I would like to make it easier for gotd and Git to co-exist.

At present it is quite easy for new users to end up in a situation
where they configure gotd, yet end up running Git's versions of
the git-upload-pack and git-receive-pack programs.
This has already happened in at least one case I am aware of.
If the user has write access to repositories it may even appear as if
gotd was working just fine, even though it is actually Git which runs
behind the scenes.

This patch adds a gitwrapper program which can be used in place of
git-upload-pack and git-receive-pack. If the requested repository can
be found in gotd.conf then gitwrapper will invoke gotsh which will
talk to gotd. Otherwise gitwrapper will invoke native git binaries.

This idea was inspired by naddy@ who compared the current situation to
the sendmail problem which resulted in the existence of mailwrapper(8).

The name is of couse a joke. I don't really feel comforable squatting
on the git* namespace, but in this case it is probably harmless. We could
change the name at any point in the future if it collides with something
important. And the program would not actually need to be installed under
its original name anyway, just as git-upload-pack and git-receive-pack.

For convenience, the OpenBSD ports tree could package gitwrapper
separately from the gotd package, and have the git package depend
on gitwrapper to provide these two programs in /usr/local/bin (the git
package currently installs them in /usr/local/bin as well as in the
git libexec directory; just libexec would then be enough).
Installing the gotd package and adding repositories to gotd.conf
would then be sufficient to make gotd work as expected.

ok?

There is also a small bug fix for lib/serve.c in there, where the size
of the canonpath buffer does not account for a NUL terminator. This
problem is triggerred by gitwrapper.

diffstat refs/heads/main refs/heads/gitwrapper
 M  Makefile                 |    2+  1-
 M  README                   |    2+  0-
 A  gitwrapper/Makefile      |   41+  0-
 A  gitwrapper/gitwrapper.1  |  114+  0-
 A  gitwrapper/gitwrapper.c  |  154+  0-
 M  got-dist.txt             |    4+  0-
 M  lib/serve.c              |    2+  2-

7 files changed, 319 insertions(+), 3 deletions(-)

diff refs/heads/main refs/heads/gitwrapper
commit - 5fdcbbb62bc65d9207f8fa4062b856ca904cdcc6
commit + 5f80e2f030835cb073b057ea49be899a3e762e81
blob - 8f2de2846e8dacea7b203a6e29ba07b05a069a13
blob + 8d6fa8e66a64509014ab534cdc80ef36d065112e
--- Makefile
+++ Makefile
@@ -7,7 +7,7 @@ SUBDIR += gotwebd gotd gotsh gotctl template
 .endif
 
 .if make(clean) || make(obj) || make(release)
-SUBDIR += gotwebd gotd gotsh gotctl template
+SUBDIR += gotwebd gotd gotsh gotctl template gitwrapper
 .endif
 
 .if make(tags) || make(cleandir)
@@ -49,6 +49,7 @@ server:
 	${MAKE} -C gotctl
 	${MAKE} -C gotd
 	${MAKE} -C gotsh
+	${MAKE} -C gitwrapper
 
 server-install:
 	${MAKE} -C gotctl install
blob - a67c022cd57805a8d11d93379be5d9306df2ec48
blob + 2328859beb94e97d832f30c6cbb5eb26ac6d3b0e
--- README
+++ README
@@ -73,6 +73,7 @@ This will install the following commands:
  gotd, the repository server program
  gotctl, the server control utility
  gotsh, the login shell for users accessing the server via the network
+ gitwrapper, like mailwrapper(8) but for git-upload-pack and git-receive-pack
 
 See the following manual page files for information about server setup:
 
@@ -80,6 +81,7 @@ See the following manual page files for information ab
  $ man -l gotd/gotd.conf.5
  $ man -l gotctl/gotctl.8
  $ man -l gotsh/gotsh.1
+ $ man -l gitwrapper/gitwrapper.1
 
 See regress/gotd/README for information about running the server test suite.
 
