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| | /*
* Copyright (C) 2012-2020 all contributors <cmogstored-public@yhbt.net>
* License: GPL-3.0+ <https://www.gnu.org/licenses/gpl-3.0.txt>
*
* All path operations we support are relative to mog_svc.docroot.
* Absolute path lookups are sometimes more expensive, especially
* for deeper directory structures, so we'll favor AT_FILE functions.
*
* However, it's somewhat common for systems to have AT_FILE functions
* to be available on the system they're built on, but not available
* on the system the code is deployed on. We'll provide fallbacks to
* the absolute path variants for everything.
*/
#include "cmogstored.h"
#define MY_PATHMAX 256
#ifndef O_NOATIME
# define O_NOATIME 0
#endif
static int noatime_flags = O_RDONLY | O_NOATIME;
static int put_flags = O_RDWR;
/*
* Like AT_FILE functions, we may be built on systems with O_CLOEXEC and
* run on systems without it. O_CLOEXEC is still too recent and was
* broken on some Linux kernels, so we always run cloexec_detect.c at
* startup.
*/
#ifdef O_CLOEXEC
void mog_cloexec_works(void)
{
noatime_flags |= O_CLOEXEC;
put_flags |= O_CLOEXEC;
}
#endif /* O_CLOEXEC */
/* we only use real *at syscalls, Gnulib workalikes aren't thread-safe */
#define GET_FSPATH(DST,SRC) do { \
int rc = snprintf((DST), sizeof(DST), "%s%s", svc->docroot, (SRC)); \
if (rc <= 0 || rc >= sizeof(DST)) { \
errno = ENAMETOOLONG; \
return -1; \
} \
} while (0)
#ifndef HAVE_FSTATAT
int mog_stat(struct mog_svc *svc, const char *path, struct stat *sb)
{
char fspath[MY_PATHMAX];
GET_FSPATH(fspath, path);
return stat(fspath, sb);
}
#endif /* !HAVE_FSTATAT */
#ifdef HAVE_OPENAT
static int open_read(struct mog_svc *svc, const char *path)
{
return openat(svc->docroot_fd, path + 1, noatime_flags);
}
int mog_open_put(struct mog_svc *svc, const char *path, int flags)
{
return openat(svc->docroot_fd, path + 1, flags | put_flags, 0600);
}
#else /* !HAVE_OPENAT */
MOG_NOINLINE static int open_read(struct mog_svc *svc, const char *path)
{
char fspath[MY_PATHMAX];
GET_FSPATH(fspath, path);
return open(fspath, noatime_flags);
}
int mog_open_put(struct mog_svc *svc, const char *path, int flags)
{
char fspath[MY_PATHMAX];
GET_FSPATH(fspath, path);
return open(fspath, flags | put_flags, 0600);
}
#endif /* !HAVE_OPENAT */
int mog_open_read(struct mog_svc *svc, const char *path)
{
int fd;
retry:
fd = open_read(svc, path);
if (fd < 0 && errno != ENOENT && (noatime_flags & O_NOATIME)) {
noatime_flags = O_RDONLY;
goto retry;
}
return fd;
}
#ifndef HAVE_UNLINKAT
int mog_unlink(struct mog_svc *svc, const char *path)
{
char fspath[MY_PATHMAX];
GET_FSPATH(fspath,path);
return unlink(fspath);
}
#endif /* !HAVE_UNLINKAT */
#ifndef HAVE_RENAMEAT
int mog_rename(struct mog_svc *svc, const char *old, const char *new)
{
char fsnew[MY_PATHMAX];
char fsold[MY_PATHMAX];
GET_FSPATH(fsold, old);
GET_FSPATH(fsnew, new);
return rename(fsold, fsnew);
}
#endif /* !HAVE_RENAMEAT */
#ifndef HAVE_MKDIRAT
int mog_mkdir(struct mog_svc *svc, const char *path, mode_t mode)
{
char fspath[MY_PATHMAX];
GET_FSPATH(fspath, path);
return mkdir(fspath, mode);
}
#endif /* !HAVE_MKDIRAT */
int mog_statvfs(struct mog_svc *svc, struct mog_dev *dev, struct statvfs *v)
{
char fspath[MY_PATHMAX];
int rc = snprintf(fspath, sizeof(fspath), "%s/dev%u",
svc->docroot, dev->devid);
if (rc <= 0) {
errno = ENAMETOOLONG;
return -1;
}
return statvfs(fspath, v);
}
|