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netcon/misc/httpd.c

@@ -1,490 +0,0 @@
-/* httpd.c - multi-client httpd, with cgi and dirindex support, in <500 LOC.
- * Run as: httpd [-p port] <root>
- * u+x or g+x files are considered cgi programs.
- */
-
-#include <dirent.h>
-#include <fcntl.h>
-#include <limits.h>
-#include <netinet/in.h>
-#include <signal.h>
-#include <stdarg.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/epoll.h>
-#include <sys/types.h>
-#include <sys/socket.h>
-#include <sys/stat.h>
-#include <unistd.h>
-
-#define LINEBUFMAX 4096
-#define REQBUFMAX 4096
-#define FILEBUFMAX 4096
-
-static const char *docroot;
-static int printreqs = 0;
-
-struct reactor {
-	int epfd;
-};
-
-struct socket {
-	int fd;
-	struct sockaddr_in sa;
-	struct reactor *r;
-	void (*read)(struct socket *);
-	void (*write)(struct socket *);
-	void (*close)(struct socket *);
-	void *priv;
-};
-
-struct client {
-	struct socket *s;
-	void (*line)(struct client *, char *);
-	void (*writedone)(struct client *);
-
-	char *rbuf;
-	size_t rbufsize;
-	size_t rbuffill;
-	char *wbuf;
-	size_t wbufsize;
-	size_t wbuffill;
-
-	char *reqmethod;
-	char *requrl;
-
-	int fillfd;
-};
-
-static void udie(const char *prefix) {
-	perror(prefix);
-	abort();
-}
-
-static void *xmalloc(size_t sz) {
-	void *p = malloc(sz);
-	if (!p)
-		abort();
-	memset(p, 0, sz);
-	return p;
-}
-
-static char *xstrdup(const char *s) {
-	char *n = strdup(s);
-	if (!n)
-		abort();
-	return n;
-}
-
-static void strlcpy(char *dest, const char *src, size_t n) {
-	strncpy(dest, src, n - 1);
-	dest[n - 1] = '\0';
-}
-
-static void strlcat(char *dest, const char *src, size_t n) {
-	strncat(dest, src, n - 1);
-	dest[n - 1] = '\0';
-}
-
-static struct reactor *reactor_new(void) {
-	struct reactor *r = xmalloc(sizeof *r);
-	r->epfd = epoll_create1(0);
-	if (r->epfd < 0)
-		udie("epoll_create1()");
-	return r;
-}
-
-static struct socket *reactor_add(struct reactor *r, int fd) {
-	struct socket *s = xmalloc(sizeof *s);
-	struct epoll_event evt;
-
-	s->fd = fd;
-	s->r = r;
-	evt.events = 0;
-	evt.data.ptr = s;
-	if (epoll_ctl(r->epfd, EPOLL_CTL_ADD, fd, &evt) < 0)
-		udie("epoll_ctl()");
-	return s;
-};
-
-static void reactor_refresh(struct reactor *r, struct socket *s) {
-	struct epoll_event evt;
-	evt.events = 0;
-	evt.data.ptr = s;
-	if (s->read)
-		evt.events |= EPOLLIN;
-	if (s->write)
-		evt.events |= EPOLLOUT;
-	if (s->close)
-		evt.events |= EPOLLRDHUP;
-	if (epoll_ctl(r->epfd, EPOLL_CTL_MOD, s->fd, &evt) < 0)
-		udie("epoll_ctl()");
-}
-
-static void reactor_del(struct reactor *r, struct socket *s) {
-	if (epoll_ctl(r->epfd, EPOLL_CTL_DEL, s->fd, NULL) < 0)
-		udie("epoll_ctl()");
-	free(s);
-}
-
-static void reactor_run(struct reactor *r) {
-	struct epoll_event evts[16];
