imap-send: drop global imap_server_conf variable

In "imap-send.c", we have a global `sturct imap_server_conf` variable
that keeps track of the configuration of the IMAP server. This variable
is being populated mostly via the Git configuration.

Refactor the code to allocate the structure on the stack instead of
having it globally. This change allows us to track its lifetime more
closely.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: pks-t

imap-send.c

@@ -82,10 +82,6 @@ struct imap_server_conf {
 	char *auth_method;
 };
 
-static struct imap_server_conf server = {
-	.ssl_verify = 1,
-};
-
 struct imap_socket {
 	int fd[2];
 	SSL *ssl;
@@ -110,6 +106,7 @@ struct imap {
 };
 
 struct imap_store {
+	const struct imap_server_conf *cfg;
 	/* currently open mailbox */
 	const char *name; /* foreign! maybe preset? */
 	int uidvalidity;
@@ -194,8 +191,8 @@ static void socket_perror(const char *func, struct imap_socket *sock, int ret)
 
 #ifdef NO_OPENSSL
 static int ssl_socket_connect(struct imap_socket *sock UNUSED,
-			      int use_tls_only UNUSED,
-			      int verify UNUSED)
+			      const struct imap_server_conf *cfg,
+			      int use_tls_only UNUSED)
 {
 	fprintf(stderr, "SSL requested but SSL support not compiled in\n");
 	return -1;
@@ -250,7 +247,9 @@ static int verify_hostname(X509 *cert, const char *hostname)
 		     cname, hostname);
 }
 
-static int ssl_socket_connect(struct imap_socket *sock, int use_tls_only, int verify)
+static int ssl_socket_connect(struct imap_socket *sock,
+			      const struct imap_server_conf *cfg,
+			      int use_tls_only)
 {
 #if (OPENSSL_VERSION_NUMBER >= 0x10000000L)
 	const SSL_METHOD *meth;
@@ -279,7 +278,7 @@ static int ssl_socket_connect(struct imap_socket *sock, int use_tls_only, int ve
 	if (use_tls_only)
 		SSL_CTX_set_options(ctx, SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3);
 
-	if (verify)
+	if (cfg->ssl_verify)
 		SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER, NULL);
 
 	if (!SSL_CTX_set_default_verify_paths(ctx)) {
@@ -306,9 +305,9 @@ static int ssl_socket_connect(struct imap_socket *sock, int use_tls_only, int ve
 	 * OpenSSL does not document this function, but the implementation
 	 * returns 1 on success, 0 on failure after calling SSLerr().
 	 */
-	ret = SSL_set_tlsext_host_name(sock->ssl, server.host);
+	ret = SSL_set_tlsext_host_name(sock->ssl, cfg->host);
 	if (ret != 1)
-		warning("SSL_set_tlsext_host_name(%s) failed.", server.host);
+		warning("SSL_set_tlsext_host_name(%s) failed.", cfg->host);
 #endif
 
 	ret = SSL_connect(sock->ssl);
@@ -317,12 +316,12 @@ static int ssl_socket_connect(struct imap_socket *sock, int use_tls_only, int ve
 		return -1;
 	}
 
-	if (verify) {
+	if (cfg->ssl_verify) {
 		/* make sure the hostname matches that of the certificate */
 		cert = SSL_get_peer_certificate(sock->ssl);
 		if (!cert)
 			return error("unable to get peer certificate.");
-		if (verify_hostname(cert, server.host) < 0)
+		if (verify_hostname(cert, cfg->host) < 0)
 			return -1;
 	}
 
@@ -895,7 +894,7 @@ static int auth_cram_md5(struct imap_store *ctx, const char *prompt)
 	int ret;
 	char *response;
 
-	response = cram(prompt, server.user, server.pass);
+	response = cram(prompt, ctx->cfg->user, ctx->cfg->pass);
 
 	ret = socket_write(&ctx->imap->buf.sock, response, strlen(response));
 	if (ret != strlen(response))
@@ -935,6 +934,7 @@ static struct imap_store *imap_open_store(struct imap_server_conf *srvc, const c
 
 	CALLOC_ARRAY(ctx, 1);
 
