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 <stdint.h>
25 #include <stdio.h>
26 #include <string.h>
27 #include <unistd.h>
28 
29 #define FCGI_VERSION_1	1
30 
31 /* subset of records that matters to us */
32 #define FCGI_BEGIN_REQUEST	 1
33 #define FCGI_END_REQUEST	 3
34 #define FCGI_PARAMS		 4
35 #define FCGI_STDIN		 5
36 #define FCGI_STDOUT		 6
37 
38 #define SUM(a, b) (((a) << 8) + (b))
39 
40 struct fcgi_header {
41 	uint8_t version;
42 	uint8_t type;
43 	uint8_t req_id1;
44 	uint8_t req_id0;
45 	uint8_t content_len1;
46 	uint8_t content_len0;
47 	uint8_t padding;
48 	uint8_t reserved;
49 };
50 
51 struct fcgi_end_req_body {
52 	unsigned char app_status3;
53 	unsigned char app_status2;
54 	unsigned char app_status1;
55 	unsigned char app_status0;
56 	unsigned char proto_status;
57 	unsigned char reserved[3];
58 };
59 
60 static int
61 prepare_header(struct fcgi_header *h, int type, int id, size_t size,
62     size_t padding)
63 {
64 	memset(h, 0, sizeof(*h));
65 
66 	h->version = FCGI_VERSION_1;
67         h->type = type;
68 	h->req_id1 = (id >> 8);
69 	h->req_id0 = (id & 0xFF);
70 	h->content_len1 = (size >> 8);
71 	h->content_len0 = (size & 0xFF);
72 	h->padding = padding;
73 
74 	return 0;
75 }
76 
77 static int
78 must_read(int sock, void *d, size_t len)
79 {
80 	ssize_t r;
81 
82 	for (;;) {
83 		switch (r = read(sock, d, len)) {
84 		case -1:
85 		case 0:
86 			return -1;
87 		default:
88 			if (r == (ssize_t)len)
89 				return 0;
90 			len -= r;
91 			d += r;
92 		}
93 	}
94 }
95 
96 static int
97 consume(int fd, size_t len)
98 {
99 	size_t	l;
100 	char	buf[64];
101 
102 	while (len != 0) {
103 		if ((l = len) > sizeof(buf))
104 			l =  sizeof(buf);
105 		if (must_read(fd, buf, l) == -1)
106                         return 0;
107 		len -= l;
108 	}
109 
110 	return 1;
111 }
112 
113 static void
114 read_header(struct fcgi_header *hdr)
115 {
116 	if (must_read(0, hdr, sizeof(*hdr)) == -1)
117 		errx(1, "must_read failed");
118 }
119 
120 /* read and consume a record of the given type */
121 static void
122 assert_record(int type)
123 {
124 	struct fcgi_header hdr;
125 
126 	read_header(&hdr);
127 
128 	if (hdr.type != type)
129 		errx(1, "expected record type %d; got %d",
130 		    type, hdr.type);
131 
132 	consume(0, SUM(hdr.content_len1, hdr.content_len0));
133 	consume(0, hdr.padding);
134 }
135 
136 int
137 main(void)
138 {
139 	struct fcgi_header	 hdr;
140 	struct fcgi_end_req_body end;
141 	const char		*msg;
142 	size_t			 len;
143 
144 	msg = "20 text/gemini\r\n# Hello, world!\n";
145 	len = strlen(msg);
146 
147 	for (;;) {
148 		warnx("waiting for a request");
149 		assert_record(FCGI_BEGIN_REQUEST);
150 
151 		/* read params */
152 		for (;;) {
153 			read_header(&hdr);
154 
155 			consume(0, SUM(hdr.content_len1, hdr.content_len0));
156 			consume(0, hdr.padding);
157 
158 			if (hdr.type != FCGI_PARAMS)
159 				errx(1, "got %d; expecting PARAMS", hdr.type);
160 
161 			if (hdr.content_len0 == 0 &&
162 			    hdr.content_len1 == 0 &&
163 			    hdr.padding == 0)
164 				break;
165 		}
166 
167 		assert_record(FCGI_STDIN);
168 
169 		warnx("sending the response");
170 
171 		prepare_header(&hdr, FCGI_STDOUT, 1, len, 0);
172 		write(0, &hdr, sizeof(hdr));
173 		write(0, msg, len);
174 
175 		warnx("closing the request");
176 
177 		prepare_header(&hdr, FCGI_END_REQUEST, 1, sizeof(end), 0);
178 		write(0, &hdr, sizeof(hdr));
179 		memset(&end, 0, sizeof(end));
180 		write(0, &end, sizeof(end));
181 	}
182 }