Tinyhttpd -- 用 C 从零写一个 HTTP 服务器

Tinyhttpd 是J. David Blackstone在1999年写的一个不到 500 行的超轻量型 Http Server，用来学习非常不错，可以帮助我们真正理解服务器程序的本质。

• 官网：http://tinyhttpd.sourceforge.net

环境：VMWare + ubuntu18.04

调通项目

• 参考项目地址：https://github.com/EZLippi/Tinyhttpd.git

mkdir HTTP
cd HTTP
git clone https://github.com/EZLippi/Tinyhttpd.git
1
2
3

由于是在linux下进行编译的。因此在make之前，需要按照github上面提示的对httpd.c文件进行修改

要为Linux编译，请执行以下操作：

1） 注释掉 #include 行。

2） 注释掉定义变量newthread的行。

3） 注释掉运行pthread_create（）的两行。

4） 取消对运行accept_request（）的行的注释。

5） 从Makefile中移除-lsocket。
1
2
3
4
5
6
7
8
9
10
11

然后运行make

make
1

bug出现了

pengge@pengge-virtual-machine:~/Desktop/HTTP/Tinyhttpd$ make
gcc -g -W -Wall -lpthread  -o httpd httpd.c
httpd.c: In function ‘execute_cgi’:
httpd.c:282:9: warning: null argument where non-null required (argument 2) [-Wnonnull]
         execl(path, NULL);
         ^
httpd.c:282:9: warning: not enough variable arguments to fit a sentinel [-Wformat=]
/usr/bin/ld: /tmp/ccg7atS8.o: in function `main':
/home/pengge/Desktop/HTTP/Tinyhttpd/httpd.c:509: undefined reference to `pthread_create'
collect2: error: ld returned 1 exit status
make: *** [Makefile:4: httpd] Error 1
1
2
3
4
5
6
7
8
9
10
11

解决方案

将 execl(path, NULL)； 改成 execl(path,  "",NULL)；  
1

即可消除警告 参考博客execl()函数出现warning: null argument where non-null required (argument 2)问题解决

接着输入如下代码

./httpd
1

但是，在网页里输入localhost:4000 浏览器没有反应.

因此又在网上试了了几种方法

linux下perl及cgi.pm的安装(perl-5.22.1)

但是还是不大行QAQ

最后直接将httpd.c文件替换为kele1997/httpd.c

代码如下

/* J. David's webserver */
/* This is a simple webserver.
 * Created November 1999 by J. David Blackstone.
 * CSE 4344 (Network concepts), Prof. Zeigler
 * University of Texas at Arlington
 */
/* This program compiles for Sparc Solaris 2.6.
 * To compile for Linux:
 *  1) Comment out the #include  line.
 *  2) Comment out the line that defines the variable newthread.
 *  3) Comment out the two lines that run pthread_create().
 *  4) Uncomment the line that runs accept_request().
 *  5) Remove -lsocket from the Makefile.
 */
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
//#include 
#include 
#include 
#include 

#define ISspace(x) isspace((int)(x))

#define SERVER_STRING "Server: jdbhttpd/0.1.0\r\n"
#define STDIN   0
#define STDOUT  1
#define STDERR  2

void accept_request(int);
void bad_request(int);
void cat(int, FILE *);
void cannot_execute(int);
void error_die(const char *);
void execute_cgi(int, const char *, const char *, const char *);
int get_line(int, char *, int);
void headers(int, const char *);
void not_found(int);
void serve_file(int, const char *);
int startup(u_short *);
void unimplemented(int);

/**********************************************************************/
/* A request has caused a call to accept() on the server port to
 * return.  Process the request appropriately.
 * Parameters: the socket connected to the client */
/**********************************************************************/
void accept_request(int arg)
{
    //int client = (intptr_t)arg;
    int client = arg;
    char buf[1024];
    size_t numchars;
    char method[255];
    char url[255];
    char path[512];
    size_t i, j;
    struct stat st;
    int cgi = 0;      /* becomes true if server decides this is a CGI
                       * program */
    char *query_string = NULL;

    numchars = get_line(client, buf, sizeof(buf));
    i = 0; j = 0;
    while (!ISspace(buf[i]) && (i < sizeof(method) - 1))
    {
        method[i] = buf[i];
        i++;
    }
    j=i;
    method[i] = '\0';

    if (strcasecmp(method, "GET") && strcasecmp(method, "POST"))
    {
        unimplemented(client);
        return;
    }

    if (strcasecmp(method, "POST") == 0)
        cgi = 1;

