Imported Upstream version 2.2.1upstream/2.2.1

1 files changed, 1060 insertions, 0 deletions

diff --git a/buffer.c b/buffer.c
new file mode 100644
index 0000000..e0a9a96
--- /dev/null
+++ b/buffer.c
@@ -0,0 +1,1060 @@
+/*
+ *  OpenVPN -- An application to securely tunnel IP networks
+ *             over a single UDP port, with support for SSL/TLS-based
+ *             session authentication and key exchange,
+ *             packet encryption, packet authentication, and
+ *             packet compression.
+ *
+ *  Copyright (C) 2002-2010 OpenVPN Technologies, Inc. <sales@openvpn.net>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation.
+ *
+ *  This program 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 General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program (see the file COPYING included with this
+ *  distribution); if not, write to the Free Software Foundation, Inc.,
+ *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include "syshead.h"
+
+#include "common.h"
+#include "buffer.h"
+#include "error.h"
+#include "mtu.h"
+
+#include "memdbg.h"
+
+size_t
+array_mult_safe (const size_t m1, const size_t m2, const size_t extra)
+{
+  const size_t limit = 0xFFFFFFFF;
+  unsigned long long res = (unsigned long long)m1 * (unsigned long long)m2 + (unsigned long long)extra;
+  if (unlikely(m1 > limit) || unlikely(m2 > limit) || unlikely(extra > limit) || unlikely(res > (unsigned long long)limit))
+    msg (M_FATAL, "attemped allocation of excessively large array");
+  return (size_t) res;
+}
+
+void
+buf_size_error (const size_t size)
+{
+  msg (M_FATAL, "fatal buffer size error, size=%lu", (unsigned long)size);
+}
+
+struct buffer
+#ifdef DMALLOC
+alloc_buf_debug (size_t size, const char *file, int line)
+#else
+alloc_buf (size_t size)
+#endif
+{
+#ifdef DMALLOC
+  return alloc_buf_gc_debug (size, NULL, file, line);
+#else
+  return alloc_buf_gc (size, NULL);
+#endif
+}
+
+struct buffer
+#ifdef DMALLOC
+alloc_buf_gc_debug (size_t size, struct gc_arena *gc, const char *file, int line)
+#else
+alloc_buf_gc (size_t size, struct gc_arena *gc)
+#endif
+{
+  struct buffer buf;
+  if (!buf_size_valid (size))
+    buf_size_error (size);
+  buf.capacity = (int)size;
+  buf.offset = 0;
+  buf.len = 0;
+#ifdef DMALLOC
+  buf.data = (uint8_t *) gc_malloc_debug (size, false, gc, file, line);
+#else
+  buf.data = (uint8_t *) gc_malloc (size, false, gc);
+#endif
+  if (size)
+    *buf.data = 0;
+  return buf;
+}
+
+struct buffer
+#ifdef DMALLOC
+clone_buf_debug (const struct buffer* buf, const char *file, int line)
+#else
+clone_buf (const struct buffer* buf)
+#endif
+{
+  struct buffer ret;
+  ret.capacity = buf->capacity;
+  ret.offset = buf->offset;
+  ret.len = buf->len;
+#ifdef DMALLOC
+  ret.data = (uint8_t *) openvpn_dmalloc (file, line, buf->capacity);
+#else
+  ret.data = (uint8_t *) malloc (buf->capacity);
+#endif
+  check_malloc_return (ret.data);
+  memcpy (BPTR (&ret), BPTR (buf), BLEN (buf));
+  return ret;
+}
+
+#ifdef BUF_INIT_TRACKING
+
+bool
+buf_init_debug (struct buffer *buf, int offset, const char *file, int line)
+{
