X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/8002af617f063c404ae06f0b93eb36557ae3d155..HEAD:/buffer.c diff --git a/buffer.c b/buffer.c index 044caafb..e02e1e35 100644 --- a/buffer.c +++ b/buffer.c @@ -1,3 +1,4 @@ +/* $OpenBSD: buffer.c,v 1.31 2006/08/03 03:34:41 deraadt Exp $ */ /* * Author: Tatu Ylonen * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland @@ -12,19 +13,31 @@ */ #include "includes.h" -RCSID("$OpenBSD: buffer.c,v 1.13 2001/04/12 19:15:24 markus Exp $"); + +#include + +#include +#include +#include #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; } @@ -34,8 +47,11 @@ buffer_init(Buffer *buffer) 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); + } } /* @@ -53,11 +69,28 @@ buffer_clear(Buffer *buffer) /* Appends data to the buffer, expanding it if necessary. */ void -buffer_append(Buffer *buffer, const char *data, u_int len) +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) { - char *cp; - buffer_append_space(buffer, &cp, len); - memcpy(cp, data, len); + /* + * 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); } /* @@ -66,9 +99,15 @@ buffer_append(Buffer *buffer, const char *data, u_int len) * to the allocated region. */ -void -buffer_append_space(Buffer *buffer, char **datap, u_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; @@ -77,25 +116,45 @@ buffer_append_space(Buffer *buffer, char **datap, u_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. */ @@ -108,39 +167,67 @@ buffer_len(Buffer *buffer) /* Gets data from the beginning of the buffer. */ -void -buffer_get(Buffer *buffer, char *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. */ -char * +void * buffer_ptr(Buffer *buffer) { return buffer->buf + buffer->offset; @@ -151,8 +238,8 @@ buffer_ptr(Buffer *buffer) void buffer_dump(Buffer *buffer) { - int i; - u_char *ucp = (u_char *) buffer->buf; + u_int i; + u_char *ucp = buffer->buf; for (i = buffer->offset; i < buffer->end; i++) { fprintf(stderr, "%02x", ucp[i]);