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#include "password-buffer.h"
#include "log.h"
#include "swaylock.h"
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <limits.h>
#include <sys/mman.h>
static bool mlock_supported = true;
static long int page_size = 0;
static long int get_page_size() {
if (!page_size) {
page_size = sysconf(_SC_PAGESIZE);
}
return page_size;
}
// password_buffer_lock expects addr to be page alligned
static bool password_buffer_lock(char *addr, size_t size) {
int retries = 5;
while (mlock(addr, size) != 0 && retries > 0) {
switch (errno) {
case EAGAIN:
retries--;
if (retries == 0) {
swaylock_log(LOG_ERROR, "mlock() supported but failed too often.");
return false;
}
break;
case EPERM:
swaylock_log_errno(LOG_ERROR, "Unable to mlock() password memory: Unsupported!");
mlock_supported = false;
return true;
default:
swaylock_log_errno(LOG_ERROR, "Unable to mlock() password memory.");
return false;
}
}
return true;
}
// password_buffer_unlock expects addr to be page alligned
static bool password_buffer_unlock(char *addr, size_t size) {
if (mlock_supported) {
if (munlock(addr, size) != 0) {
swaylock_log_errno(LOG_ERROR, "Unable to munlock() password memory.");
return false;
}
}
return true;
}
char *password_buffer_create(size_t size) {
void *buffer;
int result = posix_memalign(&buffer, get_page_size(), size);
if (result) {
//posix_memalign doesn't set errno according to the man page
errno = result;
swaylock_log_errno(LOG_ERROR, "failed to alloc password buffer");
return NULL;
}
if (!password_buffer_lock(buffer, size)) {
free(buffer);
return NULL;
}
return buffer;
}
void password_buffer_destroy(char *buffer, size_t size) {
clear_buffer(buffer, size);
password_buffer_unlock(buffer, size);
free(buffer);
}
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