3 files changed, 40 insertions, 5 deletions

diff --git a/shell/ash.c b/shell/ash.c
index 63eb4947c..87190c453 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -193,12 +193,14 @@
 //config:       case-insensitive filename globbing.
 //config:
 //config:config ASH_IGNORE_CR
-//config:       bool "Ignore CR in scripts"
+//config:       bool "Ignore CR in CRLF line endings"
 //config:       default y
 //config:       depends on (ASH || SH_IS_ASH || BASH_IS_ASH) && PLATFORM_MINGW32
 //config:       help
-//config:       Allow CRs to be ignored when shell scripts are parsed.  This
-//config:       makes it possible to run scripts with CRLF line endings.
+//config:       Allow CRs to be ignored when they appear in CRLF line endings
+//config:       but not in other circumstances.  This isn't a general-purpose
+//config:       option:  it only covers certain new cases which are under test.
+//config:       Enabled by default.  May be removed in future.
 //config:
 //config:endif # ash options
 
@@ -6806,6 +6808,9 @@ ifsbreakup(char *string, struct arglist *arglist)
         const char *ifs, *realifs;
         int ifsspc;
         int nulonly;
+#if ENABLE_ASH_IGNORE_CR
+        int lshift = 0;
+#endif
 
         start = string;
         if (ifslastp != NULL) {
@@ -6816,7 +6821,33 @@ ifsbreakup(char *string, struct arglist *arglist)
                 do {
                         int afternul;
 
+#if ENABLE_ASH_IGNORE_CR
+                        /* Adjust region offsets for left-shifted string. */
+                        ifsp->begoff -= lshift;
+                        ifsp->endoff -= lshift;
+#endif
                         p = string + ifsp->begoff;
+#if ENABLE_ASH_IGNORE_CR
+                        if (ifsp->endoff > ifsp->begoff + 1) {
+                                /* Transform CRLF to LF.  Skip regions having zero or
+                                 * one characters:  they can't contain CRLF.  If the
+                                 * region shrinks shift the rest of the string left. */
+                                int oldlen = ifsp->endoff - ifsp->begoff;
+                                int newlen = remove_cr(p, oldlen);
+                                int delta = oldlen - newlen;
+
+                                if (delta > 0) {
+                                        char *t = string + ifsp->endoff;
+                                        char *s = string + ifsp->endoff - delta;
+
+                                        while (*t)
+                                                *s++ = *t++;
+                                        *s = '\0';
+                                        lshift += delta;
+                                        ifsp->endoff -= delta;
+                                }
+                        }
+#endif
                         afternul = nulonly;
                         nulonly = ifsp->nulonly;
                         ifs = nulonly ? nullstr : realifs;
diff --git a/shell/shell_common.c b/shell/shell_common.c
index 399d5e684..c0dd32fb4 100644
--- a/shell/shell_common.c
+++ b/shell/shell_common.c
@@ -19,7 +19,7 @@
 #include "libbb.h"
 #include "shell_common.h"
 
-#if !ENABLE_PLATFORM_MINGW32
+#if !ENABLE_PLATFORM_MINGW32 || ENABLE_ASH_IGNORE_CR
 const char defifsvar[] ALIGN1 = "IFS= \t\n";
 #else
 const char defifsvar[] ALIGN1 = "IFS= \t\n\r";
diff --git a/testsuite/sh.tests b/testsuite/sh.tests
index 872611a1b..6fc3ca104 100755
--- a/testsuite/sh.tests
+++ b/testsuite/sh.tests
@@ -89,8 +89,12 @@ IyEvYmluL3NoICAtIAplY2hvICJIZWxsbyB3b3JsZCIK
 "
 rm -f shebang_leading_argument_trailing_space.sh
 
-testing "remove CRs from string being evaluated" \
+testing "sh remove CRs from string being evaluated" \
         "sh -c \"$(printf 'set -e\r\necho Hello world\r\n')\"" \
         "Hello world\n" "" ""
 
+testing "sh preserve lone CRs during field splitting" \
+        "sh input" \
+        "Hello\r world\n" "echo \$(printf \"Hello\\\\r\\\\r\\\\nworld\\\\r\\\\n\")" ""
+
 exit $FAILCOUNT