webserv.c

基于三星S3C2410 LINUX的网络开发原码

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <string.h>
void read_til_crnl(FILE *fp);
void process_rq(char *rq, int fd);
void header(FILE *fp, char *content_type);
void cannot_do(int fd);
void do_404(char *item, int fd);
int isadir(char *f);
int do_ls(char *dir, int fd);
char *file_type(char *f);
int ends_in_cgi(char *f);
int do_exec(char *prog, int fd);
int do_cat(char *f, int fd);

int main(int ac, char *av[])
{
	int sock, fd;
	FILE *fpin;
	char request[BUFSIZ];
	if(ac == 1){
		fprintf(stderr, "usage: ws portnum\n");
		exit(1);
	}
	sock = make_server_socket(atoi(av[1]));
	if(sock == -1) exit(2);
	
	while(1){
		fd = accept(sock, NULL, NULL);
		fpin = fdopen(fd, "r");
		
		fgets(request, BUFSIZ, fpin);
		printf("got a call: request = %s", request);
		read_til_crnl(fpin);
		
		process_rq(request, fd);
		
		fclose(fpin);
	}
}

void read_til_crnl(FILE *fp)
{
	char buf[BUFSIZ];
	while(fgets(buf, BUFSIZ, fp) != NULL && strcmp(buf,"\r\n") != 0);
}

void process_rq(char *rq, int fd)
{
	char cmd[BUFSIZ], arg[BUFSIZ];
	if(fork() != 0)
		return;
	
	strcpy(arg, "./");
	if(sscanf(rq, "%s %s", cmd, arg+2) != 2)
		return;
		
	if(strcmp(cmd, "GET") != 0)
		cannot_do(fd);
	else if(not_exist(arg))
		do_404(arg,fd);
	else if(isadir(arg))
		do_ls(arg, fd);
	else if(ends_in_cgi(arg))
		do_exec(arg, fd);
	else
		do_cat(arg, fd);						
}

void header(FILE *fp, char *content_type)
{
	fprintf(fp, "HTTP/1.0 200 ok\r\n");
	if(content_type)
		fprintf(fp, "Content-type:%s\r\n", content_type);
}

void cannot_do(int fd)
{
	FILE *fp = fdopen(fd, "w");
	
	fprintf(fp, "HTTP/1.0 501 Not Implemented\r\n");
	fprintf(fp, "Content-type: text/plain\r\n");
	fprintf(fp, "\r\n");
	
	fprintf(fp, "That command is not yet implemented\r\n");
	fclose(fp);
}

void do_404(char *item, int fd)
{
	FILE *fp = fdopen(fd, "w");
	
	fprintf(fp, "HTTP/1.0 404 Not Found\r\n");
	fprintf(fp, "Content-type: text/plain\r\n");
	fprintf(fp, "\r\n");
	
	fprintf(fp, "The item you requested: %s\r\nis not found\r\n", item);
	fclose(fp);
}

int isadir(char *f)
{
	struct stat info;
	return (stat(f, &info) != -1 && S_ISDIR(info.st_mode));
}

int not_exist(char *f)
{
	struct stat info;
	return (stat(f, &info) == -1);
}

int do_ls(char *dir, int fd)
{
	FILE *fp;
	fp = fdopen(fd, "w");
	header(fp, "text/plain");
	fprintf(fp, "\r\n");
	fflush(fp);
	
	dup2(fd, 1);
	dup2(fd, 2);
	close(fd);
	execlp("ls", "ls", "-l", dir, NULL);
	perror(dir);
	exit(1);
}

char *file_type(char *f)
{
	char *cp;
	if((cp = strrchr(f, '.')) != NULL)
		return cp+1;
}

int ends_in_cgi(char *f)
{
	return (strcmp(file_type(f), "cgi") == 0);
}

int do_exec(char *prog, int fd)
{
	FILE *fp;
	
	fp = fdopen(fd, "w");
	header(fp, NULL);
	fflush(fp);
	dup2(fd,1);
	dup2(fd,2);
	close(fd);
	execl(prog, prog, NULL);
	perror(prog);
}

int do_cat(char *f, int fd)
{
	char *extension = file_type(f);
	char *content = "text/plain";
	FILE *fpsock, *fpfile;
	int c;
	
	if(strcmp(extension, "html") == 0)
		content = "text/html";
	else if(strcmp(extension, "gif") == 0)
		content = "image/gif";
	else if(strcmp(extension, "jpg") == 0)
		content = "image/jpg";
	else if(strcmp(extension, "jpeg") == 0)
		content = "image/jpeg";
		
	fpsock = fdopen(fd, "w");
	fpfile = fopen(f, "r");
	if(fpsock != NULL && fpfile != NULL)
	{
		header(fpsock, content);
		fprintf(fpsock, "\r\n");
		while((c = getc(fpfile)) != EOF)
			putc(c, fpsock);
		fclose(fpfile);
		fclose(fpsock);	
	}
	exit(0);
}