diff options
Diffstat (limited to 'grub-core/lib/envblk.c')
| -rw-r--r-- | grub-core/lib/envblk.c | 297 |
1 files changed, 297 insertions, 0 deletions
diff --git a/grub-core/lib/envblk.c b/grub-core/lib/envblk.c new file mode 100644 index 0000000..2e4e78b --- /dev/null +++ b/grub-core/lib/envblk.c @@ -0,0 +1,297 @@ +/* envblk.c - Common functions for environment block. */ +/* + * GRUB -- GRand Unified Bootloader + * Copyright (C) 2008,2009 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 + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * GRUB is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with GRUB. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <config.h> +#include <grub/types.h> +#include <grub/misc.h> +#include <grub/mm.h> +#include <grub/lib/envblk.h> + +grub_envblk_t +grub_envblk_open (char *buf, grub_size_t size) +{ + grub_envblk_t envblk; + + if (size < sizeof (GRUB_ENVBLK_SIGNATURE) + || grub_memcmp (buf, GRUB_ENVBLK_SIGNATURE, + sizeof (GRUB_ENVBLK_SIGNATURE) - 1)) + { + grub_error (GRUB_ERR_BAD_FILE_TYPE, "invalid environment block"); + return 0; + } + + envblk = grub_malloc (sizeof (*envblk)); + if (envblk) + { + envblk->buf = buf; + envblk->size = size; + } + + return envblk; +} + +void +grub_envblk_close (grub_envblk_t envblk) +{ + grub_free (envblk->buf); + grub_free (envblk); +} + +static int +escaped_value_len (const char *value) +{ + int n = 0; + char *p; + + for (p = (char *) value; *p; p++) + { + if (*p == '\\' || *p == '\n') + n += 2; + else + n++; + } + + return n; +} + +static char * +find_next_line (char *p, const char *pend) +{ + while (p < pend) + { + if (*p == '\\') + p += 2; + else if (*p == '\n') + break; + else + p++; + } + + return p + 1; +} + +int +grub_envblk_set (grub_envblk_t envblk, const char *name, const char *value) +{ + char *p, *pend; + char *space; + int found = 0; + int nl; + int vl; + int i; + + nl = grub_strlen (name); + vl = escaped_value_len (value); + p = envblk->buf + sizeof (GRUB_ENVBLK_SIGNATURE) - 1; + pend = envblk->buf + envblk->size; + + /* First, look at free space. */ + for (space = pend - 1; *space == '#'; space--) + ; + + if (*space != '\n') + /* Broken. */ + return 0; + + space++; + + while (p + nl + 1 < space) + { + if (grub_memcmp (p, name, nl) == 0 && p[nl] == '=') + { + int len; + + /* Found the same name. */ + p += nl + 1; + + /* Check the length of the current value. */ + len = 0; + while (p + len < pend && p[len] != '\n') + { + if (p[len] == '\\') + len += 2; + else + len++; + } + + if (p + len >= pend) + /* Broken. */ + return 0; + + if (pend - space < vl - len) + /* No space. */ + return 0; + + if (vl < len) + { + /* Move the following characters backward, and fill the new + space with harmless characters. */ + grub_memmove (p + vl, p + len, pend - (p + len)); + grub_memset (space - (len - vl), '#', len - vl); + } + else + /* Move the following characters forward. */ + grub_memmove (p + vl, p + len, pend - (p + vl)); + + found = 1; + break; + } + + p = find_next_line (p, pend); + } + + if (! found) + { + /* Append a new variable. */ + + if (pend - space < nl + 1 + vl + 1) + /* No space. */ + return 0; + + grub_memcpy (space, name, nl); + p = space + nl; + *p++ = '='; + } + + /* Write the value. */ + for (i = 0; value[i]; i++) + { + if (value[i] == '\\' || value[i] == '\n') + *p++ = '\\'; + + *p++ = value[i]; + } + + *p = '\n'; + return 1; +} + +void +grub_envblk_delete (grub_envblk_t envblk, const char *name) +{ + char *p, *pend; + int nl; + + nl = grub_strlen (name); + p = envblk->buf + sizeof (GRUB_ENVBLK_SIGNATURE) - 1; + pend = envblk->buf + envblk->size; + + while (p + nl + 1 < pend) + { + if (grub_memcmp (p, name, nl) == 0 && p[nl] == '=') + { + /* Found. */ + int len = nl + 1; + + while (p + len < pend) + { + if (p[len] == '\n') + break; + else if (p[len] == '\\') + len += 2; + else + len++; + } + + if (p + len >= pend) + /* Broken. */ + return; + + len++; + grub_memmove (p, p + len, pend - (p + len)); + grub_memset (pend - len, '#', len); + break; + } + + p = find_next_line (p, pend); + } +} + +void +grub_envblk_iterate (grub_envblk_t envblk, + void *hook_data, + int hook (const char *name, const char *value, void *hook_data)) +{ + char *p, *pend; + + p = envblk->buf + sizeof (GRUB_ENVBLK_SIGNATURE) - 1; + pend = envblk->buf + envblk->size; + + while (p < pend) + { + if (*p != '#') + { + char *name; + char *value; + char *name_start, *name_end, *value_start; + char *q; + int ret; + + name_start = p; + while (p < pend && *p != '=') + p++; + if (p == pend) + /* Broken. */ + return; + name_end = p; + + p++; + value_start = p; + while (p < pend) + { + if (*p == '\n') + break; + else if (*p == '\\') + p += 2; + else + p++; + } + + if (p >= pend) + /* Broken. */ + return; + + name = grub_malloc (p - name_start + 1); + if (! name) + /* out of memory. */ + return; + + value = name + (value_start - name_start); + + grub_memcpy (name, name_start, name_end - name_start); + name[name_end - name_start] = '\0'; + + for (p = value_start, q = value; *p != '\n'; ++p) + { + if (*p == '\\') + *q++ = *++p; + else + *q++ = *p; + } + *q = '\0'; + + ret = hook (name, value, hook_data); + grub_free (name); + if (ret) + return; + } + + p = find_next_line (p, pend); + } +} |