btrfs-progs/utils-lib.c

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#include "kerncompat.h"
#include "common/utils.h"
#include <unistd.h>
#include <stdlib.h>
#include <limits.h>
#include <sys/ioctl.h>
#include <ioctl.h>
#if BTRFS_FLAT_INCLUDES
#include "ctree.h"
#else
#include <btrfs/ctree.h>
#endif /* BTRFS_FLAT_INCLUDES */
/*
* This function should be only used when parsing command arg, it won't return
* error to its caller and rather exit directly just like usage().
*/
u64 arg_strtou64(const char *str)
{
u64 value;
char *ptr_parse_end = NULL;
value = strtoull(str, &ptr_parse_end, 0);
if (ptr_parse_end && *ptr_parse_end != '\0') {
fprintf(stderr, "ERROR: %s is not a valid numeric value.\n",
str);
exit(1);
}
/*
* if we pass a negative number to strtoull, it will return an
* unexpected number to us, so let's do the check ourselves.
*/
if (str[0] == '-') {
fprintf(stderr, "ERROR: %s: negative value is invalid.\n",
str);
exit(1);
}
if (value == ULLONG_MAX) {
fprintf(stderr, "ERROR: %s is too large.\n", str);
exit(1);
}
return value;
}
/*
* For a given:
* - file or directory return the containing tree root id
* - subvolume return its own tree id
* - BTRFS_EMPTY_SUBVOL_DIR_OBJECTID (directory with ino == 2) the result is
* undefined and function returns -1
*/
int lookup_path_rootid(int fd, u64 *rootid)
{
struct btrfs_ioctl_ino_lookup_args args;
int ret;
memset(&args, 0, sizeof(args));
args.treeid = 0;
args.objectid = BTRFS_FIRST_FREE_OBJECTID;
ret = ioctl(fd, BTRFS_IOC_INO_LOOKUP, &args);
if (ret < 0)
return -errno;
*rootid = args.treeid;
return 0;
}