-	int n;
-	int i;
-	struct socket *s;
-
-	n = epoll_wait(r->epfd, evts, sizeof(evts) / sizeof(evts[0]), -1);
-	if (n < 0)
-		udie("epoll_wait()");
-	for (i = 0; i < n; i++) {
-		s = evts[i].data.ptr;
-		if (evts[i].events & (EPOLLRDHUP | EPOLLERR | EPOLLHUP)) {
-			if (s->close)
-				s->close(s);
-			reactor_del(r, s);
-		} else if ((evts[i].events & EPOLLIN) && s->read) {
-			s->read(s);
-		} else if ((evts[i].events & EPOLLOUT) && s->write) {
-			s->write(s);
-		}
-	}
-}
-
-static void reqline(struct client *, char *);
-
-static struct client *client_new(struct socket *s) {
-	struct client *c = xmalloc(sizeof *c);
-	c->s = s;
-	c->rbuf = xmalloc(REQBUFMAX);
-	c->rbufsize = REQBUFMAX;
-	c->rbuffill = 0;
-	c->line = reqline;
-	c->wbufsize = 0;
-	c->wbuffill = 0;
-	c->writedone = NULL;
-	return c;
-}
-
-static void client_read(struct socket *s) {
-	struct client *c = s->priv;
-	char *p;
-	ssize_t len;
-
-	len = read(s->fd, c->rbuf + c->rbuffill, c->rbufsize - c->rbuffill);
-	if (len < 0)
-		udie("read()");
-	c->rbuffill += len;
-	while ((p = strstr(c->rbuf, "\n"))) {
-		*p = '\0';
-		if (p > c->rbuf && p[-1] == '\r')
-			p[-1] = '\0';
-		p++;
-		c->line(c, c->rbuf);
-		memmove(c->rbuf, p, c->rbufsize - (p - c->rbuf));
-		c->rbuffill -= (p - c->rbuf);
-		memset(c->rbuf + c->rbuffill, 0, c->rbufsize - c->rbuffill);
-	}
-}
-
-static void client_write(struct socket *s) {
-	struct client *c = s->priv;
-	ssize_t len;
-
-	len = write(s->fd, c->wbuf, c->wbuffill);
-	if (len < 0)
-		udie("write()");
-	if ((size_t)len < c->wbuffill)
-		memmove(c->wbuf, c->wbuf + len, c->wbuffill - len);
-	c->wbuffill -= len;
-	if (c->wbuffill)
-		return;
-	free(c->wbuf);
-	c->wbuf = NULL;
-	c->wbufsize = 0;
-	s->write = NULL;
-	c->writedone(c);
-}
-
-static void client_writeb(struct client *c, const char *buf, size_t len) {
-	if (!c->wbufsize || c->wbufsize - c->wbuffill < len) {
-		size_t growby = len - (c->wbufsize - c->wbuffill);
-		c->wbuf = realloc(c->wbuf, c->wbufsize + growby);
-		c->wbufsize += growby;
-	}
-	memcpy(c->wbuf + c->wbuffill, buf, len);
-	c->wbuffill += len;
-	if (!c->s->write) {
-		c->s->write = client_write;
-		reactor_refresh(c->s->r, c->s);
-	}
-}
-
-static void client_writeln(struct client *c, const char *fmt, ...) {
-	char buf[LINEBUFMAX];
-	va_list ap;
-	char *p;
-
-	va_start(ap, fmt);
-	vsnprintf(buf, LINEBUFMAX, fmt, ap);
-	va_end(ap);
-
-	p = buf + strlen(buf);
-	if (p > buf + LINEBUFMAX - 2)
-		p = buf + LINEBUFMAX - 2;
-	*p++ = '\r';
-	*p++ = '\n';
-	client_writeb(c, buf, p - buf);
-}
-
-static void client_writedone(struct client *c) {
-	close(c->s->fd);
-}
-
-static void client_refillbuf(struct client *c) {
-	char buf[FILEBUFMAX];
-	ssize_t len;
-
-	len = read(c->fillfd, buf, sizeof(buf));
-	if (len < 0)