    i = 0;
    while (ISspace(buf[j]) && (j < numchars))
        j++;
    while (!ISspace(buf[j]) && (i < sizeof(url) - 1) && (j < numchars))
    {
        url[i] = buf[j];
        i++; j++;
    }
    url[i] = '\0';

    if (strcasecmp(method, "GET") == 0)
    {
        query_string = url;
        while ((*query_string != '?') && (*query_string != '\0'))
            query_string++;
        if (*query_string == '?')
        {
            cgi = 1;
            *query_string = '\0';
            query_string++;
        }
    }

    sprintf(path, "htdocs%s", url);
    if (path[strlen(path) - 1] == '/')
        strcat(path, "index.html");
    if (stat(path, &st) == -1) {
        while ((numchars > 0) && strcmp("\n", buf))  /* read & discard headers */
            numchars = get_line(client, buf, sizeof(buf));
        not_found(client);
    }
    else
    {
        if ((st.st_mode & S_IFMT) == S_IFDIR)
            strcat(path, "/index.html");
        if ((st.st_mode & S_IXUSR) ||
                (st.st_mode & S_IXGRP) ||
                (st.st_mode & S_IXOTH)    )
            cgi = 1;
        if (!cgi)
            serve_file(client, path);
        else
            execute_cgi(client, path, method, query_string);
    }

    close(client);
}

/**********************************************************************/
/* Inform the client that a request it has made has a problem.
 * Parameters: client socket */
/**********************************************************************/
void bad_request(int client)
{
    char buf[1024];

    sprintf(buf, "HTTP/1.0 400 BAD REQUEST\r\n");
    send(client, buf, sizeof(buf), 0);
    sprintf(buf, "Content-type: text/html\r\n");
    send(client, buf, sizeof(buf), 0);
    sprintf(buf, "\r\n");
    send(client, buf, sizeof(buf), 0);
    sprintf(buf, "
Your browser sent a bad request, ");
    send(client, buf, sizeof(buf), 0);
    sprintf(buf, "such as a POST without a Content-Length.\r\n");
    send(client, buf, sizeof(buf), 0);
}

/**********************************************************************/
/* Put the entire contents of a file out on a socket.  This function
 * is named after the UNIX "cat" command, because it might have been
 * easier just to do something like pipe, fork, and exec("cat").
 * Parameters: the client socket descriptor
 *             FILE pointer for the file to cat */
/**********************************************************************/
void cat(int client, FILE *resource)
{
    char buf[1024];

    fgets(buf, sizeof(buf), resource);
    while (!feof(resource))
    {
        send(client, buf, strlen(buf), 0);
        fgets(buf, sizeof(buf), resource);
    }
}

/**********************************************************************/
/* Inform the client that a CGI script could not be executed.
 * Parameter: the client socket descriptor. */
/**********************************************************************/
void cannot_execute(int client)
{
    char buf[1024];

    sprintf(buf, "HTTP/1.0 500 Internal Server Error\r\n");
    send(client, buf, strlen(buf), 0);
    sprintf(buf, "Content-type: text/html\r\n");
    send(client, buf, strlen(buf), 0);
    sprintf(buf, "\r\n");
    send(client, buf, strlen(buf), 0);
    sprintf(buf, "
Error prohibited CGI execution.\r\n");
    send(client, buf, strlen(buf), 0);
}

/**********************************************************************/
/* Print out an error message with perror() (for system errors; based
 * on value of errno, which indicates system call errors) and exit the
 * program indicating an error. */
/**********************************************************************/
void error_die(const char *sc)
{
    perror(sc);
    exit(1);
}

/**********************************************************************/
/* Execute a CGI script.  Will need to set environment variables as
 * appropriate.
 * Parameters: client socket descriptor
 *             path to the CGI script */
/**********************************************************************/
void execute_cgi(int client, const char *path,
        const char *method, const char *query_string)
{
    char buf[1024];
    int cgi_output[2];
    int cgi_input[2];
    pid_t pid;
    int status;
    int i;
    char c;
    int numchars = 1;
    int content_length = -1;

    buf[0] = 'A'; buf[1] = '\0';
    if (strcasecmp(method, "GET") == 0)
        while ((numchars > 0) && strcmp("\n", buf))  /* read & discard headers */
            numchars = get_line(client, buf, sizeof(buf));
    else if (strcasecmp(method, "POST") == 0) /*POST*/
    {
        numchars = get_line(client, buf, sizeof(buf));
        while ((numchars > 0) && strcmp("\n", buf))
        {
            buf[15] = '\0';
            if (strcasecmp(buf, "Content-Length:") == 0)
                content_length = atoi(&(buf[16]));
            numchars = get_line(client, buf, sizeof(buf));
        }
        if (content_length == -1) {
            bad_request(client);
            return;
        }
    }
    else/*HEAD or other*/
    {
    }