blob - /dev/null
blob + cd56f97718ffa1b0dc5eabec3e2e6048cbb763b7 (mode 644)
--- /dev/null
+++ gitwrapper/Makefile
@@ -0,0 +1,41 @@
+.PATH:${.CURDIR}/../lib
+.PATH:${.CURDIR}/../gotd
+
+.include "../got-version.mk"
+
+.if ${GOT_RELEASE} == "Yes"
+BINDIR ?=	${PREFIX}/bin
+.endif
+
+PROG=		gitwrapper
+SRCS=		gitwrapper.c parse.y log.c serve.c auth.c listen.c pkt.c \
+		error.c gitproto.c hash.c reference.c object.c object_parse.c \
+		path.c object_idset.c object_create.c inflate.c opentemp.c \
+		lockfile.c repository.c gotconfig.c pack.c bloom.c buf.c \
+		object_cache.c privsep_stub.c pollfd.c imsg.c \
+		reference_parse.c object_open_io.c sigs.c deflate.c \
+		read_gotconfig.c read_gitconfig.c delta_cache.c delta.c \
+		murmurhash2.c date.c gitconfig.c
+
+CLEANFILES = parse.h
+
+MAN =		${PROG}.conf.5 ${PROG}.1
+
+CPPFLAGS = -I${.CURDIR}/../include -I${.CURDIR}/../lib -I${.CURDIR}/../gotd
+
+.if defined(PROFILE)
+LDADD = -lutil_p -lz_p -lm_p -lc_p -levent_p
+.else
+LDADD = -lutil -lz -lm -levent
+.endif
+DPADD = ${LIBZ} ${LIBUTIL}
+
+.if ${GOT_RELEASE} != "Yes"
+NOMAN = Yes
+.endif
+
+realinstall:
+	${INSTALL} ${INSTALL_COPY} -o ${BINOWN} -g ${BINGRP} \
+	-m ${BINMODE} ${PROG} ${BINDIR}/${PROG}
+
+.include <bsd.prog.mk>
blob - /dev/null
blob + 8004ca843253b513410b2966d13a37298da5689b (mode 644)
--- /dev/null
+++ gitwrapper/gitwrapper.1
@@ -0,0 +1,114 @@
+.\"
+.\" Copyright (c) 2023 Stefan Sperling
+.\"
+.\" Permission to use, copy, modify, and distribute this software for any
+.\" purpose with or without fee is hereby granted, provided that the above
+.\" copyright notice and this permission notice appear in all copies.
+.\"
+.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+.\"
+.Dd $Mdocdate$
+.Dt GITWRAPPER 1
+.Os
+.Sh NAME
+.Nm gitwrapper
+.Nd invoke an appropriate Git repository server
+.Sh SYNOPSIS
+.Nm Fl c Sq Cm git-receive-pack Ar repository-path
+.Nm Fl c Sq Cm git-upload-pack Ar repository-path
+.Sh DESCRIPTION
+At one time, the only Git repository server software easily available
+was built into
+.Xr git-upload-pack 1
+and
+.Xr git-receive-pack 1
+which are part of the
+.Xr git 1
+suite.
+As a result of this, most Git client implementations had the path and
+calling conventions expected by
+.Xr git 1
+compiled in.
+.Pp
+Times have changed, however.  On a modern system, the administrator may
+wish to use one of several available Git repository servers, such as
+.Xr gotd 8 .
+.Pp
+It would be difficult to modify all Git client software typically available
+on a system, so most of the authors of alternative Git servers have written
+their programs so that they use the same calling conventions as
+.Xr git-upload-pack 1
+and
+.Xr git-receive-pack 1
+and may be put into place in their stead.
+.Pp
+Although having drop-in replacements for
+.Xr git-upload-pack 1
+and
+.Xr git-receive-pack 1
+helps in installing alternative Git servers, it essentially makes the
