contrib/credential/gnome-keyring/git-credential-gnome-keyring.c - jrn/git - Git at Google

 /*
  * Copyright (C) 2011 John Szakmeister <john@szakmeister.net>
  *               2012 Philipp A. Hartmann <pah@qo.cx>
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
  *  the Free Software Foundation; either version 2 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 General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License
  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
  */

 /*
  * Credits:
  * - GNOME Keyring API handling originally written by John Szakmeister
  * - ported to credential helper API by Philipp A. Hartmann
  */

 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
 #include <glib.h>
 #include <gnome-keyring.h>

 #ifdef GNOME_KEYRING_DEFAULT

    /* Modern gnome-keyring */

 #include <gnome-keyring-memory.h>

 #else

    /*
     * Support ancient gnome-keyring, circ. RHEL 5.X.
     * GNOME_KEYRING_DEFAULT seems to have been introduced with Gnome 2.22,
     * and the other features roughly around Gnome 2.20, 6 months before.
     * Ubuntu 8.04 used Gnome 2.22 (I think).  Not sure any distro used 2.20.
     * So the existence/non-existence of GNOME_KEYRING_DEFAULT seems like
     * a decent thing to use as an indicator.
     */

 #define GNOME_KEYRING_DEFAULT NULL

 /*
  * ancient gnome-keyring returns DENIED when an entry is not found.
  * Setting NO_MATCH to DENIED will prevent us from reporting DENIED
  * errors during get and erase operations, but we will still report
  * DENIED errors during a store.
  */
 #define GNOME_KEYRING_RESULT_NO_MATCH GNOME_KEYRING_RESULT_DENIED

 #define gnome_keyring_memory_alloc g_malloc
 #define gnome_keyring_memory_free gnome_keyring_free_password
 #define gnome_keyring_memory_strdup g_strdup

 static const char *gnome_keyring_result_to_message(GnomeKeyringResult result)
 {
 	switch (result) {
 	case GNOME_KEYRING_RESULT_OK:
 		return "OK";
 	case GNOME_KEYRING_RESULT_DENIED:
 		return "Denied";
 	case GNOME_KEYRING_RESULT_NO_KEYRING_DAEMON:
 		return "No Keyring Daemon";
 	case GNOME_KEYRING_RESULT_ALREADY_UNLOCKED:
 		return "Already UnLocked";
 	case GNOME_KEYRING_RESULT_NO_SUCH_KEYRING:
 		return "No Such Keyring";
 	case GNOME_KEYRING_RESULT_BAD_ARGUMENTS:
 		return "Bad Arguments";
 	case GNOME_KEYRING_RESULT_IO_ERROR:
 		return "IO Error";
 	case GNOME_KEYRING_RESULT_CANCELLED:
 		return "Cancelled";
 	case GNOME_KEYRING_RESULT_ALREADY_EXISTS:
 		return "Already Exists";
 	default:
 		return "Unknown Error";
 	}
 }

 /*
  * Support really ancient gnome-keyring, circ. RHEL 4.X.
  * Just a guess for the Glib version.  Glib 2.8 was roughly Gnome 2.12 ?
  * Which was released with gnome-keyring 0.4.3 ??
  */
 #if GLIB_MAJOR_VERSION == 2 && GLIB_MINOR_VERSION < 8

 static void gnome_keyring_done_cb(GnomeKeyringResult result, gpointer user_data)
 {
 	gpointer *data = (gpointer *)user_data;
 	int *done = (int *)data[0];
 	GnomeKeyringResult *r = (GnomeKeyringResult *)data[1];

 	*r = result;
 	*done = 1;
 }

 static void wait_for_request_completion(int *done)
 {
 	GMainContext *mc = g_main_context_default();
 	while (!*done)
 		g_main_context_iteration(mc, TRUE);
 }

 static GnomeKeyringResult gnome_keyring_item_delete_sync(const char *keyring, guint32 id)
 {
 	int done = 0;
 	GnomeKeyringResult result;
 	gpointer data[] = { &done, &result };

 	gnome_keyring_item_delete(keyring, id, gnome_keyring_done_cb, data,
 		NULL);

 	wait_for_request_completion(&done);

 	return result;
 }

 #endif
 #endif

 /*
  * This credential struct and API is simplified from git's credential.{h,c}
  */
 struct credential {
 	char *protocol;
 	char *host;
 	unsigned short port;
 	char *path;
 	char *username;
 	char *password;
 };

