/*
 * POSIX-compatible libc layer
 *
 * Samuel Thibault <Samuel.Thibault@eu.citrix.net>, October 2007
 *
 * Provides the UNIXish part of the standard libc function.
 *
 * Relatively straight-forward: just multiplex the file descriptor operations
 * among the various file types (console, FS, network, ...)
 */

//#define LIBC_VERBOSE
//#define LIBC_DEBUG

#ifdef LIBC_DEBUG
#define DEBUG(fmt,...) printk(fmt, ##__VA_ARGS__)
#else
#define DEBUG(fmt,...)
#endif

#ifdef HAVE_LIBC
#include <os.h>
#include <console.h>
#include <sched.h>
#include <events.h>
#include <wait.h>
#include <netfront.h>
#include <blkfront.h>
#include <fbfront.h>
#include <xenbus.h>
#include <xs.h>

#include <sys/types.h>
#include <sys/unistd.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <time.h>
#include <errno.h>
#include <fcntl.h>
#include <pthread.h>
#include <assert.h>
#include <dirent.h>
#include <stdlib.h>
#include <math.h>

#ifdef HAVE_LWIP
#include <lwip/sockets.h>
#endif
#include <fs.h>

#define debug(fmt, ...) \

#define print_unsupported(fmt, ...) \
    printk("Unsupported function "fmt" called in Mini-OS kernel\n", ## __VA_ARGS__);

/* Crash on function call */
#define unsupported_function_crash(function) \
    int __unsup_##function(void) asm(#function); \
    int __unsup_##function(void) \
    { \
	print_unsupported(#function); \
	do_exit(); \
    }

/* Log and err out on function call */
#define unsupported_function_log(type, function, ret) \
    type __unsup_##function(void) asm(#function); \
    type __unsup_##function(void) \
    { \
	print_unsupported(#function); \
	errno = ENOSYS; \
	return ret; \
    }

/* Err out on function call */
#define unsupported_function(type, function, ret) \
    type __unsup_##function(void) asm(#function); \
    type __unsup_##function(void) \
    { \
	errno = ENOSYS; \
	return ret; \
    }

#define NOFILE 32
extern int xc_evtchn_close(int fd);
extern int xc_interface_close(int fd);

pthread_mutex_t fd_lock = PTHREAD_MUTEX_INITIALIZER;
struct file files[NOFILE] = {
    { .type = FTYPE_CONSOLE }, /* stdin */
    { .type = FTYPE_CONSOLE }, /* stdout */
    { .type = FTYPE_CONSOLE }, /* stderr */
};

DECLARE_WAIT_QUEUE_HEAD(event_queue);

int alloc_fd(enum fd_type type)
{
    int i;
    pthread_mutex_lock(&fd_lock);
    for (i=0; i<NOFILE; i++) {
	if (files[i].type == FTYPE_NONE) {
	    files[i].type = type;
	    pthread_mutex_unlock(&fd_lock);
	    return i;
	}
    }
    pthread_mutex_unlock(&fd_lock);
    printk("Too many opened files\n");
    do_exit();
}

void close_all_files(void)
{
    int i;
    pthread_mutex_lock(&fd_lock);
    for (i=NOFILE - 1; i > 0; i--)
	if (files[i].type != FTYPE_NONE)
            close(i);
    pthread_mutex_unlock(&fd_lock);
}

int dup2(int oldfd, int newfd)
{
    pthread_mutex_lock(&fd_lock);
    if (files[newfd].type != FTYPE_NONE)
	close(newfd);
    // XXX: this is a bit bogus, as we are supposed to share the offset etc
    files[newfd] = files[oldfd];
    pthread_mutex_unlock(&fd_lock);
    return 0;
}

pid_t getpid(void)
{
    return 1;
}

pid_t getppid(void)
{
    return 1;
}

pid_t setsid(void)
{
    return 1;
}

char *getcwd(char *buf, size_t size)
{
    snprintf(buf, size, "/");
    return buf;
}

#define LOG_PATH "/var/log/"

int mkdir(const char *pathname, mode_t mode)
{
    int ret;
    ret = fs_create(fs_import, (char *) pathname, 1, mode);
    if (ret < 0) {
        errno = EIO;
        return -1;
    }
    return 0;
}

int open(const char *pathname, int flags, ...)
{
    int fs_fd, fd;
    /* Ugly, but fine.  */
    if (!strncmp(pathname,LOG_PATH,strlen(LOG_PATH))) {
	fd = alloc_fd(FTYPE_CONSOLE);
        printk("open(%s) -> %d\n", pathname, fd);
        return fd;
    }
    printk("open(%s, %x)", pathname, flags);
    switch (flags & ~O_ACCMODE) {
        case 0:
            fs_fd = fs_open(fs_import, (void *) pathname);
            break;
        case O_CREAT|O_TRUNC:
        {
            va_list ap;
            mode_t mode;
            va_start(ap, flags);
            mode = va_arg(ap, mode_t);
            va_end(ap);
            fs_fd = fs_create(fs_import, (void *) pathname, 0, mode);
            break;
        }
        default:
            printk(" unsupported flags\n");
            do_exit();
    }
    if (fs_fd < 0) {
	errno = EIO;
	return -1;
    }
    fd = alloc_fd(FTYPE_FILE);
    printk("-> %d\n", fd);
    files[fd].file.fd = fs_fd;
    files[fd].file.offset = 0;
    return fd;
}
#if defined(__x86_64__) || defined(__ia64__)
__typeof__(open) open64 __attribute__((__alias__("open")));
#endif