+  buf->debug_file = file;
+  buf->debug_line = line;
+  return buf_init_dowork (buf, offset);
+}
+
+static inline int
+buf_debug_line (const struct buffer *buf)
+{
+  return buf->debug_line;
+}
+
+static const char *
+buf_debug_file (const struct buffer *buf)
+{
+  return buf->debug_file;
+}
+
+#else
+
+#define buf_debug_line(buf) 0
+#define buf_debug_file(buf) "[UNDEF]"
+
+#endif
+
+void
+buf_clear (struct buffer *buf)
+{
+  if (buf->capacity > 0)
+    memset (buf->data, 0, buf->capacity);
+  buf->len = 0;
+  buf->offset = 0;
+}
+
+bool
+buf_assign (struct buffer *dest, const struct buffer *src)
+{
+  if (!buf_init (dest, src->offset))
+    return false;
+  return buf_write (dest, BPTR (src), BLEN (src));
+}
+
+struct buffer
+clear_buf ()
+{
+  struct buffer buf;
+  CLEAR (buf);
+  return buf;
+}
+
+void
+free_buf (struct buffer *buf)
+{
+  if (buf->data)
+    free (buf->data);
+  CLEAR (*buf);
+}
+
+/*
+ * Return a buffer for write that is a subset of another buffer
+ */
+struct buffer
+buf_sub (struct buffer *buf, int size, bool prepend)
+{
+  struct buffer ret;
+  uint8_t *data;
+
+  CLEAR (ret);
+  data = prepend ? buf_prepend (buf, size) : buf_write_alloc (buf, size);
+  if (data)
+    {
+      ret.capacity = size;
+      ret.data = data;
+    }
+  return ret;
+}
+
+/*
+ * printf append to a buffer with overflow check
+ */
+bool
+buf_printf (struct buffer *buf, const char *format, ...)
+{
+  int ret = false;
+  if (buf_defined (buf))
+    {
+      va_list arglist;
+      uint8_t *ptr = BEND (buf);
+      int cap = buf_forward_capacity (buf);
+
+      if (cap > 0)
+	{
+	  int stat;
+	  va_start (arglist, format);
+	  stat = vsnprintf ((char *)ptr, cap, format, arglist);
+	  va_end (arglist);
+	  *(buf->data + buf->capacity - 1) = 0; /* windows vsnprintf needs this */
+	  buf->len += (int) strlen ((char *)ptr);
+	  if (stat >= 0 && stat < cap)
+	    ret = true;
+	}
+    }
+  return ret;
+}
+
+/*
+ * This is necessary due to certain buggy implementations of snprintf,
+ * that don't guarantee null termination for size > 0.
+ *
+ * This function is duplicated into service-win32/openvpnserv.c
+ * Any modifications here should be done to the other place as well.
+ */
+
+int openvpn_snprintf(char *str, size_t size, const char *format, ...)
+{
+  va_list arglist;
+  int ret = 0;
+  if (size > 0)
+    {
+      va_start (arglist, format);
+      ret = vsnprintf (str, size, format, arglist);
+      va_end (arglist);
+      str[size - 1] = 0;
+    }
+  return ret;
+}
+
+/*
+ * write a string to the end of a buffer that was
+ * truncated by buf_printf
+ */
+void
+buf_catrunc (struct buffer *buf, const char *str)
+{
+  if (buf_forward_capacity (buf) <= 1)
+    {
+      int len = (int) strlen (str) + 1;
+      if (len < buf_forward_capacity_total (buf))
+	{
+	  strncpynt ((char *)(buf->data + buf->capacity - len), str, len);
+	}
+    }
+}
+
+/*
+ * convert a multi-line output to one line
+ */
+void
+convert_to_one_line (struct buffer *buf)
+{
+  uint8_t *cp = BPTR(buf);
+  int len = BLEN(buf);
+  while (len--)
+    {
+      if (*cp == '\n')
+	*cp = '|';
+      ++cp;
