file.c

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/*
 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 * Licensed under the GPL
 */

#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <sys/ioctl.h>
#include <sys/mount.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/un.h>
#include <os.h>

static void copy_stat(struct uml_stat *dst, const struct stat64 *src)
{
    *dst = ((struct uml_stat) {
        .ust_dev     = src->st_dev,     /* device */
        .ust_ino     = src->st_ino,     /* inode */
        .ust_mode    = src->st_mode,    /* protection */
        .ust_nlink   = src->st_nlink,   /* number of hard links */
        .ust_uid     = src->st_uid,     /* user ID of owner */
        .ust_gid     = src->st_gid,     /* group ID of owner */
        .ust_size    = src->st_size,    /* total size, in bytes */
        .ust_blksize = src->st_blksize, /* blocksize for filesys I/O */
        .ust_blocks  = src->st_blocks,  /* number of blocks allocated */
        .ust_atime   = src->st_atime,   /* time of last access */
        .ust_mtime   = src->st_mtime,   /* time of last modification */
        .ust_ctime   = src->st_ctime,   /* time of last change */
    });
}

int os_stat_fd(const int fd, struct uml_stat *ubuf)
{
    struct stat64 sbuf;
    int err;

    CATCH_EINTR(err = fstat64(fd, &sbuf));
    if (err < 0)
        return -errno;

    if (ubuf != NULL)
        copy_stat(ubuf, &sbuf);
    return err;
}

int os_stat_file(const char *file_name, struct uml_stat *ubuf)
{
    struct stat64 sbuf;
    int err;

    CATCH_EINTR(err = stat64(file_name, &sbuf));
    if (err < 0)
        return -errno;

    if (ubuf != NULL)
        copy_stat(ubuf, &sbuf);
    return err;
}

int os_access(const char *file, int mode)
{
    int amode, err;

    amode = (mode & OS_ACC_R_OK ? R_OK : 0) |
        (mode & OS_ACC_W_OK ? W_OK : 0) |
        (mode & OS_ACC_X_OK ? X_OK : 0) |
        (mode & OS_ACC_F_OK ? F_OK : 0);

    err = access(file, amode);
    if (err < 0)
        return -errno;

    return 0;
}

/* FIXME? required only by hostaudio (because it passes ioctls verbatim) */
int os_ioctl_generic(int fd, unsigned int cmd, unsigned long arg)
{
    int err;

    err = ioctl(fd, cmd, arg);
    if (err < 0)
        return -errno;

    return err;
}

/* FIXME: ensure namebuf in os_get_if_name is big enough */
int os_get_ifname(int fd, char* namebuf)
{
    if (ioctl(fd, SIOCGIFNAME, namebuf) < 0)
        return -errno;

    return 0;
}

int os_set_slip(int fd)
{
    int disc, sencap;

    disc = N_SLIP;
    if (ioctl(fd, TIOCSETD, &disc) < 0)
        return -errno;

    sencap = 0;
    if (ioctl(fd, SIOCSIFENCAP, &sencap) < 0)
        return -errno;

    return 0;
}

int os_mode_fd(int fd, int mode)
{
    int err;

    CATCH_EINTR(err = fchmod(fd, mode));
    if (err < 0)
        return -errno;

    return 0;
}

int os_file_type(char *file)
{
    struct uml_stat buf;
    int err;

    err = os_stat_file(file, &buf);
    if (err < 0)
        return err;

    if (S_ISDIR(buf.ust_mode))
        return OS_TYPE_DIR;
    else if (S_ISLNK(buf.ust_mode))
        return OS_TYPE_SYMLINK;
    else if (S_ISCHR(buf.ust_mode))
        return OS_TYPE_CHARDEV;
    else if (S_ISBLK(buf.ust_mode))
        return OS_TYPE_BLOCKDEV;
    else if (S_ISFIFO(buf.ust_mode))
        return OS_TYPE_FIFO;
    else if (S_ISSOCK(buf.ust_mode))
        return OS_TYPE_SOCK;
    else return OS_TYPE_FILE;
}

int os_file_mode(const char *file, struct openflags *mode_out)
{
    int err;

