Add igp gopher server for text.causal.agency

4 files changed, 201 insertions, 2 deletions

diff --git a/www/text.causal.agency/.gitignore b/www/text.causal.agency/.gitignore
index 37dd51ef..8fe3acc9 100644
--- a/www/text.causal.agency/.gitignore
+++ b/www/text.causal.agency/.gitignore
@@ -1,2 +1,3 @@
 *.txt
 feed.atom
+igp
diff --git a/www/text.causal.agency/Makefile b/www/text.causal.agency/Makefile
index 380af0fd..223c4e2f 100644
--- a/www/text.causal.agency/Makefile
+++ b/www/text.causal.agency/Makefile
@@ -1,4 +1,7 @@
-WEBROOT = /usr/local/www/text.causal.agency
+WEBROOT ?= /usr/local/www/text.causal.agency
+LIBEXEC ?= /usr/local/libexec
+
+CFLAGS += -Wall -Wextra
 
 TXTS += 001-make.txt
 TXTS += 002-writing-mdoc.txt
@@ -26,7 +29,11 @@ feed.atom: feed.sh ${TXTS}
 	sh feed.sh > feed.atom
 
 clean:
-	rm -f ${TXTS} feed.atom
+	rm -f ${TXTS} feed.atom igp
 
 install: ${TXTS} feed.atom
 	install -p -m 644 ${TXTS} feed.atom ${WEBROOT}
+
+install-igp: igp
+	install igp ${LIBEXEC}
+	install -p -m 644 igp.c ${WEBROOT}
diff --git a/www/text.causal.agency/igp.1 b/www/text.causal.agency/igp.1
new file mode 100644
index 00000000..ccfaeaa6
--- /dev/null
+++ b/www/text.causal.agency/igp.1
@@ -0,0 +1,49 @@
+.Dd January 14, 2021
+.Dt IGP 1
+.Os
+.
+.Sh NAME
+.Nm igp
+.Nd insane gopher posse
+.
+.Sh SYNOPSIS
+.Nm
+.Op Fl h Ar host
+.Op Fl p Ar port
+.Ar directory
+.
+.Sh DESCRIPTION
+The
+.Nm
+utility is a simple
+Internet Gopher server
+which can be started by
+.Xr inetd 8 .
+It serves directory listings
+and files under
+.Ar directory .
+.
+.Pp
+The arguments are as follows:
+.Bl -tag -width Ds
+.It Fl h Ar host
+Set the host used in directory listings.
+The default is the local host name.
+.It Fl p Ar port
+Set the port used in directory listeings.
+The default is port 70.
+.El
+.
+.Sh STANDARDS
+.Rs
+.%A B. Alberti
+.%A F. Anklesaria
+.%A D. Johnson
+.%A P. Lindner
+.%A M. McCahill
+.%A D. Torrey
+.%T The Internet Gopher Protocol
+.%I IETF
+.%R RFC 1436
+.%D March 1993
+.Re
diff --git a/www/text.causal.agency/igp.c b/www/text.causal.agency/igp.c
new file mode 100644
index 00000000..8e3c742f
--- /dev/null
+++ b/www/text.causal.agency/igp.c
@@ -0,0 +1,142 @@
+/* Copyright (C) 2021  C. McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <dirent.h>
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/uio.h>
+#include <sysexits.h>
+#include <time.h>
+#include <unistd.h>
+
+#ifdef __FreeBSD__
+#include <sys/capsicum.h>
+#endif
+
+static int compar(const void *_a, const void *_b) {
+	const struct dirent *a = _a;
+	const struct dirent *b = _b;
+	if (a->d_type != b->d_type) {
+		return (a->d_type > b->d_type) - (a->d_type < b->d_type);
+	}
+	return strcmp(a->d_name, b->d_name);
+}
+
+int main(int argc, char *argv[]) {
