Change "date added" attribute of a file on OSX

Question

I have been using Terminal to change the "date added" attribute of a file without success.

What I'm doing is:

1. Display the attributes of a file:

   mdls file_name

2. Display the "date added" attribute:

   xattr -p "kMDItemDateAdded" file_name

3. Change it:

   sudo xattr -w "kMDItemDateAdded" "201111111111.11" file_name

The third instruction does not work! Whereas touching the file with the same date value DOES change date modified.

I'm running Yosemite. Any ideas from the community?

Answer 1

Thanks to Ken Thomases above for pointing me in the direction of setattrlist; the following code works for me on macOS Monterey 12.5.1.

#include <stdlib.h>
#include <string.h>
#include <sys/attr.h>
#include <unistd.h>

/*
 * Get kMDItemDateAdded of path.
 *
 * Returns:
 *   • 0 on success
 *   • 1 if a system call failed: check errno
 *   • 2 if something else went wrong
 */
int get_date_added(const char* path, struct timespec * out) {
    attrgroup_t request_attrs = ATTR_CMN_RETURNED_ATTRS | ATTR_CMN_ADDEDTIME;

    struct attrlist request;
    memset(&request, 0, sizeof(request));
    request.bitmapcount = ATTR_BIT_MAP_COUNT;
    request.commonattr = request_attrs;

    typedef struct {
        u_int32_t length;
        attribute_set_t returned;
        struct timespec added;
    } __attribute__((aligned(4), packed)) response_buf_t;

    response_buf_t response;

    int err = getattrlist(path, &request, &response, sizeof(response), 0);
    if (err != 0) {
        return 1;
    }
    if (response.length != sizeof(response)) {
        // Need a different-sized buffer; but provided one of exactly required
        // size?!
        return 2;
    }
    if (response.returned.commonattr != request_attrs) {
        // Didn’t get back all requested common attributes
        return 2;
    }

    out->tv_sec = response.added.tv_sec;
    out->tv_nsec = response.added.tv_nsec;

    return 0;
}

/*
 * Set kMDItemDateAdded of path.
 *
 * Returns:
 *   • 0 on success
 *   • 1 if a system call failed: check errno
 */
int set_date_added(const char* path, struct timespec in) {
    attrgroup_t request_attrs = ATTR_CMN_ADDEDTIME;

    struct attrlist request;
    memset(&request, 0, sizeof(request));
    request.bitmapcount = ATTR_BIT_MAP_COUNT;
    request.commonattr = request_attrs;

    typedef struct {
        struct timespec added;
    } __attribute__((aligned(4), packed)) request_buf_t;

    request_buf_t request_buf;
    request_buf.added.tv_sec = in.tv_sec;
    request_buf.added.tv_nsec = in.tv_nsec;

    int err = setattrlist(path, &request, &request_buf, sizeof(request_buf), 0);
    if (err != 0) {
        return 1;
    }

    return 0;
}