listxattr(2)

💖 listxattr(2) — bestie edition ✨

okay so you want to read the listxattr(2) manual page but make it fun?? say less. this is the Linux System Calls Manual entry for the little trio of syscalls that go peek at your extended attribute names. no cap, they're icons. 👑

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🌸 NAME 🌸

listxattr, llistxattr, flistxattr — list extended attribute names 💅

📚 LIBRARY 📚

Standard C library (libc, -lc) — yes bestie, just link the libc like always.

✨ SYNOPSIS ✨

#include <sys/xattr.h>

ssize_t listxattr(const char *path, char *_Nullable list, size_t size);
ssize_t llistxattr(const char *path, char *_Nullable list, size_t size);
ssize_t flistxattr(int fd, char *_Nullable list, size_t size);

look at those three little signatures. triplets. main character energy fr fr. 🫶

💜 DESCRIPTION 💜

Extended attributes are name:value pairs associated with inodes (files, directories, symbolic links, etc.). They are extensions to the normal attributes which are associated with all inodes in the system (i.e., the stat(2) data). A complete overview of extended attributes concepts can be found in xattr(7). 🦋

listxattr() retrieves the list of extended attribute names associated with the given path in the filesystem. The retrieved list is placed in list, a caller-allocated buffer whose size (in bytes) is specified in the argument size. The list is the set of (null-terminated) names, one after the other. Names of extended attributes to which the calling process does not have access may be omitted from the list. The length of the attribute name list is returned. ⭐

llistxattr() is identical to listxattr(), except in the case of a symbolic link, where the list of names of extended attributes associated with the link itself is retrieved, not the file that it refers to. (the extra l is giving "i look at the link bestie, not what it points to" 💅)

flistxattr() is identical to listxattr(), only the open file referred to by fd (as returned by open(2)) is interrogated in place of path. the extra f = file descriptor era. 🔥

A single extended attribute name is a null-terminated string. The name includes a namespace prefix; there may be several, disjoint namespaces associated with an individual inode. 🌈

If size is specified as zero, these calls return the current size of the list of extended attribute names (and leave list unchanged). This can be used to determine the size of the buffer that should be supplied in a subsequent call. (But, bear in mind that there is a possibility that the set of extended attributes may change between the two calls, so that it is still necessary to check the return status from the second call.) not me warning you about a race condition, but yeah, it's lowkey real. 😭

🎀 Example

The list of names is returned as an unordered array of null-terminated character strings (attribute names are separated by null bytes ('\0')), like this:

user.name1\0system.name1\0user.name2\0

Filesystems that implement POSIX ACLs using extended attributes might return a list like this:

system.posix_acl_access\0system.posix_acl_default\0

see?? literally just names glued together with \0 between them. that's the whole vibe. 💀

🫶 RETURN VALUE 🫶

On success, a nonnegative number is returned indicating the size of the extended attribute name list. On failure, -1 is returned and errno is set to indicate the error.

😭 ERRORS 😭

• E2BIG — The size of the list of extended attribute names is larger than the maximum size allowed; the list cannot be retrieved. This can happen on filesystems that support an unlimited number of extended attributes per file, such as XFS, for example. See BUGS.
• ENOTSUP — Extended attributes are not supported by the filesystem, or are disabled. (rip, the filesystem said no 🙈)
• ERANGE — The size of the list buffer is too small to hold the result. (your buffer ate too little, bestie, grow it and try again)

In addition, the errors documented in stat(2) can also occur.

👑 STANDARDS 👑

Linux.

🧚 HISTORY 🧚

Linux 2.4, glibc 2.3. ancient icons honestly. they've been slaying since forever. ✨

💀 BUGS 💀

As noted in xattr(7), the VFS imposes a limit of 64 kB on the size of the extended attribute name list returned by listxattr(). If the total size of attribute names attached to a file exceeds this limit, it is no longer possible to retrieve the list of attribute names.

okay so important: 64 kB cap. go over it and the list is unrecoverable, periodt. no workaround in this page. 🚨

💅 EXAMPLES 💅

The following program demonstrates the usage of listxattr() and getxattr(2). For the file whose pathname is provided as a command-line argument, it lists all extended file attributes and their values.

