1 /*
2  * Copyright (c) 2021 Omar Polo <op@omarpolo.com>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 /*
18  * Test program for fastcgi.  It speaks the protocol over stdin.
19  * Can't handle more than one request at the same time.
20  */
21 
22 #include "../config.h"
23 
24 #include <sys/socket.h>
25 #include <sys/stat.h>
26 #include <sys/un.h>
27 
28 #include <errno.h>
29 #include <stdint.h>
30 #include <stdio.h>
31 #include <stdlib.h>
32 #include <string.h>
33 #include <unistd.h>
34 
35 #define FCGI_VERSION_1	1
36 
37 /* subset of records that matters to us */
38 #define FCGI_BEGIN_REQUEST	 1
39 #define FCGI_END_REQUEST	 3
40 #define FCGI_PARAMS		 4
41 #define FCGI_STDIN		 5
42 #define FCGI_STDOUT		 6
43 
44 #define SUM(a, b) (((a) << 8) + (b))
45 
46 struct fcgi_header {
47 	uint8_t version;
48 	uint8_t type;
49 	uint8_t req_id1;
50 	uint8_t req_id0;
51 	uint8_t content_len1;
52 	uint8_t content_len0;
53 	uint8_t padding;
54 	uint8_t reserved;
55 };
56 
57 struct fcgi_end_req_body {
58 	unsigned char app_status3;
59 	unsigned char app_status2;
60 	unsigned char app_status1;
61 	unsigned char app_status0;
62 	unsigned char proto_status;
63 	unsigned char reserved[3];
64 };
65 
66 static int
67 prepare_header(struct fcgi_header *h, int type, int id, size_t size,
68     size_t padding)
69 {
70 	memset(h, 0, sizeof(*h));
71 
72 	h->version = FCGI_VERSION_1;
73         h->type = type;
74 	h->req_id1 = (id >> 8);
75 	h->req_id0 = (id & 0xFF);
76 	h->content_len1 = (size >> 8);
77 	h->content_len0 = (size & 0xFF);
78 	h->padding = padding;
79 
80 	return 0;
81 }
82 
83 static void
84 must_read(int sock, void *d, size_t len)
85 {
86 	ssize_t r;
87 
88 	while (len > 0) {
89 		switch (r = read(sock, d, len)) {
90 		case -1:
91 			err(1, "read");
92 		case 0:
93 			errx(1, "EOF");
94 		default:
95 			len -= r;
96 			d += r;
97 		}
98 	}
99 }
100 
101 static void
102 must_write(int sock, const void *d, size_t len)
103 {
104 	ssize_t w;
105 
106 	while (len > 0) {
107 		switch (w = write(sock, d, len)) {
108 		case -1:
109 			err(1, "write");
110 		case 0:
111 			errx(1, "EOF");
112 		default:
113 			len -= w;
114 			d += w;
115 		}
116 	}
117 }
118 
119 static int
120 consume(int fd, size_t len)
121 {
122 	size_t	l;
123 	char	buf[64];
124 
125 	while (len != 0) {
126 		if ((l = len) > sizeof(buf))
127 			l =  sizeof(buf);
128 		must_read(fd, buf, l);
129 		len -= l;
130 	}
131 
132 	return 1;
133 }
134 
135 static void
136 read_header(int fd, struct fcgi_header *hdr)
137 {
138 	must_read(fd, hdr, sizeof(*hdr));
139 }
140 
141 /* read and consume a record of the given type */
142 static void
143 assert_record(int fd, int type)
144 {
145 	struct fcgi_header hdr;
146 
147 	read_header(fd, &hdr);
148 
149 	if (hdr.type != type)
150 		errx(1, "expected record type %d; got %d",
151 		    type, hdr.type);
152 
153 	consume(fd, SUM(hdr.content_len1, hdr.content_len0));
154 	consume(fd, hdr.padding);
155 }
156 
157 int
158 main(int argc, char **argv)
159 {
160 	struct fcgi_header	 hdr;
161 	struct fcgi_end_req_body end;
162 	struct sockaddr_un	 sun;
163 	const char		*path;
164 	const char		*msg;
165 	size_t			 len;
166 	int			 ch, sock, s;
167 
168 	msg = "20 text/gemini\r\n# hello from fastcgi!\n";
169 	len = strlen(msg);
170 
171 	while ((ch = getopt(argc, argv, "")) != -1)
172 		errx(1, "wrong usage");
173 	argc -= optind;
174 	argv += optind;
175 	if (argc != 1)
176 		errx(1, "wrong usage");
177 
178 	path = argv[0];
179 
180 	if ((sock = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
181 		err(1, "socket");
182 
183 	memset(&sun, 0, sizeof(sun));
184 	sun.sun_family = AF_UNIX;
185 	(void)strlcpy(sun.sun_path, path, sizeof(sun.sun_path));
186 
187 	if (unlink(path) == -1 && errno != ENOENT)
188 		err(1, "unlink %s", path);
189 
190 	if (bind(sock, (struct sockaddr *)&sun, sizeof(sun)) == -1)
191 		err(1, "bind");
192 
193 	if (listen(sock, 5) == -1)
194 		err(1, "listen");
195 
196 	for (;;) {
197 		if ((s = accept(sock, NULL, NULL)) == -1) {
198 			warn("retrying; accept failed");
199 			continue;
200 		}
201 
202 		assert_record(s, FCGI_BEGIN_REQUEST);
203 
204 		/* read params */
205 		for (;;) {
206 			read_header(s, &hdr);
207 
208 			consume(s, SUM(hdr.content_len1, hdr.content_len0));
209 			consume(s, hdr.padding);
210 
211 			if (hdr.type != FCGI_PARAMS)
212 				errx(1, "got %d; expecting PARAMS", hdr.type);
213 
214 			if (hdr.content_len0 == 0 &&
215 			    hdr.content_len1 == 0 &&
216 			    hdr.padding == 0)
217 				break;
218 		}
219 
220 		assert_record(s, FCGI_STDIN);
221 
222 		prepare_header(&hdr, FCGI_STDOUT, 1, len, 0);
223 		must_write(s, &hdr, sizeof(hdr));
224 		must_write(s, msg, len);
225 
226 		prepare_header(&hdr, FCGI_END_REQUEST, 1, sizeof(end), 0);
227 		write(s, &hdr, sizeof(hdr));
228 		memset(&end, 0, sizeof(end));
229 		write(s, &end, sizeof(end));
230 	}
231 }