Fix misc. problems (#217)

- force external commands to english locale
- some string/mem fixes
- fix pusb_get_process_envvar() returning local variable

Maybe affected/fixed issues by this: #205, #199 - but needs testing/validation

src/local.c

@@ -117,6 +117,13 @@ char *pusb_get_tty_from_display_server(const char *display)
 				DIR *d_fd = opendir(fd_path);
 				if (d_fd == NULL) {
 					log_debug("	Determining tty by display server failed (running 'pamusb-check' as user?)\n", fd_path);
+
+					xfree(cmdline_path);
+					xfree(cmdline);
+					xfree(fd_path);
+					xfree(link_path);
+					xfree(fd_target);
+
 					return NULL;
 				}
 
@@ -136,6 +143,11 @@ char *pusb_get_tty_from_display_server(const char *display)
 								closedir(d_fd);
 								closedir(d_proc);
 
+								xfree(cmdline_path);
+								xfree(cmdline);
+								xfree(fd_path);
+								xfree(link_path);
+
 								return fd_target;
 							}
 						}
@@ -147,6 +159,12 @@ char *pusb_get_tty_from_display_server(const char *display)
 	}
 	closedir(d_proc);
 
+	xfree(cmdline_path);
+	xfree(cmdline);
+	xfree(fd_path);
+	xfree(link_path);
+	xfree(fd_target);
+
 	return NULL;
 }
 
@@ -177,7 +195,7 @@ char *pusb_get_tty_by_xorg_display(const char *display, const char *user)
 
 char *pusb_get_tty_by_loginctl()
 {
-	char loginctl_cmd[BUFSIZ] = "LOGINCTL_SESSION_ID=`loginctl user-status | grep -m 1  \"├─session-\" | grep -o '[0-9]\\+'`; loginctl show-session $LOGINCTL_SESSION_ID -p TTY | awk -F= '{print $2}'";
+	char loginctl_cmd[BUFSIZ] = "LC_ALL=c; LOGINCTL_SESSION_ID=`loginctl user-status | grep -m 1  \"├─session-\" | grep -o '[0-9]\\+'`; loginctl show-session $LOGINCTL_SESSION_ID -p TTY | awk -F= '{print $2}'";
 	char buf[BUFSIZ];
 	FILE *fp;
 
@@ -209,7 +227,7 @@ char *pusb_get_tty_by_loginctl()
 
 int pusb_is_loginctl_local()
 {
-	char loginctl_cmd[BUFSIZ] = "LOGINCTL_SESSION_ID=`loginctl user-status | grep -m 1  \"├─session-\" | grep -o '[0-9]\\+'`; loginctl show-session $LOGINCTL_SESSION_ID -p Remote | awk -F= '{print $2}'";
+	char loginctl_cmd[BUFSIZ] = "LC_ALL=c; LOGINCTL_SESSION_ID=`loginctl user-status | grep -m 1  \"├─session-\" | grep -o '[0-9]\\+'`; loginctl show-session $LOGINCTL_SESSION_ID -p Remote | awk -F= '{print $2}'";
 	char buf[BUFSIZ];
 	FILE *fp;
 
@@ -312,9 +330,7 @@ int pusb_local_login(t_pusb_options *opts, const char *user, const char *service
 		{
 			// DISPLAY contains not only display but also default screen, truncate screen part in this case
 			log_debug("	DISPLAY contains screen, truncating...\n");
-			char display_tmp[sizeof(display)];
-			snprintf(display_tmp, sizeof(display) - 2, "%s", display);
-			snprintf(display, strnlen(display_tmp, (sizeof(display_tmp)+1))-1, "%s", display_tmp);
+			memset(display + strlen(display) - 2, 0, 2);
 		}
 
 		local_request = pusb_is_tty_local((char *) display);

src/process.c

@@ -34,7 +34,7 @@
  * @param pid PID of the process
  * @param name Name of the process
  * 
- * Source: http://stackoverflow.com/questions/15545341/process-name-from-its-pid-in-linux
+ * Source: https://stackoverflow.com/questions/15545341/process-name-from-its-pid-in-linux
  */
 void pusb_get_process_name(const pid_t pid, char * name) 
 {
@@ -70,7 +70,7 @@ void pusb_get_process_parent_id(const pid_t pid, pid_t * ppid)
 		size_t size = fread(buffer, sizeof (char), sizeof (buffer), fp);
 		if (size > 0) 
 		{
-			// See: http://man7.org/linux/man-pages/man5/proc.5.html section /proc/[pid]/stat
+			// See: https://man7.org/linux/man-pages/man5/proc.5.html section /proc/[pid]/stat
 			strtok(buffer, " "); // (1) pid  %d
 			strtok(NULL, " "); // (2) comm  %s
 			strtok(NULL, " "); // (3) state  %c
@@ -82,19 +82,25 @@ void pusb_get_process_parent_id(const pid_t pid, pid_t * ppid)
 }
 
