cgitsb/cache.c

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C
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/* cache.c: cache management
*
* Copyright (C) 2006 Lars Hjemli
*
* Licensed under GNU General Public License v2
* (see COPYING for full license text)
*/
#include "cgit.h"
#include "cache.h"
const int NOLOCK = -1;
char *cache_safe_filename(const char *unsafe)
{
static char buf[4][PATH_MAX];
static int bufidx;
char *s;
char c;
bufidx++;
bufidx &= 3;
s = buf[bufidx];
while(unsafe && (c = *unsafe++) != 0) {
if (c == '/' || c == ' ' || c == '&' || c == '|' ||
c == '>' || c == '<' || c == '.')
c = '_';
*s++ = c;
}
*s = '\0';
return buf[bufidx];
}
int cache_exist(struct cacheitem *item)
{
if (stat(item->name, &item->st)) {
item->st.st_mtime = 0;
return 0;
}
return 1;
}
int cache_create_dirs()
{
char *path;
path = fmt("%s", ctx.cfg.cache_root);
if (mkdir(path, S_IRWXU) && errno!=EEXIST)
return 0;
if (!ctx.repo)
return 0;
path = fmt("%s/%s", ctx.cfg.cache_root,
cache_safe_filename(ctx.repo->url));
if (mkdir(path, S_IRWXU) && errno!=EEXIST)
return 0;
if (ctx.qry.page) {
path = fmt("%s/%s/%s", ctx.cfg.cache_root,
cache_safe_filename(ctx.repo->url),
ctx.qry.page);
if (mkdir(path, S_IRWXU) && errno!=EEXIST)
return 0;
}
return 1;
}
int cache_refill_overdue(const char *lockfile)
{
struct stat st;
if (stat(lockfile, &st))
return 0;
else
return (time(NULL) - st.st_mtime > ctx.cfg.cache_max_create_time);
}
int cache_lock(struct cacheitem *item)
{
int i = 0;
char *lockfile = xstrdup(fmt("%s.lock", item->name));
top:
if (++i > ctx.cfg.max_lock_attempts)
die("cache_lock: unable to lock %s: %s",
item->name, strerror(errno));
item->fd = open(lockfile, O_WRONLY|O_CREAT|O_EXCL, S_IRUSR|S_IWUSR);
if (item->fd == NOLOCK && errno == ENOENT && cache_create_dirs())
goto top;
if (item->fd == NOLOCK && errno == EEXIST &&
cache_refill_overdue(lockfile) && !unlink(lockfile))
goto top;
free(lockfile);
return (item->fd > 0);
}
int cache_unlock(struct cacheitem *item)
{
close(item->fd);
return (rename(fmt("%s.lock", item->name), item->name) == 0);
}
int cache_cancel_lock(struct cacheitem *item)
{
return (unlink(fmt("%s.lock", item->name)) == 0);
}
int cache_expired(struct cacheitem *item)
{
if (item->ttl < 0)
return 0;
return item->st.st_mtime + item->ttl * 60 < time(NULL);
}