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