Add GPG_ERR_BOGUS_STRING and an experimental gpgrt_pending.

* src/visibility.c (gpgrt_pending, gpgrt_pending_unlocked): New.
* src/estream.c (_gpgrt_pending, _gpgrt_pending_unlocked): New.
(check_pending): new.
(check_pending_fbf, check_pending_nbf): New.
(es_func_mem_read, es_func_fd_read, es_func_w32_read)
(es_func_fp_read, es_fill): Take care of the special 0 value for SIZE.

10 files changed, 160 insertions, 7 deletions

diff --git a/NEWS b/NEWS
index 2e49b0c..4330408 100644
--- a/NEWS
+++ b/NEWS
@@ -32,6 +32,9 @@ Noteworthy changes in version 1.17 (unreleased) [C12/A12/R_]
  GPG_ERR_BAD_HS_FINISHED          NEW.
  GPG_ERR_BAD_HS_SERVER_KEX        NEW.
  GPG_ERR_BAD_HS_CLIENT_KEX        NEW.
+ GPG_ERR_BOGUS_STRING             NEW.
+ gpgrt_pending                    NEW.
+ gpgrt_pending_unlocked           NEW.
 
 
 Noteworthy changes in version 1.16 (2014-09-18) [C12/A12/R2]
diff --git a/doc/errorref.txt b/doc/errorref.txt
index 666dca6..07b7cd4 100644
--- a/doc/errorref.txt
+++ b/doc/errorref.txt
@@ -219,7 +219,12 @@ GPG_ERR_INV_ARG			Invalid argument
 52	GPG_ERR_NOT_PROCESSED		Data not processed
 53	GPG_ERR_UNUSABLE_PUBKEY		Unusable public key
 54	GPG_ERR_UNUSABLE_SECKEY		Unusable secret key
-55	GPG_ERR_INV_VALUE		Invalid value
+
+GPG_ERR_INV_VALUE		Invalid value
+
+    NTBTLS: - A DH parameter is out of range
+
+
 56	GPG_ERR_BAD_CERT_CHAIN		Bad certificate chain
 
 GPG_ERR_MISSING_CERT		Missing certificate
@@ -516,7 +521,13 @@ GPG_ERR_LIMIT_REACHED           Limit reached
         GnuPG: gpgtar: Extract directory can't be created because too
         many of directories with a similar name are already existing.
 
-184	GPG_ERR_NOT_INITIALIZED		Not initialized
+GPG_ERR_NOT_INITIALIZED		Not initialized
+
+    An operation can't be performed because something has not been
+    initialized.  This might be a missing initialization of an entire
+    subsystems or a prerequisite for using a function is not
+    fulfilled.
+
 185	GPG_ERR_MISSING_ISSUER_CERT	Missing issuer certificate
 186	GPG_ERR_NO_KEYSERVER		No keyserver available
 
@@ -699,6 +710,13 @@ GPG_ERR_BAD_HS_CLIENT_KEX       Bad client key exchange message in handshake
     NTBTLS: - As the description says.
 
 
+GPG_ERR_BOGUS_STRING            Bogus string
+
+    Used if a protocol sends length prefixed strings which contain a
+    Nul byte and further processing would discard the rest of the
+    string.  May also be used if a string contains unexpected and
+    possible dangerous characters (e.g. control characters in a domain
+    name).
 
 
 GPG_ERR_KEY_DISABLED            Key disabled
diff --git a/src/err-codes.h.in b/src/err-codes.h.in
index 9274530..704049c 100644
--- a/src/err-codes.h.in
+++ b/src/err-codes.h.in
@@ -273,8 +273,8 @@
 247	GPG_ERR_BAD_HS_FINISHED		Bad finished message in handshake
 248	GPG_ERR_BAD_HS_SERVER_KEX	Bad server key exchange message in handshake
 249	GPG_ERR_BAD_HS_CLIENT_KEX	Bad client key exchange message in handshake
-
-# 250 and 251 are free to be used.
+250	GPG_ERR_BOGUS_STRING		Bogus string
+# 251 is free to be used.
 
