1 files changed, 170 insertions, 0 deletions
diff --git a/fcgiwrap.c b/fcgiwrap.c
new file mode 100644
index 0000000..577b13c
--- /dev/null
+++ b/fcgiwrap.c
@@ -0,0 +1,170 @@
+#include <fcgi_stdio.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/select.h>
+#include <errno.h>
+#include <string.h>
+#include <sys/stat.h>
+
+#define FCGI_BUF_SIZE 4096
+
+static int write_all(int fd, char *buf, size_t size)
+{
+	size_t nleft = size;
+	while (nleft > 0) {
+		ssize_t nwritten = write(fd, buf, nleft);
+		if (nwritten < 0)
+			return nleft - size; /* zero or negative to indicate error */
+
+		buf += nwritten;
+		nleft -= nwritten;
+	}
+
+	return size;
+}
+
+static void fcgi_pass(int fd_stdin, int fd_stdout, int fd_stderr)
+{
+	char buf[FCGI_BUF_SIZE];
+	size_t nread;
+	fd_set rset;
+	int maxfd = (fd_stdout > fd_stderr) ? fd_stdout : fd_stderr;
+	int nready;
+
+	/* slurp the whole input and pass it to CGI */
+
+	while ((nread = fread(buf, 1, sizeof(buf), stdin))) {
+		if (write_all(fd_stdin, buf, nread) <= 0) return;
+	}
+
+	close(fd_stdin);
+
+	/* now wait for CGI replies on stdout and stderr */
+
+	while (fd_stdout >= 0 && fd_stderr >= 0) {
+		FD_ZERO(&rset);
+		if (fd_stdout >= 0) FD_SET(fd_stdout, &rset);
+		if (fd_stderr >= 0) FD_SET(fd_stderr, &rset);
+		nready = select(maxfd, &rset, NULL, NULL, NULL);
+		if (nready < 0) {
+			if (errno == EAGAIN) continue;
+			return; /* better error checking needed */
+		}
+		if (fd_stdout >= 0 && FD_ISSET(fd_stdout, &rset)) {
+			nread = read(fd_stdout, buf, sizeof(buf));
+			if (nread <= 0) {
+				close(fd_stdout);
+				fd_stdout = -1;
+			}
+			fwrite(buf, 1, nread, stdout);
+		}
+		if (fd_stderr >= 0 && FD_ISSET(fd_stderr, &rset)) {
+			nread = read(fd_stderr, buf, sizeof(buf));
+			if (nread <= 0) {
+				close(fd_stderr);
+				fd_stderr = -1;
+			}
+			fwrite(buf, 1, nread, stderr);
+		}
+	}
+}
+
+char *get_cgi_filename()
+{
+	int buflen = 1, docrootlen;
+	char *buf;
+	char *docroot, *scriptname, *p;
+	struct stat s;
+
+	if ((p = getenv("DOCUMENT_ROOT"))) {
+		docroot = p;
+		buflen += docrootlen = strlen(p);
+	} else {
+		return NULL;
+	}
+
+	if ((p = getenv("SCRIPT_NAME"))) {
+		buflen += strlen(p);
+		scriptname = p;
+	} else {
+		return NULL;
+	}
+
+	buf = malloc(buflen);
+	if (!buf) return NULL;
+
+	strcpy(buf, docroot);
+	strcpy(buf + docrootlen, scriptname);
+
+	while(1) {
+		if (lstat(buf, &s) == 0) {
+			if (!S_ISREG(s.st_mode) || ((s.st_mode & S_IXOTH) == 0))
+				return NULL; /* 403 */
+
+			return buf;
+		}
+		p = strrchr(buf, '/');
+		if (!p) break;
+			*p = 0;
+	}
+
+	return NULL;
+}
+
+static void handle_fcgi_request()
+{
+	int pipe_in[2];
+	int pipe_out[2];
+	int pipe_err[2];
+	char *filename;
+
+	/* XXX error handling */
+	pipe(pipe_in);
+	pipe(pipe_out);
+	pipe(pipe_err);
+
+	switch(fork()) {
+		case -1:
+			return;
+
+		case 0: /* child */
+			filename = get_cgi_filename();
+			if (!filename) {
+				puts("Status: 403 Forbidden\nContent-type: text/plain\n\n403");
+				exit(99);
+			}
+			close(pipe_in[1]);
+			close(pipe_out[0]);
+			close(pipe_err[0]);
+
+			dup2(pipe_in[0], 0);
+			dup2(pipe_out[1], 1);
+			dup2(pipe_err[1], 2);
+
+			execl(filename, filename, NULL);
+			/* we _do_ want a 502 here probably */
+			exit(99);
+
+		default: /* parent */
+			close(pipe_in[0]);
+			close(pipe_out[1]);
+			close(pipe_err[1]);
+
+			fcgi_pass(pipe_in[1], pipe_out[0], pipe_err[0]);
+	}
+}
+
+int main(int argc, char **argv)
+{
+	signal(SIGCHLD, SIG_IGN);
+	signal(SIGPIPE, SIG_IGN);
+
+	while (FCGI_Accept() >= 0) {
+		handle_fcgi_request();
+	}
+
+	return 0;
+}
+