contrib/package: add uhttpd, a drop-in replacement for busybox httpd

1 files changed, 506 insertions, 0 deletions

diff --git a/contrib/package/uhttpd/src/uhttpd-cgi.c b/contrib/package/uhttpd/src/uhttpd-cgi.c
new file mode 100644
index 000000000..4c1265bd1
--- /dev/null
+++ b/contrib/package/uhttpd/src/uhttpd-cgi.c
@@ -0,0 +1,506 @@
+#include "uhttpd.h"
+#include "uhttpd-cgi.h"
+#include "uhttpd-utils.h"
+
+static struct http_response * uh_cgi_header_parse(char *buf, int len, int *off)
+{
+	char *bufptr = NULL;
+	char *hdrname = NULL;
+	int hdrcount = 0;
+	int pos = 0;
+
+	static struct http_response res;
+
+
+	if( (bufptr = strfind(buf, len, "\r\n\r\n", 4)) != NULL )
+	{
+		*off = (int)(bufptr - buf) + 4;
+
+		memset(&res, 0, sizeof(res));
+
+		res.statuscode = 200;
+		res.statusmsg  = "OK";
+
+		bufptr = &buf[0];
+
+		for( pos = 0; pos < len; pos++ )
+		{
+			if( !hdrname && (buf[pos] == ':') )
+			{
+				buf[pos++] = 0;
+
+				if( (pos < len) && (buf[pos] == ' ') )
+					pos++;
+
+				if( pos < len )
+				{
+					hdrname = bufptr;
+					bufptr = &buf[pos];
+				}
+			}
+
+			else if( (buf[pos] == '\r') || (buf[pos] == '\n') )
+			{
+				buf[pos++] = 0;
+
+				if( ! hdrname )
+					break;
+
+				if( (pos < len) && (buf[pos] == '\n') )
+					pos++;
+
+				if( pos < len )
+				{
+					if( (hdrcount + 1) < array_size(res.headers) )
+					{
+						if( ! strcasecmp(hdrname, "Status") )
+						{
+							res.statuscode = atoi(bufptr);
+
+							if( res.statuscode < 100 )
+								res.statuscode = 200;
+
+							if( ((bufptr = strchr(bufptr, ' ')) != NULL) && (&bufptr[1] != 0) )
+								res.statusmsg = &bufptr[1];
+						}
+						else
+						{
+							res.headers[hdrcount++] = hdrname;
+							res.headers[hdrcount++] = bufptr;
+						}
+
+						bufptr = &buf[pos];
+						hdrname = NULL;
+					}
+					else
+					{
+						return NULL;
+					}
+				}
+			}
+		}
+
+		return &res;
+	}
+
+	return NULL;
+}
+
+static char * uh_cgi_header_lookup(struct http_response *res, const char *hdrname)
+{
+	int i;
+
+	foreach_header(i, res->headers)
+	{
+		if( ! strcasecmp(res->headers[i], hdrname) )
+			return res->headers[i+1];
+	}
+
+	return NULL;
+}
+
+static void uh_cgi_error_500(struct client *cl, struct http_request *req, const char *message)
+{
+	uh_http_sendf(cl, NULL,
+		"HTTP/%.1f 500 Internal Server Error\r\n"
+		"Content-Type: text/plain\r\n%s\r\n",
+			req->version, 
+			(req->version > 1.0)
+				? "Transfer-Encoding: chunked\r\n" : ""
+	);
+
+	uh_http_send(cl, req, message, -1);
+}
+
+
+void uh_cgi_request(struct client *cl, struct http_request *req)
+{
+	int i, hdroff, bufoff;
+	int hdrlen = 0;
+	int buflen = 0;
+	int fd_max = 0;
+	int content_length = 0;
+	int header_sent = 0;
+
+	int rfd[2] = { 0, 0 };
+	int wfd[2] = { 0, 0 };
+
+	char buf[UH_LIMIT_MSGHEAD];
+	char hdr[UH_LIMIT_MSGHEAD];
+
+	fd_set reader;
+	fd_set writer;
+
+	struct timeval timeout;
+	struct http_response *res;
+	struct uh_path_info *pi;
+
+
+	/* spawn pipes for me->child, child->me */
+	if( (pipe(rfd) < 0) || (pipe(wfd) < 0) )
+	{
+		uh_http_sendhf(cl, 500, "Internal Server Error",
+			"Failed to create pipe: %s", strerror(errno));