 252	GPG_ERR_KEY_DISABLED		Key disabled
 253	GPG_ERR_KEY_ON_CARD		Not possible with a card based key
diff --git a/src/estream.c b/src/estream.c
index 46be363..2537141 100644
--- a/src/estream.c
+++ b/src/estream.c
@@ -625,6 +625,9 @@ es_func_mem_read (void *cookie, void *buffer, size_t size)
   estream_cookie_mem_t mem_cookie = cookie;
   gpgrt_ssize_t ret;
 
+  if (!size)  /* Just the pending data check.  */
+    return (mem_cookie->data_len - mem_cookie->offset)? 0 : -1;
+
   if (size > mem_cookie->data_len - mem_cookie->offset)
     size = mem_cookie->data_len - mem_cookie->offset;
 
@@ -898,7 +901,9 @@ es_func_fd_read (void *cookie, void *buffer, size_t size)
   estream_cookie_fd_t file_cookie = cookie;
   gpgrt_ssize_t bytes_read;
 
-  if (IS_INVALID_FD (file_cookie->fd))
+  if (!size)
+    bytes_read = -1; /* We don't know whether anything is pending.  */
+  else if (IS_INVALID_FD (file_cookie->fd))
     {
       _gpgrt_yield ();
       bytes_read = 0;
@@ -1057,7 +1062,9 @@ es_func_w32_read (void *cookie, void *buffer, size_t size)
   estream_cookie_w32_t w32_cookie = cookie;
   gpgrt_ssize_t bytes_read;
 
-  if (w32_cookie->hd == INVALID_HANDLE_VALUE)
+  if (!size)
+    bytes_to_read = -1; /* We don't know whether anything is pending.  */
+  else if (w32_cookie->hd == INVALID_HANDLE_VALUE)
     {
       _gpgrt_yield ();
       bytes_read = 0;
@@ -1273,6 +1280,9 @@ es_func_fp_read (void *cookie, void *buffer, size_t size)
   estream_cookie_fp_t file_cookie = cookie;
   gpgrt_ssize_t bytes_read;
 
+  if (!size)
+    return -1; /* We don't know whether anything is pending.  */
+
   if (file_cookie->fp)
     {
       if (pre_syscall_func)
@@ -1602,6 +1612,8 @@ es_fill (estream_t stream)
       _set_errno (EOPNOTSUPP);
       err = -1;
     }
+  else if (!stream->buffer_size)
+    err = 0;
   else
     {
       gpgrt_cookie_read_function_t func_read = stream->intern->func_read;
@@ -1937,6 +1949,18 @@ es_read_nbf (estream_t _GPGRT__RESTRICT stream,
   return err;
 }
 
+static int
+check_pending_nbf (estream_t _GPGRT__RESTRICT stream)
+{
+  gpgrt_cookie_read_function_t func_read = stream->intern->func_read;
+  char buffer[1];
+
+  if (!(*func_read) (stream->intern->cookie, buffer, 0))
+    return 1; /* Pending bytes.  */
+  return 0; /* No pending bytes or error.  */
+}
+
+
 /* Try to read BYTES_TO_READ bytes FROM STREAM into BUFFER in
    fully-buffered-mode, storing the amount of bytes read in
    *BYTES_READ.  */
@@ -1987,6 +2011,26 @@ es_read_fbf (estream_t _GPGRT__RESTRICT stream,
   return err;
 }
 
+
+static int
+check_pending_fbf (estream_t _GPGRT__RESTRICT stream)
+{
+  gpgrt_cookie_read_function_t func_read = stream->intern->func_read;
+  char buffer[1];
+
+  if (stream->data_offset == stream->data_len)
+    {
+      /* Nothing more to read in current container, check whetehr it
+         would be possible to fill the container with new data.  */
+      if (!(*func_read) (stream->intern->cookie, buffer, 0))
+        return 1; /* Pending bytes.  */
+    }
+  else
+    return 1;
+  return 0;
+}
+
+
 /* Try to read BYTES_TO_READ bytes FROM STREAM into BUFFER in
    line-buffered-mode, storing the amount of bytes read in
    *BYTES_READ.  */
@@ -2003,7 +2047,7 @@ es_read_lbf (estream_t _GPGRT__RESTRICT stream,
 }
 