    *mode_out = OPENFLAGS();

    err = access(file, W_OK);
    if (err && (errno != EACCES))
        return -errno;
    else if (!err)
        *mode_out = of_write(*mode_out);

    err = access(file, R_OK);
    if (err && (errno != EACCES))
        return -errno;
    else if (!err)
        *mode_out = of_read(*mode_out);

    return err;
}

int os_open_file(const char *file, struct openflags flags, int mode)
{
    int fd, err, f = 0;

    if (flags.r && flags.w)
        f = O_RDWR;
    else if (flags.r)
        f = O_RDONLY;
    else if (flags.w)
        f = O_WRONLY;
    else f = 0;

    if (flags.s)
        f |= O_SYNC;
    if (flags.c)
        f |= O_CREAT;
    if (flags.t)
        f |= O_TRUNC;
    if (flags.e)
        f |= O_EXCL;
    if (flags.a)
        f |= O_APPEND;

    fd = open64(file, f, mode);
    if (fd < 0)
        return -errno;

    if (flags.cl && fcntl(fd, F_SETFD, 1)) {
        err = -errno;
        close(fd);
        return err;
    }

    return fd;
}

int os_connect_socket(const char *name)
{
    struct sockaddr_un sock;
    int fd, err;

    sock.sun_family = AF_UNIX;
    snprintf(sock.sun_path, sizeof(sock.sun_path), "%s", name);

    fd = socket(AF_UNIX, SOCK_STREAM, 0);
    if (fd < 0) {
        err = -errno;
        goto out;
    }

    err = connect(fd, (struct sockaddr *) &sock, sizeof(sock));
    if (err) {
        err = -errno;
        goto out_close;
    }

    return fd;

out_close:
    close(fd);
out:
    return err;
}

void os_close_file(int fd)
{
    close(fd);
}

int os_seek_file(int fd, unsigned long long offset)
{
    unsigned long long actual;

    actual = lseek64(fd, offset, SEEK_SET);
    if (actual != offset)
        return -errno;
    return 0;
}

int os_read_file(int fd, void *buf, int len)
{
    int n = read(fd, buf, len);

    if (n < 0)
        return -errno;
    return n;
}

int os_write_file(int fd, const void *buf, int len)
{
    int n = write(fd, (void *) buf, len);

    if (n < 0)
        return -errno;
    return n;
}

int os_file_size(const char *file, unsigned long long *size_out)
{
    struct uml_stat buf;
    int err;

    err = os_stat_file(file, &buf);
    if (err < 0) {
        printk(UM_KERN_ERR "Couldn't stat \"%s\" : err = %d\n", file,
               -err);
        return err;
    }

    if (S_ISBLK(buf.ust_mode)) {
        int fd;
        long blocks;

        fd = open(file, O_RDONLY, 0);
        if (fd < 0) {
            err = -errno;
            printk(UM_KERN_ERR "Couldn't open \"%s\", "
                   "errno = %d\n", file, errno);
            return err;
        }
        if (ioctl(fd, BLKGETSIZE, &blocks) < 0) {
            err = -errno;
            printk(UM_KERN_ERR "Couldn't get the block size of "
                   "\"%s\", errno = %d\n", file, errno);
            close(fd);
            return err;
        }
        *size_out = ((long long) blocks) * 512;
        close(fd);
    }
    else *size_out = buf.ust_size;

    return 0;
}

int os_file_modtime(const char *file, unsigned long *modtime)
{
    struct uml_stat buf;
    int err;

    err = os_stat_file(file, &buf);
    if (err < 0) {
        printk(UM_KERN_ERR "Couldn't stat \"%s\" : err = %d\n", file,
               -err);
        return err;
    }

    *modtime = buf.ust_mtime;
    return 0;
}

int os_set_exec_close(int fd)
{
    int err;

    CATCH_EINTR(err = fcntl(fd, F_SETFD, FD_CLOEXEC));

    if (err < 0)
        return -errno;
    return err;
}

int os_pipe(int *fds, int stream, int close_on_exec)
{
    int err, type = stream ? SOCK_STREAM : SOCK_DGRAM;

    err = socketpair(AF_UNIX, type, 0, fds);
    if (err < 0)
        return -errno;

    if (!close_on_exec)
        return 0;

    err = os_set_exec_close(fds[0]);
    if (err < 0)
        goto error;

    err = os_set_exec_close(fds[1]);
    if (err < 0)
        goto error;

    return 0;

 error:
    printk(UM_KERN_ERR "os_pipe : Setting FD_CLOEXEC failed, err = %d\n",
           -err);
    close(fds[1]);
    close(fds[0]);
    return err;
}

int os_set_fd_async(int fd)
{
    int err, flags;

    flags = fcntl(fd, F_GETFL);
    if (flags < 0)
        return -errno;

    flags |= O_ASYNC | O_NONBLOCK;
    if (fcntl(fd, F_SETFL, flags) < 0) {
        err = -errno;
        printk(UM_KERN_ERR "os_set_fd_async : failed to set O_ASYNC "
               "and O_NONBLOCK on fd # %d, errno = %d\n", fd, errno);
        return err;
    }

    if ((fcntl(fd, F_SETSIG, SIGIO) < 0) ||
        (fcntl(fd, F_SETOWN, os_getpid()) < 0)) {
        err = -errno;
        printk(UM_KERN_ERR "os_set_fd_async : Failed to fcntl F_SETOWN "
               "(or F_SETSIG) fd %d, errno = %d\n", fd, errno);
        return err;
    }

