/* $NetBSD: common.c,v 1.31 2016/10/20 21:25:57 joerg Exp $ */ /*- * Copyright (c) 1998-2004 Dag-Erling Coïdan Smørgrav * Copyright (c) 2008, 2010 Joerg Sonnenberger * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer * in this position and unchanged. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * * $FreeBSD: common.c,v 1.53 2007/12/19 00:26:36 des Exp $ */ #if HAVE_CONFIG_H #include "config.h" #endif #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifndef MSG_NOSIGNAL #include #endif #include "fetch.h" #include "common.h" /*** Local data **************************************************************/ /* * Error messages for resolver errors */ static struct fetcherr netdb_errlist[] = { #ifdef EAI_NODATA { EAI_NODATA, FETCH_RESOLV, "Host not found" }, #endif { EAI_AGAIN, FETCH_TEMP, "Transient resolver failure" }, { EAI_FAIL, FETCH_RESOLV, "Non-recoverable resolver failure" }, { EAI_NONAME, FETCH_RESOLV, "No address record" }, { -1, FETCH_UNKNOWN, "Unknown resolver error" } }; /*** Error-reporting functions ***********************************************/ /* * Map error code to string */ static struct fetcherr * fetch_finderr(struct fetcherr *p, int e) { while (p->num != -1 && p->num != e) p++; return (p); } /* * Set error code */ void fetch_seterr(struct fetcherr *p, int e) { p = fetch_finderr(p, e); fetchLastErrCode = p->cat; snprintf(fetchLastErrString, MAXERRSTRING, "%s", p->string); } /* * Set error code according to errno */ void fetch_syserr(void) { switch (errno) { case 0: fetchLastErrCode = FETCH_OK; break; case EPERM: case EACCES: case EROFS: #ifdef EAUTH case EAUTH: #endif #ifdef ENEEDAUTH case ENEEDAUTH: #endif fetchLastErrCode = FETCH_AUTH; break; case ENOENT: case EISDIR: /* XXX */ fetchLastErrCode = FETCH_UNAVAIL; break; case ENOMEM: fetchLastErrCode = FETCH_MEMORY; break; case EBUSY: case EAGAIN: fetchLastErrCode = FETCH_TEMP; break; case EEXIST: fetchLastErrCode = FETCH_EXISTS; break; case ENOSPC: fetchLastErrCode = FETCH_FULL; break; case EADDRINUSE: case EADDRNOTAVAIL: case ENETDOWN: case ENETUNREACH: case ENETRESET: case EHOSTUNREACH: fetchLastErrCode = FETCH_NETWORK; break; case ECONNABORTED: case ECONNRESET: fetchLastErrCode = FETCH_ABORT; break; case ETIMEDOUT: fetchLastErrCode = FETCH_TIMEOUT; break; case ECONNREFUSED: case EHOSTDOWN: fetchLastErrCode = FETCH_DOWN; break; default: fetchLastErrCode = FETCH_UNKNOWN; } snprintf(fetchLastErrString, MAXERRSTRING, "%s", strerror(errno)); } /* * Emit status message */ void fetch_info(const char *fmt, ...) { va_list ap; va_start(ap, fmt); vfprintf(stderr, fmt, ap); va_end(ap); fputc('\n', stderr); } /*** Network-related utility functions ***************************************/ /* * Return the default port for a scheme */ int fetch_default_port(const char *scheme) { struct servent *se; if ((se = getservbyname(scheme, "tcp")) != NULL) return (ntohs(se->s_port)); if (strcasecmp(scheme, SCHEME_FTP) == 0) return (FTP_DEFAULT_PORT); if (strcasecmp(scheme, SCHEME_HTTP) == 0) return (HTTP_DEFAULT_PORT); return (0); } /* * Return the default proxy port for a scheme */ int fetch_default_proxy_port(const char *scheme) { if (strcasecmp(scheme, SCHEME_FTP) == 0) return (FTP_DEFAULT_PROXY_PORT); if (strcasecmp(scheme, SCHEME_HTTP) == 0) return (HTTP_DEFAULT_PROXY_PORT); return (0); } /* * Create a connection for an existing