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added session2 excercise

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This commit is contained in:
Steffen Vogel 2015-04-17 16:27:50 +02:00
parent 422b25fbf6
commit 946abd325c
2 changed files with 171 additions and 0 deletions
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15
session2/Makefile Normal file
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TARGETS = httpd
CC = gcc
CFLAGS = -g
all: $(TARGETS) Makefile
test: httpd
sudo ./httpd acme.com/ 80
clean:
rm -f $(TARGETS)
rm -f *.o *~
.PHONY: all clean

156
session2/httpd.c Normal file
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#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <fcntl.h>
#include <limits.h>
#include <netinet/in.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/sendfile.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/stat.h>
#define HTTP_200 (struct status) { 200, "OK" }
#define HTTP_400 (struct status) { 400, "Bad request" }
#define HTTP_401 (struct status) { 401, "Unauthorized" }
#define HTTP_404 (struct status) { 404, "Not Found" }
#define HTTP_405 (struct status) { 405, "Method Not Allowed" }
#define HTTP_414 (struct status) { 414, "Request-URL Too Long" }
#define HTTP_413 (struct status) { 413, "Request Entity Too Large" }
#define HTTP_500 (struct status) { 500, "Internal Server Error" }
struct status {
int code;
const char *msg;
};
int fd;
const char *error_page = "<!DOCTYPE HTML PUBLIC \"-//IETF//DTD HTML 2.0//EN\">"
"<html><head><title>%1$u %2$s</title></head><body><h1>%2$s</h1></body></html>";
void handle_error(char *msg)
{
perror(msg); exit(EXIT_FAILURE);
}
struct status errno_to_status()
{
switch (errno) {
case 0: return HTTP_200;
case EACCES: return HTTP_401;
case ENOENT: return HTTP_404;
case ENAMETOOLONG: return HTTP_414;
case EOVERFLOW: return HTTP_413;
default: return HTTP_500;
}
}
void handle_connection(int outfd)
{
char *method, *path, *version, *msg;
int infd;
struct stat st;
struct status status;
FILE *f = fdopen(outfd, "r+");
if (!f)
handle_error("Failed to open file descriptor");
if (fscanf(f, "%ms %ms HTTP/%ms", &method, &path, &version) == 3) {
if (!strcmp(path, "/")) {
if (!realloc(path, 32))
handle_error("Failed realloc");
strncpy(path, "/index.html", 32);
}
printf(">>> %s %s HTTP/%s\n", method, path, version);
if (strcasecmp(method, "GET"))
status = HTTP_405;
else if (stat(path, &st))
status = errno_to_status();
else if ((infd = open(path, O_RDONLY)))
status = errno_to_status();
}
else
status = HTTP_400;
printf("<<< HTTP/1.1 %u %s\r\n", status.code, status.msg);
fprintf(f, "HTTP/1.1 %u %s\r\n", status.code, status.msg);
fprintf(f, "Connection: close\r\n");
switch (status.code) {
case 200:
fprintf(f, "Content-length: %u\r\n\r\n", st.st_size);
sendfile(outfd, infd, 0, st.st_size);
break;
default:
fprintf(f, error_page, status.code, status.msg);
break;
}
shutdown(outfd, SHUT_RDWR);
}
void quit()
{
close(fd);
}
int main(int argc, char *argv[])
{
char htdocs[PATH_MAX] = "/var/www";
struct sockaddr_in sin = {
.sin_family = AF_INET,
.sin_addr.s_addr = INADDR_ANY,
.sin_port = htons(80)
};
if (argc > 3) {
fprintf(stderr, "usage: %s HTDOCS_DIR [PORT]\n", argv[0]);
exit(EXIT_FAILURE);
}
if (argc > 2)
sin.sin_port = htons(atoi(argv[2]));
if (argc > 1)
strncpy(htdocs, argv[1], sizeof(htdocs));
if (chroot(htdocs))
handle_error("Failed to change root");
atexit(quit); /* Close sockets */
fd = socket(AF_INET, SOCK_STREAM, 0);
if (fd < 0)
handle_error("Failed to create socket");
if (bind(fd, (struct sockaddr *) &sin, sizeof(sin)))
handle_error("Failed to bind socket");
if (listen(fd, 10))
handle_error("Failed to listen on socket");
/* Main loop */
for (;;) {
int fd2 = accept(fd, NULL, 0);
if (fork() == 0) {
close(fd);
handle_connection(fd = fd2);
exit(0);
}
else
close(fd2);
}
if (close(fd))
handle_error("Failed to close socket");
return 0;
}