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d4603077a10555d620c94a614d0546d6959f2a48
simple-http-server/server.c
源文雨 d4603077a1 优化cgi
2021-06-07 15:11:03 +08:00

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/* 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
*
* Modified June 2021 by Fumiama(源文雨)
*/
#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 <sys/wait.h>
#include <stdlib.h>
#include <pthread.h>
#define ISspace(x) isspace((int)(x))
#define SERVER_STRING "Server: tinyhttpd edited by fumiama/0.1.0\r\n"
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 *);
off_t get_file_size(const char *);
int get_line(int, char *, int);
void handle_quit(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 *cli) {
pthread_detach(pthread_self());
int client = (int)cli;
char buf[1024];
int 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[j]) && (i < sizeof(method) - 1)) {
method[i] = buf[j];
i++;
j++;
}
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 < sizeof(buf)))
j++;
while (!ISspace(buf[j]) && (i < sizeof(url) - 1) && (j < sizeof(buf))) {
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++;
}
}
//getcwd(path, sizeof(path));
//strcat(path, url);
sprintf(path, ".%s", url[1] == '#' ? url + 2 : 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) {
//getcwd(path, sizeof(path));
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, "<P>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];
size_t size = 0;
while ((size = fread(buf, sizeof(char), 1024, resource)))
send(client, buf, size, 0);
}
/**********************************************************************/
/* 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, "<P>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 /* 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;
}
}
sprintf(buf, "HTTP/1.0 200 OK\r\n");
send(client, buf, strlen(buf), 0);
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;
}
/* child: CGI script */
if (pid == 0) {
char meth_env[255];
char query_env[255];
char length_env[255];
dup2(cgi_output[1], 1);
dup2(cgi_input[0], 0);
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, path, method, query_string, 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);
}
}
/**********************************************************************/
/* Returns the size of a file. */
/* Parameters: path of the file */
/**********************************************************************/
off_t get_file_size(const char *filepath) {
struct stat statbuf;
if (stat(filepath, &statbuf) == 0)
return statbuf.st_size;
else
return -1;
}
/**********************************************************************/
/* 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);
}
/**********************************************************************/
/* Handle thread quit signal
/**********************************************************************/
void handle_quit(int signo) {
perror("handle");
pthread_exit(NULL);
}
/**********************************************************************/
/* Return the informational HTTP headers about a file. */
/* Parameters: the socket to print the headers on
* the name of the file */
/**********************************************************************/
#define ADD_HERDER(h)\
strcpy(buf + offset, h);\
offset += sizeof(h) - 1;
#define ADD_HERDER_PARAM(h, p)\
sprintf(buf + offset, h, (p));\
offset += strlen(buf + offset);
#define EXTNM_IS_NOT(name) (strcmp(filepath+extpos, name))
#define HTTP200 "HTTP/1.0 200 OK\r\n"
#define CONTENT_TYPE "Content-Type: %s\r\n"
#define CONTENT_LEN "Content-Length: %d\r\n"
void headers(int client, const char *filepath) {
char buf[1024];
uint offset = 0;
uint extpos = strlen(filepath) - 4;
ADD_HERDER(HTTP200);
ADD_HERDER(SERVER_STRING);
ADD_HERDER_PARAM(CONTENT_TYPE, EXTNM_IS_NOT("html")?(EXTNM_IS_NOT(".css")?"text/plain":"text/css"):"text/html");
ADD_HERDER_PARAM(CONTENT_LEN, get_file_size(filepath));
ADD_HERDER("\r\n");
send(client, buf, offset, 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, "<HTML><TITLE>Not Found</TITLE>\r\n");
send(client, buf, strlen(buf), 0);
sprintf(buf, "<BODY><P>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);
//FILE *fp = popen("ps -Z", "r");
//fread(buf, sizeof(buf), 1, fp);
//fclose(fp);
//send(client, buf, strlen(buf), 0);
sprintf(buf, "</BODY></HTML>\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, "rb");
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 */
/**********************************************************************/
#ifdef LISTEN_ON_IPV6
static socklen_t struct_len = sizeof(struct sockaddr_in6);
static struct sockaddr_in6 name;
#else
static socklen_t struct_len = sizeof(struct sockaddr_in);
static struct sockaddr_in name;
#endif
int startup(u_short *port) {
int httpd = 0;
#ifdef LISTEN_ON_IPV6
name.sin6_family = AF_INET6;
name.sin6_port = htons(*port);
bzero(&(name.sin6_addr), sizeof(name.sin6_addr));
httpd = socket(PF_INET6, SOCK_STREAM, 0);
#else
name.sin_family = AF_INET;
name.sin_port = htons(*port);
name.sin_addr.s_addr = INADDR_ANY;
bzero(&(name.sin_zero), 8);
httpd = socket(AF_INET, SOCK_STREAM, 0);
#endif
if (httpd == -1)
error_die("socket");
if (bind(httpd, (struct sockaddr *)&name, struct_len) < 0)
error_die("bind");
/* if dynamically allocating a port */
if (*port == 0) {
if (getsockname(httpd, (struct sockaddr *)&name, &struct_len) == -1)
error_die("getsockname");
#ifdef LISTEN_ON_IPV6
*port = ntohs(name.sin6_port);
#else
*port = ntohs(name.sin_port);
#endif
}
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, "<HTML><HEAD><TITLE>Method Not Implemented\r\n");
send(client, buf, strlen(buf), 0);
sprintf(buf, "</TITLE></HEAD>\r\n");
send(client, buf, strlen(buf), 0);
sprintf(buf, "<BODY><P>HTTP request method not supported.\r\n");
send(client, buf, strlen(buf), 0);
sprintf(buf, "</BODY></HTML>\r\n");
send(client, buf, strlen(buf), 0);
}
/**********************************************************************/
/* simple-http-server
* Usage: simple-http-server -d port chdir
/**********************************************************************/
#define ACCEPT_CLI() {\
while (1) {\
client_sock = accept(server_sock, (struct sockaddr *)&client_name, &client_name_len);\
if (client_sock == -1) break;\
signal(SIGQUIT, handle_quit);\
signal(SIGPIPE, handle_quit);\
if (pthread_create(&newthread, NULL, accept_request, client_sock) != 0) perror("pthread_create");\
}\
close(client_sock);\
error_die("accept");\
}
int main(int argc, char **argv) {
if(argc != 3 && argc != 4) puts("Usage: simple-http-server -d port chdir");
else {
int as_daemon = *(uint16_t*)argv[1] == *(uint16_t*)"-d";
int server_sock = -1;
u_short port = (u_short)atoi(argv[as_daemon?2:1]);
int client_sock = -1;
int pid = -1;
struct sockaddr_in client_name;
socklen_t client_name_len = sizeof(client_name);
pthread_t newthread;
char *cdir = argv[as_daemon?3:2];
if(chdir(cdir)) error_die("chdir");
server_sock = startup(&port);
printf("httpd running on port %d\n", port);
if(as_daemon) {
pid = fork();
while (pid > 0) { //主进程监控子进程状态，如果子进程异常终止则重启之
wait(NULL);
puts("Server subprocess exited. Restart...");
pid = fork();
}
if(pid < 0) perror("fork");
else ACCEPT_CLI();
} else ACCEPT_CLI();
}
}
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