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efivars: minor modernization for efi_set_variable

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Mike Yuan 2024-03-31 20:14:16 +08:00
parent 1ca89d32ae
commit 80d1d9f5db
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GPG Key ID: 417471C0A40F58B3
1 changed files with 6 additions and 5 deletions
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11
src/basic/efivars.c
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@ -177,12 +177,13 @@ static int efi_verify_variable(const char *variable, uint32_t attr, const void *
}
int efi_set_variable(const char *variable, const void *value, size_t size) {
static const uint32_t attr = EFI_VARIABLE_NON_VOLATILE|EFI_VARIABLE_BOOTSERVICE_ACCESS|EFI_VARIABLE_RUNTIME_ACCESS;
struct var {
uint32_t attr;
char buf[];
} _packed_ * _cleanup_free_ buf = NULL;
_cleanup_close_ int fd = -EBADF;
uint32_t attr = EFI_VARIABLE_NON_VOLATILE|EFI_VARIABLE_BOOTSERVICE_ACCESS|EFI_VARIABLE_RUNTIME_ACCESS;
bool saved_flags_valid = false;
unsigned saved_flags;
int r;
@ -190,14 +191,14 @@ int efi_set_variable(const char *variable, const void *value, size_t size) {
assert(variable);
assert(value || size == 0);
const char *p = strjoina("/sys/firmware/efi/efivars/", variable);
/* size 0 means removal, empty variable would not be enough for that */
if (size > 0 && efi_verify_variable(variable, attr, value, size) > 0) {
log_debug("Variable '%s' is already in wanted state, skipping write.", variable);
return 0;
}
const char *p = strjoina("/sys/firmware/efi/efivars/", variable);
/* Newer efivarfs protects variables that are not in an allow list with FS_IMMUTABLE_FL by default,
* to protect them for accidental removal and modification. We are not changing these variables
* accidentally however, hence let's unset the bit first. */
@ -238,10 +239,10 @@ int efi_set_variable(const char *variable, const void *value, size_t size) {
/* For some reason efivarfs doesn't update mtime automatically. Let's do it manually then. This is
* useful for processes that cache EFI variables to detect when changes occurred. */
if (futimens(fd, (struct timespec[2]) {
if (futimens(fd, (const struct timespec[2]) {
{ .tv_nsec = UTIME_NOW },
{ .tv_nsec = UTIME_NOW }
}) < 0)
}) < 0)
log_debug_errno(errno, "Failed to update mtime/atime on %s, ignoring: %m", p);
r = 0;