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#include <linux/btrfs_tree.h>
#include <linux/magic.h>
#include <sys/statfs.h>
#include <stdbool.h>
#include "prototypes.h"
static bool path_exists(const char *p)
{
struct stat sb;
return stat(p, &sb) == 0;
}
static const char *btrfs_cmd(void)
{
const char *btrfs_paths[] = {"/sbin/btrfs",
"/bin/btrfs", "/usr/sbin/btrfs", "/usr/bin/btrfs", NULL};
const char *p;
int i;
for (i = 0, p = btrfs_paths[i]; p; i++, p = btrfs_paths[i])
if (path_exists(p))
return p;
return NULL;
}
static int run_btrfs_subvolume_cmd(const char *subcmd, const char *arg1, const char *arg2)
{
int status = 0;
const char *cmd = btrfs_cmd();
const char *argv[] = {
"btrfs",
"subvolume",
subcmd,
arg1,
arg2,
NULL
};
if (access(cmd, X_OK)) {
return 1;
}
if (run_command(cmd, argv, NULL, &status))
return -1;
return status;
}
int btrfs_create_subvolume(const char *path)
{
return run_btrfs_subvolume_cmd("create", path, NULL);
}
int btrfs_remove_subvolume(const char *path)
{
return run_btrfs_subvolume_cmd("delete", "-C", path);
}
/* Adapted from btrfsprogs */
/*
* This intentionally duplicates btrfs_util_is_subvolume_fd() instead of opening
* a file descriptor and calling it, because fstat() and fstatfs() don't accept
* file descriptors opened with O_PATH on old kernels (before v3.6 and before
* v3.12, respectively), but stat() and statfs() can be called on a path that
* the user doesn't have read or write permissions to.
*
* returns:
* 1 - btrfs subvolume
* 0 - not btrfs subvolume
* -1 - error
*/
int btrfs_is_subvolume(const char *path)
{
struct stat st;
int ret;
ret = is_btrfs(path);
if (ret <= 0)
return ret;
ret = stat(path, &st);
if (ret == -1)
return -1;
if (st.st_ino != BTRFS_FIRST_FREE_OBJECTID || !S_ISDIR(st.st_mode)) {
return 0;
}
return 1;
}
/* Adapted from btrfsprogs */
int is_btrfs(const char *path)
{
struct statfs sfs;
int ret;
ret = statfs(path, &sfs);
if (ret == -1)
return -1;
return sfs.f_type == BTRFS_SUPER_MAGIC;
}
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