1 files changed, 316 insertions, 0 deletions

diff --git a/www/git.causal.agency/cgit/ui-snapshot.c b/www/git.causal.agency/cgit/ui-snapshot.c
new file mode 100644
index 00000000..556d3ed4
--- /dev/null
+++ b/www/git.causal.agency/cgit/ui-snapshot.c
@@ -0,0 +1,316 @@
+/* ui-snapshot.c: generate snapshot of a commit
+ *
+ * Copyright (C) 2006-2014 cgit Development Team <cgit@lists.zx2c4.com>
+ *
+ * Licensed under GNU General Public License v2
+ *   (see COPYING for full license text)
+ */
+
+#include "cgit.h"
+#include "ui-snapshot.h"
+#include "html.h"
+#include "ui-shared.h"
+
+static int write_archive_type(const char *format, const char *hex, const char *prefix)
+{
+	struct argv_array argv = ARGV_ARRAY_INIT;
+	const char **nargv;
+	int result;
+	argv_array_push(&argv, "snapshot");
+	argv_array_push(&argv, format);
+	if (prefix) {
+		struct strbuf buf = STRBUF_INIT;
+		strbuf_addstr(&buf, prefix);
+		strbuf_addch(&buf, '/');
+		argv_array_push(&argv, "--prefix");
+		argv_array_push(&argv, buf.buf);
+		strbuf_release(&buf);
+	}
+	argv_array_push(&argv, hex);
+	/*
+	 * Now we need to copy the pointers to arguments into a new
+	 * structure because write_archive will rearrange its arguments
+	 * which may result in duplicated/missing entries causing leaks
+	 * or double-frees in argv_array_clear.
+	 */
+	nargv = xmalloc(sizeof(char *) * (argv.argc + 1));
+	/* argv_array guarantees a trailing NULL entry. */
+	memcpy(nargv, argv.argv, sizeof(char *) * (argv.argc + 1));
+
+	result = write_archive(argv.argc, nargv, NULL, the_repository, NULL, 0);
+	argv_array_clear(&argv);
+	free(nargv);
+	return result;
+}
+
+static int write_tar_archive(const char *hex, const char *prefix)
+{
+	return write_archive_type("--format=tar", hex, prefix);
+}
+
+static int write_zip_archive(const char *hex, const char *prefix)
+{
+	return write_archive_type("--format=zip", hex, prefix);
+}
+
+static int write_compressed_tar_archive(const char *hex,
+					const char *prefix,
+					char *filter_argv[])
+{
+	int rv;
+	struct cgit_exec_filter f;
+	cgit_exec_filter_init(&f, filter_argv[0], filter_argv);
+
+	cgit_open_filter(&f.base);
+	rv = write_tar_archive(hex, prefix);
+	cgit_close_filter(&f.base);
+	return rv;
+}
+
+static int write_tar_gzip_archive(const char *hex, const char *prefix)
+{
+	char *argv[] = { "gzip", "-n", NULL };
+	return write_compressed_tar_archive(hex, prefix, argv);
+}
+
+static int write_tar_bzip2_archive(const char *hex, const char *prefix)
+{
+	char *argv[] = { "bzip2", NULL };
+	return write_compressed_tar_archive(hex, prefix, argv);
+}
+
+static int write_tar_lzip_archive(const char *hex, const char *prefix)
+{
+	char *argv[] = { "lzip", NULL };
+	return write_compressed_tar_archive(hex, prefix, argv);
+}
+
+static int write_tar_xz_archive(const char *hex, const char *prefix)
+{
+	char *argv[] = { "xz", NULL };
+	return write_compressed_tar_archive(hex, prefix, argv);
+}
+
+static int write_tar_zstd_archive(const char *hex, const char *prefix)
+{
+	char *argv[] = { "zstd", "-T0", NULL };
+	return write_compressed_tar_archive(hex, prefix, argv);
+}
+
+const struct cgit_snapshot_format cgit_snapshot_formats[] = {