+configuration of the system depend on hard installing new programs in /usr.
+This leads to configuration problems for many administrators, since they may
+wish to install a new Git server without altering the system provided /usr.
+(This may be, for example, to avoid having upgrade problems when a new
+version of the system is installed over the old.)  They may also have a
+shared /usr among several machines, and may wish to avoid placing implicit
+configuration information in a read-only /usr.
+.Pp
+The
+.Nm
+program is designed to replace
+.Xr git-upload-pack 1
+and
+.Xr git-receive-pack 1
+and to invoke an appropriate Git server based on configuration information
+placed in
+.Xr gotd.conf 5 .
+This permits the administrator to configure which Git server is to be
+invoked on the system at run-time.
+Git repositories which are listed in
+.Xr gotd.conf 5 .
+and exist on the filesystem will be served by
+.Xr gotsh 1 .
+Any other Git repositories will be served by
+.Xr git-upload-pack 1
+and
+.Xr git-receive-pack 1 .
+.Sh FILES
+Configuration for
+.Xr gotd 8
+is kept in
+.Pa /etc/gotd.conf.
+.Pp
+.Pa git-upload-pack
+and
+.Pa git-receive-pack
+are typically set up as a symlink to
+.Nm
+which is not usually invoked on its own.
+.Sh ENVIRONMENT
+.Bl -tag -width GOTD_CONF_PATH
+.It Ev GOTD_CONF_PATH
+Set the path to the configuration file for
+.Xr gotd 8 .
+If not specified, the default path
+.Pa /etc/gotd.conf
+will be used.
+.El
+.Sh SEE ALSO
+.Xr got 1 ,
+.Xr gotd.conf 5 ,
+.Xr gotd 8 ,
+.Xr mailwrapper 8
+.Sh AUTHORS
+.An Stefan Sperling Aq Mt stsp@openbsd.org
+.Sh BUGS
+The entire reason this program exists is a crock. Instead, a command for
+invoking a Git server should be standardized or the Git protocol should
+be changed to make the path to the program discoverable by Git clients.
blob - /dev/null
blob + 3135f87bdfa68c4442e5c84237960f6e108d785b (mode 644)
--- /dev/null
+++ gitwrapper/gitwrapper.c
@@ -0,0 +1,154 @@
+/*
+ * Copyright (c) 2023 Stefan Sperling <stsp@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/*
+ * Resolve path namespace conflicts for git-upload-pack and git-receive-pack.
+ */
+
+#include <sys/queue.h>
+#include <sys/types.h>
+#include <sys/uio.h>
+#include <sys/wait.h>
+
+#include <err.h>
+#include <errno.h>
+#include <event.h>
+#include <imsg.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sha1.h>
+#include <sha2.h>
+#include <util.h>
+#include <unistd.h>
+
+#include "got_error.h"
+#include "got_path.h"
+#include "got_serve.h"
+
+#include "gotd.h"
+
+#ifndef GITWRAPPER_GIT_LIBEXEC_DIR
+#define GITWRAPPER_GIT_LIBEXEC_DIR "/usr/local/libexec/git"
+#endif
+
+__dead static void
+usage(void)
+{
+	fprintf(stderr, "usage: %s -c '%s|%s repository-path'\n",
+	    getprogname(), GOT_SERVE_CMD_SEND, GOT_SERVE_CMD_FETCH);
+	exit(1);
+}
+
+int
+main(int argc, char *argv[])
+{
+	const struct got_error *error;
+	const char *confpath = NULL;
+	char *command = NULL, *repo_name = NULL; /* for matching gotd.conf */
