtl/msdos/dos.pp  | 3 +--
 rtl/watcom/dos.pp | 8 ++++----
 3 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/rtl/go32v2/dos.pp b/rtl/go32v2/dos.pp
index dbe31e29ad..bcc80344cf 100644
--- a/rtl/go32v2/dos.pp
+++ b/rtl/go32v2/dos.pp
@@ -436,8 +436,7 @@ begin
   seg_move (get_ds, PtrInt (ExecBufPtr), DosMemSelector, TB, Pred (Current_Dos_Buffer_Pos));
 { allocate FCB see dosexec code }
   arg_ofs:=1;
-  while (c[arg_ofs] in [' ',#9]) and
-   (arg_ofs<length(c)) do
+  while (arg_ofs<length(c)) and (c[arg_ofs] in [' ',#9]) do
     inc(arg_ofs);
   dosregs.ax:=$2901;
   dosregs.ds:=(la_c+arg_ofs) shr 4;
diff --git a/rtl/msdos/dos.pp b/rtl/msdos/dos.pp
index 16a6bd7561..8e5830b825 100644
--- a/rtl/msdos/dos.pp
+++ b/rtl/msdos/dos.pp
@@ -237,8 +237,7 @@ begin
     GetShortName(p);
   { allocate FCB see dosexec code }
   arg_ofs:=1;
-  while (c[arg_ofs] in [' ',#9]) and
-   (arg_ofs<length(c)) do
+  while (arg_ofs<length(c)) and (c[arg_ofs] in [' ',#9]) do
     inc(arg_ofs);
   dosregs.ax:=$2901;
   dosregs.ds:=Seg(c[arg_ofs]);
diff --git a/rtl/watcom/dos.pp b/rtl/watcom/dos.pp
index 4985d37502..d2e1a43bf2 100644
--- a/rtl/watcom/dos.pp
+++ b/rtl/watcom/dos.pp
@@ -228,7 +228,7 @@ begin
   la_e:=la_e+16;
 { allocate FCB see dosexec code }
   arg_ofs:=1;
-  while (c[arg_ofs] in [' ',#9]) do
+  while (arg_ofs < Length (C)) and (c[arg_ofs] in [' ',#9]) do
    inc(arg_ofs);
   dosregs.ax:=$2901;
   dosregs.ds:=(la_c+arg_ofs) shr 4;
@@ -239,12 +239,12 @@ begin
 { allocate second FCB see dosexec code }
   repeat
     inc(arg_ofs);
-  until (c[arg_ofs] in [' ',#9,#13]);
-  if c[arg_ofs]<>#13 then
+  until (Arg_Ofs >= Length (C)) or (c[arg_ofs] in [' ',#9,#13]);
+  if (c[arg_ofs]<>#13) and (Arg_Ofs < Length (C)) then
    begin
      repeat
        inc(arg_ofs);
-     until not (c[arg_ofs] in [' ',#9]);
+     until (Arg_Ofs > Length (C)) or not (c[arg_ofs] in [' ',#9]);
    end;
   dosregs.ax:=$2901;
   dosregs.ds:=(la_c+arg_ofs) shr 4;