/* env.c - Environment variables */
/*
* GRUB -- GRand Unified Bootloader
- * Copyright (C) 2003,2005 Free Software Foundation, Inc.
+ * Copyright (C) 2003,2005,2006 Free Software Foundation, Inc.
*
* GRUB is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
#define HASHSZ 13
/* A hashtable for quick lookup of variables. */
-static struct grub_env_var *grub_env[HASHSZ];
+struct grub_env_context
+{
+ struct grub_env_var *vars[HASHSZ];
+
+ struct grub_env_var *sorted;
+
+ /* One level deeper on the stack. */
+ struct grub_env_context *next;
+};
+
+/* The global context for environment variables. */
+static struct grub_env_context grub_env_context;
-/* The variables in a sorted list. */
-static struct grub_env_var *grub_env_sorted;
+/* The nested contexts for regular variables. */
+static struct grub_env_context *grub_env_var_context = &grub_env_context;
/* Return the hash representation of the string S. */
static unsigned int grub_env_hashval (const char *s)
struct grub_env_var *var;
int idx = grub_env_hashval (name);
- for (var = grub_env[idx]; var; var = var->next)
+ /* Look for the variable in the current context. */
+ for (var = grub_env_var_context->vars[idx]; var; var = var->next)
if (! grub_strcmp (var->name, name))
return var;
+
+ /* Look for the variable in the environment context. */
+ for (var = grub_env_context.vars[idx]; var; var = var->next)
+ if (! grub_strcmp (var->name, name))
+ return var;
+
return 0;
}
grub_err_t
-grub_env_set (const char *var, const char *val)
+grub_env_context_open (void)
{
- int idx = grub_env_hashval (var);
+ struct grub_env_context *context;
+ int i;
+
+ context = grub_malloc (sizeof (*context));
+ if (! context)
+ return grub_errno;
+
+ for (i = 0; i < HASHSZ; i++)
+ context->vars[i] = 0;
+ context->next = grub_env_var_context;
+ context->sorted = 0;
+
+ grub_env_var_context = context;
+
+ return GRUB_ERR_NONE;
+}
+
+grub_err_t
+grub_env_context_close (void)
+{
+ struct grub_env_context *context;
struct grub_env_var *env;
+ struct grub_env_var *prev = 0;
+
+ context = grub_env_var_context->next;
+
+ /* Free the variables associated with this context. */
+ for (env = grub_env_var_context->sorted; env; env = env->sort_next)
+ {
+ /* XXX: What if a hook is associated with this variable? */
+ grub_free (prev);
+ prev = env;
+ }
+ grub_free (prev);
+
+ /* Restore the previous context. */
+ grub_free (grub_env_var_context);
+ grub_env_var_context = context;
+
+ return GRUB_ERR_NONE;
+}
+
+static void
+grub_env_insert (struct grub_env_context *context,
+ struct grub_env_var *env)
+{
+ struct grub_env_var **grub_env = context->vars;
struct grub_env_var *sort;
struct grub_env_var **sortp;
-
+ int idx = grub_env_hashval (env->name);
+
+ /* Insert it in the hashtable. */
+ env->prevp = &grub_env[idx];
+ env->next = grub_env[idx];
+ if (grub_env[idx])
+ grub_env[idx]->prevp = &env->next;
+ grub_env[idx] = env;
+
+ /* Insert it in the sorted list. */
+ sortp = &context->sorted;
+ sort = context->sorted;
+ while (sort)
+ {
+ if (grub_strcmp (sort->name, env->name) > 0)
+ break;
+
+ sortp = &sort->sort_next;
+ sort = sort->sort_next;
+ }
+ env->sort_prevp = sortp;
+ env->sort_next = sort;
+ if (sort)
+ sort->sort_prevp = &env->sort_next;
+ *sortp = env;
+}
+
+
+static void
+grub_env_remove (struct grub_env_var *env)
+{
+ /* Remove the entry from the variable table. */
+ *env->prevp = env->next;
+ if (env->next)
+ env->next->prevp = env->prevp;
+
+ /* And from the sorted list. */
+ *env->sort_prevp = env->sort_next;