+	const char *repo_path = NULL; /* as passed on the command line */
+	char *gitcommand = NULL;
+	struct gotd gotd;
+	struct gotd_repo *repo = NULL;
+	pid_t pid;
+	int st = -1;
+
+#ifndef PROFILE
+	if (pledge("stdio rpath proc exec", NULL) == -1)
+		err(1, "pledge");
+#endif
+
+	confpath = getenv("GOTD_CONF_PATH");
+	if (confpath == NULL)
+		confpath = GOTD_CONF_PATH;
+
+	if (strcmp(argv[0], GOT_SERVE_CMD_SEND) == 0 ||
+	    strcmp(argv[0], GOT_SERVE_CMD_FETCH) == 0) {
+		if (argc != 2)
+			usage();
+		command = strdup(argv[0]);
+		if (command == NULL) {
+			error = got_error_from_errno("strdup");
+			goto done;
+		}
+		repo_path = argv[1];
+	} else {
+		if (argc != 3 || strcmp(argv[1], "-c") != 0)
+			usage();
+		repo_path = argv[2];
+		error = got_serve_parse_command(&command, &repo_name,
+		    repo_path);
+		if (error && error->code == GOT_ERR_BAD_PACKET)
+			usage();
+		if (error)
+			goto done;
+	}
+
+	if (parse_config(confpath, PROC_GOTD, &gotd) == 0) {
+		TAILQ_FOREACH(repo, &gotd.repos, entry) {
+			if (got_path_cmp(repo->name, repo_name,
+			    strlen(repo->name), strlen(repo_name)) == 0)
+				break;
+		}
+	}
+
+	if (asprintf(&gitcommand, "%s/%s",
+	    GITWRAPPER_GIT_LIBEXEC_DIR, command) == -1) {
+		error = got_error_from_errno("asprintf");
+		goto done;
+	}
+
+	/*
+	 * Invoke gotsh(1) if the repository was found in gotd.conf.
+	 * Otherwise invoke native git(1) tooling which we expect to
+	 * be found in GITWRAPPER_GIT_LIBEXEC_DIR.
+	 */
+	switch (pid = fork()) {
+	case -1:
+		goto done;
+	case 0:
+		if (repo) {
+			if (execlp("gotsh", command, repo_name,
+			    (char *)NULL) ==  -1) {
+				error = got_error_from_errno("execlp");
+				goto done;
+			 }
+		} else {
+			if (execl(gitcommand, gitcommand, repo_path,
+			    (char *)NULL) == -1) {
+				error = got_error_from_errno("execlp");
+				goto done;
+			 }
+		}
+		_exit(127);
+	}
+
+	while (waitpid(pid, &st, 0) == -1) {
+		if (errno != EINTR)
+			break;
+	}
+done:
+	free(command);
+	free(repo_name);
+	free(gitcommand);
+	if (error) {
+		fprintf(stderr, "%s: %s\n", getprogname(), error->msg);
+		return 1;
+	}
+
+	return 0;
+}
blob - 0779cab1856784fdd06081ce2ddf025599ae207a
blob + e030b87f2810cd0261799b0a15ef3e38beeb6ae0
--- got-dist.txt
+++ got-dist.txt
@@ -5,6 +5,10 @@
 /Makefile.inc
 /README
 /TODO
+/gitwrapper
+/gitwrapper/Makefile
+/gitwrapper/gitwrapper.1
+/gitwrapper/gitwrapper.c
 /got
 /got-version.mk
 /got/Makefile
blob - 14220632c56b0614a6dab68fe22981fd134183c8
blob + 8ef2f8a5f604c4672e7ef11adbba4c6af455fd18
--- lib/serve.c
+++ lib/serve.c
@@ -130,12 +130,12 @@ got_serve_parse_command(char **command, char **repo_pa
 		goto done;
 	}
 	pathlen = strlen(abspath);
-	canonpath = malloc(pathlen);
+	canonpath = malloc(pathlen + 1);
 	if (canonpath == NULL) {
 		err = got_error_from_errno("malloc");
 		goto done;
 	}
-	err = got_canonpath(abspath, canonpath, pathlen);
+	err = got_canonpath(abspath, canonpath, pathlen + 1);
 	if (err)
 		goto done;