X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/5260325f3150ad441f310d31239beeb765f716ed..HEAD:/buffer.c diff --git a/buffer.c b/buffer.c index 4cab175b..e02e1e35 100644 --- a/buffer.c +++ b/buffer.c @@ -1,49 +1,65 @@ +/* $OpenBSD: buffer.c,v 1.31 2006/08/03 03:34:41 deraadt Exp $ */ /* - * - * buffer.c - * * Author: Tatu Ylonen - * * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland * All rights reserved - * - * Created: Sat Mar 18 04:15:33 1995 ylo - * * 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" -RCSID("$Id$"); + +#include + +#include +#include +#include #include "xmalloc.h" #include "buffer.h" -#include "ssh.h" +#include "log.h" + +#define BUFFER_MAX_CHUNK 0x100000 +#define BUFFER_MAX_LEN 0xa00000 +#define BUFFER_ALLOCSZ 0x008000 /* Initializes the buffer structure. */ -void +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; } /* Frees any memory used for the buffer. */ -void +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); + } } -/* Clears any data from the buffer, making it empty. This does not actually - zero the memory. */ +/* + * Clears any data from the buffer, making it empty. This does not actually + * zero the memory. + */ -void +void buffer_clear(Buffer *buffer) { buffer->offset = 0; @@ -52,21 +68,46 @@ buffer_clear(Buffer *buffer) /* Appends data to the buffer, expanding it if necessary. */ -void -buffer_append(Buffer *buffer, const char *data, unsigned int len) +void +buffer_append(Buffer *buffer, const void *data, u_int len) { - char *cp; - buffer_append_space(buffer, &cp, len); - memcpy(cp, data, len); + void *p; + p = buffer_append_space(buffer, len); + memcpy(p, data, len); } -/* 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. */ +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, char **datap, unsigned int len) +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; @@ -75,28 +116,50 @@ buffer_append_space(Buffer *buffer, char **datap, unsigned int len) restart: /* If there is enough space to store all data, store it now. */ if (buffer->end + len < buffer->alloc) { - *datap = buffer->buf + buffer->end; + p = buffer->buf + buffer->end; buffer->end += len; - return; + 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) + 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. */ -unsigned int +u_int buffer_len(Buffer *buffer) { return buffer->end - buffer->offset; @@ -104,38 +167,67 @@ buffer_len(Buffer *buffer) /* Gets data from the beginning of the buffer. */ -void -buffer_get(Buffer *buffer, char *buf, unsigned 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 than in buffer"); + 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. */ -void -buffer_consume(Buffer *buffer, unsigned int bytes) +int +buffer_consume_ret(Buffer *buffer, u_int bytes) { - if (bytes > buffer->end - buffer->offset) - fatal("buffer_get trying to get more bytes than in buffer"); + 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. */ -void -buffer_consume_end(Buffer *buffer, unsigned int bytes) +int +buffer_consume_end_ret(Buffer *buffer, u_int bytes) { if (bytes > buffer->end - buffer->offset) - fatal("buffer_get trying to get more bytes than in buffer"); + 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. */ -char * +void * buffer_ptr(Buffer *buffer) { return buffer->buf + buffer->offset; @@ -143,13 +235,18 @@ buffer_ptr(Buffer *buffer) /* Dumps the contents of the buffer to stderr. */ -void +void buffer_dump(Buffer *buffer) { - int i; - unsigned char *ucp = (unsigned char *) buffer->buf; - - for (i = buffer->offset; i < buffer->end; i++) - fprintf(stderr, " %02x", ucp[i]); - fprintf(stderr, "\n"); + 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"); }