+    }
+}
+
+/* NOTE: requires that string be null terminated */
+void
+buf_write_string_file (const struct buffer *buf, const char *filename, int fd)
+{
+  const int len = strlen ((char *) BPTR (buf));
+  const int size = write (fd, BPTR (buf), len);
+  if (size != len)
+    msg (M_ERR, "Write error on file '%s'", filename);
+}
+
+/*
+ * Garbage collection
+ */
+
+void *
+#ifdef DMALLOC
+gc_malloc_debug (size_t size, bool clear, struct gc_arena *a, const char *file, int line)
+#else
+gc_malloc (size_t size, bool clear, struct gc_arena *a)
+#endif
+{
+  void *ret;
+  if (a)
+    {
+      struct gc_entry *e;
+#ifdef DMALLOC
+      e = (struct gc_entry *) openvpn_dmalloc (file, line, size + sizeof (struct gc_entry));
+#else
+      e = (struct gc_entry *) malloc (size + sizeof (struct gc_entry));
+#endif
+      check_malloc_return (e);
+      ret = (char *) e + sizeof (struct gc_entry);
+      e->next = a->list;
+      a->list = e;
+    }
+  else
+    {
+#ifdef DMALLOC
+      ret = openvpn_dmalloc (file, line, size);
+#else
+      ret = malloc (size);
+#endif
+      check_malloc_return (ret);
+    }
+#ifndef ZERO_BUFFER_ON_ALLOC
+  if (clear)
+#endif
+    memset (ret, 0, size);
+  return ret;
+}
+
+void
+x_gc_free (struct gc_arena *a)
+{
+  struct gc_entry *e;
+  e = a->list;
+  a->list = NULL;
+  
+  while (e != NULL)
+    {
+      struct gc_entry *next = e->next;
+      free (e);
+      e = next;
+    }
+}
+
+/*
+ * Transfer src arena to dest, resetting src to an empty arena.
+ */
+void
+gc_transfer (struct gc_arena *dest, struct gc_arena *src)
+{
+  if (dest && src)
+    {
+      struct gc_entry *e = src->list;
+      if (e)
+	{
+	  while (e->next != NULL)
+	    e = e->next;
+	  e->next = dest->list;
+	  dest->list = src->list;
+	  src->list = NULL;
+	}
+    }
+}
+
+/*
+ * Hex dump -- Output a binary buffer to a hex string and return it.
+ */
+
+char *
+format_hex_ex (const uint8_t *data, int size, int maxoutput,
+	       int space_break, const char* separator,
+	       struct gc_arena *gc)
+{
+  struct buffer out = alloc_buf_gc (maxoutput ? maxoutput :
+				    ((size * 2) + (size / space_break) * (int) strlen (separator) + 2),
+				    gc);
+  int i;
+  for (i = 0; i < size; ++i)
+    {
+      if (separator && i && !(i % space_break))
+	buf_printf (&out, "%s", separator);
+      buf_printf (&out, "%02x", data[i]);
+    }
+  buf_catrunc (&out, "[more...]");
+  return (char *)out.data;
+}
+
+/*
+ * remove specific trailing character
+ */
+
+void
+buf_rmtail (struct buffer *buf, uint8_t remove)
+{
+  uint8_t *cp = BLAST(buf);
+  if (cp && *cp == remove)
+    {
+      *cp = '\0';
+      --buf->len;
+    }
+}
+
+/*
+ * force a null termination even it requires
+ * truncation of the last char.
+ */
+void
+buf_null_terminate (struct buffer *buf)
+{
+  char *last = (char *) BLAST (buf);
+  if (last && *last == '\0') /* already terminated? */
+    return;
+
+  if (!buf_safe (buf, 1))    /* make space for trailing null */
+    buf_inc_len (buf, -1);
+
+  buf_write_u8 (buf, 0);
+}
+
+/*
+ * Remove trailing \r and \n chars and ensure
+ * null termination.
