一个几百行代码实现的http服务器tinyhttpd
2024-08-20 08:05:18
/* 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 <pthread.h> 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 <stdio.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <ctype.h>
#include <strings.h>
#include <string.h>
#include <sys/stat.h>
#include <pthread.h>
#include <sys/wait.h>
#include <stdlib.h>
#include <stdint.h> #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(void *);
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(void *arg)
{
int client = (intptr_t)arg;
char buf[];
size_t numchars;
char method[];
char url[];
char path[];
size_t i, j;
struct stat st;
int cgi = ; /* becomes true if server decides this is a CGI
* program */
char *query_string = NULL; numchars = get_line(client, buf, sizeof(buf));
i = ; j = ;
while (!ISspace(buf[i]) && (i < sizeof(method) - ))
{
method[i] = buf[i];
i++;
}
j=i;
method[i] = '\0'; if (strcasecmp(method, "GET") && strcasecmp(method, "POST"))
{
unimplemented(client);
return;
} if (strcasecmp(method, "POST") == )
cgi = ; i = ;
while (ISspace(buf[j]) && (j < numchars))
j++;
while (!ISspace(buf[j]) && (i < sizeof(url) - ) && (j < numchars))
{
url[i] = buf[j];
i++; j++;
}
url[i] = '\0'; if (strcasecmp(method, "GET") == )
{
query_string = url;
while ((*query_string != '?') && (*query_string != '\0'))
query_string++;
if (*query_string == '?')
{
cgi = ;
*query_string = '\0';
query_string++;
}
} sprintf(path, "htdocs%s", url);
if (path[strlen(path) - ] == '/')
strcat(path, "index.html");
if (stat(path, &st) == -) {
while ((numchars > ) && 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 = ;
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[]; sprintf(buf, "HTTP/1.0 400 BAD REQUEST\r\n");
send(client, buf, sizeof(buf), );
sprintf(buf, "Content-type: text/html\r\n");
send(client, buf, sizeof(buf), );
sprintf(buf, "\r\n");
send(client, buf, sizeof(buf), );
sprintf(buf, "<P>Your browser sent a bad request, ");
send(client, buf, sizeof(buf), );
sprintf(buf, "such as a POST without a Content-Length.\r\n");
send(client, buf, sizeof(buf), );
} /**********************************************************************/
/* 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[]; fgets(buf, sizeof(buf), resource);
while (!feof(resource))
{
send(client, buf, strlen(buf), );
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[]; sprintf(buf, "HTTP/1.0 500 Internal Server Error\r\n");
send(client, buf, strlen(buf), );
sprintf(buf, "Content-type: text/html\r\n");
send(client, buf, strlen(buf), );
sprintf(buf, "\r\n");
send(client, buf, strlen(buf), );
sprintf(buf, "<P>Error prohibited CGI execution.\r\n");
send(client, buf, strlen(buf), );
} /**********************************************************************/
/* 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();
} /**********************************************************************/
/* 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[];
int cgi_output[];
int cgi_input[];
pid_t pid;
int status;
int i;
char c;
int numchars = ;
int content_length = -; buf[] = 'A'; buf[] = '\0';
if (strcasecmp(method, "GET") == )
while ((numchars > ) && strcmp("\n", buf)) /* read & discard headers */
numchars = get_line(client, buf, sizeof(buf));
else if (strcasecmp(method, "POST") == ) /*POST*/
{
numchars = get_line(client, buf, sizeof(buf));
while ((numchars > ) && strcmp("\n", buf))
{
buf[] = '\0';
if (strcasecmp(buf, "Content-Length:") == )
content_length = atoi(&(buf[]));
numchars = get_line(client, buf, sizeof(buf));
}
if (content_length == -) {
bad_request(client);
return;
}
}
else/*HEAD or other*/
{
} if (pipe(cgi_output) < ) {
cannot_execute(client);
return;
}
if (pipe(cgi_input) < ) {
cannot_execute(client);
return;
} if ( (pid = fork()) < ) {
cannot_execute(client);
return;
}
sprintf(buf, "HTTP/1.0 200 OK\r\n");
send(client, buf, strlen(buf), );
if (pid == ) /* child: CGI script */
{
char meth_env[];
char query_env[];
char length_env[]; dup2(cgi_output[], STDOUT);
dup2(cgi_input[], STDIN);
close(cgi_output[]);
close(cgi_input[]);
sprintf(meth_env, "REQUEST_METHOD=%s", method);
putenv(meth_env);
if (strcasecmp(method, "GET") == ) {
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();
} else { /* parent */
