setxattr(2)

1SETXATTR(2)                Linux Programmer's Manual               SETXATTR(2)
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NAME

6       setxattr, lsetxattr, fsetxattr - set an extended attribute value
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SYNOPSIS

9       #include <sys/xattr.h>
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11       int setxattr(const char *path, const char *name,
12                     const void *value, size_t size, int flags);
13       int lsetxattr(const char *path, const char *name,
14                     const void *value, size_t size, int flags);
15       int fsetxattr(int fd, const char *name,
16                     const void *value, size_t size, int flags);
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DESCRIPTION

19       Extended attributes are name:value pairs associated with inodes (files,
20       directories, symbolic links, etc.).  They are extensions to the  normal
21       attributes  which  are  associated with all inodes in the system (i.e.,
22       the stat(2) data).  A complete overview of extended attributes concepts
23       can be found in xattr(7).
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25       setxattr()  sets the value of the extended attribute identified by name
26       and associated with the given path in the filesystem.  The  size  argu‐
27       ment  specifies  the  size  (in bytes) of value; a zero-length value is
28       permitted.
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30       lsetxattr() is identical to setxattr(), except in the case  of  a  sym‐
31       bolic link, where the extended attribute is set on the link itself, not
32       the file that it refers to.
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34       fsetxattr() is identical to setxattr(), only the extended attribute  is
35       set  on  the  open  file  referred to by fd (as returned by open(2)) in
36       place of path.
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38       An extended attribute name is a null-terminated string.  The  name  in‐
39       cludes  a  namespace  prefix; there may be several, disjoint namespaces
40       associated with an individual inode.  The value of an  extended  attri‐
41       bute  is  a  chunk  of  arbitrary  textual  or binary data of specified
42       length.
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44       By default (i.e., flags is zero), the extended attribute will  be  cre‐
45       ated  if it does not exist, or the value will be replaced if the attri‐
46       bute already exists.  To modify these semantics, one of  the  following
47       values can be specified in flags:
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49       XATTR_CREATE
50              Perform a pure create, which fails if the named attribute exists
51              already.
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53       XATTR_REPLACE
54              Perform a pure replace operation, which fails if the  named  at‐
55              tribute does not already exist.
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RETURN VALUE

58       On  success, zero is returned.  On failure, -1 is returned and errno is
59       set to indicate the error.
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ERRORS

62       EDQUOT Disk quota limits meant that there is insufficient space remain‐
63              ing to store the extended attribute.
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65       EEXIST XATTR_CREATE was specified, and the attribute exists already.
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67       ENODATA
68              XATTR_REPLACE was specified, and the attribute does not exist.
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70       ENOSPC There  is insufficient space remaining to store the extended at‐
71              tribute.
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73       ENOTSUP
74              The namespace prefix of name is not valid.
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76       ENOTSUP
77              Extended attributes are not supported by the filesystem, or  are
78              disabled,
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80       EPERM  The   file   is   marked   immutable   or   append-only.    (See
81              ioctl_iflags(2).)
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83       In addition, the errors documented in stat(2) can also occur.
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85       ERANGE The size of name or value exceeds a filesystem-specific limit.
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VERSIONS

88       These system calls have been available on Linux since kernel 2.4; glibc
89       support is provided since version 2.3.
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CONFORMING TO

92       These system calls are Linux-specific.
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COLOPHON

99       This page is part of release 5.13 of the Linux  man-pages  project.   A
100       description  of  the project, information about reporting bugs, and the
101       latest    version    of    this    page,    can     be     found     at
102       https://www.kernel.org/doc/man-pages/.
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106Linux                             2021-03-22                       SETXATTR(2)