+	/* .tar must remain the 0 index */
+	{ ".tar",	"application/x-tar",	write_tar_archive	},
+	{ ".tar.gz",	"application/x-gzip",	write_tar_gzip_archive	},
+	{ ".tar.bz2",	"application/x-bzip2",	write_tar_bzip2_archive	},
+	{ ".tar.lz",	"application/x-lzip",	write_tar_lzip_archive	},
+	{ ".tar.xz",	"application/x-xz",	write_tar_xz_archive	},
+	{ ".tar.zst",	"application/x-zstd",	write_tar_zstd_archive	},
+	{ ".zip",	"application/x-zip",	write_zip_archive	},
+	{ NULL }
+};
+
+static struct notes_tree snapshot_sig_notes[ARRAY_SIZE(cgit_snapshot_formats)];
+
+const struct object_id *cgit_snapshot_get_sig(const char *ref,
+					      const struct cgit_snapshot_format *f)
+{
+	struct notes_tree *tree;
+	struct object_id oid;
+
+	if (get_oid(ref, &oid))
+		return NULL;
+
+	tree = &snapshot_sig_notes[f - &cgit_snapshot_formats[0]];
+	if (!tree->initialized) {
+		struct strbuf notes_ref = STRBUF_INIT;
+
+		strbuf_addf(&notes_ref, "refs/notes/signatures/%s",
+			    f->suffix + 1);
+
+		init_notes(tree, notes_ref.buf, combine_notes_ignore, 0);
+		strbuf_release(&notes_ref);
+	}
+
+	return get_note(tree, &oid);
+}
+
+static const struct cgit_snapshot_format *get_format(const char *filename)
+{
+	const struct cgit_snapshot_format *fmt;
+
+	for (fmt = cgit_snapshot_formats; fmt->suffix; fmt++) {
+		if (ends_with(filename, fmt->suffix))
+			return fmt;
+	}
+	return NULL;
+}
+
+const unsigned cgit_snapshot_format_bit(const struct cgit_snapshot_format *f)
+{
+	return BIT(f - &cgit_snapshot_formats[0]);
+}
+
+static int make_snapshot(const struct cgit_snapshot_format *format,
+			 const char *hex, const char *prefix,
+			 const char *filename)
+{
+	struct object_id oid;
+
+	if (get_oid(hex, &oid)) {
+		cgit_print_error_page(404, "Not found",
+				"Bad object id: %s", hex);
+		return 1;
+	}
+	if (!lookup_commit_reference(the_repository, &oid)) {
+		cgit_print_error_page(400, "Bad request",
+				"Not a commit reference: %s", hex);
+		return 1;
+	}
+	ctx.page.etag = oid_to_hex(&oid);
+	ctx.page.mimetype = xstrdup(format->mimetype);
+	ctx.page.filename = xstrdup(filename);
+	cgit_print_http_headers();
+	init_archivers();
+	format->write_func(hex, prefix);
+	return 0;
+}
+
+static int write_sig(const struct cgit_snapshot_format *format,
+		     const char *hex, const char *archive,
+		     const char *filename)
+{
+	const struct object_id *note = cgit_snapshot_get_sig(hex, format);
+	enum object_type type;
+	unsigned long size;
+	char *buf;
+
+	if (!note) {
+		cgit_print_error_page(404, "Not found",
+				"No signature for %s", archive);
+		return 0;
+	}
+
+	buf = read_object_file(note, &type, &size);
+	if (!buf) {
+		cgit_print_error_page(404, "Not found", "Not found");
+		return 0;
+	}
+
+	html("X-Content-Type-Options: nosniff\n");
+	html("Content-Security-Policy: default-src 'none'\n");
+	ctx.page.etag = oid_to_hex(note);
+	ctx.page.mimetype = xstrdup("application/pgp-signature");
+	ctx.page.filename = xstrdup(filename);
+	cgit_print_http_headers();
+
+	html_raw(buf, size);
+	free(buf);
+	return 0;
+}
+
+/* Try to guess the requested revision from the requested snapshot name.
