#define _GNU_SOURCE
#include <fcntl.h>
#include <unistd.h>
#include <sys/prctl.h>

#include "pthread_impl.h"

int pthread_getname_np(pthread_t thread, char *name, size_t len)
{
    int fd, cs, status = 0;
    char f[sizeof "/proc/self/task//comm" + 3*sizeof(int)];

    if (len < 16) return ERANGE;

    if (thread == pthread_self())
        return prctl(PR_GET_NAME, (unsigned long)name, 0UL, 0UL, 0UL) ? errno : 0;

    snprintf(f, sizeof f, "/proc/self/task/%d/comm", thread->tid);
    pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
    if ((fd = open(f, O_RDONLY|O_CLOEXEC)) < 0 || (len = read(fd, name, len)) < 0) status = errno;
    else name[len-1] = 0; 
    /* remove trailing new line only if successful*/
    /*It seems that Linux indeed always adds a newline, so removing it
    unconditionally seems fine.*/

    if (fd >= 0) close(fd);
    pthread_setcancelstate(cs, 0);
    return status;
}