    if (pipe(cgi_output) < 0) {
        cannot_execute(client);
        return;
    }
    if (pipe(cgi_input) < 0) {
        cannot_execute(client);
        return;
    }

    if ( (pid = fork()) < 0 ) {
        cannot_execute(client);
        return;
    }
    sprintf(buf, "HTTP/1.0 200 OK\r\n");
    send(client, buf, strlen(buf), 0);
    if (pid == 0)  /* child: CGI script */
    {
        char meth_env[255];
        char query_env[255];
        char length_env[255];

        dup2(cgi_output[1], STDOUT);
        dup2(cgi_input[0], STDIN);
        close(cgi_output[0]);
        close(cgi_input[1]);
        sprintf(meth_env, "REQUEST_METHOD=%s", method);
        putenv(meth_env);
        if (strcasecmp(method, "GET") == 0) {
            sprintf(query_env, "QUERY_STRING=%s", query_string);
            putenv(query_env);
        }
        else {   /* POST */
            sprintf(length_env, "CONTENT_LENGTH=%d", content_length);
            putenv(length_env);
        }
        execl(path,"", NULL);
        exit(0);
    } else {    /* parent */
        close(cgi_output[1]);
        close(cgi_input[0]);
        if (strcasecmp(method, "POST") == 0)
            for (i = 0; i < content_length; i++) {
                recv(client, &c, 1, 0);
                write(cgi_input[1], &c, 1);
            }
        while (read(cgi_output[0], &c, 1) > 0)
            send(client, &c, 1, 0);

        close(cgi_output[0]);
        close(cgi_input[1]);
        waitpid(pid, &status, 0);
    }
}

/**********************************************************************/
/* Get a line from a socket, whether the line ends in a newline,
 * carriage return, or a CRLF combination.  Terminates the string read
 * with a null character.  If no newline indicator is found before the
 * end of the buffer, the string is terminated with a null.  If any of
 * the above three line terminators is read, the last character of the
 * string will be a linefeed and the string will be terminated with a
 * null character.
 * Parameters: the socket descriptor
 *             the buffer to save the data in
 *             the size of the buffer
 * Returns: the number of bytes stored (excluding null) */
/**********************************************************************/
int get_line(int sock, char *buf, int size)
{
    int i = 0;
    char c = '\0';
    int n;

    while ((i < size - 1) && (c != '\n'))
    {
        n = recv(sock, &c, 1, 0);
        /* DEBUG printf("%02X\n", c); */
        if (n > 0)
        {
            if (c == '\r')
            {
                n = recv(sock, &c, 1, MSG_PEEK);
                /* DEBUG printf("%02X\n", c); */
                if ((n > 0) && (c == '\n'))
                    recv(sock, &c, 1, 0);
                else
                    c = '\n';
            }
            buf[i] = c;
            i++;
        }
        else
            c = '\n';
    }
    buf[i] = '\0';

    return(i);
}

/**********************************************************************/
/* Return the informational HTTP headers about a file. */
/* Parameters: the socket to print the headers on
 *             the name of the file */
/**********************************************************************/
void headers(int client, const char *filename)
{
    char buf[1024];
    (void)filename;  /* could use filename to determine file type */

    strcpy(buf, "HTTP/1.0 200 OK\r\n");
    send(client, buf, strlen(buf), 0);
    strcpy(buf, SERVER_STRING);
    send(client, buf, strlen(buf), 0);
    sprintf(buf, "Content-Type: text/html\r\n");
    send(client, buf, strlen(buf), 0);
    strcpy(buf, "\r\n");
    send(client, buf, strlen(buf), 0);
}

/**********************************************************************/
/* Give a client a 404 not found status message. */
/**********************************************************************/
void not_found(int client)
{
    char buf[1024];

    sprintf(buf, "HTTP/1.0 404 NOT FOUND\r\n");
    send(client, buf, strlen(buf), 0);
    sprintf(buf, SERVER_STRING);
    send(client, buf, strlen(buf), 0);
    sprintf(buf, "Content-Type: text/html\r\n");
    send(client, buf, strlen(buf), 0);
    sprintf(buf, "\r\n");
    send(client, buf, strlen(buf), 0);
    sprintf(buf, "\r\n");
    send(client, buf, strlen(buf), 0);
    sprintf(buf, "
The server could not fulfill\r\n");
    send(client, buf, strlen(buf), 0);
    sprintf(buf, "your request because the resource specified\r\n");
    send(client, buf, strlen(buf), 0);
    sprintf(buf, "is unavailable or nonexistent.\r\n");
    send(client, buf, strlen(buf), 0);
    sprintf(buf, "\r\n");
    send(client, buf, strlen(buf), 0);
}