+ */
+void
+buf_chomp (struct buffer *buf)
+{
+  while (true)
+    {
+      char *last = (char *) BLAST (buf);
+      if (!last)
+	break;
+      if (char_class (*last, CC_CRLF|CC_NULL))
+	{
+	  if (!buf_inc_len (buf, -1))
+	    break;
+	}
+      else
+	break;
+    }
+  buf_null_terminate (buf);
+}
+
+const char *
+skip_leading_whitespace (const char *str)
+{
+  while (*str)
+    {
+      const char c = *str;
+      if (!(c == ' ' || c == '\t'))
+	break;
+      ++str;
+    }
+  return str;
+}
+
+/*
+ * like buf_null_terminate, but operate on strings
+ */
+void
+string_null_terminate (char *str, int len, int capacity)
+{
+  ASSERT (len >= 0 && len <= capacity && capacity > 0);
+  if (len < capacity)
+    *(str + len) = '\0';
+  else if (len == capacity)
+    *(str + len - 1) = '\0';
+}
+
+/*
+ * Remove trailing \r and \n chars.
+ */
+void
+chomp (char *str)
+{
+  rm_trailing_chars (str, "\r\n");
+}
+
+/*
+ * Remove trailing chars
+ */
+void
+rm_trailing_chars (char *str, const char *what_to_delete)
+{
+  bool modified;
+  do {
+    const int len = strlen (str);
+    modified = false;
+    if (len > 0)
+      {
+	char *cp = str + (len - 1);
+	if (strchr (what_to_delete, *cp) != NULL)
+	  {
+	    *cp = '\0';
+	    modified = true;
+	  }
+      }
+  } while (modified);
+}
+
+/*
+ * Allocate a string
+ */
+char *
+#ifdef DMALLOC
+string_alloc_debug (const char *str, struct gc_arena *gc, const char *file, int line)
+#else
+string_alloc (const char *str, struct gc_arena *gc)
+#endif
+{
+  if (str)
+    {
+      const int n = strlen (str) + 1;
+      char *ret;
+
+#ifdef DMALLOC
+      ret = (char *) gc_malloc_debug (n, false, gc, file, line);
+#else
+      ret = (char *) gc_malloc (n, false, gc);
+#endif
+      memcpy (ret, str, n);
+      return ret;
+    }
+  else
+    return NULL;
+}
+
+/*
+ * Erase all characters in a string
+ */
+void
+string_clear (char *str)
+{
+  if (str)
+    {
+      const int len = strlen (str);
+      if (len > 0)
+	memset (str, 0, len);
+    }
+}
+
+/*
+ * Return the length of a string array
+ */
+int
+string_array_len (const char **array)
+{
+  int i = 0;
+  if (array)
+    {
+      while (array[i])
+        ++i;
+    }
+  return i;
+}
+
+char *
+print_argv (const char **p, struct gc_arena *gc, const unsigned int flags)
+{
+  struct buffer out = alloc_buf_gc (256, gc);
+  int i = 0;
+  for (;;)
+    {
+      const char *cp = *p++;
+      if (!cp)
+	break;
+      if (i)
+	buf_printf (&out, " ");
+      if (flags & PA_BRACKET)
+	buf_printf (&out, "[%s]", cp);
+      else
+	buf_printf (&out, "%s", cp);
+      ++i;
+    }
+  return BSTR (&out);
+}
+
+/*
+ * Allocate a string inside a buffer
+ */
+struct buffer
+#ifdef DMALLOC
+string_alloc_buf_debug (const char *str, struct gc_arena *gc, const char *file, int line)
+#else
+string_alloc_buf (const char *str, struct gc_arena *gc)
+#endif
+{
+  struct buffer buf;
+
+  ASSERT (str);
+
+#ifdef DMALLOC
+  buf_set_read (&buf, (uint8_t*) string_alloc_debug (str, gc, file, line), strlen (str) + 1);
+#else
+  buf_set_read (&buf, (uint8_t*) string_alloc (str, gc), strlen (str) + 1);
+#endif
+
+  if (buf.len > 0) /* Don't count trailing '\0' as part of length */
+    --buf.len;
+
+  return buf;
+}
+
+/*
+ * String comparison
+ */
+
+bool
+buf_string_match_head_str (const struct buffer *src, const char *match)
+{
+  const int size = strlen (match);