 #define CREDENTIAL_INIT { NULL, NULL, 0, NULL, NULL, NULL }

 typedef int (*credential_op_cb)(struct credential *);

 struct credential_operation {
 	char *name;
 	credential_op_cb op;
 };

 #define CREDENTIAL_OP_END { NULL, NULL }

 /* ----------------- GNOME Keyring functions ----------------- */

 /* create a special keyring option string, if path is given */
 static char *keyring_object(struct credential *c)
 {
 	if (!c->path)
 		return NULL;

 	if (c->port)
 		return g_strdup_printf("%s:%hd/%s", c->host, c->port, c->path);

 	return g_strdup_printf("%s/%s", c->host, c->path);
 }

 static int keyring_get(struct credential *c)
 {
 	char *object = NULL;
 	GList *entries;
 	GnomeKeyringNetworkPasswordData *password_data;
 	GnomeKeyringResult result;

 	if (!c->protocol || !(c->host || c->path))
 		return EXIT_FAILURE;

 	object = keyring_object(c);

 	result = gnome_keyring_find_network_password_sync(
 				c->username,
 				NULL /* domain */,
 				c->host,
 				object,
 				c->protocol,
 				NULL /* authtype */,
 				c->port,
 				&entries);

 	g_free(object);

 	if (result == GNOME_KEYRING_RESULT_NO_MATCH)
 		return EXIT_SUCCESS;

 	if (result == GNOME_KEYRING_RESULT_CANCELLED)
 		return EXIT_SUCCESS;

 	if (result != GNOME_KEYRING_RESULT_OK) {
 		g_critical("%s", gnome_keyring_result_to_message(result));
 		return EXIT_FAILURE;
 	}

 	/* pick the first one from the list */
 	password_data = (GnomeKeyringNetworkPasswordData *)entries->data;

 	gnome_keyring_memory_free(c->password);
 	c->password = gnome_keyring_memory_strdup(password_data->password);

 	if (!c->username)
 		c->username = g_strdup(password_data->user);

 	gnome_keyring_network_password_list_free(entries);

 	return EXIT_SUCCESS;
 }


 static int keyring_store(struct credential *c)
 {
 	guint32 item_id;
 	char *object = NULL;
 	GnomeKeyringResult result;

 	/*
 	 * Sanity check that what we are storing is actually sensible.
 	 * In particular, we can't make a URL without a protocol field.
 	 * Without either a host or pathname (depending on the scheme),
 	 * we have no primary key. And without a username and password,
 	 * we are not actually storing a credential.
 	 */
 	if (!c->protocol || !(c->host || c->path) ||
 	    !c->username || !c->password)
 		return EXIT_FAILURE;

 	object = keyring_object(c);

 	result = gnome_keyring_set_network_password_sync(
 				GNOME_KEYRING_DEFAULT,
 				c->username,
 				NULL /* domain */,
 				c->host,
 				object,
 				c->protocol,
 				NULL /* authtype */,
 				c->port,
 				c->password,
 				&item_id);

 	g_free(object);

 	if (result != GNOME_KEYRING_RESULT_OK &&
 	    result != GNOME_KEYRING_RESULT_CANCELLED) {
 		g_critical("%s", gnome_keyring_result_to_message(result));
 		return EXIT_FAILURE;
 	}

 	return EXIT_SUCCESS;
 }

 static int keyring_erase(struct credential *c)
 {
 	char *object = NULL;
 	GList *entries;
 	GnomeKeyringNetworkPasswordData *password_data;
 	GnomeKeyringResult result;

 	/*
 	 * Sanity check that we actually have something to match
 	 * against. The input we get is a restrictive pattern,
 	 * so technically a blank credential means "erase everything".
 	 * But it is too easy to accidentally send this, since it is equivalent
 	 * to empty input. So explicitly disallow it, and require that the
 	 * pattern have some actual content to match.
 	 */
 	if (!c->protocol && !c->host && !c->path && !c->username)
 		return EXIT_FAILURE;

 	object = keyring_object(c);

 	result = gnome_keyring_find_network_password_sync(
 				c->username,
 				NULL /* domain */,
 				c->host,
 				object,
 				c->protocol,
 				NULL /* authtype */,
 				c->port,
 				&entries);

 	g_free(object);

 	if (result == GNOME_KEYRING_RESULT_NO_MATCH)
 		return EXIT_SUCCESS;

 	if (result == GNOME_KEYRING_RESULT_CANCELLED)
 		return EXIT_SUCCESS;

 	if (result != GNOME_KEYRING_RESULT_OK) {
 		g_critical("%s", gnome_keyring_result_to_message(result));
 		return EXIT_FAILURE;
 	}