+	ctx->cfg = srvc;
 	ctx->imap = CALLOC_ARRAY(imap, 1);
 	imap->buf.sock.fd[0] = imap->buf.sock.fd[1] = -1;
 	imap->in_progress_append = &imap->in_progress;
@@ -1035,7 +1035,7 @@ static struct imap_store *imap_open_store(struct imap_server_conf *srvc, const c
 		imap->buf.sock.fd[1] = dup(s);
 
 		if (srvc->use_ssl &&
-		    ssl_socket_connect(&imap->buf.sock, 0, srvc->ssl_verify)) {
+		    ssl_socket_connect(&imap->buf.sock, srvc, 0)) {
 			close(s);
 			goto bail;
 		}
@@ -1068,8 +1068,7 @@ static struct imap_store *imap_open_store(struct imap_server_conf *srvc, const c
 		if (!srvc->use_ssl && CAP(STARTTLS)) {
 			if (imap_exec(ctx, NULL, "STARTTLS") != RESP_OK)
 				goto bail;
-			if (ssl_socket_connect(&imap->buf.sock, 1,
-					       srvc->ssl_verify))
+			if (ssl_socket_connect(&imap->buf.sock, srvc, 1))
 				goto bail;
 			/* capabilities may have changed, so get the new capabilities */
 			if (imap_exec(ctx, NULL, "CAPABILITY") != RESP_OK)
@@ -1299,23 +1298,24 @@ static int split_msg(struct strbuf *all_msgs, struct strbuf *msg, int *ofs)
 static int git_imap_config(const char *var, const char *val,
 			   const struct config_context *ctx, void *cb)
 {
+	struct imap_server_conf *cfg = cb;
 
 	if (!strcmp("imap.sslverify", var))
-		server.ssl_verify = git_config_bool(var, val);
+		cfg->ssl_verify = git_config_bool(var, val);
 	else if (!strcmp("imap.preformattedhtml", var))
-		server.use_html = git_config_bool(var, val);
+		cfg->use_html = git_config_bool(var, val);
 	else if (!strcmp("imap.folder", var))
-		return git_config_string(&server.folder, var, val);
+		return git_config_string(&cfg->folder, var, val);
 	else if (!strcmp("imap.user", var))
-		return git_config_string(&server.user, var, val);
+		return git_config_string(&cfg->user, var, val);
 	else if (!strcmp("imap.pass", var))
-		return git_config_string(&server.pass, var, val);
+		return git_config_string(&cfg->pass, var, val);
 	else if (!strcmp("imap.tunnel", var))
-		return git_config_string(&server.tunnel, var, val);
+		return git_config_string(&cfg->tunnel, var, val);
 	else if (!strcmp("imap.authmethod", var))
-		return git_config_string(&server.auth_method, var, val);
+		return git_config_string(&cfg->auth_method, var, val);
 	else if (!strcmp("imap.port", var))
-		server.port = git_config_int(var, val, ctx->kvi);
+		cfg->port = git_config_int(var, val, ctx->kvi);
 	else if (!strcmp("imap.host", var)) {
 		if (!val) {
 			return config_error_nonbool(var);
@@ -1324,11 +1324,11 @@ static int git_imap_config(const char *var, const char *val,
 				val += 5;
 			else if (starts_with(val, "imaps:")) {
 				val += 6;
-				server.use_ssl = 1;
+				cfg->use_ssl = 1;
 			}
 			if (starts_with(val, "//"))
 				val += 2;
-			server.host = xstrdup(val);
+			cfg->host = xstrdup(val);
 		}
 	} else
 		return git_default_config(var, val, ctx, cb);
@@ -1497,12 +1497,15 @@ static int curl_append_msgs_to_imap(struct imap_server_conf *server,
 
 int cmd_main(int argc, const char **argv)
 {
+	struct imap_server_conf server = {
+		.ssl_verify = 1,
+	};
 	struct strbuf all_msgs = STRBUF_INIT;
 	int total;
 	int nongit_ok;
 
 	setup_git_directory_gently(&nongit_ok);
-	git_config(git_imap_config, NULL);
+	git_config(git_imap_config, &server);
 
 	argc = parse_options(argc, (const char **)argv, "", imap_send_options, imap_send_usage, 0);