/**********************************************************************/
/* Send a regular file to the client.  Use headers, and report
 * errors to client if they occur.
 * Parameters: a pointer to a file structure produced from the socket
 *              file descriptor
 *             the name of the file to serve */
/**********************************************************************/
void serve_file(int client, const char *filename)
{
    FILE *resource = NULL;
    int numchars = 1;
    char buf[1024];

    buf[0] = 'A'; buf[1] = '\0';
    while ((numchars > 0) && strcmp("\n", buf))  /* read & discard headers */
        numchars = get_line(client, buf, sizeof(buf));

    resource = fopen(filename, "r");
    if (resource == NULL)
        not_found(client);
    else
    {
        headers(client, filename);
        cat(client, resource);
    }
    fclose(resource);
}

/**********************************************************************/
/* This function starts the process of listening for web connections
 * on a specified port.  If the port is 0, then dynamically allocate a
 * port and modify the original port variable to reflect the actual
 * port.
 * Parameters: pointer to variable containing the port to connect on
 * Returns: the socket */
/**********************************************************************/
int startup(u_short *port)
{
    int httpd = 0;
    int on = 1;
    struct sockaddr_in name;

    httpd = socket(PF_INET, SOCK_STREAM, 0);
    if (httpd == -1)
        error_die("socket");
    memset(&name, 0, sizeof(name));
    name.sin_family = AF_INET;
    name.sin_port = htons(*port);
    name.sin_addr.s_addr = htonl(INADDR_ANY);
    if ((setsockopt(httpd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on))) < 0)  
    {  
        error_die("setsockopt failed");
    }
    if (bind(httpd, (struct sockaddr *)&name, sizeof(name)) < 0)
        error_die("bind");
    if (*port == 0)  /* if dynamically allocating a port */
    {
        socklen_t namelen = sizeof(name);
        if (getsockname(httpd, (struct sockaddr *)&name, &namelen) == -1)
            error_die("getsockname");
        *port = ntohs(name.sin_port);
    }
    if (listen(httpd, 5) < 0)
        error_die("listen");
    return(httpd);
}

/**********************************************************************/
/* Inform the client that the requested web method has not been
 * implemented.
 * Parameter: the client socket */
/**********************************************************************/
void unimplemented(int client)
{
    char buf[1024];

    sprintf(buf, "HTTP/1.0 501 Method Not Implemented\r\n");
    send(client, buf, strlen(buf), 0);
    sprintf(buf, SERVER_STRING);
    send(client, buf, strlen(buf), 0);
    sprintf(buf, "Content-Type: text/html\r\n");
    send(client, buf, strlen(buf), 0);
    sprintf(buf, "\r\n");
    send(client, buf, strlen(buf), 0);
    sprintf(buf, "\r\n");
    send(client, buf, strlen(buf), 0);
    sprintf(buf, "
HTTP request method not supported.\r\n");
    send(client, buf, strlen(buf), 0);
    sprintf(buf, "\r\n");
    send(client, buf, strlen(buf), 0);
}

/**********************************************************************/

int main(void)
{
    int server_sock = -1;
    u_short port = 4000;
    int client_sock = -1;
    struct sockaddr_in client_name;
    socklen_t  client_name_len = sizeof(client_name);
    //pthread_t newthread;

    server_sock = startup(&port);
    printf("httpd running on port %d\n", port);

    while (1)
    {
        client_sock = accept(server_sock,
                (struct sockaddr *)&client_name,
                &client_name_len);
        if (client_sock == -1)
            error_die("accept");
         accept_request(client_sock);
        //if (pthread_create(&newthread , NULL, (void *)accept_request, (void *)(intptr_t)client_sock) != 0)
         //   perror("pthread_create");
    }

    close(server_sock);

    return(0);
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517

之后

make clean
make
./httpd
1
2
3

界面就跳出来了。

注意：如果想要暂停连接

netstat -nap
1

然后

kill -9 Pid
1

但是现在还有个问题就浏览器输入字符串没有颜色显示。（待填坑QAQ）

颜色的问题可以参考:https://github.com/qiyeboy/SourceAnalysis/tree/master/TinyHttpd/tinyhttpd-0.1.0_for_linux

参考资料：

https://github.com/AngryHacker/articles/blob/master/src/code_reading/tinyhttpd.md