 	/* pick the first one from the list (delete all matches?) */
 	password_data = (GnomeKeyringNetworkPasswordData *)entries->data;

 	result = gnome_keyring_item_delete_sync(
 		password_data->keyring, password_data->item_id);

 	gnome_keyring_network_password_list_free(entries);

 	if (result != GNOME_KEYRING_RESULT_OK) {
 		g_critical("%s", gnome_keyring_result_to_message(result));
 		return EXIT_FAILURE;
 	}

 	return EXIT_SUCCESS;
 }

 /*
  * Table with helper operation callbacks, used by generic
  * credential helper main function.
  */
 static struct credential_operation const credential_helper_ops[] = {
 	{ "get",   keyring_get },
 	{ "store", keyring_store },
 	{ "erase", keyring_erase },
 	CREDENTIAL_OP_END
 };

 /* ------------------ credential functions ------------------ */

 static void credential_init(struct credential *c)
 {
 	memset(c, 0, sizeof(*c));
 }

 static void credential_clear(struct credential *c)
 {
 	g_free(c->protocol);
 	g_free(c->host);
 	g_free(c->path);
 	g_free(c->username);
 	gnome_keyring_memory_free(c->password);

 	credential_init(c);
 }

 static int credential_read(struct credential *c)
 {
 	char *buf;
 	size_t line_len;
 	char *key;
 	char *value;

 	key = buf = gnome_keyring_memory_alloc(1024);

 	while (fgets(buf, 1024, stdin)) {
 		line_len = strlen(buf);

 		if (line_len && buf[line_len-1] == '\n')
 			buf[--line_len] = '\0';

 		if (!line_len)
 			break;

 		value = strchr(buf, '=');
 		if (!value) {
 			g_warning("invalid credential line: %s", key);
 			gnome_keyring_memory_free(buf);
 			return -1;
 		}
 		*value++ = '\0';

 		if (!strcmp(key, "protocol")) {
 			g_free(c->protocol);
 			c->protocol = g_strdup(value);
 		} else if (!strcmp(key, "host")) {
 			g_free(c->host);
 			c->host = g_strdup(value);
 			value = strrchr(c->host, ':');
 			if (value) {
 				*value++ = '\0';
 				c->port = atoi(value);
 			}
 		} else if (!strcmp(key, "path")) {
 			g_free(c->path);
 			c->path = g_strdup(value);
 		} else if (!strcmp(key, "username")) {
 			g_free(c->username);
 			c->username = g_strdup(value);
 		} else if (!strcmp(key, "password")) {
 			gnome_keyring_memory_free(c->password);
 			c->password = gnome_keyring_memory_strdup(value);
 			while (*value)
 				*value++ = '\0';
 		}
 		/*
 		 * Ignore other lines; we don't know what they mean, but
 		 * this future-proofs us when later versions of git do
 		 * learn new lines, and the helpers are updated to match.
 		 */
 	}

 	gnome_keyring_memory_free(buf);

 	return 0;
 }

 static void credential_write_item(FILE *fp, const char *key, const char *value)
 {
 	if (!value)
 		return;
 	fprintf(fp, "%s=%s\n", key, value);
 }

 static void credential_write(const struct credential *c)
 {
 	/* only write username/password, if set */
 	credential_write_item(stdout, "username", c->username);
 	credential_write_item(stdout, "password", c->password);
 }

 static void usage(const char *name)
 {
 	struct credential_operation const *try_op = credential_helper_ops;
 	const char *basename = strrchr(name, '/');

 	basename = (basename) ? basename + 1 : name;
 	fprintf(stderr, "usage: %s <", basename);
 	while (try_op->name) {
 		fprintf(stderr, "%s", (try_op++)->name);
 		if (try_op->name)
 			fprintf(stderr, "%s", "|");
 	}
 	fprintf(stderr, "%s", ">\n");
 }

 int main(int argc, char *argv[])
 {
 	int ret = EXIT_SUCCESS;

 	struct credential_operation const *try_op = credential_helper_ops;
 	struct credential cred = CREDENTIAL_INIT;

 	if (!argv[1]) {
 		usage(argv[0]);
 		exit(EXIT_FAILURE);
 	}

 	g_set_application_name("Git Credential Helper");

 	/* lookup operation callback */
 	while (try_op->name && strcmp(argv[1], try_op->name))
 		try_op++;

