#include <sys/types.h>
#include <sys/mman.h>
#include <sys/stat.h>

#include <assert.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <dirent.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "_lxcstats.h"

char *
_lxcst_join_path(char *dest, size_t size, const char *left, const char *right)
{
    if (*right != '/') {
        _lxcst_strlcpy(dest, left, size);
        _lxcst_strlcat(dest, "/", size);
        _lxcst_strlcat(dest, right, size);
    } else {
        _lxcst_strlcpy(dest, right, size);
    }

    return (dest);
}

int
_lxcst_isdir(const struct _lxcst_controller *hdl, const struct dirent *d)
{
    struct stat sb;
    char        buf[PATH_MAX];

    _lxcst_join_path(buf, sizeof(buf), hdl->cgroup_dir, d->d_name);

    if (stat(buf, &sb) == -1) {
        warn("can't stat file: %s", buf);
        return (0);
    }

    return (sb.st_mode & S_IFDIR);
}

/*
 * Files under cgroups are virtual and always have a size of zero so we have to
 * do some reallocs.
 */
ssize_t
_lxcst_read_file(const char *path, char **content)
{
    char        buf[1024];
    int         fd;
    ssize_t     ret;
    ssize_t     size;
    char        *p;
    int         sverrno;

    assert(path);
    assert(content);

    *content = NULL;
    size = 0;

    fd = open(path, O_RDONLY);
    if (fd != -1) {

        while (1) {
            ret = read(fd, buf, sizeof(buf));
            if (ret == -1) {
                if (errno == EINTR)
                    continue ;
                break ;
            }
            if (ret == 0)
                break ;

            p = realloc(*content, size + ret);
            if (!p)
                break ;

            *content = p;
            memcpy(&content[0][size], buf, ret);
            size += ret;
        }

        if (*content) {
            close(fd);
            return (size);
        }

        sverrno = errno;
        close(fd);
        errno = sverrno;
    }

    free(*content);
    return (ret);
}