contrib/package: add uhttpd, a drop-in replacement for busybox httpd
[project/luci.git] / contrib / package / uhttpd / src / uhttpd-cgi.c
diff --git a/contrib/package/uhttpd/src/uhttpd-cgi.c b/contrib/package/uhttpd/src/uhttpd-cgi.c
new file mode 100644 (file)
index 0000000..4c1265b
--- /dev/null
@@ -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;
+       }
+}
+