From 9efa856065494eb48e6e69ed0966187e43355d91 Mon Sep 17 00:00:00 2001
From: Greg Alexander <gitgreg@galexander.org>
Date: Wed, 16 May 2018 16:23:12 -0400
Subject: [PATCH] add option to set environment variables

---
 NOTES                                         |  1 -
 dropbear/dbutil.c                             | 46 +++++++++++++++++++
 jni/config.h                                  |  1 +
 jni/interface.c                               |  5 +-
 res/xml/preferences.xml                       |  5 ++
 src/org/galexander/sshd/Prefs.java            |  3 ++
 .../galexander/sshd/SimpleSSHDService.java    |  5 +-
 7 files changed, 61 insertions(+), 5 deletions(-)

diff --git a/NOTES b/NOTES
index daa8c09..fa1c1d6 100644
--- a/NOTES
+++ b/NOTES
@@ -530,7 +530,6 @@ environment...just one name=value per line.
 
 
 XXX - document su change
-XXX - add environment variable option (one name=value per line, just passed into setenv())
 XXX - document environment variables
 
 
diff --git a/dropbear/dbutil.c b/dropbear/dbutil.c
index 6e57613..13c9c7b 100644
--- a/dropbear/dbutil.c
+++ b/dropbear/dbutil.c
@@ -570,6 +570,50 @@ int spawn_command(void(*exec_fn)(void *user_data), void *exec_data,
 	}
 }
 
+
+static void
+install_environment(void)
+{
+	char *s = conf_env;
+	if (!s) {
+		return;
+	}
+	while (*s) {
+		char *name, *val;
+		int name_len, val_len;
+
+		name = s;
+		while (*s && (*s != '=') && (*s != '\r') && (*s != '\n')) {
+			s++;
+		}
+		name_len = s-name;
+		if (*s == '=') {
+			s++;
+			val = s;
+			while (*s && (*s != '\r') && (*s != '\n')) {
+				s++;
+			}
+			val_len = s-val;
+		} else {
+			val = "";
+			val_len = 0;
+		}
+		while ((*s == '\r') || (*s == '\n')) {
+			s++;
+		}
+		if (name_len) {
+			char *n = m_malloc(name_len+1);
+			char *v = m_malloc(val_len+1);
+			memcpy(n, name, name_len);
+			memcpy(v, val, val_len);
+			n[name_len] = 0;
+			v[val_len] = 0;
+			setenv(n, v, /*overwrite=*/1);	/* might fail *shrug* */
+		}
+	}
+}
+
+
 /* Runs a command with "sh -c". Will close FDs (except stdin/stdout/stderr) and
  * re-enabled SIGPIPE. If cmd is NULL, will run a login shell.
  */
@@ -626,6 +670,8 @@ void run_shell_command(const char* cmd, unsigned int maxfd, char* usershell) {
 		m_close(i);
 	}
 
+	install_environment();
+
 	execv(usershell, argv);
 }
 
diff --git a/jni/config.h b/jni/config.h
index 6746888..1e0ce2d 100644
--- a/jni/config.h
+++ b/jni/config.h
@@ -41,6 +41,7 @@ extern const char *conf_shell;
 extern const char *conf_home;
 const char *conf_path_file(const char *fn);
 extern int conf_rsyncbuffer;
+extern const char *conf_env;
 
 
 #endif /* __CONFIG_H__ */
diff --git a/jni/interface.c b/jni/interface.c
index b8cdc5a..8d1ee19 100644
--- a/jni/interface.c
+++ b/jni/interface.c
@@ -9,7 +9,7 @@
 #include <fcntl.h>
 #include <ctype.h>
 
-const char *conf_path = "", *conf_shell = "", *conf_home = "";
+const char *conf_path = "", *conf_shell = "", *conf_home = "", *conf_env = "";
 int conf_rsyncbuffer = 0;
 
 /* NB - this will leak memory like crazy if called often.... */
@@ -116,7 +116,7 @@ JNIEXPORT jint JNICALL
 Java_org_galexander_sshd_SimpleSSHDService_start_1sshd(JNIEnv *env_,
 	jclass cl,
 	jint port, jobject jpath, jobject jshell, jobject jhome, jobject jextra,
-	jint rsyncbuffer)
+	jint rsyncbuffer, jobject jenv)
 {
 	pid_t pid;
 	const char *extra;
@@ -129,6 +129,7 @@ Java_org_galexander_sshd_SimpleSSHDService_start_1sshd(JNIEnv *env_,
 	conf_home = from_java_string(jhome);
 	extra = from_java_string(jextra);
 	conf_rsyncbuffer = rsyncbuffer;
+	conf_env = from_java_string(jenv);
 
 	pid = fork();
 	if (pid == 0) {
diff --git a/res/xml/preferences.xml b/res/xml/preferences.xml
index 2c14afa..6d1d760 100644
--- a/res/xml/preferences.xml
+++ b/res/xml/preferences.xml
@@ -44,4 +44,9 @@
 	android:title="Extra Commandline"
 	android:summary="Commandline options for dropbear server"
 	android:defaultValue="" />
+    <EditTextPreference
+	android:key="env"
+	android:title="Environment Variables"
+	android:summary="Environment variables (one &quot;name=value&quot; per line)."
+	android:defaultValue="" />
 </PreferenceScreen>
diff --git a/src/org/galexander/sshd/Prefs.java b/src/org/galexander/sshd/Prefs.java
index 7b0f425..7d8260f 100644
--- a/src/org/galexander/sshd/Prefs.java
+++ b/src/org/galexander/sshd/Prefs.java
@@ -46,6 +46,9 @@ public class Prefs {
 	public static String get_extra() {
 		return pref.getString("extra", "");
 	}
+	public static String get_env() {
+		return pref.getString("env", "");
+	}
 
 	public static SharedPreferences.Editor edit() {
 		return pref.edit();
diff --git a/src/org/galexander/sshd/SimpleSSHDService.java b/src/org/galexander/sshd/SimpleSSHDService.java
index d7a33bc..e048bad 100644
--- a/src/org/galexander/sshd/SimpleSSHDService.java
+++ b/src/org/galexander/sshd/SimpleSSHDService.java
@@ -129,7 +129,8 @@ public class SimpleSSHDService extends Service {
 		final int pid = start_sshd(Prefs.get_port(),
 			Prefs.get_path(), Prefs.get_shell(),
 			Prefs.get_home(), Prefs.get_extra(),
-			(Prefs.get_rsyncbuffer() ? 1 : 0));
+			(Prefs.get_rsyncbuffer() ? 1 : 0),
+			Prefs.get_env());
 
 		long now = System.currentTimeMillis();
 		if (pid != 0) {
@@ -178,7 +179,7 @@ public class SimpleSSHDService extends Service {
 
 	private static native int start_sshd(int port, String path,
 			String shell, String home, String extra,
-			int rsyncbuffer);
+			int rsyncbuffer, String env);
 	private static native void kill(int pid);
 	private static native int waitpid(int pid);
 	static {