+
+		if( rfd[0] > 0 ) close(rfd[0]);
+		if( rfd[1] > 0 ) close(rfd[1]);
+		if( wfd[0] > 0 ) close(wfd[0]);
+		if( wfd[1] > 0 ) close(wfd[1]);
+
+		return;
+	}
+
+	/* fork off child process */
+	switch( fork() )
+	{
+		/* oops */
+		case -1:
+			uh_http_sendhf(cl, 500, "Internal Server Error",
+				"Failed to fork child: %s", strerror(errno));
+			return;
+
+		/* exec child */
+		case 0:
+			/* child */
+			close(rfd[0]);
+			close(wfd[1]);
+
+			/* patch stdout and stdin to pipes */
+			dup2(rfd[1], 1);
+			dup2(wfd[0], 0);
+
+			if( (pi = uh_path_lookup(cl, req->url)) != NULL )
+			{
+				/* check for regular, world-executable file */
+				if( (pi->stat.st_mode & S_IFREG) &&
+				    (pi->stat.st_mode & S_IXOTH)
+				) {
+					/* build environment */
+					clearenv();
+
+					/* common information */
+					setenv("GATEWAY_INTERFACE", "CGI/1.1", 1);
+					setenv("SERVER_SOFTWARE", "uHTTPd", 1);
+					setenv("PATH", "/usr/bin:/bin", 1);
+
+#ifdef HAVE_TLS
+					/* https? */
+					if( cl->tls )
+						setenv("HTTPS", "on", 1);
+#endif
+
+					/* addresses */
+					setenv("SERVER_NAME", sa_straddr(&cl->servaddr), 1);
+					setenv("SERVER_ADDR", sa_straddr(&cl->servaddr), 1);
+					setenv("SERVER_PORT", sa_strport(&cl->servaddr), 1);
+					setenv("REMOTE_HOST", sa_straddr(&cl->peeraddr), 1);
+					setenv("REMOTE_ADDR", sa_straddr(&cl->peeraddr), 1);
+					setenv("REMOTE_PORT", sa_strport(&cl->peeraddr), 1);
+
+					/* path information */
+					setenv("SCRIPT_NAME", pi->name, 1);
+					setenv("SCRIPT_FILENAME", pi->phys, 1);
+					setenv("SCRIPT_WORKDIR", pi->wdir, 1);	/* nonstandard */
+					setenv("DOCUMENT_ROOT", pi->root, 1);
+					setenv("QUERY_STRING", pi->query ? pi->query : "", 1);
+
+					if( pi->info )
+						setenv("PATH_INFO", pi->info, 1);
+
+
+					/* http version */
+					if( req->version > 1.0 )
+						setenv("SERVER_PROTOCOL", "HTTP/1.1", 1);
+					else
+						setenv("SERVER_PROTOCOL", "HTTP/1.0", 1);
+
+					/* request method */
+					switch( req->method )
+					{
+						case UH_HTTP_MSG_GET:
+							setenv("REQUEST_METHOD", "GET", 1);
+							break;
+
+						case UH_HTTP_MSG_HEAD:
+							setenv("REQUEST_METHOD", "HEAD", 1);
+							break;
+
+						case UH_HTTP_MSG_POST:
+							setenv("REQUEST_METHOD", "POST", 1);
+							break;
+					}
+
+					/* request url */
+					setenv("REQUEST_URI", req->url, 1);
+
+					/* request message headers */
+					foreach_header(i, req->headers)
+					{
+						if( ! strcasecmp(req->headers[i], "Accept") )
+							setenv("HTTP_ACCEPT", req->headers[i+1], 1);
+
+						else if( ! strcasecmp(req->headers[i], "Accept-Charset") )
+							setenv("HTTP_ACCEPT_CHARSET", req->headers[i+1], 1);
+
+						else if( ! strcasecmp(req->headers[i], "Accept-Encoding") )
+							setenv("HTTP_ACCEPT_ENCODING", req->headers[i+1], 1);
+
+						else if( ! strcasecmp(req->headers[i], "Accept-Language") )
+							setenv("HTTP_ACCEPT_LANGUAGE", req->headers[i+1], 1);
+
+						else if( ! strcasecmp(req->headers[i], "Authorization") )
+							setenv("HTTP_AUTHORIZATION", req->headers[i+1], 1);
+
+						else if( ! strcasecmp(req->headers[i], "Connection") )
