diff options
Diffstat (limited to 'drivers/firmware/efi/libstub/efi-stub-helper.c')
| -rw-r--r-- | drivers/firmware/efi/libstub/efi-stub-helper.c | 44 |
1 files changed, 32 insertions, 12 deletions
diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c index 0d0007355c1e..4d544f395403 100644 --- a/drivers/firmware/efi/libstub/efi-stub-helper.c +++ b/drivers/firmware/efi/libstub/efi-stub-helper.c @@ -206,15 +206,6 @@ efi_status_t efi_parse_options(char const *cmdline) } /* - * Get the number of UTF-8 bytes corresponding to an UTF-16 character. - * This overestimates for surrogates, but that is okay. - */ -static int efi_utf8_bytes(u16 c) -{ - return 1 + (c >= 0x80) + (c >= 0x800); -} - -/* * Convert an UTF-16 string, not necessarily null terminated, to UTF-8. */ static u8 *efi_utf16_to_utf8(u8 *dst, const u16 *src, int n) @@ -274,10 +265,39 @@ char *efi_convert_cmdline(efi_loaded_image_t *image, if (options) { s2 = options; - while (*s2 && *s2 != '\n' - && options_chars < load_options_chars) { - options_bytes += efi_utf8_bytes(*s2++); + while (options_chars < load_options_chars) { + u16 c = *s2++; + + if (c == L'\0' || c == L'\n') + break; + /* + * Get the number of UTF-8 bytes corresponding to a + * UTF-16 character. + * The first part handles everything in the BMP. + */ + options_bytes += 1 + (c >= 0x80) + (c >= 0x800); options_chars++; + /* + * Add one more byte for valid surrogate pairs. Invalid + * surrogates will be replaced with 0xfffd and take up + * only 3 bytes. + */ + if ((c & 0xfc00) == 0xd800) { + /* + * If the very last word is a high surrogate, + * we must ignore it since we can't access the + * low surrogate. + */ + if (options_chars == load_options_chars) { + options_bytes -= 3; + options_chars--; + break; + } else if ((*s2 & 0xfc00) == 0xdc00) { + options_bytes++; + options_chars++; + s2++; + } + } } } |