Initial commit of openssh-5.9p1
Change-Id: I991b8d22c9904ed6ced33a096776f4f342af52a8
Signed-off-by: Mike Lockwood <lockwood@google.com>
diff --git a/buffer.c b/buffer.c
new file mode 100644
index 0000000..ae97003
--- /dev/null
+++ b/buffer.c
@@ -0,0 +1,252 @@
+/* $OpenBSD: buffer.c,v 1.32 2010/02/09 03:56:28 djm Exp $ */
+/*
+ * Author: Tatu Ylonen <ylo@cs.hut.fi>
+ * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
+ * All rights reserved
+ * Functions for manipulating fifo buffers (that can grow if needed).
+ *
+ * As far as I am concerned, the code I have written for this software
+ * can be used freely for any purpose. Any derived versions of this
+ * software must be clearly marked as such, and if the derived work is
+ * incompatible with the protocol description in the RFC file, it must be
+ * called by a name other than "ssh" or "Secure Shell".
+ */
+
+#include "includes.h"
+
+#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)
+{
+ const u_int len = 4096;
+
+ buffer->alloc = 0;
+ buffer->buf = xmalloc(len);
+ buffer->alloc = len;
+ buffer->offset = 0;
+ buffer->end = 0;
+}
+
+/* Frees any memory used for the buffer. */
+
+void
+buffer_free(Buffer *buffer)
+{
+ if (buffer->alloc > 0) {
+ memset(buffer->buf, 0, buffer->alloc);
+ buffer->alloc = 0;
+ xfree(buffer->buf);
+ }
+}
+
+/*
+ * Clears any data from the buffer, making it empty. This does not actually
+ * zero the memory.
+ */
+
+void
+buffer_clear(Buffer *buffer)
+{
+ buffer->offset = 0;
+ buffer->end = 0;
+}
+
+/* Appends data to the buffer, expanding it if necessary. */
+
+void
+buffer_append(Buffer *buffer, const void *data, u_int len)
+{
+ void *p;
+ p = buffer_append_space(buffer, len);
+ 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
+ * to the allocated region.
+ */
+
+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 = 0;
+ }
+restart:
+ /* If there is enough space to store all data, store it now. */
+ if (buffer->end + len < buffer->alloc) {
+ p = buffer->buf + buffer->end;
+ buffer->end += len;
+ return p;
+ }
+
+ /* 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. */
+ newlen = roundup(buffer->alloc + len, BUFFER_ALLOCSZ);
+ if (newlen > BUFFER_MAX_LEN)
+ 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
+buffer_len(const Buffer *buffer)
+{
+ return buffer->end - buffer->offset;
+}
+
+/* Gets data from the beginning of the buffer. */
+
+int
+buffer_get_ret(Buffer *buffer, void *buf, u_int len)
+{
+ 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 (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 (buffer_consume_end_ret(buffer, bytes) == -1)
+ fatal("buffer_consume_end: trying to get more bytes than in buffer");
+}
+
+/* Returns a pointer to the first used byte in the buffer. */
+
+void *
+buffer_ptr(const Buffer *buffer)
+{
+ return buffer->buf + buffer->offset;
+}
+
+/* Dumps the contents of the buffer to stderr. */
+
+void
+buffer_dump(const Buffer *buffer)
+{
+ u_int i;
+ u_char *ucp = buffer->buf;
+
+ for (i = buffer->offset; i < buffer->end; i++) {
+ fprintf(stderr, "%02x", ucp[i]);
+ if ((i-buffer->offset)%16==15)
+ fprintf(stderr, "\r\n");
+ else if ((i-buffer->offset)%2==1)
+ fprintf(stderr, " ");
+ }
+ fprintf(stderr, "\r\n");
+}