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/*
* Copyright (c) 2014
* Canonical, Ltd. (All rights reserved)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License published by the Free Software Foundation.
*
* This program 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 this program; if not, contact Novell, Inc. or Canonical
* Ltd.
*/
#include <ctype.h>
#include <dirent.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdarg.h>
#include <sys/types.h>
#include <unistd.h>
#include <sys/stat.h>
#include "lib.h"
#include "parser.h"
#include "policy_cache.h"
#define le16_to_cpu(x) ((uint16_t)(le16toh (*(uint16_t *) x)))
const char header_string[] = "\004\010\000version\000\002";
#define HEADER_STRING_SIZE 12
#define VERSION_STRING_SIZE 4
bool valid_cached_file_version(const char *cachename)
{
char buffer[HEADER_STRING_SIZE + VERSION_STRING_SIZE];
autofclose FILE *f;
if (!(f = fopen(cachename, "r"))) {
PERROR("Error: Could not read cache file '%s', skipping...\n", cachename);
return false;
}
size_t res = fread(buffer, 1, HEADER_STRING_SIZE + VERSION_STRING_SIZE, f);
if (res < HEADER_STRING_SIZE + VERSION_STRING_SIZE) {
if (debug_cache)
pwarn("%s: cache file '%s' invalid size\n", progname, cachename);
return false;
}
/* 12 byte header that is always the same and then 4 byte version # */
if (memcmp(buffer, header_string, HEADER_STRING_SIZE) != 0) {
if (debug_cache)
pwarn("%s: cache file '%s' has wrong header\n", progname, cachename);
return false;
}
uint32_t version = cpu_to_le32(ENCODE_VERSION(force_complain,
policy_version,
parser_abi_version,
kernel_abi_version));
if (memcmp(buffer + HEADER_STRING_SIZE, &version, VERSION_STRING_SIZE) != 0) {
if (debug_cache)
pwarn("%s: cache file '%s' has wrong version\n", progname, cachename);
return false;
}
return true;
}
void set_cache_tstamp(struct timespec t)
{
mru_skip_cache = 0;
cache_tstamp = t;
}
void update_mru_tstamp(FILE *file, const char *name)
{
struct stat stat_file;
if (fstat(fileno(file), &stat_file))
return;
if (tstamp_cmp(mru_policy_tstamp, stat_file.st_mtim) < 0)
/* keep track of the most recent policy tstamp */
mru_policy_tstamp = stat_file.st_mtim;
if (tstamp_is_null(cache_tstamp))
return;
if (tstamp_cmp(stat_file.st_mtim, cache_tstamp) > 0) {
if (debug_cache)
pwarn("%s: file '%s' is newer than cache file\n", progname, name);
mru_skip_cache = 1;
}
}
char *cache_filename(aa_policy_cache *pc, int dir, const char *basename)
{
char *cachename;
autofree char *path;
path = aa_policy_cache_dir_path(pc, dir);
if (!path || asprintf(&cachename, "%s/%s", path, basename) < 0) {
PERROR("Memory allocation error.");
return NULL;
}
return cachename;
}
void valid_read_cache(const char *cachename)
{
struct stat stat_bin;
/* Load a binary cache if it exists and is newest */
if (!skip_read_cache) {
if (stat(cachename, &stat_bin) == 0 &&
stat_bin.st_size > 0) {
if (valid_cached_file_version(cachename))
set_cache_tstamp(stat_bin.st_mtim);
else if (!cond_clear_cache)
write_cache = 0;
} else {
if (!cond_clear_cache)
write_cache = 0;
if (debug_cache)
pwarn("%s: Invalid or missing cache file '%s' (%s)\n", progname, cachename, strerror(errno));
}
}
}
int cache_hit(const char *cachename)
{
if (!mru_skip_cache) {
if (show_cache)
PERROR("Cache hit: %s\n", cachename);
return true;
}
return false;
}
int setup_cache_tmp(const char **cachetmpname, const char *cachename)
{
char *tmpname;
int cache_fd = -1;
*cachetmpname = NULL;
if (write_cache) {
/* Otherwise, set up to save a cached copy */
if (asprintf(&tmpname, "%s-XXXXXX", cachename) < 0) {
perror("asprintf");
return -1;
}
if ((cache_fd = mkstemp(tmpname)) < 0) {
perror("mkstemp");
return -1;
}
*cachetmpname = tmpname;
}
return cache_fd;
}
void install_cache(const char *cachetmpname, const char *cachename)
{
/* Only install the generate cache file if it parsed correctly
and did not have write/close errors */
if (cachetmpname) {
struct timespec times[2];
/* set the mtime of the cache file to the most newest mtime
* of policy files used to generate it
*/
times[0].tv_sec = 0;
times[0].tv_nsec = UTIME_OMIT;
times[1] = mru_policy_tstamp;
if (utimensat(AT_FDCWD, cachetmpname, times, 0) < 0) {
PERROR("%s: Failed to set the mtime of cache file '%s': %m\n",
progname, cachename);
unlink(cachetmpname);
return;
}
if (rename(cachetmpname, cachename) < 0) {
pwarn("Warning failed to write cache: %s\n", cachename);
unlink(cachetmpname);
}
else if (show_cache) {
PERROR("Wrote cache: %s\n", cachename);
}
}
}
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