2016-01-05  Martin Sebor  <msebor@redhat.com>

	[BZ #19432]
	* iconvdata/Makefile: Add bug-iconv11. 
	* iconvdata/bug-iconv11.c: New test.
	* iconvdata/ibm930.c: Do not reject redundant shift sequences.
	* iconvdata/ibm933.c: Same.
	* iconvdata/ibm935.c: Same.
	* iconvdata/ibm937.c: Same.
	* iconvdata/ibm939.c: Same.

diff --git a/iconvdata/Makefile b/iconvdata/Makefile
index ae5dde6..357530b 100644
--- a/iconvdata/Makefile
+++ b/iconvdata/Makefile
@@ -68,7 +68,7 @@ modules.so := $(addsuffix .so, $(modules))
 ifeq (yes,$(build-shared))
 tests = bug-iconv1 bug-iconv2 tst-loading tst-e2big tst-iconv4 bug-iconv4 \
 	tst-iconv6 bug-iconv5 bug-iconv6 tst-iconv7 bug-iconv8 bug-iconv9 \
-	bug-iconv10
+	bug-iconv10 bug-iconv11
 ifeq ($(have-thread-library),yes)
 tests += bug-iconv3
 endif
diff --git a/iconvdata/bug-iconv11.c b/iconvdata/bug-iconv11.c
new file mode 100644
index 0000000..3f39780
--- /dev/null
+++ b/iconvdata/bug-iconv11.c
@@ -0,0 +1,116 @@
+/* bug 19432: iconv rejects redundant escape sequences in IBM903,
+              IBM905, IBM907, and IBM909 
+
+   Copyright (C) 2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <iconv.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+// The longest test input sequence.
+#define MAXINBYTES    8
+#define MAXOUTBYTES   (MAXINBYTES * MB_LEN_MAX)
+
+// Verify that a conversion of the INPUT sequence consisting of
+// INBYTESLEFT bytes in the encoding specified by the codeset
+// named by FROM_SET is successful.
+// Return 0 on success, non-zero on iconv() failure.
+
+static int
+test_ibm93x (const char *from_set, const char *input, size_t inbytesleft)
+{
+  const char to_set[] = "UTF-8";
+  iconv_t cd = iconv_open (to_set, from_set);
+  if (cd == (iconv_t) -1)
+    {
+      printf ("iconv_open(\"%s\", \"%s\"): %s\n",
+              from_set, to_set, strerror (errno));
+      return 1;
+    }
+
+  char output [MAXOUTBYTES];
+  size_t outbytesleft = sizeof output;
+
+  char *inbuf = (char*)input;
+  char *outbuf = output;
+
+  printf ("iconv(cd, %p, %zu, %p, %zu)\n",
+          inbuf, inbytesleft, outbuf, outbytesleft);
+
+  errno = 0;
+  size_t ret = iconv (cd, &inbuf, &inbytesleft, &outbuf, &outbytesleft);
+  printf ("  ==> %td: %s\n"
+          "  inbuf%+td, inbytesleft=%zu, outbuf%+td, outbytesleft=%zu\n",
+          ret, strerror (errno),
+          inbuf - input, inbytesleft, outbuf - output, outbytesleft);
+
+  // Return 0 on success, non-zero on iconv() failure.
+  return ret == (size_t)-1 || errno;
+}
+
+static int
+do_test (void)
+{
+  // State-dependent encodings to exercise.
+  static const char* const to_code[] = {
+    "IBM930", "IBM933", "IBM935", "IBM937", "IBM939"
+  };
+
+  static const size_t ncodesets = sizeof to_code / sizeof *to_code;
+
+  // A source sequence containing a redundant shift sequence.
+  //              <SO><SI>G<SI>
+  static const struct {
+    char txt[MAXINBYTES];
+    size_t len;
+  } input[] = {
+#define DATA(s) { s, sizeof s - 1 }
+    // <SI>: denotes the shift-in 1-byte escape sequence, changing
+    //       the encoder from a sigle-byte encoding to multibyte
+    // <SO>: denotes the shift-out 1-byte escape sequence, switching
+    //       the encoder from a multibyte to a single-byte state
+
+    DATA ("\x0e"),               // <SI> (not redundant)
+    DATA ("\x0f"),               // <S0> (redundant with initial state)
+    DATA ("\x0e\x0e"),           // <SI><SI>
+    DATA ("\x0e\x0f\x0f"),       // <SI><SO><SO>
+    DATA ("\x0f\x0f"),           // <SO><SO>
+    DATA ("\x0f\x0e\x0e"),       // <SO><SI><SI>
+    DATA ("\x0e\x0f\xc7\x0f"),   // <SI><SO><G><SO>
+    DATA ("\xc7\x0f")            // <G><SO> (redundant with initial state)
+  };
+
+  static const size_t ninputs = sizeof input / sizeof *input;
+
+  int ret = 0;
+
+  size_t i, j;
+
+  // Iterate over the IBM93x codesets above and exercise each with
+  // the input sequences above.
