123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202 |
- /* Copyright (c) 2001 Matej Pfajfar.
- * Copyright (c) 2001-2004, Roger Dingledine.
- * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
- * Copyright (c) 2007-2019, The Tor Project, Inc. */
- /* See LICENSE for licensing information */
- /**
- * \file buffers_net.c
- * \brief Read and write data on a buf_t object.
- **/
- #define BUFFERS_PRIVATE
- #include "lib/net/buffers_net.h"
- #include "lib/container/buffers.h"
- #include "lib/log/log.h"
- #include "lib/log/util_bug.h"
- #include "lib/net/nettypes.h"
- #ifdef _WIN32
- #include <winsock2.h>
- #endif
- #include <stdlib.h>
- #ifdef PARANOIA
- /** Helper: If PARANOIA is defined, assert that the buffer in local variable
- * <b>buf</b> is well-formed. */
- #define check() STMT_BEGIN buf_assert_ok(buf); STMT_END
- #else
- #define check() STMT_NIL
- #endif /* defined(PARANOIA) */
- /** Read up to <b>at_most</b> bytes from the socket <b>fd</b> into
- * <b>chunk</b> (which must be on <b>buf</b>). If we get an EOF, set
- * *<b>reached_eof</b> to 1. Return -1 on error, 0 on eof or blocking,
- * and the number of bytes read otherwise. */
- static inline int
- read_to_chunk(buf_t *buf, chunk_t *chunk, tor_socket_t fd, size_t at_most,
- int *reached_eof, int *socket_error)
- {
- ssize_t read_result;
- if (at_most > CHUNK_REMAINING_CAPACITY(chunk))
- at_most = CHUNK_REMAINING_CAPACITY(chunk);
- read_result = tor_socket_recv(fd, CHUNK_WRITE_PTR(chunk), at_most, 0);
- if (read_result < 0) {
- int e = tor_socket_errno(fd);
- if (!ERRNO_IS_EAGAIN(e)) { /* it's a real error */
- #ifdef _WIN32
- if (e == WSAENOBUFS)
- log_warn(LD_NET,"recv() failed: WSAENOBUFS. Not enough ram?");
- #endif
- *socket_error = e;
- return -1;
- }
- return 0; /* would block. */
- } else if (read_result == 0) {
- log_debug(LD_NET,"Encountered eof on fd %d", (int)fd);
- *reached_eof = 1;
- return 0;
- } else { /* actually got bytes. */
- buf->datalen += read_result;
- chunk->datalen += read_result;
- log_debug(LD_NET,"Read %ld bytes. %d on inbuf.", (long)read_result,
- (int)buf->datalen);
- tor_assert(read_result < INT_MAX);
- return (int)read_result;
- }
- }
- /** Read from socket <b>s</b>, writing onto end of <b>buf</b>. Read at most
- * <b>at_most</b> bytes, growing the buffer as necessary. If recv() returns 0
- * (because of EOF), set *<b>reached_eof</b> to 1 and return 0. Return -1 on
- * error; else return the number of bytes read.
- */
- /* XXXX indicate "read blocked" somehow? */
- int
- buf_read_from_socket(buf_t *buf, tor_socket_t s, size_t at_most,
- int *reached_eof,
- int *socket_error)
- {
- /* XXXX It's stupid to overload the return values for these functions:
- * "error status" and "number of bytes read" are not mutually exclusive.
- */
- int r = 0;
- size_t total_read = 0;
- check();
- tor_assert(reached_eof);
- tor_assert(SOCKET_OK(s));
- if (BUG(buf->datalen >= INT_MAX))
- return -1;
- if (BUG(buf->datalen >= INT_MAX - at_most))
- return -1;
- while (at_most > total_read) {
- size_t readlen = at_most - total_read;
- chunk_t *chunk;
- if (!buf->tail || CHUNK_REMAINING_CAPACITY(buf->tail) < MIN_READ_LEN) {
- chunk = buf_add_chunk_with_capacity(buf, at_most, 1);
- if (readlen > chunk->memlen)
- readlen = chunk->memlen;
- } else {
- size_t cap = CHUNK_REMAINING_CAPACITY(buf->tail);
- chunk = buf->tail;
- if (cap < readlen)
- readlen = cap;
- }
- r = read_to_chunk(buf, chunk, s, readlen, reached_eof, socket_error);
- check();
- if (r < 0)
- return r; /* Error */
- tor_assert(total_read+r < INT_MAX);
- total_read += r;
- if ((size_t)r < readlen) { /* eof, block, or no more to read. */
- break;
- }
- }
- return (int)total_read;
- }
- /** Helper for buf_flush_to_socket(): try to write <b>sz</b> bytes from chunk
- * <b>chunk</b> of buffer <b>buf</b> onto socket <b>s</b>. On success, deduct
- * the bytes written from *<b>buf_flushlen</b>. Return the number of bytes
- * written on success, 0 on blocking, -1 on failure.
- */
- static inline int
- flush_chunk(tor_socket_t s, buf_t *buf, chunk_t *chunk, size_t sz,
- size_t *buf_flushlen)
- {
- ssize_t write_result;
- if (sz > chunk->datalen)
- sz = chunk->datalen;
- write_result = tor_socket_send(s, chunk->data, sz, 0);
- if (write_result < 0) {
- int e = tor_socket_errno(s);
- if (!ERRNO_IS_EAGAIN(e)) { /* it's a real error */
- #ifdef _WIN32
- if (e == WSAENOBUFS)
- log_warn(LD_NET,"write() failed: WSAENOBUFS. Not enough ram?");
- #endif
- return -1;
- }
- log_debug(LD_NET,"write() would block, returning.");
- return 0;
- } else {
- *buf_flushlen -= write_result;
- buf_drain(buf, write_result);
- tor_assert(write_result < INT_MAX);
- return (int)write_result;
- }
- }
- /** Write data from <b>buf</b> to the socket <b>s</b>. Write at most
- * <b>sz</b> bytes, decrement *<b>buf_flushlen</b> by
- * the number of bytes actually written, and remove the written bytes
- * from the buffer. Return the number of bytes written on success,
- * -1 on failure. Return 0 if write() would block.
- */
- int
- buf_flush_to_socket(buf_t *buf, tor_socket_t s, size_t sz,
- size_t *buf_flushlen)
- {
- /* XXXX It's stupid to overload the return values for these functions:
- * "error status" and "number of bytes flushed" are not mutually exclusive.
- */
- int r;
- size_t flushed = 0;
- tor_assert(buf_flushlen);
- tor_assert(SOCKET_OK(s));
- if (BUG(*buf_flushlen > buf->datalen)) {
- *buf_flushlen = buf->datalen;
- }
- if (BUG(sz > *buf_flushlen)) {
- sz = *buf_flushlen;
- }
- check();
- while (sz) {
- size_t flushlen0;
- tor_assert(buf->head);
- if (buf->head->datalen >= sz)
- flushlen0 = sz;
- else
- flushlen0 = buf->head->datalen;
- r = flush_chunk(s, buf, buf->head, flushlen0, buf_flushlen);
- check();
- if (r < 0)
- return r;
- flushed += r;
- sz -= r;
- if (r == 0 || (size_t)r < flushlen0) /* can't flush any more now. */
- break;
- }
- tor_assert(flushed < INT_MAX);
- return (int)flushed;
- }
|