+  if (size < 0 || size > src->len)
+    return false;
+  return memcmp (BPTR (src), match, size) == 0;
+}
+
+bool
+buf_string_compare_advance (struct buffer *src, const char *match)
+{
+  if (buf_string_match_head_str (src, match))
+    {
+      buf_advance (src, strlen (match));
+      return true;
+    }
+  else
+    return false;
+}
+
+int
+buf_substring_len (const struct buffer *buf, int delim)
+{
+  int i = 0;
+  struct buffer tmp = *buf;
+  int c;
+
+  while ((c = buf_read_u8 (&tmp)) >= 0)
+    {
+      ++i;
+      if (c == delim)
+	return i;
+    }
+  return -1;
+}
+
+/*
+ * String parsing
+ */
+
+bool
+buf_parse (struct buffer *buf, const int delim, char *line, const int size)
+{
+  bool eol = false;
+  int n = 0;
+  int c;
+
+  ASSERT (size > 0);
+
+  do
+    {
+      c = buf_read_u8 (buf);
+      if (c < 0)
+	eol = true;
+      if (c <= 0 || c == delim)
+	c = 0;
+      if (n >= size)
+	break;
+      line[n++] = c;
+    }
+  while (c);
+
+  line[size-1] = '\0';
+  return !(eol && !strlen (line));
+}
+
+/*
+ * Print a string which might be NULL
+ */
+const char *
+np (const char *str)
+{
+  if (str)
+    return str;
+  else
+    return "[NULL]";
+}
+
+/*
+ * Classify and mutate strings based on character types.
+ */
+
+bool
+char_class (const unsigned char c, const unsigned int flags)
+{
+  if (!flags)
+    return false;
+  if (flags & CC_ANY)
+    return true;
+
+  if ((flags & CC_NULL) && c == '\0')
+    return true;
+
+  if ((flags & CC_ALNUM) && isalnum (c))
+    return true;
+  if ((flags & CC_ALPHA) && isalpha (c))
+    return true;
+  if ((flags & CC_ASCII) && isascii (c))
+    return true;
+  if ((flags & CC_CNTRL) && iscntrl (c))
+    return true;
+  if ((flags & CC_DIGIT) && isdigit (c))
+    return true;
+  if ((flags & CC_PRINT) && isprint (c))
+    return true;
+  if ((flags & CC_PUNCT) && ispunct (c))
+    return true;    
+  if ((flags & CC_SPACE) && isspace (c))
+    return true;
+  if ((flags & CC_XDIGIT) && isxdigit (c))
+    return true;
+
+  if ((flags & CC_BLANK) && (c == ' ' || c == '\t'))
+    return true;
+  if ((flags & CC_NEWLINE) && c == '\n')
+    return true;
+  if ((flags & CC_CR) && c == '\r')
+    return true;
+
+  if ((flags & CC_BACKSLASH) && c == '\\')
+    return true;
+  if ((flags & CC_UNDERBAR) && c == '_')
+    return true;
+  if ((flags & CC_DASH) && c == '-')
+    return true;
+  if ((flags & CC_DOT) && c == '.')
+    return true;
+  if ((flags & CC_COMMA) && c == ',')
+    return true;
+  if ((flags & CC_COLON) && c == ':')
+    return true;
+  if ((flags & CC_SLASH) && c == '/')
+    return true;
+  if ((flags & CC_SINGLE_QUOTE) && c == '\'')
+    return true;
+  if ((flags & CC_DOUBLE_QUOTE) && c == '\"')
+    return true;
+  if ((flags & CC_REVERSE_QUOTE) && c == '`')
+    return true;
+  if ((flags & CC_AT) && c == '@')
+    return true;
+  if ((flags & CC_EQUAL) && c == '=')
+    return true;
+
+  return false;
+}
+
+static inline bool
+char_inc_exc (const char c, const unsigned int inclusive, const unsigned int exclusive)
+{
+  return char_class (c, inclusive) && !char_class (c, exclusive);
+}
+
+bool
+string_class (const char *str, const unsigned int inclusive, const unsigned int exclusive)
+{
+  char c;
+  ASSERT (str);
+  while ((c = *str++))
+    {
+      if (!char_inc_exc (c, inclusive, exclusive))
+	return false;
+    }
+  return true;
+}
+
+/*
+ * Modify string in place.
