fetch-pack: -k option to keep downloaded pack.

Split out the functions that deal with the socketpair after
finishing git protocol handshake to receive the packed data into
a separate file, and use it in fetch-pack to keep/explode the
received pack data.  We earlier had something like that on
clone-pack side once, but the list discussion resulted in the
decision that it makes sense to always keep the pack for
clone-pack, so unpacking option is not enabled on the clone-pack
side, but we later still could do so easily if we wanted to with
this change.

Signed-off-by: Junio C Hamano <junkio@cox.net>

1 files changed, 172 insertions, 0 deletions

diff --git a/fetch-clone.c b/fetch-clone.c
new file mode 100644
index 0000000..2b2aa15
--- /dev/null
+++ b/fetch-clone.c
@@ -0,0 +1,172 @@
+#include "cache.h"
+#include <sys/wait.h>
+
+static int finish_pack(const char *pack_tmp_name, const char *me)
+{
+	int pipe_fd[2];
+	pid_t pid;
+	char idx[PATH_MAX];
+	char final[PATH_MAX];
+	char hash[41];
+	unsigned char sha1[20];
+	char *cp;
+	int err = 0;
+
+	if (pipe(pipe_fd) < 0)
+		die("%s: unable to set up pipe", me);
+
+	strcpy(idx, pack_tmp_name); /* ".git/objects/pack-XXXXXX" */
+	cp = strrchr(idx, '/');
+	memcpy(cp, "/pidx", 5);
+
+	pid = fork();
+	if (pid < 0)
+		die("git-clone-pack: unable to fork off git-index-pack");
+	if (!pid) {
+		close(0);
+		dup2(pipe_fd[1], 1);
+		close(pipe_fd[0]);
+		close(pipe_fd[1]);
+		execlp("git-index-pack","git-index-pack",
+		       "-o", idx, pack_tmp_name, NULL);
+		error("cannot exec git-index-pack <%s> <%s>",
+		      idx, pack_tmp_name);
+		exit(1);
+	}
+	close(pipe_fd[1]);
+	if (read(pipe_fd[0], hash, 40) != 40) {
+		error("%s: unable to read from git-index-pack", me);
+		err = 1;
+	}
+	close(pipe_fd[0]);
+
+	for (;;) {
+		int status, code;
+		int retval = waitpid(pid, &status, 0);
+
+		if (retval < 0) {
+			if (errno == EINTR)
+				continue;
+			error("waitpid failed (%s)", strerror(retval));
+			goto error_die;
+		}
+		if (WIFSIGNALED(status)) {
+			int sig = WTERMSIG(status);
+			error("git-index-pack died of signal %d", sig);
+			goto error_die;
+		}
+		if (!WIFEXITED(status)) {
+			error("git-index-pack died of unnatural causes %d",
+			      status);
+			goto error_die;
+		}
+		code = WEXITSTATUS(status);
+		if (code) {
+			error("git-index-pack died with error code %d", code);
+			goto error_die;
+		}
+		if (err)
+			goto error_die;
+		break;
+	}
+	hash[40] = 0;
+	if (get_sha1_hex(hash, sha1)) {
+		error("git-index-pack reported nonsense '%s'", hash);
+		goto error_die;
+	}
+	/* Now we have pack in pack_tmp_name[], and
+	 * idx in idx[]; rename them to their final names.
+	 */
+	snprintf(final, sizeof(final),
+		 "%s/pack/pack-%s.pack", get_object_directory(), hash);
+	move_temp_to_file(pack_tmp_name, final);
+	chmod(final, 0444);
+	snprintf(final, sizeof(final),
+		 "%s/pack/pack-%s.idx", get_object_directory(), hash);
+	move_temp_to_file(idx, final);
+	chmod(final, 0444);
+	return 0;
+
+ error_die:
+	unlink(idx);
+	unlink(pack_tmp_name);
+	exit(1);
+}
+
+int receive_unpack_pack(int fd[2], const char *me, int quiet)
+{
+	int status;
+	pid_t pid;
+
+	pid = fork();
+	if (pid < 0)
+		die("%s: unable to fork off git-unpack-objects", me);
+	if (!pid) {
+		dup2(fd[0], 0);
+		close(fd[0]);
+		close(fd[1]);
+		execlp("git-unpack-objects", "git-unpack-objects",
+		       quiet ? "-q" : NULL, NULL);
+		die("git-unpack-objects exec failed");
+	}
+	close(fd[0]);
+	close(fd[1]);
+	while (waitpid(pid, &status, 0) < 0) {
+		if (errno != EINTR)
+			die("waiting for git-unpack-objects: %s",
+			    strerror(errno));
+	}
+	if (WIFEXITED(status)) {
+		int code = WEXITSTATUS(status);
+		if (code)
+			die("git-unpack-objects died with error code %d",
+			    code);
+		return 0;
+	}
+	if (WIFSIGNALED(status)) {
+		int sig = WTERMSIG(status);
+		die("git-unpack-objects died of signal %d", sig);
+	}
+	die("git-unpack-objects died of unnatural causes %d", status);
+}
+
+int receive_keep_pack(int fd[2], const char *me)
+{
+	char tmpfile[PATH_MAX];
+	int ofd, ifd;
+
+	ifd = fd[0];
+	snprintf(tmpfile, sizeof(tmpfile),
+		 "%s/pack/tmp-XXXXXX", get_object_directory());
+	ofd = mkstemp(tmpfile);
+	if (ofd < 0)
+		return error("unable to create temporary file %s", tmpfile);
+
+	while (1) {
+		char buf[8192];
+		ssize_t sz, wsz, pos;
+		sz = read(ifd, buf, sizeof(buf));
+		if (sz == 0)
+			break;
+		if (sz < 0) {
+			error("error reading pack (%s)", strerror(errno));
+			close(ofd);
+			unlink(tmpfile);
+			return -1;
+		}
+		pos = 0;
+		while (pos < sz) {
+			wsz = write(ofd, buf + pos, sz - pos);
+			if (wsz < 0) {
+				error("error writing pack (%s)",
+				      strerror(errno));
+				close(ofd);
+				unlink(tmpfile);
+				return -1;
+			}
+			pos += wsz;
+		}
+	}
+	close(ofd);
+	return finish_pack(tmpfile, me);
+}