+							setenv("HTTP_CONNECTION", req->headers[i+1], 1);
+
+						else if( ! strcasecmp(req->headers[i], "Cookie") )
+							setenv("HTTP_COOKIE", req->headers[i+1], 1);
+
+						else if( ! strcasecmp(req->headers[i], "Host") )
+							setenv("HTTP_HOST", req->headers[i+1], 1);
+
+						else if( ! strcasecmp(req->headers[i], "Referer") )
+							setenv("HTTP_REFERER", req->headers[i+1], 1);
+
+						else if( ! strcasecmp(req->headers[i], "User-Agent") )
+							setenv("HTTP_USER_AGENT", req->headers[i+1], 1);
+
+						else if( ! strcasecmp(req->headers[i], "Content-Type") )
+							setenv("CONTENT_TYPE", req->headers[i+1], 1);
+
+						else if( ! strcasecmp(req->headers[i], "Content-Length") )
+							setenv("CONTENT_LENGTH", req->headers[i+1], 1);
+					}
+
+
+					/* execute child code ... */
+					if( chdir(pi->wdir) )
+						perror("chdir()");
+
+					execl(pi->phys, pi->phys, NULL);
+
+					/* in case it fails ... */
+					printf(
+						"Status: 500 Internal Server Error\r\n\r\n"
+						"Unable to launch the requested CGI program:\n"
+						"  %s: %s\n",
+							pi->phys, strerror(errno)
+					);
+				}
+
+				/* 403 */
+				else
+				{
+					printf(
+						"Status: 403 Forbidden\r\n\r\n"
+						"Access to this resource is forbidden\n"
+					);
+				}
+			}
+
+			/* 404 */
+			else
+			{
+				printf(
+					"Status: 404 Not Found\r\n\r\n"
+					"Unable to launch the requested CGI program:\n"
+					"  No such file or directory\n"
+				);
+			}
+
+			close(wfd[0]);
+			close(rfd[1]);
+			exit(0);
+
+			break;
+
+		/* parent; handle I/O relaying */
+		default:
+			/* close unneeded pipe ends */
+			close(rfd[1]);
+			close(wfd[0]);
+
+			/* max watch fd */
+			fd_max = max(rfd[0], wfd[1]) + 1;
+
+			/* find content length */
+			if( req->method == UH_HTTP_MSG_POST )
+			{
+				foreach_header(i, req->headers)
+				{
+					if( ! strcasecmp(req->headers[i], "Content-Length") )
+					{
+						content_length = atoi(req->headers[i+1]);
+						break;
+					}
+				}
+			}
+
+
+			memset(hdr, 0, sizeof(hdr));
+
+			/* I/O loop, watch our pipe ends and dispatch child reads/writes from/to socket */
+			while( 1 )
+			{
+				FD_ZERO(&reader);
+				FD_ZERO(&writer);
+
+				FD_SET(rfd[0], &reader);
+				FD_SET(wfd[1], &writer);
+
+				timeout.tv_sec = 3;
+				timeout.tv_usec = 0;
+
+				/* wait until we can read or write or both */
+				if( select(fd_max, &reader, (content_length > -1) ? &writer : NULL, NULL, &timeout) > 0 )
+				{
+					/* ready to write to cgi program */
+					if( FD_ISSET(wfd[1], &writer) )
+					{
+						/* there is unread post data waiting */
+						if( content_length > 0 )
+						{
+							/* read it from socket ... */
+							if( (buflen = uh_tcp_recv(cl, buf, min(content_length, sizeof(buf)))) > 0 )
+							{
+								/* ... and write it to child's stdin */
+								if( write(wfd[1], buf, buflen) < 0 )
+									perror("write()");
+
+								content_length -= buflen;
+							}
+
+							/* unexpected eof! */
+							else
+							{
+								if( write(wfd[1], "", 0) < 0 )
+									perror("write()");
+
+								content_length = 0;
+							}
+						}
+
+						/* there is no more post data, close pipe to child's stdin */