 /* Try to read BYTES_TO_READ bytes FROM STREAM into BUFFER, storing
-   *the amount of bytes read in BYTES_READ.  */
+   the amount of bytes read in BYTES_READ.  */
 static int
 es_readn (estream_t _GPGRT__RESTRICT stream,
 	  void *_GPGRT__RESTRICT buffer_arg,
@@ -2062,6 +2106,39 @@ es_readn (estream_t _GPGRT__RESTRICT stream,
   return err;
 }
 
+
+/* Return true if at least one byte is pending for read.  This is a
+   best effort check and it it possible that bytes are still pending
+   even if false is returned.  If the stream is in writing mode it is
+   switched to read mode.  */
+static int
+check_pending (estream_t _GPGRT__RESTRICT stream)
+{
+  if (stream->flags.writing)
+    {
+      /* Switching to reading mode -> flush output.  */
+      if (es_flush (stream))
+	return 0; /* Better return 0 on error.  */
+      stream->flags.writing = 0;
+    }
+
+  /* Check unread data first.  */
+  if (stream->unread_data_len)
+    return 1;
+
+  switch (stream->intern->strategy)
+    {
+    case _IONBF:
+      return check_pending_nbf (stream);
+    case _IOLBF:
+    case _IOFBF:
+      return check_pending_fbf (stream);
+    }
+
+  return 0;
+}
+
+
 /* Try to unread DATA_N bytes from DATA into STREAM, storing the
    amount of bytes successfully unread in *BYTES_UNREAD.  */
 static void
@@ -3394,6 +3471,34 @@ _gpgrt_syshd (estream_t stream, es_syshd_t *syshd)
 
 
 int
+_gpgrt_pending_unlocked (estream_t stream)
+{
+  return check_pending (stream);
+}
+
+
+/* Return true if there is at least one byte pending for read on
+   STREAM.  This does only work if the backend supports checking for
+   pending bytes and is thus mostly useful with cookie based backends.
+
+   Note that if this function is used with cookie based functions, the
+   read cookie may be called with 0 for the SIZE argument.  If bytes
+   are pending the function is expected to return -1 in this case and
+   thus deviates from the standard behavior of read(2).   */
+int
+_gpgrt_pending (estream_t stream)
+{
+  int ret;
+
+  lock_stream (stream);
+  ret = _gpgrt_pending_unlocked (stream);
+  unlock_stream (stream);
+
+  return ret;
+}
+
+
+int
 _gpgrt_feof_unlocked (estream_t stream)
 {
   return es_get_indicator (stream, 0, 1);
diff --git a/src/gpg-error.def.in b/src/gpg-error.def.in
index ac20a69..f17522e 100644
--- a/src/gpg-error.def.in
+++ b/src/gpg-error.def.in
@@ -137,4 +137,7 @@ EXPORTS
  gpg_err_deinit               @102
  gpgrt_set_alloc_func         @103
 
+ gpgrt_pending                @104
+ gpgrt_pending_unlocked       @105
+
 ;; end of file with public symbols for Windows.
diff --git a/src/gpg-error.h.in b/src/gpg-error.h.in
index 80ce391..6ac6e0a 100644
--- a/src/gpg-error.h.in
+++ b/src/gpg-error.h.in
@@ -496,6 +496,8 @@ int gpgrt_ferror (gpgrt_stream_t stream);
 int gpgrt_ferror_unlocked (gpgrt_stream_t stream);
 void gpgrt_clearerr (gpgrt_stream_t stream);
 void gpgrt_clearerr_unlocked (gpgrt_stream_t stream);
+int gpgrt_pending (gpgrt_stream_t stream);
+int gpgrt_pending_unlocked (gpgrt_stream_t stream);
 
