net.c (3606B)
1 /* Copyright 2021 Jacob R. Edwards 2 * 3 * This file is part of gawk. 4 * 5 * This program is free software: you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License as published by 7 * the Free Software Foundation, either version 3 of the License, or 8 * (at your option) any later version. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program. If not, see <https://www.gnu.org/licenses/>. 17 */ 18 19 #include <sys/socket.h> 20 #include <errno.h> 21 #include <netdb.h> 22 #include <poll.h> 23 #include <stdio.h> 24 #include <string.h> 25 #include <unistd.h> 26 27 #include "gawk.h" 28 #include "util.h" 29 30 int 31 resolve(char const *host, char const *port) 32 { 33 int error, s; 34 struct addrinfo hints; 35 struct addrinfo *ai, *ai0; 36 37 memset(&hints, 0, sizeof(hints)); 38 hints.ai_family = AF_UNSPEC; 39 hints.ai_socktype = SOCK_STREAM; 40 hints.ai_protocol = IPPROTO_TCP; 41 42 error = getaddrinfo(host, port, &hints, &ai0); 43 if (error) { 44 warn(0, "unable to resolve '%s' (%s): %s", 45 host, port, gai_strerror(error)); 46 return -1; 47 } 48 49 s = -1; 50 for (ai = ai0; ai && s == -1; ai = ai->ai_next) { 51 s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 52 if (s != -1 && connect(s, ai->ai_addr, ai->ai_addrlen) == -1) { 53 close(s); 54 s = -1; 55 } 56 } 57 freeaddrinfo(ai0); 58 59 if (s == -1) 60 warn(errno, "unable to connect '%s' (%s)", host, port); 61 return s; 62 } 63 64 int 65 gphre(int sock, char const *message) 66 { 67 char tmp[MY_PATH_MAX]; 68 int n; 69 70 n = strcspn(message, "?"); 71 if (message[n] == '\0') 72 n = send(sock, message, n, 0); 73 else { 74 strlcpy(tmp, message, n + 1); 75 tr(tmp + n, message + n, '?', ' '); 76 tmp[n] = '\t'; 77 n = send(sock, tmp, strlen(tmp), 0); 78 } 79 80 if (n == -1) { 81 warn(errno, "unable to send message"); 82 return 1; 83 } 84 if (shutdown(sock, SHUT_WR)) { 85 warn(errno, "shutdown"); 86 return 1; 87 } 88 return 0; 89 } 90 91 int 92 recvtxt(int s, FILE *output) 93 { 94 FILE *input; 95 char *bufp; 96 char buf[MY_LINE_MAX]; 97 98 input = fdopen(s, "r"); 99 if (input == NULL) { 100 warn(errno, "fdopen"); 101 return 1; 102 } 103 104 /* 105 * While the specification says strip leading periods if 106 * there are multiple I think it must mean only one (see 107 * RFC 1436 Appendix). 108 */ 109 while ((bufp = fgets(buf, sizeof(buf), input)) != NULL) { 110 if (*bufp == '.') 111 if (strcmp(++bufp, "\r\n") == 0) 112 break; 113 if (fputs(bufp, output) == EOF) 114 return 1; 115 } 116 117 return 0; 118 } 119 120 int 121 recvbin(int s, FILE *output) 122 { 123 char buf[MY_CHUNK_MAX]; 124 ssize_t bytes; 125 126 while ((bytes = recv(s, buf, sizeof(buf), 0)) > 0) 127 /* NOTE: cast is safe, bytes _is_ >0 */ 128 if (fwrite(buf, 1, bytes, output) != (size_t)bytes) 129 return 1; 130 return 0; 131 } 132 133 int 134 gphto(int sock, char const *path, int bin, int timeout) 135 { 136 FILE *fp; 137 int status; 138 struct pollfd pfd; 139 140 pfd.fd = sock; 141 pfd.events = POLLRDNORM; 142 if (poll(&pfd, 1, timeout) < 1) { 143 warn(errno, "unable to recieve response"); 144 return 1; 145 } 146 147 fp = wfopen(path, "w+"); 148 if (fp == NULL) 149 return 1; 150 151 if (bin) 152 status = recvbin(sock, fp); 153 else status = recvtxt(sock, fp); 154 if (wfclose(fp) || status) 155 return 1; 156 return 0; 157 } 158 159 int 160 gopher(char **addr, char const *path, int bin, int timeout) 161 { 162 int sock; 163 164 sock = resolve(addr[AR_HOST], addr[AR_PORT]); 165 if (sock == -1) 166 return 1; 167 168 if (gphre(sock, addr[AR_PATH]) != 0 || 169 gphto(sock, path, bin, timeout) != 0) { 170 close(sock); 171 return 1; 172 } 173 return close(sock); 174 }