2N/A/* envblk.c - Common functions for environment block. */
2N/A/*
2N/A * GRUB -- GRand Unified Bootloader
2N/A * Copyright (C) 2008,2009 Free Software Foundation, Inc.
2N/A *
2N/A * GRUB is free software: you can redistribute it and/or modify
2N/A * it under the terms of the GNU General Public License as published by
2N/A * the Free Software Foundation, either version 3 of the License, or
2N/A * (at your option) any later version.
2N/A *
2N/A * GRUB is distributed in the hope that it will be useful,
2N/A * but WITHOUT ANY WARRANTY; without even the implied warranty of
2N/A * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
2N/A * GNU General Public License for more details.
2N/A *
2N/A * You should have received a copy of the GNU General Public License
2N/A * along with GRUB. If not, see <http://www.gnu.org/licenses/>.
2N/A */
2N/A
2N/A#include <config.h>
2N/A#include <grub/types.h>
2N/A#include <grub/misc.h>
2N/A#include <grub/mm.h>
2N/A#include <grub/lib/envblk.h>
2N/A
2N/Agrub_envblk_t
2N/Agrub_envblk_open (char *buf, grub_size_t size)
2N/A{
2N/A grub_envblk_t envblk;
2N/A
2N/A if (size < sizeof (GRUB_ENVBLK_SIGNATURE)
2N/A || grub_memcmp (buf, GRUB_ENVBLK_SIGNATURE,
2N/A sizeof (GRUB_ENVBLK_SIGNATURE) - 1))
2N/A {
2N/A grub_error (GRUB_ERR_BAD_FILE_TYPE, "invalid environment block");
2N/A return 0;
2N/A }
2N/A
2N/A envblk = grub_malloc (sizeof (*envblk));
2N/A if (envblk)
2N/A {
2N/A envblk->buf = buf;
2N/A envblk->size = size;
2N/A }
2N/A
2N/A return envblk;
2N/A}
2N/A
2N/Avoid
2N/Agrub_envblk_close (grub_envblk_t envblk)
2N/A{
2N/A grub_free (envblk->buf);
2N/A grub_free (envblk);
2N/A}
2N/A
2N/Astatic int
2N/Aescaped_value_len (const char *value)
2N/A{
2N/A int n = 0;
2N/A char *p;
2N/A
2N/A for (p = (char *) value; *p; p++)
2N/A {
2N/A if (*p == '\\' || *p == '\n')
2N/A n += 2;
2N/A else
2N/A n++;
2N/A }
2N/A
2N/A return n;
2N/A}
2N/A
2N/Astatic char *
2N/Afind_next_line (char *p, const char *pend)
2N/A{
2N/A while (p < pend)
2N/A {
2N/A if (*p == '\\')
2N/A p += 2;
2N/A else if (*p == '\n')
2N/A break;
2N/A else
2N/A p++;
2N/A }
2N/A
2N/A return p + 1;
2N/A}
2N/A
2N/Aint
2N/Agrub_envblk_set (grub_envblk_t envblk, const char *name, const char *value)
2N/A{
2N/A char *p, *pend;
2N/A char *space;
2N/A int found = 0;
2N/A int nl;
2N/A int vl;
2N/A int i;
2N/A
2N/A nl = grub_strlen (name);
2N/A vl = escaped_value_len (value);
2N/A p = envblk->buf + sizeof (GRUB_ENVBLK_SIGNATURE) - 1;
2N/A pend = envblk->buf + envblk->size;
2N/A
2N/A /* First, look at free space. */
2N/A for (space = pend - 1; *space == '#'; space--)
2N/A ;
2N/A
2N/A if (*space != '\n')
2N/A /* Broken. */
2N/A return 0;
2N/A
2N/A space++;
2N/A
2N/A while (p + nl + 1 < space)
2N/A {
2N/A if (grub_memcmp (p, name, nl) == 0 && p[nl] == '=')
2N/A {
2N/A int len;
2N/A
2N/A /* Found the same name. */
2N/A p += nl + 1;
2N/A
2N/A /* Check the length of the current value. */
2N/A len = 0;
2N/A while (p + len < pend && p[len] != '\n')
2N/A {
2N/A if (p[len] == '\\')
2N/A len += 2;
2N/A else
2N/A len++;
2N/A }
2N/A
2N/A if (p + len >= pend)
2N/A /* Broken. */
2N/A return 0;
2N/A