To keep the code simple, the program assumes that attribute keys and values are constant during the execution of the program. A production program should expect and handle changes during execution of the program. For example, the number of bytes required for attribute keys might increase between the two calls to listxattr(). An application could handle this possibility using a loop that retries the call (perhaps up to a predetermined maximum number of attempts) with a larger buffer each time it fails with the error ERANGE. Calls to getxattr(2) could be handled similarly. (translation: this demo is cute but naive, real code should loop on ERANGE. not me telling you to be robust 💅)

The following output was recorded by first creating a file, setting some extended file attributes, and then listing the attributes with the example program. 🍓

🌸 Example output 🌸

$ touch /tmp/foo;
$ setfattr -n user.fred -v chocolate /tmp/foo;
$ setfattr -n user.frieda -v bar /tmp/foo;
$ setfattr -n user.empty /tmp/foo;
$ ./listxattr /tmp/foo;
user.fred: chocolate
user.frieda: bar
user.empty: <no value>

chocolate fr. the attributes are serving. 🍫✨

💜 Program source (listxattr.c) 💜

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/xattr.h>

int
main(int argc, char *argv[])
{
    char     *buf, *key, *val;
    ssize_t  buflen, keylen, vallen;

    if (argc != 2) {
        fprintf(stderr, "Usage: %s path\n", argv[0]);
        exit(EXIT_FAILURE);
    }

    /*
     * Determine the length of the buffer needed.
     */
    buflen = listxattr(argv[1], NULL, 0);
    if (buflen == -1) {
        perror("listxattr");
        exit(EXIT_FAILURE);
    }
    if (buflen == 0) {
        printf("%s has no attributes.\n", argv[1]);
        exit(EXIT_SUCCESS);
    }

    /*
     * Allocate the buffer.
     */
    buf = malloc(buflen);
    if (buf == NULL) {
        perror("malloc");
        exit(EXIT_FAILURE);
    }

    /*
     * Copy the list of attribute keys to the buffer.
     */
    buflen = listxattr(argv[1], buf, buflen);
    if (buflen == -1) {
        perror("listxattr");
        exit(EXIT_FAILURE);
    }

    /*
     * Loop over the list of zero terminated strings with the
     * attribute keys.  Use the remaining buffer length to determine
     * the end of the list.
     */
    key = buf;
    while (buflen > 0) {

        /*
         * Output attribute key.
         */
        printf("%s: ", key);

        /*
         * Determine length of the value.
         */
        vallen = getxattr(argv[1], key, NULL, 0);
        if (vallen == -1)
            perror("getxattr");

        if (vallen > 0) {

            /*
             * Allocate value buffer.
             * One extra byte is needed to append 0x00.
             */
            val = malloc(vallen + 1);
            if (val == NULL) {
                perror("malloc");
                exit(EXIT_FAILURE);
            }

            /*
             * Copy value to buffer.
             */
            vallen = getxattr(argv[1], key, val, vallen);
            if (vallen == -1) {
                perror("getxattr");
            } else {
                /*
                 * Output attribute value.
                 */
                val[vallen] = 0;
                printf("%s", val);
            }

            free(val);
        } else if (vallen == 0) {
            printf("<no value>");
        }

        printf("\n");

        /*
         * Forward to next attribute key.
         */
        keylen = strlen(key) + 1;
        buflen -= keylen;
        key += keylen;
    }

    free(buf);
    exit(EXIT_SUCCESS);
}

like. that's it. two listxattr calls, one malloc, walk the \0-separated names, done. iconic. 🎀

🌈 SEE ALSO 🌈

getfattr(1), setfattr(1), getxattr(2), open(2), removexattr(2), setxattr(2), stat(2), symlink(7), xattr(7)

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this was brought to you by Linux man-pages 6.20, dated 2026-02-08 — shoutout to the man-pages girlies for keeping listxattr(2) documented since Linux 2.4. mwah. 💖 hope this helped bestie, go forth and enumerate those xattrs ✨🌈💅