-		udie("read()");
-	if (len == 0) {
-		c->writedone = client_writedone;
-		close(c->fillfd);
-	} else {
-		c->writedone = client_refillbuf;
-	}
-	client_writeb(c, buf, len);
-}
-
-static void client_close(struct socket *s) {
-	struct client *c = s->priv;
-	free(c->reqmethod);
-	free(c->requrl);
-	free(c->rbuf);
-	free(c->wbuf);
-	free(c);
-	/* ... */
-}
-
-static void listener_read(struct socket *s) {
-	struct sockaddr_in sa;
-	socklen_t salen = sizeof(sa);
-	int nfd = accept(s->fd, (struct sockaddr *)&sa, &salen);
-	struct socket *n;
-	if (nfd == -1)
-		udie("accept()");
-	if (fcntl(nfd, F_SETFD, FD_CLOEXEC) < 0)
-		udie("fcntl()");
-	n = reactor_add(s->r, nfd);
-	memcpy(&n->sa, &sa, sizeof(n->sa));
-	n->read = client_read;
-	n->close = client_close;
-	reactor_refresh(s->r, n);
-	n->priv = client_new(n);
-}
-
-static void error(struct client *c, int code) {
-	client_writeln(c, "HTTP/1.1 %u Error", code);
-	client_writeln(c, "");
-	c->writedone = client_writedone;
-}
-
-static void iptobuf(struct client *c, char *buf) {
-	unsigned int ip = ntohl(c->s->sa.sin_addr.s_addr);
-	sprintf(buf, "%u.%u.%u.%u", (ip >> 24) & 0xFF,
-	        (ip >> 16) & 0xFF, (ip >> 8) & 0xFF, ip & 0xFF);
-}
-
-static void runcgi(struct client *c, const char *prog, const char *args) {
-	char buf[] = "REMOTE_ADDR=255.255.255.255";
-	iptobuf(c, buf + strlen("REMOTE_ADDR="));
-	putenv(buf);
-	dup2(c->s->fd, 0);
-	dup2(c->s->fd, 1);
-	dup2(c->s->fd, 2);
-	execl(prog, prog, args, NULL);
-}
-
-static void cgi(struct client *c, const char *prog, const char *args) {
-	int p;
-	p = fork();
-	if (!p)
-		runcgi(c, prog, args);
-	else if (p < 0)
-		error(c, 500);
-	else
-		c->writedone = client_writedone;
-}
-
-static void genindex(struct client *c, const char *url) {
-	DIR *d = fdopendir(c->fillfd);
-	struct dirent *e;
-
-	client_writeln(c, "Content-Type: text/html");
-	client_writeln(c, "");
-
-	client_writeln(c, "<html>");
-	client_writeln(c, "  <head>");
-	client_writeln(c, "    <title>Index of %s</title>", url);
-	client_writeln(c, "  </head>");
-	client_writeln(c, "  <body>");
-	client_writeln(c, "    <h1>Index of %s</h1>", url);
-	client_writeln(c, "    <ul>");
-	while ((e = readdir(d))) {
-		client_writeln(c, "      <li>");
-		client_writeln(c, "        <a href=\"%s%s%s\">%s</a>", url,
-		               url[strlen(url) - 1] == '/' ? "" : "/", e->d_name,
-		               e->d_name);
-		client_writeln(c, "      </li>");
-	}
-	client_writeln(c, "    </ul>");
-	client_writeln(c, "  </body>");
-	client_writeln(c, "</html>");
-	closedir(d);
-	c->writedone = client_writedone;
-}
-
-static void get(struct client *c, char *url) {
-	char rp[PATH_MAX];
-	char *rpcanon;
-	char *rest;
-	struct stat st;
-
-	strlcpy(rp, docroot, sizeof(rp));
-	if ((rest = strchr(url, '?')))
