Add functionality to write to a temp file through url arguments

README.md

@@ -76,6 +76,7 @@ OPTIONS:
     -g, --gid               Group id to run with
     -s, --signal            Signal to send to the command when exit it (default: 1, SIGHUP)
     -a, --url-arg           Allow client to send command line arguments in URL (eg: http://localhost:7681?arg=foo&arg=bar)
+    -f, --arg-file          File prefix for a unique generated temp file that URL arguments are written to (ex. /tmp/prefix); the generated file's full path is then passed in as a command line argument (ex. /tmp/prefix{unique string})
     -R, --readonly          Do not allow clients to write to the TTY
     -t, --client-option     Send option to client (format: key=value), repeat to add more options
     -T, --terminal-type     Terminal type to report, default: xterm-256color

man/ttyd.1

@@ -63,6 +63,9 @@ Cross platform: macOS, Linux, FreeBSD/OpenBSD, OpenWrt/LEDE, Windows
       Allow client to send command line arguments in URL (eg: 
 \[la]http://localhost:7681?arg=foo&arg=bar\[ra])
 
+.PP
+\-f, \-\-arg\-file
+      File prefix for a unique generated temp file that URL arguments are written to (ex. /tmp/prefix); the generated file's full path is then passed in as a command line argument (ex. /tmp/prefix{unique string})
 .PP
 \-R, \-\-readonly
       Do not allow clients to write to the TTY

man/ttyd.man.md

@@ -40,6 +40,9 @@ ttyd 1 "September 2016" ttyd "User Manual"
   -a, --url-arg
       Allow client to send command line arguments in URL (eg: http://localhost:7681?arg=foo&arg=bar)
 
+  -f, --arg-file
+      File prefix for a unique generated temp file that URL arguments are written to (ex. /tmp/prefix); the generated file's full path is then passed in as a command line argument (ex. /tmp/prefix{unique string})
+
   -R, --readonly
       Do not allow clients to write to the TTY
 

src/protocol.c

@@ -102,9 +102,34 @@ static bool spawn_process(struct pss_tty *pss, uint16_t columns, uint16_t rows)
   for (i = 0; i < server->argc; i++) {
     argv[n++] = server->argv[i];
   }
-  for (i = 0; i < pss->argc; i++) {
-    argv[n++] = pss->args[i];
+  if (server->url_arg) {
+    for (i = 0; i < pss->argc; i++) {
+      argv[n++] = pss->args[i];
+    }
   }
+  else if (server->arg_file != NULL) {
+    int fd = -1;
+    // mkstemp requires the file path to have suffix XXXXXX (len 7)
+    int file_path_len = strlen(server->arg_file) + 7;
+    char *filePath = xmalloc(file_path_len);
+    snprintf(filePath, file_path_len, "%sXXXXXX", server->arg_file);
+
+    if ((fd = mkstemp(filePath)) == -1) {
+      lwsl_err("Creation of temp file failed with error: %d (%s)\n", errno, strerror(errno));
+      return false;
+    }
+
+    for (i = 0; i < pss->argc; i++) {
+      if (dprintf(fd, "%s\n", pss->args[i]) < 0) {
+        lwsl_err("Write to temp file failed with error: %d (%s)\n", errno, strerror(errno));
+        return false;
+      }
+    }
+
+    argv[n++] = filePath;
+    close(fd);
+  }
+
   argv[n] = NULL;
 
   pty_process *process = process_init((void *) pss, server->loop, argv);
@@ -178,7 +203,7 @@ int callback_tty(struct lws *wsi, enum lws_callback_reasons reason, void *user,
       pss->wsi = wsi;
       pss->lws_close_status = LWS_CLOSE_STATUS_NOSTATUS;
 