+ * Guaranteed to not increase string length.
+ */
+bool
+string_mod (char *str, const unsigned int inclusive, const unsigned int exclusive, const char replace)
+{
+  const char *in = str;
+  bool ret = true;
+
+  ASSERT (str);
+
+  while (true)
+    {
+      char c = *in++;
+      if (c)
+	{
+	  if (!char_inc_exc (c, inclusive, exclusive))
+	    {
+	      c = replace;
+	      ret = false;
+	    }
+	  if (c)
+	    *str++ = c;
+	}
+      else
+	{
+	  *str = '\0';
+	  break;
+	}
+    }
+  return ret;
+}
+
+const char *
+string_mod_const (const char *str,
+		  const unsigned int inclusive,
+		  const unsigned int exclusive,
+		  const char replace,
+		  struct gc_arena *gc)
+{
+  if (str)
+    {
+      char *buf = string_alloc (str, gc);
+      string_mod (buf, inclusive, exclusive, replace);
+      return buf;
+    }
+  else
+    return NULL;
+}
+
+void
+string_replace_leading (char *str, const char match, const char replace)
+{
+  ASSERT (match != '\0');
+  while (*str)
+    {
+      if (*str == match)
+	*str = replace;
+      else
+	break;
+      ++str;
+    }
+}
+
+#ifdef CHARACTER_CLASS_DEBUG
+
+#define CC_INCLUDE    (CC_PRINT)
+#define CC_EXCLUDE    (0)
+#define CC_REPLACE    ('.')
+
+void
+character_class_debug (void)
+{
+  char buf[256];
+
+  while (fgets (buf, sizeof (buf), stdin) != NULL)
+    {
+      string_mod (buf, CC_INCLUDE, CC_EXCLUDE, CC_REPLACE);
+      printf ("%s", buf);
+    }
+}
+
+#endif
+
+#ifdef VERIFY_ALIGNMENT
+void
+valign4 (const struct buffer *buf, const char *file, const int line)
+{
+  if (buf && buf->len)
+    {
+      int msglevel = D_ALIGN_DEBUG;
+      const unsigned int u = (unsigned int) BPTR (buf);
+
+      if (u & (PAYLOAD_ALIGN-1))
+	msglevel = D_ALIGN_ERRORS;
+
+      msg (msglevel, "%sAlignment at %s/%d ptr=" ptr_format " OLC=%d/%d/%d I=%s/%d",
+	   (msglevel == D_ALIGN_ERRORS) ? "ERROR: " : "",
+	   file,
+	   line,
+	   (ptr_type)buf->data,
+	   buf->offset,
+	   buf->len,
+	   buf->capacity,
+	   buf_debug_file (buf),
+	   buf_debug_line (buf));
+    }
+}
+#endif
+
+/*
+ * struct buffer_list
+ */
+
+#ifdef ENABLE_BUFFER_LIST
+
+struct buffer_list *
+buffer_list_new (const int max_size)
+{
+  struct buffer_list *ret;
+  ALLOC_OBJ_CLEAR (ret, struct buffer_list);
+  ret->max_size = max_size;
+  ret->size = 0;
+  return ret;
+}
+
+void
+buffer_list_free (struct buffer_list *ol)
+{
+  if (ol)
+    {
+      buffer_list_reset (ol);
+      free (ol);
+    }
+}
+
+bool
+buffer_list_defined (const struct buffer_list *ol)
+{
+  return ol->head != NULL;
+}
+
+void
+buffer_list_reset (struct buffer_list *ol)
+{
+  struct buffer_entry *e = ol->head;
+  while (e)
+    {
+      struct buffer_entry *next = e->next;
+      free_buf (&e->buf);
+      free (e);
+      e = next;
+    }
+  ol->head = ol->tail = NULL;
+  ol->size = 0;