 /**
- * Read environment variable of another process
+ * Read environment variable of another process via its /proc/processId/environ file. To so so
+ * it replaces the zero bytes by # to be able to use strtok on its content. When the requested variable 
+ * is found its name and the equals/assign character will be cut off and the result then returned.
  *
  * @param pid pid of process to read the environment of
  * @param var envvar to look up
  *
  * @return content of var if found, else NULL
+ *
+ * @see https://man7.org/linux/man-pages/man7/environ.7.html
+ * @see https://askubuntu.com/a/978715
  */
 char *pusb_get_process_envvar(pid_t pid, char *var)
 {
 	char buffer[BUFSIZ];
+	char* output = xmalloc(BUFSIZ);
+
 	sprintf(buffer, "/proc/%d/environ", pid);
 	FILE* fp = fopen(buffer, "r");
-	char *variable_content = (char *)xmalloc(BUFSIZ);
 	if (fp) 
 	{
 		size_t size = fread(buffer, sizeof (char), sizeof (buffer), fp);
@@ -104,20 +110,22 @@ char *pusb_get_process_envvar(pid_t pid, char *var)
 			if (!buffer[i] && i != size) buffer[i] = '#'; // replace \0 with "#" since strtok uses \0 internally
 		}
 
-		if (size > 0) 
+		if (size > 0)
 		{
-			variable_content = strtok(buffer, "#");
+			char* variable_content = strtok(buffer, "#");
 			while (variable_content != NULL)
 			{
-				if (strncmp(var, variable_content, strnlen(var, sizeof(var))) == 0) 
+				if (strncmp(var, variable_content, strlen(var)) == 0)
 				{
-					return variable_content + strnlen(var, sizeof(var)) + 1;
+					return output;
 				}
 
 				variable_content = strtok(NULL, "#");
+				strcpy(output,  variable_content + (strlen(var) +1)); // cut var= and set output string
 			}
 		}
 	}
 
+	xfree(output);
 	return NULL;
 }

src/tmux.c

@@ -29,8 +29,6 @@ char *pusb_tmux_get_client_tty(pid_t env_pid)
     if (tmux_details == NULL) 
     {
         log_debug("		No TMUX env var, checking parent process in case this is a sudo request\n");
-
-        tmux_details = (char *)xmalloc(BUFSIZ);
         tmux_details = pusb_get_process_envvar(env_pid, "TMUX");
 
         if (tmux_details == NULL) 
@@ -46,8 +44,8 @@ char *pusb_tmux_get_client_tty(pid_t env_pid)
     char *tmux_socket_path = strtok(tmux_details, ",");
     log_debug("		Got tmux_socket_path: %s\n", tmux_socket_path);
 
-    char get_tmux_session_details_cmd[64];
-    sprintf(get_tmux_session_details_cmd, "tmux -S \"%s\" list-clients -t \"\\$%s\"", tmux_socket_path, tmux_client_id);
+    char get_tmux_session_details_cmd[128];
+    sprintf(get_tmux_session_details_cmd, "LC_ALL=c; tmux -S \"%s\" list-clients -t \"\\$%s\"", tmux_socket_path, tmux_client_id);
     log_debug("		Built get_tmux_session_details_cmd: %s\n", get_tmux_session_details_cmd);
 
     char buf[BUFSIZ];
@@ -101,7 +99,7 @@ int pusb_tmux_has_remote_clients(const char* username)
     {
         log_debug("		Checking for IPv%d connections...\n", (4 + (i * 2)));
 
-        if ((fp = popen("w", "r")) == NULL) 
+        if ((fp = popen("LC_ALL=c; w", "r")) == NULL)
         {
             log_error("tmux detected, but couldn't get `w`. Denying since remote check for tmux impossible without it!\n");
             return (-1);