static void before_open(const char *path, int oflag, struct backup_info *info)
{
int srcfd = -1, dstfd = -1, success = 0;
struct stat st;
memset(info, 0, sizeof(*info));
// bail out if not write
if ((oflag & (O_WRONLY | O_RDWR)) == 0)
return;
// FIXME better blacklisting
if (strncmp(path, "/dev/", 5) == 0)
return;
// not implemented
if ((oflag & O_NOFOLLOW) != 0) {
uncolog_set_error(&ufp, 0, "unco:unsupported operation: open with O_NOFOLLOW against file:%s", path);
return;
}
// open source
if ((srcfd = default_open(path, O_RDONLY)) == -1) {
info->errnum = errno;
goto Exit;
}
fstat(srcfd, &st); // TODO need to check error?
// create backup and copy, update the times, and return
if ((info->backup = uncolog_get_linkname(&ufp)) == NULL) {
// errror reported by caller
goto Exit;
}
if ((dstfd = default_open(info->backup, O_WRONLY | O_CREAT | O_EXCL)) == -1) {
info->errnum = errno;
goto Exit;
}
if (kcopyfd(srcfd, dstfd) != 0) {
info->errnum = errno;
goto Exit;
}
if (unco_utimes(dstfd, &st, default_futimes) != 0) {
info->errnum = errno;
goto Exit;
}
success = 1;
Exit:
if (! success) {
if (srcfd != -1)
close(srcfd);
free(info->backup);
info->backup = NULL;
if (dstfd != -1)
close(dstfd);
}
}
int my_open(const char* path)
{
default_open(path);
check_device(drv.device);
set_rc_protocol(drv.device);
return 0;
}
extern void _setup_unco_preload()
{
char *logfn, *env, *dir = NULL, *fnbuf = NULL;
long long log_index;
int dirlock_fd = -1;
// load default handlers
default_open = (int (*)(const char*, int, ...))dlsym(RTLD_NEXT, "open");
default_mkdir = (int (*)(const char *, mode_t))dlsym(RTLD_NEXT, "mkdir");
default_futimes = (int (*)(int, const struct timeval[2]))dlsym(RTLD_NEXT, "futimes");
default_link = (int (*)(const char *, const char *))dlsym(RTLD_NEXT, "link");
default_symlink = (int (*)(const char *, const char *))dlsym(RTLD_NEXT, "symlink");
default_unlink = (int (*)(const char *))dlsym(RTLD_NEXT, "unlink");
default_rmdir = (int (*)(const char *))dlsym(RTLD_NEXT, "rmdir");
default_chown = (int (*)(const char *, uid_t, gid_t))dlsym(RTLD_NEXT, "chown");
// open the log file
if ((env = getenv("UNCO_LOG")) != NULL) {
if (env[0] == '/') {
logfn = env;
} else {
if ((dir = getcwd(NULL, 0)) == NULL) {
perror("unco:could not obtain cwd");
goto Error;
}
if ((fnbuf = ksprintf("%s/%s", dir, env)) == NULL) {
perror("unco");
goto Error;
}
logfn = fnbuf;
}
uncolog_open(&ufp, logfn, 'a', default_open, default_mkdir);
} else {
// no path given; create a new entry in the default dir
if ((dir = unco_get_default_dir(default_mkdir)) == NULL)
goto Error;
// lock the directory
if ((fnbuf = ksprintf("%s/lock", dir)) == NULL) {
perror("unco");
goto Error;
}
if ((dirlock_fd = default_open(fnbuf, O_WRONLY | O_CREAT | O_TRUNC | O_EXLOCK, 0600)) == -1) {
kerr_printf("failed to open file:%s", fnbuf);
goto Error;
}
free(fnbuf);
fnbuf = NULL;
// obtain logindex
if ((log_index = unco_get_next_logindex(dir)) == -1)
goto Error;
if ((fnbuf = ksprintf("%s/%lld", dir, log_index)) == NULL) {
perror("unco");
goto Error;
}
logfn = fnbuf;
// set UNCO_LOG, so that child processes would write to the same file
#if 1
if (set_uncolog_osx(logfn) != 0)
goto Error;
#else
setenv("UNCO_LOG", logfn, 1);
#endif
// open the log
uncolog_open(&ufp, logfn, 'w', default_open, default_mkdir);
// unlock the directory
close(dirlock_fd);
dirlock_fd = -1;
// append meta
if (uncolog_get_fd(&ufp) != -1) {
// setup procedures for a new log
log_meta();
spawn_finalizer();
}
}
free(dir);
free(fnbuf);
return;
Error:
if (dirlock_fd != -1)
close(dirlock_fd);
free(dir);
free(fnbuf);
uncolog_init_fp(&ufp);
}