+	int error;
+	const char *host = NULL;
+	const char *port = "70";
+	for (int opt; 0 < (opt = getopt(argc, argv, "h:p:"));) {
+		switch (opt) {
+			break; case 'h': host = optarg;
+			break; case 'p': port = optarg;
+			break; default:  return EX_USAGE;
+		}
+	}
+	if (optind == argc) return EX_USAGE;
+	if (!host) {
+		static char buf[256];
+		error = gethostname(buf, sizeof(buf));
+		if (error) abort();
+		host = buf;
+	}
+
+	const char *path = argv[optind];
+	int root = open(path, O_RDONLY | O_DIRECTORY);
+	if (root < 0) err(EX_NOINPUT, "/");
+
+#ifdef __FreeBSD__
+	cap_rights_t cap;
+	error = cap_enter()
+		|| cap_rights_limit(STDIN_FILENO, cap_rights_init(&cap, CAP_READ))
+		|| cap_rights_limit(STDOUT_FILENO, cap_rights_init(&cap, CAP_WRITE))
+		|| cap_rights_limit(
+			root, cap_rights_init(&cap, CAP_PREAD, CAP_FSTATAT, CAP_FSTATFS)
+		);
+	if (error) abort();
+#else
+#warning "This is completely insecure without capsicum(4)!"
+#endif
+
+	char buf[1024];
+	if (!fgets(buf, sizeof(buf), stdin)) return EX_PROTOCOL;
+	char *ptr = buf;
+	char *sel = strsep(&ptr, "\t\r\n");
+	if (sel[0] == '/') sel++;
+
+	int fd = (sel[0] ? openat(root, sel, O_RDONLY) : root);
+	if (fd < 0) err(EX_NOINPUT, "%s", sel);
+
+	struct stat stat;
+	error = fstat(fd, &stat);
+	if (error) err(EX_IOERR, "%s", sel);
+	if (!(stat.st_mode & (S_IFREG | S_IFDIR))) {
+		errx(EX_NOINPUT, "%s: Not a file or directory", sel);
+	}
+
+	if (stat.st_mode & S_IFREG) {
+#ifdef __FreeBSD__
+		error = sendfile(fd, STDOUT_FILENO, 0, 0, NULL, NULL, 0);
+		if (!error) return EX_OK;
+#endif
+		char buf[4096];
+		for (ssize_t len; 0 < (len = read(fd, buf, sizeof(buf)));) {
+			fwrite(buf, len, 1, stdout);
+		}
+		return EX_OK;
+	}
+
+	DIR *dir = fdopendir(fd);
+	if (!dir) err(EX_IOERR, "%s", sel);
+
+	size_t len = 0;
+	size_t width = 0;
+	static struct dirent ents[4096];
+	for (struct dirent *ent; len < 4096 && (ent = readdir(dir));) {
+		if (ent->d_name[0] == '.') continue;
+		if (ent->d_type != DT_REG && ent->d_type != DT_DIR) continue;
+		if (ent->d_namlen > width) width = ent->d_namlen;
+		ents[len++] = *ent;
+	}
+
+	qsort(ents, len, sizeof(ents[0]), compar);
+	for (size_t i = 0; i < len; ++i) {
+		char mtime[26] = "";
+		if (ents[i].d_type == DT_REG) {
+			error = fstatat(fd, ents[i].d_name, &stat, 0);
+			if (error) err(EX_IOERR, "%s/%s", sel, ents[i].d_name);
+			ctime_r(&stat.st_mtime, mtime);
+			mtime[24] = '\0';
+		}
+		printf(
+			"%c%-*s  %s\t%s%s%s\t%s\t%s\r\n",
+			(ents[i].d_type == DT_DIR ? '1' : '0'),
+			(int)width, ents[i].d_name, mtime,
+			sel, (sel[0] ? "/" : ""), ents[i].d_name, host, port
+		);
+	}
+
+	printf("i-- \t\t%s\t%s\r\n", host, port);
+	printf("0Served by IGP (AGPLv3)\tigp.c\ttext.causal.agency\t70\r\n");
+	printf(".\r\n");
+}