 	/* unsupported operation given -- ignore silently */
 	if (!try_op->name || !try_op->op)
 		goto out;

 	ret = credential_read(&cred);
 	if (ret)
 		goto out;

 	/* perform credential operation */
 	ret = (*try_op->op)(&cred);

 	credential_write(&cred);

 out:
 	credential_clear(&cred);
 	return ret;
 }
	/*
	* Copyright (C) 2011 John Szakmeister <john@szakmeister.net>
	* 2012 Philipp A. Hartmann <pah@qo.cx>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 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 General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, see <http://www.gnu.org/licenses/>.
	*/

	/*
	* Credits:
	* - GNOME Keyring API handling originally written by John Szakmeister
	* - ported to credential helper API by Philipp A. Hartmann
	*/

	#include <stdio.h>
	#include <string.h>
	#include <stdlib.h>
	#include <glib.h>
	#include <gnome-keyring.h>

	#ifdef GNOME_KEYRING_DEFAULT

	/* Modern gnome-keyring */

	#include <gnome-keyring-memory.h>

	#else

	/*
	* Support ancient gnome-keyring, circ. RHEL 5.X.
	* GNOME_KEYRING_DEFAULT seems to have been introduced with Gnome 2.22,
	* and the other features roughly around Gnome 2.20, 6 months before.
	* Ubuntu 8.04 used Gnome 2.22 (I think). Not sure any distro used 2.20.
	* So the existence/non-existence of GNOME_KEYRING_DEFAULT seems like
	* a decent thing to use as an indicator.
	*/

	#define GNOME_KEYRING_DEFAULT NULL

	/*
	* ancient gnome-keyring returns DENIED when an entry is not found.
	* Setting NO_MATCH to DENIED will prevent us from reporting DENIED
	* errors during get and erase operations, but we will still report
	* DENIED errors during a store.
	*/
	#define GNOME_KEYRING_RESULT_NO_MATCH GNOME_KEYRING_RESULT_DENIED

	#define gnome_keyring_memory_alloc g_malloc
	#define gnome_keyring_memory_free gnome_keyring_free_password
	#define gnome_keyring_memory_strdup g_strdup

	static const char *gnome_keyring_result_to_message(GnomeKeyringResult result)
	{
	switch (result) {
	case GNOME_KEYRING_RESULT_OK:
	return "OK";
	case GNOME_KEYRING_RESULT_DENIED:
	return "Denied";
	case GNOME_KEYRING_RESULT_NO_KEYRING_DAEMON:
	return "No Keyring Daemon";
	case GNOME_KEYRING_RESULT_ALREADY_UNLOCKED:
	return "Already UnLocked";
	case GNOME_KEYRING_RESULT_NO_SUCH_KEYRING:
	return "No Such Keyring";
	case GNOME_KEYRING_RESULT_BAD_ARGUMENTS:
	return "Bad Arguments";
	case GNOME_KEYRING_RESULT_IO_ERROR:
	return "IO Error";
	case GNOME_KEYRING_RESULT_CANCELLED:
	return "Cancelled";
	case GNOME_KEYRING_RESULT_ALREADY_EXISTS:
	return "Already Exists";
	default:
	return "Unknown Error";
	}
	}

	/*
	* Support really ancient gnome-keyring, circ. RHEL 4.X.
	* Just a guess for the Glib version. Glib 2.8 was roughly Gnome 2.12 ?
	* Which was released with gnome-keyring 0.4.3 ??
	*/
	#if GLIB_MAJOR_VERSION == 2 && GLIB_MINOR_VERSION < 8

	static void gnome_keyring_done_cb(GnomeKeyringResult result, gpointer user_data)
	{
	gpointer data = (gpointer )user_data;
	int done = (int )data[0];
	GnomeKeyringResult r = (GnomeKeyringResult )data[1];

	*r = result;
	*done = 1;
	}

	static void wait_for_request_completion(int *done)
	{
	GMainContext *mc = g_main_context_default();
	while (!*done)
	g_main_context_iteration(mc, TRUE);
	}

	static GnomeKeyringResult gnome_keyring_item_delete_sync(const char *keyring, guint32 id)
	{
	int done = 0;
	GnomeKeyringResult result;
	gpointer data[] = { &done, &result };

	gnome_keyring_item_delete(keyring, id, gnome_keyring_done_cb, data,
	NULL);

	wait_for_request_completion(&done);

	return result;
	}

	#endif
	#endif

	/*
	* This credential struct and API is simplified from git's credential.{h,c}
	*/
	struct credential {
	char *protocol;
	char *host;
	unsigned short port;
	char *path;
	char *username;
	char *password;
	};