 int gpgrt_fflush (gpgrt_stream_t stream);
 int gpgrt_fseek (gpgrt_stream_t stream, long int offset, int whence);
@@ -648,6 +650,8 @@ int gpgrt_vsnprintf (char *buf,size_t bufsize,
 # define es_ferror_unlocked   gpgrt_ferror_unlocked
 # define es_clearerr          gpgrt_clearerr
 # define es_clearerr_unlocked gpgrt_clearerr_unlocked
+# define es_pending           gpgrt_pending
+# define es_pending_unlocked  gpgrt_pending_unlocked
 # define es_fflush            gpgrt_fflush
 # define es_fseek             gpgrt_fseek
 # define es_fseeko            gpgrt_fseeko
diff --git a/src/gpg-error.vers b/src/gpg-error.vers
index 43becea..c0e599a 100644
--- a/src/gpg-error.vers
+++ b/src/gpg-error.vers
@@ -64,6 +64,8 @@ GPG_ERROR_1.0 {
     gpgrt_flockfile;
     gpgrt_ftrylockfile;
     gpgrt_funlockfile;
+    gpgrt_pending;
+    gpgrt_pending_unlocked;
     gpgrt_feof;
     gpgrt_feof_unlocked;
     gpgrt_ferror;
diff --git a/src/gpgrt-int.h b/src/gpgrt-int.h
index f97166f..8907835 100644
--- a/src/gpgrt-int.h
+++ b/src/gpgrt-int.h
@@ -102,6 +102,8 @@ int _gpgrt_ferror (gpgrt_stream_t stream);
 int _gpgrt_ferror_unlocked (gpgrt_stream_t stream);
 void _gpgrt_clearerr (gpgrt_stream_t stream);
 void _gpgrt_clearerr_unlocked (gpgrt_stream_t stream);
+int _gpgrt_pending (gpgrt_stream_t stream);
+int _gpgrt_pending_unlocked (gpgrt_stream_t stream);
 
 int _gpgrt_fflush (gpgrt_stream_t stream);
 int _gpgrt_fseek (gpgrt_stream_t stream, long int offset, int whence);
diff --git a/src/visibility.c b/src/visibility.c
index f0d7fd1..f26f58c 100644
--- a/src/visibility.c
+++ b/src/visibility.c
@@ -298,6 +298,18 @@ gpgrt_funlockfile (estream_t stream)
 }
 
 int
+gpgrt_pending (estream_t stream)
+{
+  return _gpgrt_pending (stream);
+}
+
+int
+gpgrt_pending_unlocked (estream_t stream)
+{
+  return _gpgrt_pending_unlocked (stream);
+}
+
+int
 gpgrt_feof (estream_t stream)
 {
   return _gpgrt_feof (stream);
diff --git a/src/visibility.h b/src/visibility.h
index feeb8d1..35878d7 100644
--- a/src/visibility.h
+++ b/src/visibility.h
@@ -87,6 +87,8 @@ MARK_VISIBLE (_gpgrt_get_std_stream)
 MARK_VISIBLE (gpgrt_flockfile)
 MARK_VISIBLE (gpgrt_ftrylockfile)
 MARK_VISIBLE (gpgrt_funlockfile)
+MARK_VISIBLE (gpgrt_pending)
+MARK_VISIBLE (gpgrt_pending_unlocked)
 MARK_VISIBLE (gpgrt_feof)
 MARK_VISIBLE (gpgrt_feof_unlocked)
 MARK_VISIBLE (gpgrt_ferror)
@@ -190,6 +192,8 @@ MARK_VISIBLE (gpgrt_set_alloc_func)
 #define gpgrt_flockfile             _gpgrt_USE_UNDERSCORED_FUNCTION
 #define gpgrt_ftrylockfile          _gpgrt_USE_UNDERSCORED_FUNCTION
 #define gpgrt_funlockfile           _gpgrt_USE_UNDERSCORED_FUNCTION
+#define gpgrt_pending               _gpgrt_USE_UNDERSCORED_FUNCTION
+#define gpgrt_pending_unlocked      _gpgrt_USE_UNDERSCORED_FUNCTION
 #define gpgrt_feof                  _gpgrt_USE_UNDERSCORED_FUNCTION
 #define gpgrt_feof_unlocked         _gpgrt_USE_UNDERSCORED_FUNCTION
 #define gpgrt_ferror                _gpgrt_USE_UNDERSCORED_FUNCTION