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author | des <des@FreeBSD.org> | 2008-07-22 18:58:19 +0000 |
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committer | des <des@FreeBSD.org> | 2008-07-22 18:58:19 +0000 |
commit | 666aa9cc1660793c97ef29a6cb66dfbb894dde8f (patch) | |
tree | 209e642fbe2a816041f67bc27c9800879f5541bc /crypto/openssh/buffer.c | |
parent | 624d93001f28e236c027516d88282351eb7bffbe (diff) | |
download | FreeBSD-src-666aa9cc1660793c97ef29a6cb66dfbb894dde8f.zip FreeBSD-src-666aa9cc1660793c97ef29a6cb66dfbb894dde8f.tar.gz |
Revert part of 180714 - the intent was to flatten dist, not to nuke it.
Diffstat (limited to 'crypto/openssh/buffer.c')
-rw-r--r-- | crypto/openssh/buffer.c | 252 |
1 files changed, 252 insertions, 0 deletions
diff --git a/crypto/openssh/buffer.c b/crypto/openssh/buffer.c new file mode 100644 index 0000000..e02e1e3 --- /dev/null +++ b/crypto/openssh/buffer.c @@ -0,0 +1,252 @@ +/* $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 + * 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(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(Buffer *buffer) +{ + return buffer->buf + buffer->offset; +} + +/* Dumps the contents of the buffer to stderr. */ + +void +buffer_dump(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"); +} |