+}
+
+void
+buffer_list_push (struct buffer_list *ol, const unsigned char *str)
+{
+  if (str)
+    {
+      const size_t len = strlen ((const char *)str);
+      struct buffer_entry *e = buffer_list_push_data (ol, str, len+1);
+      if (e)
+	e->buf.len = len; /* Don't count trailing '\0' as part of length */
+    }
+}
+
+struct buffer_entry *
+buffer_list_push_data (struct buffer_list *ol, const uint8_t *data, size_t size)
+{
+  struct buffer_entry *e = NULL;
+  if (data && (!ol->max_size || ol->size < ol->max_size))
+    {
+      ALLOC_OBJ_CLEAR (e, struct buffer_entry);
+
+      ++ol->size;
+      if (ol->tail)
+	{
+	  ASSERT (ol->head);
+	  ol->tail->next = e;
+	}
+      else
+	{
+	  ASSERT (!ol->head);
+	  ol->head = e;
+	}
+      e->buf = alloc_buf (size);
+      memcpy (e->buf.data, data, size);
+      e->buf.len = (int)size;
+      ol->tail = e;
+    }
+  return e;
+}
+
+struct buffer *
+buffer_list_peek (struct buffer_list *ol)
+{
+  if (ol && ol->head)
+    return &ol->head->buf;
+  else
+    return NULL;
+}
+
+void
+buffer_list_aggregate (struct buffer_list *bl, const size_t max)
+{
+  if (bl->head)
+    {
+      struct buffer_entry *more = bl->head;
+      size_t size = 0;
+      int count = 0;
+      for (count = 0; more && size <= max; ++count)
+	{
+	  size += BLEN(&more->buf);
+	  more = more->next;
+	}
+
+      if (count >= 2)
+	{
+	  int i;
+	  struct buffer_entry *e = bl->head, *f;
+
+	  ALLOC_OBJ_CLEAR (f, struct buffer_entry);
+	  f->buf.data = malloc (size);
+	  check_malloc_return (f->buf.data);
+	  f->buf.capacity = size;
+	  for (i = 0; e && i < count; ++i)
+	    {
+	      struct buffer_entry *next = e->next;
+	      buf_copy (&f->buf, &e->buf);
+	      free_buf (&e->buf);
+	      free (e);
+	      e = next;
+	    }
+	  bl->head = f;
+	  f->next = more;
+	  if (!more)
+	    bl->tail = f;
+	}
+    }
+}
+
+void
+buffer_list_pop (struct buffer_list *ol)
+{
+  if (ol && ol->head)
+    {
+      struct buffer_entry *e = ol->head->next;
+      free_buf (&ol->head->buf);
+      free (ol->head);
+      ol->head = e;
+      --ol->size;
+      if (!e)
+	ol->tail = NULL;
+    }
+}
+
+void
+buffer_list_advance (struct buffer_list *ol, int n)
+{
+  if (ol->head)
+    {
+      struct buffer *buf = &ol->head->buf;
+      ASSERT (buf_advance (buf, n));
+      if (!BLEN (buf))
+	buffer_list_pop (ol);
+    }
+}
+
+struct buffer_list *
+buffer_list_file (const char *fn, int max_line_len)
+{
+  FILE *fp = fopen (fn, "r");
+  struct buffer_list *bl = NULL;
+
+  if (fp)
+    {
+      char *line = (char *) malloc (max_line_len);
+      if (line)
+	{
+	  bl = buffer_list_new (0);
+	  while (fgets (line, max_line_len, fp) != NULL)
+	    buffer_list_push (bl, (unsigned char *)line);
+	  free (line);
+	}
+      fclose (fp);
+    }
+  return bl;
+}
+
+#endif