[gPXE-devel] Minor Scripting Improvements

[Shao Miller]

Michael Brown wrote:
>
> Looking at the patch itself...
>
> Could this be rearranged to avoid goto?  We generally use goto only for
> structured error clean-up.
>

Ok.

> Also, using -ENOTSUP as a magic value meaning "loop" seems kind of icky. 
> There's a similarity between "exit" and "loopif" here; both commands 
> need to
> set temporary state that affects the "move to next line of script" logic. 
> Maybe have "loopif" set a flag as well; still fairly icky but at least 
> it's
> icky in the same way that "exit" currently is.
>

How about abuse of the same state variable?  Something like this 80-byte 
cost attachment...  I'm not too sure why it costs so much.

If the user types in 'loopif' manually at the CLI, they'd get an 
unexpected 'exit', however.  'loopif' is really only useful for scripts.

Thanks again.

- Shao Miller
-----

diff --git a/src/hci/shell.c b/src/hci/shell.c
index 5bedbdc..825dac3 100644
--- a/src/hci/shell.c
+++ b/src/hci/shell.c
@@ -35,13 +35,13 @@ FILE_LICENCE ( GPL2_OR_LATER );
 static const char shell_prompt[] = "gPXE> ";
 
 /** Flag set in order to exit shell */
-static int exit_flag = 0;
+int shell_exit_flag = 0;
 
 /** "exit" command body */
 static int exit_exec ( int argc, char **argv __unused ) {
 
     if ( argc == 1 ) {
-        exit_flag = 1;
+        shell_exit_flag = 1;
     } else {
         printf ( "Usage: exit\n"
              "Exits the command shell\n" );
@@ -91,8 +91,8 @@ struct command help_command __command = {
 void shell ( void ) {
     char *line;
 
-    exit_flag = 0;
-    while ( ! exit_flag ) {
+    shell_exit_flag = 0;
+    while ( ! shell_exit_flag ) {
         line = readline ( shell_prompt );
         if ( line ) {
             system ( line );
diff --git a/src/image/script.c b/src/image/script.c
index 0835ecb..bc29116 100644
--- a/src/image/script.c
+++ b/src/image/script.c
@@ -29,7 +29,9 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #include <stdlib.h>
 #include <ctype.h>
 #include <errno.h>
+#include <gpxe/command.h>
 #include <gpxe/image.h>
+#include <gpxe/shell.h>
 
 struct image_type script_image_type __image_type ( PROBE_NORMAL );
 
@@ -51,7 +53,9 @@ static int script_exec ( struct image *image ) {
     unregister_image ( image );
 
     while ( offset < image->len ) {
-   
+        /* Reset the loop/exit flag */
+        shell_exit_flag = 0;
+
         /* Find length of next line, excluding any terminating '\n' */
         eol = memchr_user ( image->data, offset, '\n',
                     ( image->len - offset ) );
@@ -72,9 +76,19 @@ static int script_exec ( struct image *image ) {
                 goto done;
             }
         }
-       
-        /* Move to next line */
-        offset += ( len + 1 );
+
+        switch ( shell_exit_flag ) {
+            case 1:
+                /* "exit" command should exit this script */
+                goto done;
+            case 2:
+                /* "loopif" command told us to loop */
+                offset = 0;
+                break;
+            default:
+                /* Move to next line */
+                offset += ( len + 1 );
+        }
     }
 
     rc = 0;
@@ -124,3 +138,16 @@ struct image_type script_image_type __image_type ( 
PROBE_NORMAL ) = {
     .load = script_load,
     .exec = script_exec,
 };
+
+/** "loopif" command body */
+static int loopif_exec ( int argc, char **argv ) {
+    if ( argc > 1 && strtoul ( argv[1], NULL, 0 ) )
+        shell_exit_flag = 2;
+    return 0;
+}
+
+/** "loopif" command definition */
+struct command loopif_command __command = {
+    .name = "loopif",
+    .exec = loopif_exec,
+};
diff --git a/src/include/gpxe/shell.h b/src/include/gpxe/shell.h
index a65a344..148ea83 100644
--- a/src/include/gpxe/shell.h
+++ b/src/include/gpxe/shell.h
@@ -9,6 +9,7 @@
 
 FILE_LICENCE ( GPL2_OR_LATER );
 
+extern int shell_exit_flag;
 extern void shell ( void );
 
 #endif /* _GPXE_SHELL_H */

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://etherboot.org/pipermail/gpxe-devel/attachments/20100305/35d5c2bf/attachment.html 
-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: exit_loop2.patch
Url: http://etherboot.org/pipermail/gpxe-devel/attachments/20100305/35d5c2bf/attachment.cc