+						else
+						{
+							close(wfd[1]);
+							content_length = -1;
+						}
+					}
+
+					/* ready to read from cgi program */
+					if( FD_ISSET(rfd[0], &reader) )
+					{
+						/* read data from child ... */
+						if( (buflen = read(rfd[0], buf, sizeof(buf))) > 0 )
+						{
+							/* we have not pushed out headers yet, parse input */
+							if( ! header_sent )
+							{
+								/* head buffer not full and no end yet */
+								if( hdrlen < sizeof(hdr) )
+								{
+									bufoff = min(buflen, sizeof(hdr) - hdrlen);
+									memcpy(&hdr[hdrlen], buf, bufoff);
+									hdrlen += bufoff;
+								}
+								else
+								{
+									bufoff = 0;
+								}
+
+
+								/* try to parse header ... */
+								if( (res = uh_cgi_header_parse(hdr, hdrlen, &hdroff)) != NULL )
+								{
+									/* write status */
+									uh_http_sendf(cl, NULL, "HTTP/%.1f %03d %s\r\n",
+										req->version, res->statuscode, res->statusmsg);
+
+									/* add Content-Type if no Location or Content-Type */
+									if( !uh_cgi_header_lookup(res, "Location") &&
+									    !uh_cgi_header_lookup(res, "Content-Type")
+									) {
+										uh_http_send(cl, NULL,
+											"Content-Type: text/plain\r\n", -1);
+									}
+
+									/* if request was HTTP 1.1 we'll respond chunked */
+									if( (req->version > 1.0) &&
+									    !uh_cgi_header_lookup(res, "Transfer-Encoding")
+									) {
+										uh_http_send(cl, NULL,
+											"Transfer-Encoding: chunked\r\n", -1);
+									}
+
+									/* write headers from CGI program */
+									foreach_header(i, res->headers)
+									{
+										uh_http_sendf(cl, NULL, "%s: %s\r\n",
+											res->headers[i], res->headers[i+1]);
+									}
+
+									/* terminate header */
+									uh_http_send(cl, NULL, "\r\n", -1);
+
+									/* push out remaining head buffer */
+									if( hdroff < hdrlen )
+										uh_http_send(cl, req, &hdr[hdroff], hdrlen - hdroff);
+								}
+
+								/* ... failed and head buffer exceeded */
+								else if( hdrlen >= sizeof(hdr) )
+								{
+									uh_cgi_error_500(cl, req,
+										"The CGI program generated an invalid response:\n\n");
+
+									uh_http_send(cl, req, hdr, hdrlen);
+								}
+
+								/* ... failed but free buffer space, try again */
+								else
+								{
+									continue;
+								}
+
+								/* push out remaining read buffer */
+								if( bufoff < buflen )
+									uh_http_send(cl, req, &buf[bufoff], buflen - bufoff);
+
+								header_sent = 1;
+								continue;
+							}
+
+
+							/* headers complete, pass through buffer to socket */
+							uh_http_send(cl, req, buf, buflen);
+						}
+
+						/* looks like eof from child */
+						else
+						{
+							/* send final chunk if we're in chunked transfer mode */
+							uh_http_send(cl, req, "", 0);
+							break;
+						}
+					}
+				}
+
+				/* no activity for 3 seconds... looks dead */
+				else
+				{
+					uh_http_sendhf(cl, 504, "Gateway Timeout",
+						"The CGI script took too long to produce a response");
+
+					break;
+				}
+			}
+
+			close(rfd[0]);
+			close(wfd[1]);
+
+			break;
+	}
+}
+