+  for (i = 0; i != ncodesets; ++i)
+    for (j = 0; j != ninputs; ++j)
+      ret += test_ibm93x (to_code [i], input [i].txt, input [i].len);
+
+  return ret;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"
diff --git a/iconvdata/ibm930.c b/iconvdata/ibm930.c
index 1f60962..9d35734 100644
--- a/iconvdata/ibm930.c
+++ b/iconvdata/ibm930.c
@@ -110,24 +110,14 @@ enum
 									      \
     if (__builtin_expect (ch, 0) == SO)					      \
       {									      \
-	/* Shift OUT, change to DBCS converter.  */			      \
-	if (curcs == db)						      \
-	  {								      \
-	    result = __GCONV_ILLEGAL_INPUT;				      \
-	    break;							      \
-	  }								      \
+	/* Shift OUT, change to DBCS converter (redundant escape okay).  */   \
 	curcs = db;							      \
 	++inptr;							      \
 	continue;							      \
       }									      \
     else if (__builtin_expect (ch, 0) == SI)				      \
       {									      \
-	/* Shift IN, change to SBCS converter */			      \
-	if (curcs == sb)						      \
-	  {								      \
-	    result = __GCONV_ILLEGAL_INPUT;				      \
-	    break;							      \
-	  }								      \
+	/* Shift IN, change to SBCS converter (redundant escape okay).  */    \
 	curcs = sb;							      \
 	++inptr;							      \
 	continue;							      \
diff --git a/iconvdata/ibm933.c b/iconvdata/ibm933.c
index c984cd1..669e357 100644
--- a/iconvdata/ibm933.c
+++ b/iconvdata/ibm933.c
@@ -108,24 +108,14 @@ enum
 									      \
     if (__builtin_expect (ch, 0) == SO)					      \
       {									      \
-	/* Shift OUT, change to DBCS converter.  */			      \
-	if (curcs == db)						      \
-	  {								      \
-	    result = __GCONV_ILLEGAL_INPUT;				      \
-	    break;							      \
-	  }								      \
+	/* Shift OUT, change to DBCS converter (redundant escape okay).  */   \
 	curcs = db;							      \
 	++inptr;							      \
 	continue;							      \
       }									      \
     else if (__builtin_expect (ch, 0) == SI)				      \
       {									      \
-	/* Shift IN, change to SBCS converter.  */			      \
-	if (curcs == sb)						      \
-	  {								      \
-	    result = __GCONV_ILLEGAL_INPUT;				      \
-	    break;							      \
-	  }								      \
+	/* Shift IN, change to SBCS converter (redundant escape okay).  */    \
 	curcs = sb;							      \
 	++inptr;							      \
 	continue;							      \
diff --git a/iconvdata/ibm935.c b/iconvdata/ibm935.c
index 07f4bf2..2d3065e 100644
--- a/iconvdata/ibm935.c
+++ b/iconvdata/ibm935.c
@@ -109,24 +109,14 @@ enum
 									      \
     if (__builtin_expect(ch, 0) == SO)					      \
       {									      \
-	/* Shift OUT, change to DBCS converter.  */			      \
-	if (curcs == db)						      \
-	  {								      \
-	    result = __GCONV_ILLEGAL_INPUT;				      \
-	    break;							      \
-	  }								      \
+	/* Shift OUT, change to DBCS converter (redundant escape okay).  */   \
 	curcs = db;							      \
 	++inptr;							      \
 	continue;							      \
       }									      \
     else if (__builtin_expect (ch, 0) == SI)				      \
       {									      \
-	/* Shift IN, change to SBCS converter.  */			      \
-	if (curcs == sb)						      \
-	  {								      \
-	    result = __GCONV_ILLEGAL_INPUT;				      \
-	    break;							      \
-	  }								      \
+	/* Shift IN, change to SBCS converter (redundant escape okay).  */    \
 	curcs = sb;							      \
 	++inptr;							      \
 	continue;							      \
diff --git a/iconvdata/ibm937.c b/iconvdata/ibm937.c
index 88344a4..3ed6479 100644
--- a/iconvdata/ibm937.c
+++ b/iconvdata/ibm937.c
@@ -109,24 +109,14 @@ enum
 									      \
     if (__builtin_expect (ch, 0) == SO)					      \
       {									      \
-	/* Shift OUT, change to DBCS converter.  */			      \
-	if (curcs == db)						      \
-	  {								      \
-	    result = __GCONV_ILLEGAL_INPUT;				      \
-	    break;							      \
-	  }								      \
+	/* Shift OUT, change to DBCS converter (redundant escape okay).  */   \
 	curcs = db;							      \
 	++inptr;							      \
 	continue;							      \
       }									      \
     else if (__builtin_expect (ch, 0) == SI)				      \
       {									      \
-	/* Shift IN, change to SBCS converter.  */			      \
-	if (curcs == sb)						      \
-	  {								      \
-	    result = __GCONV_ILLEGAL_INPUT;				      \
-	    break;							      \
-	  }								      \
+	/* Shift IN, change to SBCS converter (redundant escape okay).  */    \
 	curcs = sb;							      \
 	++inptr;							      \
 	continue;							      \
diff --git a/iconvdata/ibm939.c b/iconvdata/ibm939.c
index dbdda62..c0a75f7 100644
--- a/iconvdata/ibm939.c
+++ b/iconvdata/ibm939.c
@@ -109,24 +109,14 @@ enum
 									      \
     if (__builtin_expect (ch, 0) == SO)					      \
       {									      \
-	/* Shift OUT, change to DBCS converter.  */			      \
-	if (curcs == db)						      \
-	  {								      \
-	    result = __GCONV_ILLEGAL_INPUT;				      \
-	    break;							      \
-	  }								      \
+	/* Shift OUT, change to DBCS converter (redundant escape okay).  */   \
 	curcs = db;							      \
 	++inptr;							      \
 	continue;							      \
       }									      \
     else if (__builtin_expect (ch, 0) == SI)				      \
       {									      \
-	/* Shift IN, change to SBCS converter.  */			      \
-	if (curcs == sb)						      \
-	  {								      \
-	    result = __GCONV_ILLEGAL_INPUT;				      \
-	    break;							      \
-	  }								      \
+	/* Shift IN, change to SBCS converter (redundant escape okay).  */    \
 	curcs = sb;							      \
 	++inptr;							      \
 	continue;							      \