+ * First the format extension is stripped, e.g. "cgit-0.7.2.tar.gz" become
+ * "cgit-0.7.2". If this is a valid commit object name we've got a winner.
+ * Otherwise, if the snapshot name has a prefix matching the result from
+ * repo_basename(), we strip the basename and any following '-' and '_'
+ * characters ("cgit-0.7.2" -> "0.7.2") and check the resulting name once
+ * more. If this still isn't a valid commit object name, we check if pre-
+ * pending a 'v' or a 'V' to the remaining snapshot name ("0.7.2" ->
+ * "v0.7.2") gives us something valid.
+ */
+static const char *get_ref_from_filename(const struct cgit_repo *repo,
+					 const char *filename,
+					 const struct cgit_snapshot_format *format)
+{
+	const char *reponame;
+	struct object_id oid;
+	struct strbuf snapshot = STRBUF_INIT;
+	int result = 1;
+
+	strbuf_addstr(&snapshot, filename);
+	strbuf_setlen(&snapshot, snapshot.len - strlen(format->suffix));
+
+	if (get_oid(snapshot.buf, &oid) == 0)
+		goto out;
+
+	reponame = cgit_snapshot_prefix(repo);
+	if (starts_with(snapshot.buf, reponame)) {
+		const char *new_start = snapshot.buf;
+		new_start += strlen(reponame);
+		while (new_start && (*new_start == '-' || *new_start == '_'))
+			new_start++;
+		strbuf_splice(&snapshot, 0, new_start - snapshot.buf, "", 0);
+	}
+
+	if (get_oid(snapshot.buf, &oid) == 0)
+		goto out;
+
+	strbuf_insert(&snapshot, 0, "v", 1);
+	if (get_oid(snapshot.buf, &oid) == 0)
+		goto out;
+
+	strbuf_splice(&snapshot, 0, 1, "V", 1);
+	if (get_oid(snapshot.buf, &oid) == 0)
+		goto out;
+
+	result = 0;
+	strbuf_release(&snapshot);
+
+out:
+	return result ? strbuf_detach(&snapshot, NULL) : NULL;
+}
+
+void cgit_print_snapshot(const char *head, const char *hex,
+			 const char *filename, int dwim)
+{
+	const struct cgit_snapshot_format* f;
+	const char *sig_filename = NULL;
+	char *adj_filename = NULL;
+	char *prefix = NULL;
+
+	if (!filename) {
+		cgit_print_error_page(400, "Bad request",
+				"No snapshot name specified");
+		return;
+	}
+
+	if (ends_with(filename, ".asc")) {
+		sig_filename = filename;
+
+		/* Strip ".asc" from filename for common format processing */
+		adj_filename = xstrdup(filename);
+		adj_filename[strlen(adj_filename) - 4] = '\0';
+		filename = adj_filename;
+	}
+
+	f = get_format(filename);
+	if (!f || (!sig_filename && !(ctx.repo->snapshots & cgit_snapshot_format_bit(f)))) {
+		cgit_print_error_page(400, "Bad request",
+				"Unsupported snapshot format: %s", filename);
+		return;
+	}
+
+	if (!hex && dwim) {
+		hex = get_ref_from_filename(ctx.repo, filename, f);
+		if (hex == NULL) {
+			cgit_print_error_page(404, "Not found", "Not found");
+			return;
+		}
+		prefix = xstrdup(filename);
+		prefix[strlen(filename) - strlen(f->suffix)] = '\0';
+	}
+
+	if (!hex)
+		hex = head;
+
+	if (!prefix)
+		prefix = xstrdup(cgit_snapshot_prefix(ctx.repo));
+
+	if (sig_filename)
+		write_sig(f, hex, filename, sig_filename);
+	else
+		make_snapshot(f, hex, prefix, filename);
+
+	free(prefix);
+	free(adj_filename);
+}