	#define CREDENTIAL_INIT { NULL, NULL, 0, NULL, NULL, NULL }

	typedef int (credential_op_cb)(struct credential );

	struct credential_operation {
	char *name;
	credential_op_cb op;
	};

	#define CREDENTIAL_OP_END { NULL, NULL }

	/* ----------------- GNOME Keyring functions ----------------- */

	/* create a special keyring option string, if path is given */
	static char keyring_object(struct credential c)
	{
	if (!c->path)
	return NULL;

	if (c->port)
	return g_strdup_printf("%s:%hd/%s", c->host, c->port, c->path);

	return g_strdup_printf("%s/%s", c->host, c->path);
	}

	static int keyring_get(struct credential *c)
	{
	char *object = NULL;
	GList *entries;
	GnomeKeyringNetworkPasswordData *password_data;
	GnomeKeyringResult result;

	if (!c->protocol \|\| !(c->host \|\| c->path))
	return EXIT_FAILURE;

	object = keyring_object(c);

	result = gnome_keyring_find_network_password_sync(
	c->username,
	NULL /* domain */,
	c->host,
	object,
	c->protocol,
	NULL /* authtype */,
	c->port,
	&entries);

	g_free(object);

	if (result == GNOME_KEYRING_RESULT_NO_MATCH)
	return EXIT_SUCCESS;

	if (result == GNOME_KEYRING_RESULT_CANCELLED)
	return EXIT_SUCCESS;

	if (result != GNOME_KEYRING_RESULT_OK) {
	g_critical("%s", gnome_keyring_result_to_message(result));
	return EXIT_FAILURE;
	}

	/* pick the first one from the list */
	password_data = (GnomeKeyringNetworkPasswordData *)entries->data;

	gnome_keyring_memory_free(c->password);
	c->password = gnome_keyring_memory_strdup(password_data->password);

	if (!c->username)
	c->username = g_strdup(password_data->user);

	gnome_keyring_network_password_list_free(entries);

	return EXIT_SUCCESS;
	}


	static int keyring_store(struct credential *c)
	{
	guint32 item_id;
	char *object = NULL;
	GnomeKeyringResult result;

	/*
	* Sanity check that what we are storing is actually sensible.
	* In particular, we can't make a URL without a protocol field.
	* Without either a host or pathname (depending on the scheme),
	* we have no primary key. And without a username and password,
	* we are not actually storing a credential.
	*/
	if (!c->protocol \|\| !(c->host \|\| c->path) \|\|
	!c->username \|\| !c->password)
	return EXIT_FAILURE;

	object = keyring_object(c);

	result = gnome_keyring_set_network_password_sync(
	GNOME_KEYRING_DEFAULT,
	c->username,
	NULL /* domain */,
	c->host,
	object,
	c->protocol,
	NULL /* authtype */,
	c->port,
	c->password,
	&item_id);

	g_free(object);

	if (result != GNOME_KEYRING_RESULT_OK &&
	result != GNOME_KEYRING_RESULT_CANCELLED) {
	g_critical("%s", gnome_keyring_result_to_message(result));
	return EXIT_FAILURE;
	}

	return EXIT_SUCCESS;
	}

	static int keyring_erase(struct credential *c)
	{
	char *object = NULL;
	GList *entries;
	GnomeKeyringNetworkPasswordData *password_data;
	GnomeKeyringResult result;

	/*
	* Sanity check that we actually have something to match
	* against. The input we get is a restrictive pattern,
	* so technically a blank credential means "erase everything".
	* But it is too easy to accidentally send this, since it is equivalent
	* to empty input. So explicitly disallow it, and require that the
	* pattern have some actual content to match.
	*/
	if (!c->protocol && !c->host && !c->path && !c->username)
	return EXIT_FAILURE;

	object = keyring_object(c);

	result = gnome_keyring_find_network_password_sync(
	c->username,
	NULL /* domain */,
	c->host,
	object,
	c->protocol,
	NULL /* authtype */,
	c->port,
	&entries);

	g_free(object);

	if (result == GNOME_KEYRING_RESULT_NO_MATCH)
	return EXIT_SUCCESS;

	if (result == GNOME_KEYRING_RESULT_CANCELLED)
	return EXIT_SUCCESS;

	if (result != GNOME_KEYRING_RESULT_OK) {
	g_critical("%s", gnome_keyring_result_to_message(result));
	return EXIT_FAILURE;
	}

