+/* $OpenBSD: buffer.c,v 1.31 2006/08/03 03:34:41 deraadt Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
*/
#include "includes.h"
-RCSID("$OpenBSD: buffer.c,v 1.15 2002/01/18 18:14:17 stevesk Exp $");
+
+#include <sys/param.h>
+
+#include <stdio.h>
+#include <string.h>
+#include <stdarg.h>
#include "xmalloc.h"
#include "buffer.h"
#include "log.h"
+#define BUFFER_MAX_CHUNK 0x100000
+#define BUFFER_MAX_LEN 0xa00000
+#define BUFFER_ALLOCSZ 0x008000
+
/* Initializes the buffer structure. */
void
buffer_init(Buffer *buffer)
{
- buffer->alloc = 4096;
- buffer->buf = xmalloc(buffer->alloc);
+ const u_int len = 4096;
+
+ buffer->alloc = 0;
+ buffer->buf = xmalloc(len);
+ buffer->alloc = len;
buffer->offset = 0;
buffer->end = 0;
}
void
buffer_free(Buffer *buffer)
{
- memset(buffer->buf, 0, buffer->alloc);
- xfree(buffer->buf);
+ if (buffer->alloc > 0) {
+ memset(buffer->buf, 0, buffer->alloc);
+ buffer->alloc = 0;
+ xfree(buffer->buf);
+ }
}
/*
memcpy(p, data, len);
}
+static int
+buffer_compact(Buffer *buffer)
+{
+ /*
+ * If the buffer is quite empty, but all data is at the end, move the
+ * data to the beginning.
+ */
+ if (buffer->offset > MIN(buffer->alloc, BUFFER_MAX_CHUNK)) {
+ memmove(buffer->buf, buffer->buf + buffer->offset,
+ buffer->end - buffer->offset);
+ buffer->end -= buffer->offset;
+ buffer->offset = 0;
+ return (1);
+ }
+ return (0);
+}
+
/*
* Appends space to the buffer, expanding the buffer if necessary. This does
* not actually copy the data into the buffer, but instead returns a pointer
void *
buffer_append_space(Buffer *buffer, u_int len)
{
+ u_int newlen;
void *p;
+ if (len > BUFFER_MAX_CHUNK)
+ fatal("buffer_append_space: len %u not supported", len);
+
/* If the buffer is empty, start using it from the beginning. */
if (buffer->offset == buffer->end) {
buffer->offset = 0;
buffer->end += len;
return p;
}
- /*
- * If the buffer is quite empty, but all data is at the end, move the
- * data to the beginning and retry.
- */
- if (buffer->offset > buffer->alloc / 2) {
- memmove(buffer->buf, buffer->buf + buffer->offset,
- buffer->end - buffer->offset);
- buffer->end -= buffer->offset;
- buffer->offset = 0;
+
+ /* Compact data back to the start of the buffer if necessary */
+ if (buffer_compact(buffer))
goto restart;
- }
+
/* Increase the size of the buffer and retry. */
- buffer->alloc += len + 32768;
- buffer->buf = xrealloc(buffer->buf, buffer->alloc);
+ newlen = roundup(buffer->alloc + len, BUFFER_ALLOCSZ);
+ if (newlen > BUFFER_MAX_LEN_HPN)
+ fatal("buffer_append_space: alloc %u not supported",
+ newlen);
+ buffer->buf = xrealloc(buffer->buf, 1, newlen);
+ buffer->alloc = newlen;
goto restart;
/* NOTREACHED */
}
+/*
+ * Check whether an allocation of 'len' will fit in the buffer
+ * This must follow the same math as buffer_append_space
+ */
+int
+buffer_check_alloc(Buffer *buffer, u_int len)
+{
+ if (buffer->offset == buffer->end) {
+ buffer->offset = 0;
+ buffer->end = 0;
+ }
+ restart:
+ if (buffer->end + len < buffer->alloc)
+ return (1);
+ if (buffer_compact(buffer))
+ goto restart;
+ if (roundup(buffer->alloc + len, BUFFER_ALLOCSZ) <= BUFFER_MAX_LEN)
+ return (1);
+ return (0);
+}
+
/* Returns the number of bytes of data in the buffer. */
u_int
/* Gets data from the beginning of the buffer. */
-void
-buffer_get(Buffer *buffer, void *buf, u_int len)
+int
+buffer_get_ret(Buffer *buffer, void *buf, u_int len)
{
- if (len > buffer->end - buffer->offset)
- fatal("buffer_get: trying to get more bytes %d than in buffer %d",
+ if (len > buffer->end - buffer->offset) {
+ error("buffer_get_ret: trying to get more bytes %d than in buffer %d",
len, buffer->end - buffer->offset);
+ return (-1);
+ }
memcpy(buf, buffer->buf + buffer->offset, len);
buffer->offset += len;
+ return (0);
+}
+
+void
+buffer_get(Buffer *buffer, void *buf, u_int len)
+{
+ if (buffer_get_ret(buffer, buf, len) == -1)
+ fatal("buffer_get: buffer error");
}
/* Consumes the given number of bytes from the beginning of the buffer. */
+int
+buffer_consume_ret(Buffer *buffer, u_int bytes)
+{
+ if (bytes > buffer->end - buffer->offset) {
+ error("buffer_consume_ret: trying to get more bytes than in buffer");
+ return (-1);
+ }
+ buffer->offset += bytes;
+ return (0);
+}
+
void
buffer_consume(Buffer *buffer, u_int bytes)
{
- if (bytes > buffer->end - buffer->offset)
- fatal("buffer_consume: trying to get more bytes than in buffer");
- buffer->offset += bytes;
+ if (buffer_consume_ret(buffer, bytes) == -1)
+ fatal("buffer_consume: buffer error");
}
/* Consumes the given number of bytes from the end of the buffer. */
+int
+buffer_consume_end_ret(Buffer *buffer, u_int bytes)
+{
+ if (bytes > buffer->end - buffer->offset)
+ return (-1);
+ buffer->end -= bytes;
+ return (0);
+}
+
void
buffer_consume_end(Buffer *buffer, u_int bytes)
{
- if (bytes > buffer->end - buffer->offset)
+ if (buffer_consume_end_ret(buffer, bytes) == -1)
fatal("buffer_consume_end: trying to get more bytes than in buffer");
- buffer->end -= bytes;
}
/* Returns a pointer to the first used byte in the buffer. */
void
buffer_dump(Buffer *buffer)
{
- int i;
+ u_int i;
u_char *ucp = buffer->buf;
for (i = buffer->offset; i < buffer->end; i++) {