+ if (env->sort_next)
+ env->sort_next->sort_prevp = env->sort_prevp;
+}
+
+grub_err_t
+grub_env_export (const char *var)
+{
+ struct grub_env_var *env;
+ int idx = grub_env_hashval (var);
+
+ /* Look for the variable in the current context only. */
+ for (env = grub_env_var_context->vars[idx]; env; env = env->next)
+ if (! grub_strcmp (env->name, var))
+ {
+ /* Remove the variable from the old context and reinsert it
+ into the environment. */
+ grub_env_remove (env);
+ grub_env_insert (&grub_env_context, env);
+
+ return GRUB_ERR_NONE;
+ }
+
+ return GRUB_ERR_NONE;
+}
+
+grub_err_t
+grub_env_set (const char *var, const char *val)
+{
+ struct grub_env_var *env;
+
/* If the variable does already exist, just update the variable. */
env = grub_env_find (var);
if (env)
env->value = grub_strdup (val);
if (! env->value)
goto fail;
-
- /* Insert it in the hashtable. */
- env->prevp = &grub_env[idx];
- env->next = grub_env[idx];
- if (grub_env[idx])
- grub_env[idx]->prevp = &env->next;
- grub_env[idx] = env;
-
- /* Insert it in the sorted list. */
- sortp = &grub_env_sorted;
- sort = grub_env_sorted;
- while (sort)
- {
- if (grub_strcmp (sort->name, var) > 0)
- break;
-
- sortp = &sort->sort_next;
- sort = sort->sort_next;
- }
- env->sort_prevp = sortp;
- env->sort_next = sort;
- if (sort)
- sort->sort_prevp = &env->sort_next;
- *sortp = env;
+
+ grub_env_insert (grub_env_var_context, env);
return 0;
if (env->read_hook || env->write_hook)
return;
- *env->prevp = env->next;
- if (env->next)
- env->next->prevp = env->prevp;
-
- *env->sort_prevp = env->sort_next;
- if (env->sort_next)
- env->sort_next->sort_prevp = env->sort_prevp;
+ grub_env_remove (env);
grub_free (env->name);
grub_free (env->value);
void
grub_env_iterate (int (* func) (struct grub_env_var *var))
{
- struct grub_env_var *env;
+ struct grub_env_var *env = grub_env_context.sorted;
+ struct grub_env_var *var = grub_env_var_context->sorted;
+
+ /* Initially these are the same. */
+ if (env == var)
+ var = 0;
- for (env = grub_env_sorted; env; env = env->sort_next)
- if (func (env))
- return;
+ while (env || var)
+ {
+ struct grub_env_var **cur;
+
+ /* Select the first name to be printed from the head of two
+ sorted lists. */
+ if (! env)
+ cur = &var;
+ else if (! var)
+ cur = &env;
+ else if (grub_strcmp (env->name, var->name) > 0)
+ cur = &var;
+ else
+ cur = &env;
+
+ if (func (*cur))
+ return;
+ *cur = (*cur)->sort_next;
+ }
}
grub_err_t
/*
* GRUB -- GRand Unified Bootloader
- * Copyright (C) 2003,2005 Free Software Foundation, Inc.
+ * Copyright (C) 2003,2005,2006 Free Software Foundation, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
return 0;
}
+static grub_err_t
+export_command (struct grub_arg_list *state __attribute__ ((unused)),
+ int argc, char **args)
+{
+ if (argc < 1)
+ return grub_error (GRUB_ERR_BAD_ARGUMENT,
+ "no environment variable specified");
+
+ grub_env_export (args[0]);
+ return 0;
+}
+
static grub_err_t
insmod_command (struct grub_arg_list *state __attribute__ ((unused)),
int argc, char **args)
grub_register_command ("unset", unset_command, GRUB_COMMAND_FLAG_BOTH,
"unset ENVVAR", "Remove an environment variable.", 0);
+ grub_register_command ("export", export_command, GRUB_COMMAND_FLAG_BOTH,
+ "export ENVVAR", "Export a variable.", 0);
+
grub_register_command ("insmod", insmod_command, GRUB_COMMAND_FLAG_BOTH,
"insmod MODULE",
"Insert a module. The argument can be a file or a module name.",
projects / thirdparty / grub.git / commitdiff
