[PATCH] command: Add silent mode to read command to suppress input echo

[Glenn Washburn]

This conforms to the behavior of the -s option of the bash read command.

docs/grub: Document the -s option for the read command.

Signed-off-by: Glenn Washburn <development@efficientek.com>
---
 docs/grub.texi            |  5 +++--
 grub-core/commands/read.c | 29 +++++++++++++++++++----------
 2 files changed, 22 insertions(+), 12 deletions(-)

diff --git a/docs/grub.texi b/docs/grub.texi
index eeb3118eb..5f5b67e3b 100644
--- a/docs/grub.texi
+++ b/docs/grub.texi
@@ -4924,10 +4924,11 @@ and the system will reboot.
 @node read
 @subsection read
 
-@deffn Command read [var]
+@deffn Command read [-s] [var]
 Read a line of input from the user.  If an environment variable @var{var} is
 given, set that environment variable to the line of input that was read,
-with no terminating newline.
+with no terminating newline.  If the parameter @option{-s} is used, enable
+silent mode where input is not printed to the terminal.
 @end deffn
 
 
diff --git a/grub-core/commands/read.c b/grub-core/commands/read.c
index fe3e88b15..0fba58996 100644
--- a/grub-core/commands/read.c
+++ b/grub-core/commands/read.c
@@ -23,13 +23,19 @@
 #include <grub/env.h>
 #include <grub/term.h>
 #include <grub/types.h>
-#include <grub/command.h>
+#include <grub/extcmd.h>
 #include <grub/i18n.h>
 
 GRUB_MOD_LICENSE ("GPLv3+");
 
+static const struct grub_arg_option options[] =
+  {
+    {"silent", 's', 0, N_("Do not echo input"), 0, 0},
+    {0, 0, 0, 0, 0, 0}
+  };
+
 static char *
-grub_getline (void)
+grub_getline (int silent)
 {
   int i;
   char *line;
@@ -48,7 +54,7 @@ grub_getline (void)
        break;
 
       line[i] = c;
-      if (grub_isprint (c))
+      if (!silent && grub_isprint (c))
        grub_printf ("%c", c);
       i++;
       tmp = grub_realloc (line, 1 + i + sizeof('\0'));
@@ -65,9 +71,12 @@ grub_getline (void)
 }
 
 static grub_err_t
-grub_cmd_read (grub_command_t cmd __attribute__ ((unused)), int argc, char 
**args)
+grub_cmd_read (grub_extcmd_context_t ctxt, int argc, char **args)
 {
-  char *line = grub_getline ();
+
+  struct grub_arg_list *state = ctxt->state;
+
+  char *line = grub_getline (state[0].set);
   if (! line)
     return grub_errno;
   if (argc > 0)
@@ -77,16 +86,16 @@ grub_cmd_read (grub_command_t cmd __attribute__ ((unused)), 
int argc, char **arg
   return 0;
 }
 
-static grub_command_t cmd;
+static grub_extcmd_t cmd;
 
 GRUB_MOD_INIT(read)
 {
-  cmd = grub_register_command ("read", grub_cmd_read,
-                              N_("[ENVVAR]"),
-                              N_("Set variable with user input."));
+  cmd = grub_register_extcmd ("read", grub_cmd_read, 0,
+                              N_("[-s] [ENVVAR]"),
+                              N_("Set variable with user input."), options);
 }
 
 GRUB_MOD_FINI(read)
 {
-  grub_unregister_command (cmd);
+  grub_unregister_extcmd (cmd);
 }
-- 
2.27.0