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 <stdlib.h>
27 #include <string.h>
28 #include <unistd.h>
29 
30 #define FCGI_VERSION_1	1
31 
32 /* subset of records that matters to us */
33 #define FCGI_BEGIN_REQUEST	 1
34 #define FCGI_END_REQUEST	 3
35 #define FCGI_PARAMS		 4
36 #define FCGI_STDIN		 5
37 #define FCGI_STDOUT		 6
38 
39 #define SUM(a, b) (((a) << 8) + (b))
40 
41 struct fcgi_header {
42 	uint8_t version;
43 	uint8_t type;
44 	uint8_t req_id1;
45 	uint8_t req_id0;
46 	uint8_t content_len1;
47 	uint8_t content_len0;
48 	uint8_t padding;
49 	uint8_t reserved;
50 };
51 
52 struct fcgi_end_req_body {
53 	unsigned char app_status3;
54 	unsigned char app_status2;
55 	unsigned char app_status1;
56 	unsigned char app_status0;
57 	unsigned char proto_status;
58 	unsigned char reserved[3];
59 };
60 
61 static int
62 prepare_header(struct fcgi_header *h, int type, int id, size_t size,
63     size_t padding)
64 {
65 	memset(h, 0, sizeof(*h));
66 
67 	h->version = FCGI_VERSION_1;
68         h->type = type;
69 	h->req_id1 = (id >> 8);
70 	h->req_id0 = (id & 0xFF);
71 	h->content_len1 = (size >> 8);
72 	h->content_len0 = (size & 0xFF);
73 	h->padding = padding;
74 
75 	return 0;
76 }
77 
78 static int
79 must_read(int sock, void *d, size_t len)
80 {
81 	ssize_t r;
82 
83 	for (;;) {
84 		switch (r = read(sock, d, len)) {
85 		case -1:
86 		case 0:
87 			return -1;
88 		default:
89 			if (r == (ssize_t)len)
90 				return 0;
91 			len -= r;
92 			d += r;
93 		}
94 	}
95 }
96 
97 static int
98 consume(int fd, size_t len)
99 {
100 	size_t	l;
101 	char	buf[64];
102 
103 	while (len != 0) {
104 		if ((l = len) > sizeof(buf))
105 			l =  sizeof(buf);
106 		if (must_read(fd, buf, l) == -1)
107                         return 0;
108 		len -= l;
109 	}
110 
111 	return 1;
112 }
113 
114 static void
115 read_header(struct fcgi_header *hdr)
116 {
117 	if (must_read(0, hdr, sizeof(*hdr)) == -1)
118 		exit(1);
119 }
120 
121 /* read and consume a record of the given type */
122 static void
123 assert_record(int type)
124 {
125 	struct fcgi_header hdr;
126 
127 	read_header(&hdr);
128 
129 	if (hdr.type != type)
130 		errx(1, "expected record type %d; got %d",
131 		    type, hdr.type);
132 
133 	consume(0, SUM(hdr.content_len1, hdr.content_len0));
134 	consume(0, hdr.padding);
135 }
136 
137 int
138 main(void)
139 {
140 	struct fcgi_header	 hdr;
141 	struct fcgi_end_req_body end;
142 	const char		*msg;
143 	size_t			 len;
144 
145 	msg = "20 text/gemini\r\n# Hello, world!\n";
146 	len = strlen(msg);
147 
148 	for (;;) {
149 		warnx("waiting for a request");
150 		assert_record(FCGI_BEGIN_REQUEST);
151 
152 		/* read params */
153 		for (;;) {
154 			read_header(&hdr);
155 
156 			consume(0, SUM(hdr.content_len1, hdr.content_len0));
157 			consume(0, hdr.padding);
158 
159 			if (hdr.type != FCGI_PARAMS)
160 				errx(1, "got %d; expecting PARAMS", hdr.type);
161 
162 			if (hdr.content_len0 == 0 &&
163 			    hdr.content_len1 == 0 &&
164 			    hdr.padding == 0)
165 				break;
166 		}
167 
168 		assert_record(FCGI_STDIN);
169 
170 		warnx("sending the response");
171 
172 		prepare_header(&hdr, FCGI_STDOUT, 1, len, 0);
173 		write(0, &hdr, sizeof(hdr));
174 		write(0, msg, len);
175 
176 		warnx("closing the request");
177 
178 		prepare_header(&hdr, FCGI_END_REQUEST, 1, sizeof(end), 0);
179 		write(0, &hdr, sizeof(hdr));
180 		memset(&end, 0, sizeof(end));
181 		write(0, &end, sizeof(end));
182 	}
183 }