2N/A if (pend - space < vl - len)
2N/A /* No space. */
2N/A return 0;
2N/A
2N/A if (vl < len)
2N/A {
2N/A /* Move the following characters backward, and fill the new
2N/A space with harmless characters. */
2N/A grub_memmove (p + vl, p + len, pend - (p + len));
2N/A grub_memset (space + len - vl, '#', len - vl);
2N/A }
2N/A else
2N/A /* Move the following characters forward. */
2N/A grub_memmove (p + vl, p + len, pend - (p + vl));
2N/A
2N/A found = 1;
2N/A break;
2N/A }
2N/A
2N/A p = find_next_line (p, pend);
2N/A }
2N/A
2N/A if (! found)
2N/A {
2N/A /* Append a new variable. */
2N/A
2N/A if (pend - space < nl + 1 + vl + 1)
2N/A /* No space. */
2N/A return 0;
2N/A
2N/A grub_memcpy (space, name, nl);
2N/A p = space + nl;
2N/A *p++ = '=';
2N/A }
2N/A
2N/A /* Write the value. */
2N/A for (i = 0; value[i]; i++)
2N/A {
2N/A if (value[i] == '\\' || value[i] == '\n')
2N/A *p++ = '\\';
2N/A
2N/A *p++ = value[i];
2N/A }
2N/A
2N/A *p = '\n';
2N/A return 1;
2N/A}
2N/A
2N/Avoid
2N/Agrub_envblk_delete (grub_envblk_t envblk, const char *name)
2N/A{
2N/A char *p, *pend;
2N/A int nl;
2N/A
2N/A nl = grub_strlen (name);
2N/A p = envblk->buf + sizeof (GRUB_ENVBLK_SIGNATURE) - 1;
2N/A pend = envblk->buf + envblk->size;
2N/A
2N/A while (p + nl + 1 < pend)
2N/A {
2N/A if (grub_memcmp (p, name, nl) == 0 && p[nl] == '=')
2N/A {
2N/A /* Found. */
2N/A int len = nl + 1;
2N/A
2N/A while (p + len < pend)
2N/A {
2N/A if (p[len] == '\n')
2N/A break;
2N/A else if (p[len] == '\\')
2N/A len += 2;
2N/A else
2N/A len++;
2N/A }
2N/A
2N/A if (p + len >= pend)
2N/A /* Broken. */
2N/A return;
2N/A
2N/A len++;
2N/A grub_memmove (p, p + len, pend - (p + len));
2N/A grub_memset (pend - len, '#', len);
2N/A break;
2N/A }
2N/A
2N/A p = find_next_line (p, pend);
2N/A }
2N/A}
2N/A
2N/Avoid
2N/Agrub_envblk_iterate (grub_envblk_t envblk,
2N/A int hook (const char *name, const char *value))
2N/A{
2N/A char *p, *pend;
2N/A
2N/A p = envblk->buf + sizeof (GRUB_ENVBLK_SIGNATURE) - 1;
2N/A pend = envblk->buf + envblk->size;
2N/A
2N/A while (p < pend)
2N/A {
2N/A if (*p != '#')
2N/A {
2N/A char *name;
2N/A char *value;
2N/A char *name_start, *name_end, *value_start;
2N/A char *q;
2N/A int ret;
2N/A
2N/A name_start = p;
2N/A while (p < pend && *p != '=')
2N/A p++;
2N/A if (p == pend)
2N/A /* Broken. */
2N/A return;
2N/A name_end = p;
2N/A
2N/A p++;
2N/A value_start = p;
2N/A while (p < pend)
2N/A {
2N/A if (*p == '\n')
2N/A break;
2N/A else if (*p == '\\')
2N/A p += 2;
2N/A else
2N/A p++;
2N/A }
2N/A
2N/A if (p >= pend)
2N/A /* Broken. */
2N/A return;
2N/A
2N/A name = grub_malloc (p - name_start + 1);
2N/A if (! name)
2N/A /* out of memory. */
2N/A return;
2N/A
2N/A value = name + (value_start - name_start);
2N/A
2N/A grub_memcpy (name, name_start, name_end - name_start);
2N/A name[name_end - name_start] = '\0';
2N/A
2N/A for (p = value_start, q = value; *p != '\n'; ++p)
2N/A {
2N/A if (*p == '\\')
2N/A *q++ = *++p;
2N/A else
2N/A *q++ = *p;
2N/A }
2N/A *q = '\0';
2N/A
2N/A ret = hook (name, value);
2N/A grub_free (name);
2N/A if (ret)
2N/A return;
2N/A }
2N/A
2N/A p = find_next_line (p, pend);
2N/A }
2N/A}