merge(third_party/git): Merge squashed git subtree at v2.23.0

Merge commit '1b593e1ea4' as 'third_party/git'

third_party/git/builtin/remote-ext.c

@@ -0,0 +1,202 @@
+#include "builtin.h"
+#include "transport.h"
+#include "run-command.h"
+#include "pkt-line.h"
+
+static const char usage_msg[] =
+	"git remote-ext <remote> <url>";
+
+/*
+ * URL syntax:
+ *	'command [arg1 [arg2 [...]]]'	Invoke command with given arguments.
+ *	Special characters:
+ *	'% ': Literal space in argument.
+ *	'%%': Literal percent sign.
+ *	'%S': Name of service (git-upload-pack/git-upload-archive/
+ *		git-receive-pack.
+ *	'%s': Same as \s, but with possible git- prefix stripped.
+ *	'%G': Only allowed as first 'character' of argument. Do not pass this
+ *		Argument to command, instead send this as name of repository
+ *		in in-line git://-style request (also activates sending this
+ *		style of request).
+ *	'%V': Only allowed as first 'character' of argument. Used in
+ *		conjunction with '%G': Do not pass this argument to command,
+ *		instead send this as vhost in git://-style request (note: does
+ *		not activate sending git:// style request).
+ */
+
+static char *git_req;
+static char *git_req_vhost;
+
+static char *strip_escapes(const char *str, const char *service,
+	const char **next)
+{
+	size_t rpos = 0;
+	int escape = 0;
+	char special = 0;
+	const char *service_noprefix = service;
+	struct strbuf ret = STRBUF_INIT;
+
+	skip_prefix(service_noprefix, "git-", &service_noprefix);
+
+	/* Pass the service to command. */
+	setenv("GIT_EXT_SERVICE", service, 1);
+	setenv("GIT_EXT_SERVICE_NOPREFIX", service_noprefix, 1);
+
+	/* Scan the length of argument. */
+	while (str[rpos] && (escape || str[rpos] != ' ')) {
+		if (escape) {
+			switch (str[rpos]) {
+			case ' ':
+			case '%':
+			case 's':
+			case 'S':
+				break;
+			case 'G':
+			case 'V':
+				special = str[rpos];
+				if (rpos == 1)
+					break;
+				/* fallthrough */
+			default:
+				die("Bad remote-ext placeholder '%%%c'.",
+					str[rpos]);
+			}
+			escape = 0;
+		} else
+			escape = (str[rpos] == '%');
+		rpos++;
+	}
+	if (escape && !str[rpos])
+		die("remote-ext command has incomplete placeholder");
+	*next = str + rpos;
+	if (**next == ' ')
+		++*next;	/* Skip over space */
+
+	/*
+	 * Do the actual placeholder substitution. The string will be short
+	 * enough not to overflow integers.
+	 */
+	rpos = special ? 2 : 0;		/* Skip first 2 bytes in specials. */
+	escape = 0;
+	while (str[rpos] && (escape || str[rpos] != ' ')) {
+		if (escape) {
+			switch (str[rpos]) {
+			case ' ':
+			case '%':
+				strbuf_addch(&ret, str[rpos]);
+				break;
+			case 's':
+				strbuf_addstr(&ret, service_noprefix);
+				break;
+			case 'S':
+				strbuf_addstr(&ret, service);
+				break;
+			}
+			escape = 0;
+		} else
+			switch (str[rpos]) {
+			case '%':
+				escape = 1;
+				break;
+			default:
+				strbuf_addch(&ret, str[rpos]);
+				break;
+			}
+		rpos++;
+	}
+	switch (special) {
+	case 'G':
+		git_req = strbuf_detach(&ret, NULL);
+		return NULL;
+	case 'V':
+		git_req_vhost = strbuf_detach(&ret, NULL);
+		return NULL;
+	default:
+		return strbuf_detach(&ret, NULL);
+	}
+}
+
+static void parse_argv(struct argv_array *out, const char *arg, const char *service)
+{
+	while (*arg) {
+		char *expanded = strip_escapes(arg, service, &arg);
+		if (expanded)
+			argv_array_push(out, expanded);
+		free(expanded);
+	}
+}
+
+static void send_git_request(int stdin_fd, const char *serv, const char *repo,
+	const char *vhost)
+{
+	if (!vhost)
+		packet_write_fmt(stdin_fd, "%s %s%c", serv, repo, 0);
+	else
+		packet_write_fmt(stdin_fd, "%s %s%chost=%s%c", serv, repo, 0,
+			     vhost, 0);
+}
+
+static int run_child(const char *arg, const char *service)
+{
+	int r;
+	struct child_process child = CHILD_PROCESS_INIT;
+
+	child.in = -1;
+	child.out = -1;
+	child.err = 0;
+	parse_argv(&child.args, arg, service);
+
+	if (start_command(&child) < 0)
+		die("Can't run specified command");
+
+	if (git_req)
+		send_git_request(child.in, service, git_req, git_req_vhost);
+
+	r = bidirectional_transfer_loop(child.out, child.in);
+	if (!r)
+		r = finish_command(&child);
+	else
+		finish_command(&child);
+	return r;
+}
+
+#define MAXCOMMAND 4096
+
+static int command_loop(const char *child)
+{
+	char buffer[MAXCOMMAND];
+
+	while (1) {
+		size_t i;
+		if (!fgets(buffer, MAXCOMMAND - 1, stdin)) {
+			if (ferror(stdin))
+				die("Command input error");
+			exit(0);
+		}
+		/* Strip end of line characters. */
+		i = strlen(buffer);
+		while (i > 0 && isspace(buffer[i - 1]))
+			buffer[--i] = 0;
+
+		if (!strcmp(buffer, "capabilities")) {
+			printf("*connect\n\n");
+			fflush(stdout);
+		} else if (!strncmp(buffer, "connect ", 8)) {
+			printf("\n");
+			fflush(stdout);
+			return run_child(child, buffer + 8);
+		} else {
+			fprintf(stderr, "Bad command");
+			return 1;
+		}
+	}
+}
+
+int cmd_remote_ext(int argc, const char **argv, const char *prefix)
+{
+	if (argc != 3)
+		usage(usage_msg);
+
+	return command_loop(argv[2]);
+}