close(cgi_output[]);
close(cgi_input[]);
if (strcasecmp(method, "POST") == )
for (i = ; i < content_length; i++) {
recv(client, &c, , );
write(cgi_input[], &c, );
}
while (read(cgi_output[], &c, ) > )
send(client, &c, , ); close(cgi_output[]);
close(cgi_input[]);
waitpid(pid, &status, );
}
} /**********************************************************************/
/* 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 = ;
char c = '\0';
int n; while ((i < size - ) && (c != '\n'))
{
n = recv(sock, &c, , );
/* DEBUG printf("%02X\n", c); */
if (n > )
{
if (c == '\r')
{
n = recv(sock, &c, , MSG_PEEK);
/* DEBUG printf("%02X\n", c); */
if ((n > ) && (c == '\n'))
recv(sock, &c, , );
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[];
(void)filename; /* could use filename to determine file type */ strcpy(buf, "HTTP/1.0 200 OK\r\n");
send(client, buf, strlen(buf), );
strcpy(buf, SERVER_STRING);
send(client, buf, strlen(buf), );
sprintf(buf, "Content-Type: text/html\r\n");
send(client, buf, strlen(buf), );
strcpy(buf, "\r\n");
send(client, buf, strlen(buf), );
} /**********************************************************************/
/* Give a client a 404 not found status message. */
/**********************************************************************/
void not_found(int client)
{
char buf[]; sprintf(buf, "HTTP/1.0 404 NOT FOUND\r\n");
send(client, buf, strlen(buf), );
sprintf(buf, SERVER_STRING);
send(client, buf, strlen(buf), );
sprintf(buf, "Content-Type: text/html\r\n");
send(client, buf, strlen(buf), );
sprintf(buf, "\r\n");
send(client, buf, strlen(buf), );
sprintf(buf, "<HTML><TITLE>Not Found</TITLE>\r\n");
send(client, buf, strlen(buf), );
sprintf(buf, "<BODY><P>The server could not fulfill\r\n");
send(client, buf, strlen(buf), );
sprintf(buf, "your request because the resource specified\r\n");
send(client, buf, strlen(buf), );
sprintf(buf, "is unavailable or nonexistent.\r\n");
send(client, buf, strlen(buf), );
sprintf(buf, "</BODY></HTML>\r\n");
send(client, buf, strlen(buf), );
} /**********************************************************************/
/* 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 = ;
char buf[]; buf[] = 'A'; buf[] = '\0';
while ((numchars > ) && 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 = ;
int on = ;
struct sockaddr_in name; httpd = socket(PF_INET, SOCK_STREAM, );
if (httpd == -)
error_die("socket");
memset(&name, , 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))) < )
{
error_die("setsockopt failed");
}
if (bind(httpd, (struct sockaddr *)&name, sizeof(name)) < )
error_die("bind");
if (*port == ) /* if dynamically allocating a port */
{
socklen_t namelen = sizeof(name);
if (getsockname(httpd, (struct sockaddr *)&name, &namelen) == -)
error_die("getsockname");
*port = ntohs(name.sin_port);
}
if (listen(httpd, ) < )
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[]; sprintf(buf, "HTTP/1.0 501 Method Not Implemented\r\n");
send(client, buf, strlen(buf), );
sprintf(buf, SERVER_STRING);
send(client, buf, strlen(buf), );
sprintf(buf, "Content-Type: text/html\r\n");
send(client, buf, strlen(buf), );
sprintf(buf, "\r\n");
send(client, buf, strlen(buf), );
sprintf(buf, "<HTML><HEAD><TITLE>Method Not Implemented\r\n");
send(client, buf, strlen(buf), );
sprintf(buf, "</TITLE></HEAD>\r\n");
send(client, buf, strlen(buf), );
sprintf(buf, "<BODY><P>HTTP request method not supported.\r\n");
send(client, buf, strlen(buf), );
sprintf(buf, "</BODY></HTML>\r\n");
send(client, buf, strlen(buf), );
} /**********************************************************************/ int main(void)
{
int server_sock = -;
u_short port = ;
int client_sock = -;
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 ()
{
client_sock = accept(server_sock,
(struct sockaddr *)&client_name,
&client_name_len);
if (client_sock == -)
error_die("accept");
/* accept_request(&client_sock); */
if (pthread_create(&newthread , NULL, (void *)accept_request, (void *)(intptr_t)client_sock) != )
perror("pthread_create");
} close(server_sock); return();
}
其实就是建立tcp连接，通过对数据包的解析是否有http的头字段来判断是不是http的，wireshark就是这样
下面是一个别人总结的图
这个我自己写了一下但是没实现到cgi那里，贴一个别人用windows实现的地址
https://blog.csdn.net/magictong/article/details/53201038
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