	/* pick the first one from the list (delete all matches?) */
	password_data = (GnomeKeyringNetworkPasswordData *)entries->data;

	result = gnome_keyring_item_delete_sync(
	password_data->keyring, password_data->item_id);

	gnome_keyring_network_password_list_free(entries);

	if (result != GNOME_KEYRING_RESULT_OK) {
	g_critical("%s", gnome_keyring_result_to_message(result));
	return EXIT_FAILURE;
	}

	return EXIT_SUCCESS;
	}

	/*
	* Table with helper operation callbacks, used by generic
	* credential helper main function.
	*/
	static struct credential_operation const credential_helper_ops[] = {
	{ "get", keyring_get },
	{ "store", keyring_store },
	{ "erase", keyring_erase },
	CREDENTIAL_OP_END
	};

	/* ------------------ credential functions ------------------ */

	static void credential_init(struct credential *c)
	{
	memset(c, 0, sizeof(*c));
	}

	static void credential_clear(struct credential *c)
	{
	g_free(c->protocol);
	g_free(c->host);
	g_free(c->path);
	g_free(c->username);
	gnome_keyring_memory_free(c->password);

	credential_init(c);
	}

	static int credential_read(struct credential *c)
	{
	char *buf;
	size_t line_len;
	char *key;
	char *value;

	key = buf = gnome_keyring_memory_alloc(1024);

	while (fgets(buf, 1024, stdin)) {
	line_len = strlen(buf);

	if (line_len && buf[line_len-1] == '\n')
	buf[--line_len] = '\0';

	if (!line_len)
	break;

	value = strchr(buf, '=');
	if (!value) {
	g_warning("invalid credential line: %s", key);
	gnome_keyring_memory_free(buf);
	return -1;
	}
	*value++ = '\0';

	if (!strcmp(key, "protocol")) {
	g_free(c->protocol);
	c->protocol = g_strdup(value);
	} else if (!strcmp(key, "host")) {
	g_free(c->host);
	c->host = g_strdup(value);
	value = strrchr(c->host, ':');
	if (value) {
	*value++ = '\0';
	c->port = atoi(value);
	}
	} else if (!strcmp(key, "path")) {
	g_free(c->path);
	c->path = g_strdup(value);
	} else if (!strcmp(key, "username")) {
	g_free(c->username);
	c->username = g_strdup(value);
	} else if (!strcmp(key, "password")) {
	gnome_keyring_memory_free(c->password);
	c->password = gnome_keyring_memory_strdup(value);
	while (*value)
	*value++ = '\0';
	}
	/*
	* Ignore other lines; we don't know what they mean, but
	* this future-proofs us when later versions of git do
	* learn new lines, and the helpers are updated to match.
	*/
	}

	gnome_keyring_memory_free(buf);

	return 0;
	}

	static void credential_write_item(FILE fp, const char key, const char *value)
	{
	if (!value)
	return;
	fprintf(fp, "%s=%s\n", key, value);
	}

	static void credential_write(const struct credential *c)
	{
	/* only write username/password, if set */
	credential_write_item(stdout, "username", c->username);
	credential_write_item(stdout, "password", c->password);
	}

	static void usage(const char *name)
	{
	struct credential_operation const *try_op = credential_helper_ops;
	const char *basename = strrchr(name, '/');

	basename = (basename) ? basename + 1 : name;
	fprintf(stderr, "usage: %s <", basename);
	while (try_op->name) {
	fprintf(stderr, "%s", (try_op++)->name);
	if (try_op->name)
	fprintf(stderr, "%s", "\|");
	}
	fprintf(stderr, "%s", ">\n");
	}

	int main(int argc, char *argv[])
	{
	int ret = EXIT_SUCCESS;

	struct credential_operation const *try_op = credential_helper_ops;
	struct credential cred = CREDENTIAL_INIT;

	if (!argv[1]) {
	usage(argv[0]);
	exit(EXIT_FAILURE);
	}

	g_set_application_name("Git Credential Helper");

	/* lookup operation callback */
	while (try_op->name && strcmp(argv[1], try_op->name))
	try_op++;

	/* unsupported operation given -- ignore silently */
	if (!try_op->name \|\| !try_op->op)
	goto out;

	ret = credential_read(&cred);
	if (ret)
	goto out;

	/* perform credential operation */
	ret = (*try_op->op)(&cred);

	credential_write(&cred);

	out:
	credential_clear(&cred);
	return ret;
	}