    return 0;
}

int os_clear_fd_async(int fd)
{
    int flags;

    flags = fcntl(fd, F_GETFL);
    if (flags < 0)
        return -errno;

    flags &= ~(O_ASYNC | O_NONBLOCK);
    if (fcntl(fd, F_SETFL, flags) < 0)
        return -errno;
    return 0;
}

int os_set_fd_block(int fd, int blocking)
{
    int flags;

    flags = fcntl(fd, F_GETFL);
    if (flags < 0)
        return -errno;

    if (blocking)
        flags &= ~O_NONBLOCK;
    else
        flags |= O_NONBLOCK;

    if (fcntl(fd, F_SETFL, flags) < 0)
        return -errno;

    return 0;
}

int os_accept_connection(int fd)
{
    int new;

    new = accept(fd, NULL, 0);
    if (new < 0)
        return -errno;
    return new;
}

#ifndef SHUT_RD
#define SHUT_RD 0
#endif

#ifndef SHUT_WR
#define SHUT_WR 1
#endif

#ifndef SHUT_RDWR
#define SHUT_RDWR 2
#endif

int os_shutdown_socket(int fd, int r, int w)
{
    int what, err;

    if (r && w)
        what = SHUT_RDWR;
    else if (r)
        what = SHUT_RD;
    else if (w)
        what = SHUT_WR;
    else
        return -EINVAL;

    err = shutdown(fd, what);
    if (err < 0)
        return -errno;
    return 0;
}

int os_rcv_fd(int fd, int *helper_pid_out)
{
    int new, n;
    char buf[CMSG_SPACE(sizeof(new))];
    struct msghdr msg;
    struct cmsghdr *cmsg;
    struct iovec iov;

    msg.msg_name = NULL;
    msg.msg_namelen = 0;
    iov = ((struct iovec) { .iov_base  = helper_pid_out,
                .iov_len   = sizeof(*helper_pid_out) });
    msg.msg_iov = &iov;
    msg.msg_iovlen = 1;
    msg.msg_control = buf;
    msg.msg_controllen = sizeof(buf);
    msg.msg_flags = 0;

    n = recvmsg(fd, &msg, 0);
    if (n < 0)
        return -errno;
    else if (n != iov.iov_len)
        *helper_pid_out = -1;

    cmsg = CMSG_FIRSTHDR(&msg);
    if (cmsg == NULL) {
        printk(UM_KERN_ERR "rcv_fd didn't receive anything, "
               "error = %d\n", errno);
        return -1;
    }
    if ((cmsg->cmsg_level != SOL_SOCKET) ||
        (cmsg->cmsg_type != SCM_RIGHTS)) {
        printk(UM_KERN_ERR "rcv_fd didn't receive a descriptor\n");
        return -1;
    }

    new = ((int *) CMSG_DATA(cmsg))[0];
    return new;
}

int os_create_unix_socket(const char *file, int len, int close_on_exec)
{
    struct sockaddr_un addr;
    int sock, err;

    sock = socket(PF_UNIX, SOCK_DGRAM, 0);
    if (sock < 0)
        return -errno;

    if (close_on_exec) {
        err = os_set_exec_close(sock);
        if (err < 0)
            printk(UM_KERN_ERR "create_unix_socket : "
                   "close_on_exec failed, err = %d", -err);
    }

    addr.sun_family = AF_UNIX;

    snprintf(addr.sun_path, len, "%s", file);

    err = bind(sock, (struct sockaddr *) &addr, sizeof(addr));
    if (err < 0)
        return -errno;

    return sock;
}

void os_flush_stdout(void)
{
    fflush(stdout);
}

int os_lock_file(int fd, int excl)
{
    int type = excl ? F_WRLCK : F_RDLCK;
    struct flock lock = ((struct flock) { .l_type   = type,
                          .l_whence = SEEK_SET,
                          .l_start  = 0,
                          .l_len    = 0 } );
    int err, save;

    err = fcntl(fd, F_SETLK, &lock);
    if (!err)
        goto out;

    save = -errno;
    err = fcntl(fd, F_GETLK, &lock);
    if (err) {
        err = -errno;
        goto out;
    }

    printk(UM_KERN_ERR "F_SETLK failed, file already locked by pid %d\n",
           lock.l_pid);
    err = save;
 out:
    return err;
}

unsigned os_major(unsigned long long dev)
{
    return major(dev);
}

unsigned os_minor(unsigned long long dev)
{
    return minor(dev);
}

unsigned long long os_makedev(unsigned major, unsigned minor)
{
    return makedev(major, minor);
}