descriptor. */ conn_t * fetch_reopen(int sd) { conn_t *conn; /* allocate and fill connection structure */ if ((conn = calloc(1, sizeof(*conn))) == NULL) return (NULL); conn->ftp_home = NULL; conn->cache_url = NULL; conn->next_buf = NULL; conn->next_len = 0; conn->sd = sd; conn->buf_events = POLLIN; return (conn); } /* * Bind a socket to a specific local address */ int fetch_bind(int sd, int af, const char *addr) { struct addrinfo hints, *res, *res0; memset(&hints, 0, sizeof(hints)); hints.ai_family = af; hints.ai_socktype = SOCK_STREAM; hints.ai_protocol = 0; if (getaddrinfo(addr, NULL, &hints, &res0)) return (-1); for (res = res0; res; res = res->ai_next) { if (bind(sd, res->ai_addr, res->ai_addrlen) == 0) return (0); } return (-1); } /* * Establish a TCP connection to the specified port on the specified host. */ conn_t * fetch_connect(struct url *url, int af, int verbose) { conn_t *conn; char pbuf[10]; const char *bindaddr; struct addrinfo hints, *res, *res0; int sd, error; if (verbose) fetch_info("looking up %s", url->host); /* look up host name and set up socket address structure */ snprintf(pbuf, sizeof(pbuf), "%d", url->port); memset(&hints, 0, sizeof(hints)); hints.ai_family = af; hints.ai_socktype = SOCK_STREAM; hints.ai_protocol = 0; if ((error = getaddrinfo(url->host, pbuf, &hints, &res0)) != 0) { netdb_seterr(error); return (NULL); } bindaddr = getenv("FETCH_BIND_ADDRESS"); if (verbose) fetch_info("connecting to %s:%d", url->host, url->port); /* try to connect */ for (sd = -1, res = res0; res; sd = -1, res = res->ai_next) { if ((sd = socket(res->ai_family, res->ai_socktype, res->ai_protocol)) == -1) continue; if (bindaddr != NULL && *bindaddr != '\0' && fetch_bind(sd, res->ai_family, bindaddr) != 0) { fetch_info("failed to bind to '%s'", bindaddr); close(sd); continue; } if (connect(sd, res->ai_addr, res->ai_addrlen) == 0) break; close(sd); } freeaddrinfo(res0); if (sd == -1) { fetch_syserr(); return (NULL); } if ((conn = fetch_reopen(sd)) == NULL) { fetch_syserr(); close(sd); return (NULL); } conn->cache_url = fetchCopyURL(url); conn->cache_af = af; return (conn); } static conn_t *connection_cache; static int cache_global_limit = 0; static int cache_per_host_limit = 0; /* * Initialise cache with the given limits. */ void fetchConnectionCacheInit(int global_limit, int per_host_limit) { if (global_limit < 0) cache_global_limit = INT_MAX; else if (per_host_limit > global_limit) cache_global_limit = per_host_limit; else cache_global_limit = global_limit; if (per_host_limit < 0) cache_per_host_limit = INT_MAX; else cache_per_host_limit = per_host_limit; } /* * Flush cache and free all associated resources. */ void fetchConnectionCacheClose(void) { conn_t *conn; while ((conn = connection_cache) != NULL) { connection_cache = conn->next_cached; (*conn->cache_close)(conn); } } /* * Check connection cache for an existing entry matching * protocol/host/port/user/password/family. */ conn_t * fetch_cache_get(const struct url *url, int af) { conn_t *conn, *last_conn = NULL; for (conn = connection_cache; conn; conn = conn->next_cached) { if (conn->cache_url->port == url->port && strcmp(conn->cache_url->scheme, url->scheme) == 0 && strcmp(conn->cache_url->host, url->host) == 0 && strcmp(conn->cache_url->user, url->user) == 0 && strcmp(conn->cache_url->pwd, url->pwd) == 0 && (conn->cache_af == AF_UNSPEC || af == AF_UNSPEC || conn->cache_af == af)) { if (last_conn != NULL) last_conn->next_cached = conn->next_cached; else connection_cache = conn->next_cached; return conn; } } return NULL; } /* * Put the connection back into the cache for reuse. * If the connection is freed due to LRU or if the cache * is explicitly closed, the given callback is called. */ void fetch_cache_put(conn_t *conn, int (*closecb)(conn_t *)) { conn_t *iter, *last; int global_count, host_count; if (conn->cache_url == NULL || cache_global_limit == 0) { (*closecb)(conn); return; } global_count = host_count = 0; last = NULL; for (iter = connection_cache; iter; last = iter, iter = iter->next_cached) { ++global_count; if (strcmp(conn->cache_url->host, iter->cache_url->host) == 0) ++host_count; if (global_count < cache_global_limit && host_count < cache_per_host_limit) continue; --global_count; if (last != NULL) last->next_cached = iter->next_cached; else connection_cache = iter->next_cached; (*iter->cache_close)(iter); } conn->cache_close = closecb; conn->next_cached = connection_cache; connection_cache = conn; } /* * Enable SSL on a connection. */ int fetch_ssl(conn_t *conn, const struct url *URL, int verbose) { #ifdef WITH_SSL /* Init the SSL library and context */ if (!SSL_library_init()){ fprintf(stderr, "SSL library init failed\n"); return (-1); } SSL_load_error_strings(); conn->ssl_meth = SSLv23_client_method(); conn->ssl_ctx = SSL_CTX_new(conn->ssl_meth); SSL_CTX_set_mode(conn->ssl_ctx, SSL_MODE_AUTO_RETRY); conn->ssl = SSL_new(conn->ssl_ctx); if (conn->ssl == NULL){ fprintf(stderr, "SSL context creation failed\n"); return (-1); } conn->buf_events = 0; SSL_set_fd(conn->ssl, conn->sd); #if OPENSSL_VERSION_NUMBER >= 0x0090806fL && !defined(OPENSSL_NO_TLSEXT) if (!SSL_set_tlsext_host_name(conn->ssl, (char *)(uintptr_t)URL->host)) { fprintf(stderr, "TLS server name indication extension failed for host %s\n", URL->host); return (-1); } #endif if (SSL_connect(conn->ssl) == -1){ ERR_print_errors_fp(stderr); return (-1); } if (verbose) { X509_NAME *name; char *str; fprintf(stderr, "SSL connection established using %s\n", SSL_get_cipher(conn->ssl)); conn->ssl_cert = SSL_get_peer_certificate(conn->ssl); name = X509_get_subject_name(conn->ssl_cert); str = X509_NAME_oneline(name, 0, 0); printf("Certificate subject: %s\n", str); free(str); name = X509_get_issuer_name(conn->ssl_cert); str = X509_NAME_oneline(name, 0, 0); printf("Certificate issuer: %s\n", str); free(str); } return (0); #else (void)conn; (void)verbose; fprintf(stderr, "SSL support disabled\n"); return (-1); #endif } static int compute_timeout(const struct timeval *tv) { struct timeval cur; int timeout; gettimeofday(&cur, NULL); timeout = (tv->tv_sec - cur.tv_sec) * 1000 + (tv->tv_usec - cur.tv_usec) / 1000; return timeout; } /* * Read a character from a connection w/ timeout */ ssize_t fetch_read(conn_t *conn, char *buf, size_t len) { struct timeval timeout_end; struct pollfd pfd; int timeout_cur; ssize_t rlen; int r; if (len == 0) return 0; if (conn->next_len != 0) { if (conn->next_len < len) len = conn->next_len; memmove(buf, conn->next_buf, len); conn->next_len -= len; conn->next_buf += len; return len; } if (fetchTimeout) { gettimeofday(&timeout_end, NULL); timeout_end.tv_sec += fetchTimeout; } pfd.fd = conn->sd; for (;;) { pfd.events = conn->buf_events; if (fetchTimeout && pfd.events) { do { timeout_cur = compute_timeout(&timeout_end); if (timeout_cur < 0) { errno = ETIMEDOUT; fetch_syserr(); return (-1); } errno = 0; r = poll(&pfd, 1, timeout_cur); if (r == -1) { if (errno == EINTR && fetchRestartCalls) continue; fetch_syserr(); return (-1); } } while (pfd.revents == 0); } #ifdef WITH_SSL if (conn->ssl != NULL) { rlen = SSL_read(conn->ssl, buf, len); if (rlen == -1) { switch (SSL_get_error(conn->ssl, rlen)) { case SSL_ERROR_WANT_READ: conn->buf_events = POLLIN; break; case SSL_ERROR_WANT_WRITE: conn->buf_events = POLLOUT; break; default: errno = EIO; fetch_syserr(); return -1; } } else { /* Assume buffering on the SSL layer. */ conn->buf_events = 0; } } else #endif rlen = read(conn->sd, buf, len); if (rlen >= 0) break; if (errno != EINTR || !fetchRestartCalls) return (-1); } return (rlen); } /* * Read a line of text from a connection w/ timeout */ #define MIN_BUF_SIZE 1024 int fetch_getln(conn_t *conn) { char *tmp, *next; size_t tmpsize; ssize_t len; if (conn->buf == NULL) { if ((conn->buf = malloc(MIN_BUF_SIZE)) == NULL) { errno = ENOMEM; return (-1); } conn->bufsize = MIN_BUF_SIZE; } conn->buflen = 0; next = NULL; do { /* * conn->bufsize != conn->buflen at this point, * so the buffer can be NUL-terminated below for * the case of len == 0. */ len = fetch_read(conn, conn->buf + conn->buflen, conn->bufsize - conn->buflen); if (len == -1) return (-1); if (len == 0) break; next = memchr(conn->buf + conn->buflen, '\n', len); conn->buflen += len; if (conn->buflen == conn->bufsize && next == NULL) { tmp = conn->buf; tmpsize = conn->bufsize * 2; if (tmpsize < conn->bufsize) { errno = ENOMEM; return (-1); } if ((tmp = realloc(tmp, tmpsize)) == NULL) { errno = ENOMEM; return (-1); } conn->buf = tmp; conn->bufsize = tmpsize; } } while (next == NULL); if (next != NULL) { *next = '\0'; conn->next_buf = next + 1; conn->next_len = conn->buflen - (conn->next_buf - conn->buf); conn->buflen = next - conn->buf; } else { conn->buf[conn->buflen] = '\0'; conn->next_len = 0; } return (0); } /* * Write a vector to a connection w/ timeout * Note: can modify the iovec. */ ssize_t fetch_write(conn_t *conn, const void *buf, size_t len) { struct timeval now, timeout, waittv; fd_set writefds; ssize_t wlen, total; int r; #ifndef MSG_NOSIGNAL static int killed_sigpipe; #endif #ifndef MSG_NOSIGNAL if (!killed_sigpipe) { signal(SIGPIPE, SIG_IGN); killed_sigpipe = 1; } #endif if (fetchTimeout) { FD_ZERO(&writefds); gettimeofday(&timeout, NULL); timeout.tv_sec += fetchTimeout; } total = 0; while (len) { while (fetchTimeout && !FD_ISSET(conn->sd, &writefds)) { FD_SET(conn->sd, &writefds); gettimeofday(&now, NULL); waittv.tv_sec = timeout.tv_sec - now.tv_sec; waittv.tv_usec = timeout.tv_usec - now.tv_usec; if (waittv.tv_usec < 0) { waittv.tv_usec += 1000000; waittv.tv_sec--; } if (waittv.tv_sec < 0) { errno = ETIMEDOUT; fetch_syserr(); return (-1); } errno = 0; r = select(conn->sd + 1, NULL, &writefds, NULL, &waittv); if (r == -1) { if (errno == EINTR && fetchRestartCalls) continue; return (-1); } } errno = 0; #ifdef WITH_SSL if (conn->ssl != NULL) wlen = SSL_write(conn->ssl, buf, len); else #endif #ifndef MSG_NOSIGNAL wlen = send(conn->sd, buf, len, 0); #else wlen = send(conn->sd, buf, len, MSG_NOSIGNAL); #endif if (wlen == 0) { /* we consider a short write a failure */ errno = EPIPE; fetch_syserr(); return (-1); } if (wlen < 0) { if (errno == EINTR && fetchRestartCalls) continue; return (-1); } total += wlen; buf = (const char *)buf + wlen; len -= wlen; } return (total); } /* * Close connection */ int fetch_close(conn_t *conn) { int ret; ret = close(conn->sd); if (conn->cache_url) fetchFreeURL(conn->cache_url); free(conn->ftp_home); free(conn->buf); free(conn); return (ret); } /*** Directory-related utility functions *************************************/ int fetch_add_entry(struct url_list *ue, struct url *base, const char *name, int pre_quoted) { struct url *tmp; char *tmp_name; size_t base_doc_len, name_len, i; unsigned char c; if (strchr(name, '/') != NULL || strcmp(name, "..") == 0 || strcmp(name, ".") == 0) return 0; if (strcmp(base->doc, "/") == 0) base_doc_len = 0; else base_doc_len = strlen(base->doc); name_len = 1; for (i = 0; name[i] != '\0'; ++i) { if ((!pre_quoted && name[i] == '%') || !fetch_urlpath_safe(name[i])) name_len += 3; else ++name_len; } tmp_name = malloc( base_doc_len + name_len + 1); if (tmp_name == NULL) { errno = ENOMEM; fetch_syserr(); return (-1); } if (ue->length + 1 >= ue->alloc_size) { tmp = realloc(ue->urls, (ue->alloc_size * 2 + 1) * sizeof(*tmp)); if (tmp == NULL) { free(tmp_name); errno = ENOMEM; fetch_syserr(); return (-1); } ue->alloc_size = ue->alloc_size * 2 + 1; ue->urls = tmp; } tmp = ue->urls + ue->length; strcpy(tmp->scheme, base->scheme); strcpy(tmp->user, base->user); strcpy(tmp->pwd, base->pwd); strcpy(tmp->host, base->host); tmp->port = base->port; tmp->doc = tmp_name; memcpy(tmp->doc, base->doc, base_doc_len); tmp->doc[base_doc_len] = '/'; for (i = base_doc_len + 1; *name != '\0'; ++name) { if ((!pre_quoted && *name == '%') || !fetch_urlpath_safe(*name)) { tmp->doc[i++] = '%'; c = (unsigned char)*name / 16; if (c < 10) tmp->doc[i++] = '0' + c; else tmp->doc[i++] = 'a' - 10 + c; c = (unsigned char)*name % 16; if (c < 10) tmp->doc[i++] = '0' + c; else tmp->doc[i++] = 'a' - 10 + c; } else { tmp->doc[i++] = *name; } } tmp->doc[i] = '\0'; tmp->offset = 0; tmp->length = 0; tmp->last_modified = -1; ++ue->length; return (0); } void fetchInitURLList(struct url_list *ue) { ue->length = ue->alloc_size = 0; ue->urls = NULL; } int fetchAppendURLList(struct url_list *dst, const struct url_list *src) { size_t i, j, len; len = dst->length + src->length; if (len > dst->alloc_size) { struct url *tmp; tmp = realloc(dst->urls, len * sizeof(*tmp)); if (tmp == NULL) { errno = ENOMEM; fetch_syserr(); return (-1); } dst->alloc_size = len; dst->urls = tmp; } for (i = 0, j = dst->length; i < src->length; ++i, ++j) { dst->urls[j] = src->urls[i]; dst->urls[j].doc = strdup(src->urls[i].doc); if (dst->urls[j].doc == NULL) { while (i-- > 0) free(dst->urls[j].doc); fetch_syserr(); return -1; } } dst->length = len; return 0; } void fetchFreeURLList(struct url_list *ue) { size_t i; for (i = 0; i < ue->length; ++i) free(ue->urls[i].doc); free(ue->urls); ue->length = ue->alloc_size = 0; } /*** Authentication-related utility functions ********************************/ static const char * fetch_read_word(FILE *f) { static char word[1024]; if (fscanf(f, " %1023s ", word) != 1) return (NULL); return (word); } /* * Get authentication data for a URL from .netrc */ int fetch_netrc_auth(struct url *url) { char fn[PATH_MAX]; const char *word; char *p; FILE *f; if ((p = getenv("NETRC")) != NULL) { if (snprintf(fn, sizeof(fn), "%s", p) >= (int)sizeof(fn)) { fetch_info("$NETRC specifies a file name " "longer than PATH_MAX"); return (-1); } } else { if ((p = getenv("HOME")) != NULL) { struct passwd *pwd; if ((pwd = getpwuid(getuid())) == NULL || (p = pwd->pw_dir) == NULL) return (-1); } if (snprintf(fn, sizeof(fn), "%s/.netrc", p) >= (int)sizeof(fn)) return (-1); } if ((f = fopen(fn, "r")) == NULL) return (-1); while ((word = fetch_read_word(f)) != NULL) { if (strcmp(word, "default") == 0) break; if (strcmp(word, "machine") == 0 && (word = fetch_read_word(f)) != NULL && strcasecmp(word, url->host) == 0) { break; } } if (word == NULL) goto ferr; while ((word = fetch_read_word(f)) != NULL) { if (strcmp(word, "login") == 0) { if ((word = fetch_read_word(f)) == NULL) goto ferr; if (snprintf(url->user, sizeof(url->user), "%s", word) > (int)sizeof(url->user)) { fetch_info("login name in .netrc is too long"); url->user[0] = '\0'; } } else if (strcmp(word, "password") == 0) { if ((word = fetch_read_word(f)) == NULL) goto ferr; if (snprintf(url->pwd, sizeof(url->pwd), "%s", word) > (int)sizeof(url->pwd)) { fetch_info("password in .netrc is too long"); url->pwd[0] = '\0'; } } else if (strcmp(word, "account") == 0) { if ((word = fetch_read_word(f)) == NULL) goto ferr; /* XXX not supported! */ } else { break; } } fclose(f); return (0); ferr: fclose(f); return (-1); } /* * The no_proxy environment variable specifies a set of domains for * which the proxy should not be consulted; the contents is a comma-, * or space-separated list of domain names. A single asterisk will * override all proxy variables and no transactions will be proxied * (for compatability with lynx and curl, see the discussion at * ). */ int fetch_no_proxy_match(const char *host) { const char *no_proxy, *p, *q; size_t h_len, d_len; if ((no_proxy = getenv("NO_PROXY")) == NULL && (no_proxy = getenv("no_proxy")) == NULL) return (0); /* asterisk matches any hostname */ if (strcmp(no_proxy, "*") == 0) return (1); h_len = strlen(host); p = no_proxy; do { /* position p at the beginning of a domain suffix */ while (*p == ',' || isspace((unsigned char)*p)) p++; /* position q at the first separator character */ for (q = p; *q; ++q) if (*q == ',' || isspace((unsigned char)*q)) break; d_len = q - p; if (d_len > 0 && h_len > d_len && strncasecmp(host + h_len - d_len, p, d_len) == 0) { /* domain name matches */ return (1); } p = q + 1; } while (*q); return (0); } struct fetchIO { void *io_cookie; ssize_t (*io_read)(void *, void *, size_t); ssize_t (*io_write)(void *, const void *, size_t); void (*io_close)(void *); }; void fetchIO_close(fetchIO *f) { if (f->io_close != NULL) (*f->io_close)(f->io_cookie); free(f); } fetchIO * fetchIO_unopen(void *io_cookie, ssize_t (*io_read)(void *, void *, size_t), ssize_t (*io_write)(void *, const void *, size_t), void (*io_close)(void *)) { fetchIO *f; f = malloc(sizeof(*f)); if (f == NULL) return f; f->io_cookie = io_cookie; f->io_read = io_read; f->io_write = io_write; f->io_close = io_close; return f; } ssize_t fetchIO_read(fetchIO *f, void *buf, size_t len) { if (f->io_read == NULL) return EBADF; return (*f->io_read)(f->io_cookie, buf, len); } ssize_t fetchIO_write(fetchIO *f, const void *buf, size_t len) { if (f->io_read == NULL) return EBADF; return (*f->io_write)(f->io_cookie, buf, len); }