New setting: Read password from external command

Closes #314.

5 files changed, 82 insertions, 8 deletions

diff --git a/contrib/config-example b/contrib/config-example
index f52d3a0..dbc8cc5 100644
--- a/contrib/config-example
+++ b/contrib/config-example
@@ -5,6 +5,8 @@
 # User
 #user = your@user.name
 #password = password
+# or
+#password_command = gpg --decrypt ~/password
 
 # Proxy (for those who are not living in the USA)
 #control_proxy = http://127.0.0.1:9090/
diff --git a/contrib/pianobar.1 b/contrib/pianobar.1
index 4cc6d00..53bb301 100644
--- a/contrib/pianobar.1
+++ b/contrib/pianobar.1
@@ -297,6 +297,12 @@ Icon for loved songs.
 Your pandora.com password. Plain-text.
 
 .TP
+.B password_command = gpg --decrypt ~/password
+Use output of command as password. This setting is overridden by specifying a
+password with
+.B password.
+
+.TP
 .B proxy = http://user:password@host:port/
 Use a http proxy. Note that this setting overrides the http_proxy environment
 variable. Only "Basic" http authentication is supported.
diff --git a/src/main.c b/src/main.c
index 1d24167..2465334 100644
--- a/src/main.c
+++ b/src/main.c
@@ -31,6 +31,7 @@ THE SOFTWARE.
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
+/* fork () */
 #include <unistd.h>
 #include <sys/select.h>
 #include <time.h>
@@ -46,6 +47,10 @@ THE SOFTWARE.
 #include <stdbool.h>
 #include <limits.h>
 #include <signal.h>
+/* waitpid () */
+#include <sys/types.h>
+#include <sys/wait.h>
+
 
 /* pandora.com library */
 #include <piano.h>
@@ -92,22 +97,78 @@ static bool BarMainLoginUser (BarApp_t *app) {
 
 /*	ask for username/password if none were provided in settings
  */
-static void BarMainGetLoginCredentials (BarSettings_t *settings,
+static bool BarMainGetLoginCredentials (BarSettings_t *settings,
 		BarReadlineFds_t *input) {
 	if (settings->username == NULL) {
 		char nameBuf[100];
+
 		BarUiMsg (settings, MSG_QUESTION, "Email: ");
 		BarReadlineStr (nameBuf, sizeof (nameBuf), input, BAR_RL_DEFAULT);
 		settings->username = strdup (nameBuf);
 	}
+
 	if (settings->password == NULL) {
 		char passBuf[100];
-		BarUiMsg (settings, MSG_QUESTION, "Password: ");
-		BarReadlineStr (passBuf, sizeof (passBuf), input, BAR_RL_NOECHO);
-		/* write missing newline */
-		puts ("");
-		settings->password = strdup (passBuf);
+
+		if (settings->passwordCmd == NULL) {
+			BarUiMsg (settings, MSG_QUESTION, "Password: ");
+			BarReadlineStr (passBuf, sizeof (passBuf), input, BAR_RL_NOECHO);
+			/* write missing newline */
+			puts ("");
+			settings->password = strdup (passBuf);
+		} else {
+			pid_t chld;
+			int pipeFd[2];
+
+			BarUiMsg (settings, MSG_INFO, "Requesting password from external helper... ");
+
+			if (pipe (pipeFd) == -1) {
+				BarUiMsg (settings, MSG_NONE, "Error: %s\n", strerror (errno));
+				return false;
+			}
+
+			chld = fork ();
+			if (chld == 0) {
+				/* child */
+				close (pipeFd[0]);
+				dup2 (pipeFd[1], fileno (stdout));
+				execl ("/bin/sh", "/bin/sh", "-c", settings->passwordCmd, (char *) NULL);
+				BarUiMsg (settings, MSG_NONE, "Error: %s\n", strerror (errno));
+				close (pipeFd[1]);
+				exit (1);
+			} else if (chld == -1) {
+				BarUiMsg (settings, MSG_NONE, "Error: %s\n", strerror (errno));
+				return false;
+			} else {
+				/* parent */
+				int status;
+
+				close (pipeFd[1]);
+				memset (passBuf, 0, sizeof (passBuf));
+				read (pipeFd[0], passBuf, sizeof (passBuf)-1);
+				close (pipeFd[0]);
+
+				/* drop trailing newlines */
+				ssize_t len = strlen (passBuf)-1;
+				while (len >= 0 && passBuf[len] == '\n') {
+					passBuf[len] = '\0';
+					--len;
+				}
+
+				waitpid (chld, &status, 0);
+				if (WEXITSTATUS (status) == 0) {
+					settings->password = strdup (passBuf);
+					BarUiMsg (settings, MSG_NONE, "Ok.\n");
+				} else {
+					BarUiMsg (settings, MSG_NONE, "Error: Exit status %i.\n", WEXITSTATUS (status));
+					return false;
+				}
+			}
+
+		}
 	}
+
+	return true;
 }
 
 /*	get station list
@@ -270,7 +331,9 @@ static void BarMainPrintTime (BarApp_t *app) {
 static void BarMainLoop (BarApp_t *app) {
 	pthread_t playerThread;
 
-	BarMainGetLoginCredentials (&app->settings, &app->input);
+	if (!BarMainGetLoginCredentials (&app->settings, &app->input)) {
+		return;
+	}
 
 	BarMainLoadProxy (&app->settings, &app->waith);
 
diff --git a/src/settings.c b/src/settings.c
index c8bcbfe..014c561 100644
--- a/src/settings.c
+++ b/src/settings.c
@@ -86,6 +86,7 @@ void BarSettingsDestroy (BarSettings_t *settings) {
 	free (settings->proxy);
 	free (settings->username);
 	free (settings->password);
+	free (settings->passwordCmd);
 	free (settings->autostartStation);
 	free (settings->eventCmd);
 	free (settings->loveIcon);
@@ -189,6 +190,8 @@ void BarSettingsRead (BarSettings_t *settings) {
 				settings->username = strdup (val);
 			} else if (streq ("password", key)) {
 				settings->password = strdup (val);
+			} else if (streq ("password_command", key)) {
+				settings->passwordCmd = strdup (val);
 			} else if (streq ("rpc_host", key)) {
 				free (settings->rpcHost);
 				settings->rpcHost = strdup (val);
diff --git a/src/settings.h b/src/settings.h
index 0f4c6de..30915c2 100644
--- a/src/settings.h
+++ b/src/settings.h
@@ -87,7 +87,7 @@ typedef struct {
 	BarStationSorting_t sortOrder;
 	PianoAudioQuality_t audioQuality;
 	char *username;
-	char *password;
+	char *password, *passwordCmd;
 	char *controlProxy; /* non-american listeners need this */
 	char *proxy;
 	char *autostartStation;