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[script] Implement "goto" in iPXE scripts

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Allow script labels to be defined using the syntax

  :<labelname>

(nothing else allowed on the line, including whitespace).  Labels are
ignored during script execution, but can be used as the target of the
"goto" command.  For example:

  #!ipxe

  goto machine_${net0/ip} || goto machine_default

  # Linux kernel boot
  :machine_10.0.0.101
  :machine_10.0.0.102
  set filename http://my.boot.server/vmlinuz
  goto done

  # Default configuration
  :machine_default
  set filename pxelinux.0
  goto done

  # Boot selected configuration
  :done
  chain ${filename}

Originally-implemented-by: Shao Miller <shao.miller@yrdsb.edu.on.ca>
Originally-implemented-by: Stefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown 2010-11-22 04:19:24 +00:00
parent 9ba988809d
commit 6d68ffee39
1 changed files with 194 additions and 30 deletions
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224
src/image/script.c
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@ -27,12 +27,119 @@ FILE_LICENCE ( GPL2_OR_LATER );
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <ctype.h>
#include <errno.h>
#include <getopt.h>
#include <ipxe/command.h>
#include <ipxe/parseopt.h>
#include <ipxe/image.h>
struct image_type script_image_type __image_type ( PROBE_NORMAL );
/** Currently running script
*
* This is a global in order to allow goto_exec() to update the
* offset.
*/
static struct image *script;
/** Offset within current script
*
* This is a global in order to allow goto_exec() to update the
* offset.
*/
static size_t script_offset;
/**
* Process script lines
*
* @v process_line Line processor
* @v terminate Termination check
* @ret rc Return status code
*/
static int process_script ( int ( * process_line ) ( const char *line ),
int ( * terminate ) ( int rc ) ) {
off_t eol;
size_t len;
int rc;
script_offset = 0;
do {
/* Find length of next line, excluding any terminating '\n' */
eol = memchr_user ( script->data, script_offset, '\n',
( script->len - script_offset ) );
if ( eol < 0 )
eol = script->len;
len = ( eol - script_offset );
/* Copy line, terminate with NUL, and execute command */
{
char cmdbuf[ len + 1 ];
copy_from_user ( cmdbuf, script->data,
script_offset, len );
cmdbuf[len] = '\0';
DBG ( "$ %s\n", cmdbuf );
/* Move to next line */
script_offset += ( len + 1 );
/* Process line */
rc = process_line ( cmdbuf );
if ( terminate ( rc ) )
return rc;
}
} while ( script_offset < script->len );
return rc;
}
/**
* Terminate script processing if line processing failed
*
* @v rc Line processing status
* @ret terminate Terminate script processing
*/
static int terminate_on_failure ( int rc ) {
return ( rc != 0 );
}
/**
* Terminate script processing if line processing succeeded
*
* @v rc Line processing status
* @ret terminate Terminate script processing
*/
static int terminate_on_success ( int rc ) {
return ( rc == 0 );
}
/**
* Execute script line
*
* @v line Line of script
* @ret rc Return status code
*/
static int script_exec_line ( const char *line ) {
int rc;
/* Skip label lines */
if ( line[0] == ':' )
return 0;
/* Execute command */
if ( ( rc = system ( line ) ) != 0 ) {
printf ( "Aborting on \"%s\"\n", line );
return rc;
}
return 0;
}
/**
* Execute script
*
@ -40,9 +147,8 @@ struct image_type script_image_type __image_type ( PROBE_NORMAL );
* @ret rc Return status code
*/
static int script_exec ( struct image *image ) {
size_t offset = 0;
off_t eol;
size_t len;
struct image *saved_script;
size_t saved_offset;
int rc;
/* Temporarily de-register image, so that a "boot" command
@ -50,36 +156,19 @@ static int script_exec ( struct image *image ) {
*/
unregister_image ( image );
while ( offset < image->len ) {
/* Find length of next line, excluding any terminating '\n' */
eol = memchr_user ( image->data, offset, '\n',
( image->len - offset ) );
if ( eol < 0 )
eol = image->len;
len = ( eol - offset );
/* Preserve state of any currently-running script */
saved_script = script;
saved_offset = script_offset;
/* Copy line, terminate with NUL, and execute command */
{
char cmdbuf[ len + 1 ];
/* Initialise state for this script */
script = image;
copy_from_user ( cmdbuf, image->data, offset, len );
cmdbuf[len] = '\0';
DBG ( "$ %s\n", cmdbuf );
if ( ( rc = system ( cmdbuf ) ) != 0 ) {
DBG ( "Command \"%s\" failed: %s\n",
cmdbuf, strerror ( rc ) );
goto done;
}
}
/* Move to next line */
offset += ( len + 1 );
}
/* Process script */
rc = process_script ( script_exec_line, terminate_on_failure );
rc = 0;
done:
/* Re-register image and return */
/* Restore saved state, re-register image, and return */
script_offset = saved_offset;
script = saved_script;
register_image ( image );
return rc;
}
@ -129,3 +218,78 @@ struct image_type script_image_type __image_type ( PROBE_NORMAL ) = {
.load = script_load,
.exec = script_exec,
};
/** "goto" options */
struct goto_options {};
/** "goto" option list */
static struct option_descriptor goto_opts[] = {};
/** "goto" command descriptor */
static struct command_descriptor goto_cmd =
COMMAND_DESC ( struct goto_options, goto_opts, 1, 1,
"<label>", "" );
/**
* Current "goto" label
*
* Valid only during goto_exec(). Consider this part of a closure.
*/
static const char *goto_label;
/**
* Check for presence of label
*
* @v line Script line
* @ret rc Return status code
*/
static int goto_find_label ( const char *line ) {
if ( line[0] != ':' )
return -ENOENT;
if ( strcmp ( goto_label, &line[1] ) != 0 )
return -ENOENT;
return 0;
}
/**
* "goto" command
*
* @v argc Argument count
* @v argv Argument list
* @ret rc Return status code
*/
static int goto_exec ( int argc, char **argv ) {
struct goto_options opts;
size_t saved_offset;
int rc;
/* Parse options */
if ( ( rc = parse_options ( argc, argv, &goto_cmd, &opts ) ) != 0 )
return rc;
/* Sanity check */
if ( ! script ) {
printf ( "Not in a script\n" );
return -ENOTTY;
}
/* Parse label */
goto_label = argv[optind];
/* Find label */
saved_offset = script_offset;
if ( ( rc = process_script ( goto_find_label,
terminate_on_success ) ) != 0 ) {
script_offset = saved_offset;
return rc;
}
return 0;
}
/** "goto" command */
struct command goto_command __command = {
.name = "goto",
.exec = goto_exec,
};