-      if (server->url_arg) {
+      if (server->url_arg || server->arg_file != NULL) {
         while (lws_hdr_copy_fragment(wsi, buf, sizeof(buf), WSI_TOKEN_HTTP_URI_ARGS, n++) > 0) {
           if (strncmp(buf, "arg=", 4) == 0) {
             pss->args = xrealloc(pss->args, (pss->argc + 1) * sizeof(char *));

src/server.c

@@ -73,6 +73,7 @@ static const struct option options[] = {
     {"ssl-key", required_argument, NULL, 'K'},
     {"ssl-ca", required_argument, NULL, 'A'},
     {"url-arg", no_argument, NULL, 'a'},
+    {"arg-file", required_argument, NULL, 'f'},
     {"readonly", no_argument, NULL, 'R'},
     {"terminal-type", required_argument, NULL, 'T'},
     {"client-option", required_argument, NULL, 't'},
@@ -86,10 +87,10 @@ static const struct option options[] = {
     {NULL, 0, 0, 0}};
 
 #if LWS_LIBRARY_VERSION_NUMBER < 4000000
-static const char *opt_string = "p:i:c:u:g:s:I:b:6aSC:K:A:Rt:T:Om:oBd:vh";
+static const char *opt_string = "p:i:c:u:g:s:I:b:6af:SC:K:A:Rt:T:Om:oBd:vh";
 #endif
 #if LWS_LIBRARY_VERSION_NUMBER >= 4000000
-static const char *opt_string = "p:i:c:u:g:s:I:b:P:6aSC:K:A:Rt:T:Om:oBd:vh";
+static const char *opt_string = "p:i:c:u:g:s:I:b:P:6af:SC:K:A:Rt:T:Om:oBd:vh";
 #endif
 
 static void print_help() {
@@ -107,6 +108,7 @@ static void print_help() {
           "    -g, --gid               Group id to run with\n"
           "    -s, --signal            Signal to send to the command when exit it (default: 1, SIGHUP)\n"
           "    -a, --url-arg           Allow client to send command line arguments in URL (eg: http://localhost:7681?arg=foo&arg=bar)\n"
+          "    -f, --arg-file          File prefix for a unique generated temp file that URL arguments are written to (ex. /tmp/prefix); the generated file's full path is then passed in as a command line argument (ex. /tmp/prefix{unique string})\n"
           "    -R, --readonly          Do not allow clients to write to the TTY\n"
           "    -t, --client-option     Send option to client (format: key=value), repeat to add more options\n"
           "    -T, --terminal-type     Terminal type to report, default: xterm-256color\n"
@@ -182,6 +184,7 @@ static struct server *server_new(int argc, char **argv, int start) {
 
 static void server_free(struct server *ts) {
   if (ts == NULL) return;
+  if (ts->arg_file != NULL) free(ts->arg_file);
   if (ts->credential != NULL) free(ts->credential);
   if (ts->index != NULL) free(ts->index);
   free(ts->command);
@@ -321,6 +324,11 @@ int main(int argc, char **argv) {
         break;
       case 'a':
         server->url_arg = true;
+        server->arg_file = NULL;
+        break;
+      case 'f':
+        server->arg_file = strdup(optarg);
+        server->url_arg = false;
         break;
       case 'R':
         server->readonly = true;
@@ -537,7 +545,8 @@ int main(int argc, char **argv) {
     lwsl_notice("  websocket: %s\n", endpoints.ws);
   }
   if (server->check_origin) lwsl_notice("  check origin: true\n");
-  if (server->url_arg) lwsl_notice("  allow url arg: true\n");
+  if (server->url_arg) lwsl_notice("  allow url arg to cli arg: true\n");
+  if (server->arg_file != NULL) lwsl_notice("  temp file name prefix: %s\n", server->arg_file);
   if (server->readonly) lwsl_notice("  readonly: true\n");
   if (server->max_clients > 0)
     lwsl_notice("  max clients: %d\n", server->max_clients);

src/server.h

@@ -65,6 +65,7 @@ struct server {
   int sig_code;            // close signal
   char sig_name[20];       // human readable signal string
   bool url_arg;            // allow client to send cli arguments in URL
+  char *arg_file;          // file prefix for a generated temp file that URL arguments are written to
   bool readonly;           // whether not allow clients to write to the TTY
   bool check_origin;       // whether allow websocket connection from different origin
   int max_clients;         // maximum clients to support