-		*rest++ = '\0';
-	strlcat(rp, url, sizeof(rp));
-	rpcanon = realpath(rp, NULL);
-	if (!rpcanon) {
-		error(c, 404);
-		return;
-	}
-
-	if (strstr(rpcanon, docroot) != rpcanon) {
-		error(c, 403);
-		free(rpcanon);
-		return;
-	}
-
-	c->fillfd = open(rpcanon, O_RDONLY);
-	if (c->fillfd == -1) {
-		free(rpcanon);
-		error(c, 403);	/* XXX: not all open() failures are 403s */
-		return;
-	}
-
-	if (fstat(c->fillfd, &st) == -1)
-		udie("fstat()");
-
-	client_writeln(c, "HTTP/1.1 200 OK");
-
-	if (S_ISDIR(st.st_mode)) {
-		genindex(c, url);
-	} else if (st.st_mode & (S_IXUSR | S_IXGRP)) {
-		cgi(c, rpcanon, rest);
-	} else {
-		client_writeln(c, "");
-		client_refillbuf(c);
-	}
-	free(rpcanon);
-}
-
-static void reqdone(struct client *c) {
-	if (printreqs) {
-		char buf[32];
-		iptobuf(c, buf);
-		printf("%s %s %s\n", buf, c->reqmethod, c->requrl);
-	}
-	if (!strcasecmp(c->reqmethod, "GET"))
-		get(c, c->requrl);
-	else
-		error(c, 405);
-}
-
-static void reqhdr(struct client *c, char *line) {
-
-	if (!strlen(line)) {
-		reqdone(c);
-		return;
-	}
-
-	/* XXX */
-}
-
-static void reqline(struct client *c, char *line) {
-	char *method, *url, *version;
-
-	method = strtok(line, " ");
-	url = strtok(NULL, " ");
-	version = strtok(NULL, " ");
-
-	if (!method || !url) {
-		error(c, 400);
-		return;
-	}
-
-	c->reqmethod = xstrdup(method);
-	c->requrl = xstrdup(url);
-	c->line = reqhdr;
-}
-
-static int serve(int port) {
-	int sfd = socket(AF_INET, SOCK_STREAM, 0);
-	struct sockaddr_in sa;
-	if (sfd == -1)
-		udie("socket()");
-	memset(&sa, 0, sizeof(sa));
-	sa.sin_family = AF_INET;
-	sa.sin_addr.s_addr = htonl(INADDR_ANY);
-	sa.sin_port = htons(port);
-	if (bind(sfd, (struct sockaddr *)&sa, sizeof(sa)) < 0)
-		udie("bind()");
-	if (listen(sfd, 20) < 0)
-		udie("listen()");
-	if (fcntl(sfd, F_SETFD, FD_CLOEXEC) < 0)
-		udie("fcntl()");
-	return sfd;
-}
-
-static void usage(const char *progn) {
-	printf("Usage: %s [-p port] [-v] <root>\n", progn);
-}
-
-int main(int argc, char *argv[]) {
-	struct reactor *r = reactor_new();
-	struct socket *listener;
-	int opt;
-	int port = 80;
-	
-	while ((opt = getopt(argc, argv, "p:v")) != -1) {
-		switch (opt) {
-			case 'p':
-				port = atoi(optarg);
-				break;
-			case 'v':
-				printreqs = 1;
-				break;
-			default:
-				usage(argv[0]);
-				exit(1);
-		}
-	}
-
-	if (optind >= argc) {
-		usage(argv[0]);
-		exit(1);
-	}
-
-	docroot = argv[optind];
-
-	listener = reactor_add(r, serve(port));
-	listener->read = listener_read;
-	reactor_refresh(r, listener);
-
-	signal(SIGCHLD, SIG_IGN);
-
-	while (1) {
-		reactor_run(r);
-	}
-}