int isatty(int fd)
{
    return files[fd].type == FTYPE_CONSOLE;
}

int read(int fd, void *buf, size_t nbytes)
{
    switch (files[fd].type) {
	case FTYPE_CONSOLE: {
	    int ret;
            DEFINE_WAIT(w);
            while(1) {
                add_waiter(w, console_queue);
                ret = xencons_ring_recv(buf, nbytes);
                if (ret)
                    break;
                schedule();
            }
            remove_waiter(w);
            return ret;
        }
	case FTYPE_FILE: {
	    ssize_t ret;
	    if (nbytes > PAGE_SIZE)
		nbytes = PAGE_SIZE;
	    ret = fs_read(fs_import, files[fd].file.fd, buf, nbytes, files[fd].file.offset);
	    if (ret > 0) {
		files[fd].file.offset += ret;
		return ret;
	    } else if (ret < 0) {
		errno = EIO;
		return -1;
	    }
	    return 0;
	}
#ifdef HAVE_LWIP
	case FTYPE_SOCKET:
	    return lwip_read(files[fd].socket.fd, buf, nbytes);
#endif
	case FTYPE_TAP: {
	    ssize_t ret;
	    ret = netfront_receive(files[fd].tap.dev, buf, nbytes);
	    if (ret <= 0) {
		errno = EAGAIN;
		return -1;
	    }
	    return ret;
	}
        case FTYPE_KBD: {
            int ret, n;
            n = nbytes / sizeof(union xenkbd_in_event);
            ret = kbdfront_receive(files[fd].kbd.dev, buf, n);
	    if (ret <= 0) {
		errno = EAGAIN;
		return -1;
	    }
	    return ret * sizeof(union xenkbd_in_event);
        }
        case FTYPE_FB: {
            int ret, n;
            n = nbytes / sizeof(union xenfb_in_event);
            ret = fbfront_receive(files[fd].fb.dev, buf, n);
	    if (ret <= 0) {
		errno = EAGAIN;
		return -1;
	    }
	    return ret * sizeof(union xenfb_in_event);
        }
	default:
	    break;
    }
    printk("read(%d): Bad descriptor\n", fd);
    errno = EBADF;
    return -1;
}

int write(int fd, const void *buf, size_t nbytes)
{
    switch (files[fd].type) {
	case FTYPE_CONSOLE:
	    console_print((char *)buf, nbytes);
	    return nbytes;
	case FTYPE_FILE: {
	    ssize_t ret;
	    if (nbytes > PAGE_SIZE)
		nbytes = PAGE_SIZE;
	    ret = fs_write(fs_import, files[fd].file.fd, (void *) buf, nbytes, files[fd].file.offset);
	    if (ret > 0) {
		files[fd].file.offset += ret;
		return ret;
	    } else if (ret < 0) {
		errno = EIO;
		return -1;
	    }
	    return 0;
	}
#ifdef HAVE_LWIP
	case FTYPE_SOCKET:
	    return lwip_write(files[fd].socket.fd, (void*) buf, nbytes);
#endif
	case FTYPE_TAP:
	    netfront_xmit(files[fd].tap.dev, (void*) buf, nbytes);
	    return nbytes;
	default:
	    break;
    }
    printk("write(%d): Bad descriptor\n", fd);
    errno = EBADF;
    return -1;
}

off_t lseek(int fd, off_t offset, int whence)
{
    if (files[fd].type != FTYPE_FILE) {
	errno = ESPIPE;
	return (off_t) -1;
    }
    switch (whence) {
	case SEEK_SET:
	    files[fd].file.offset = offset;
	    break;
	case SEEK_CUR:
	    files[fd].file.offset += offset;
	    break;
	case SEEK_END: {
	    struct stat st;
	    int ret;
	    ret = fstat(fd, &st);
	    if (ret)
		return -1;
	    files[fd].file.offset = st.st_size + offset;
	    break;
	}
	default:
	    errno = EINVAL;
	    return -1;
    }
    return files[fd].file.offset;
}
#if defined(__x86_64__) || defined(__ia64__)
__typeof__(lseek) lseek64 __attribute__((__alias__("lseek")));
#endif

int fsync(int fd) {
    switch (files[fd].type) {
	case FTYPE_FILE: {
	    int ret;
	    ret = fs_sync(fs_import, files[fd].file.fd);
	    if (ret < 0) {
		errno = EIO;
		return -1;
	    }
	    return 0;
	}
	default:
	    break;
    }
    printk("fsync(%d): Bad descriptor\n", fd);
    errno = EBADF;
    return -1;
}

int close(int fd)
{
    printk("close(%d)\n", fd);
    switch (files[fd].type) {
        default:
	    files[fd].type = FTYPE_NONE;
	    return 0;
	case FTYPE_FILE: {
	    int ret = fs_close(fs_import, files[fd].file.fd);
	    files[fd].type = FTYPE_NONE;
	    if (ret < 0) {
		errno = EIO;
		return -1;
	    }
	    return 0;
	}
	case FTYPE_XENBUS:
            xs_daemon_close((void*)(intptr_t) fd);
            return 0;
#ifdef HAVE_LWIP
	case FTYPE_SOCKET: {
	    int res = lwip_close(files[fd].socket.fd);
	    files[fd].type = FTYPE_NONE;
	    return res;
	}
#endif
	case FTYPE_XC:
	    xc_interface_close(fd);
	    return 0;
	case FTYPE_EVTCHN:
            xc_evtchn_close(fd);
            return 0;
	case FTYPE_GNTMAP:
	    xc_gnttab_close(fd);
	    return 0;
	case FTYPE_TAP:
	    shutdown_netfront(files[fd].tap.dev);
	    files[fd].type = FTYPE_NONE;
	    return 0;
	case FTYPE_BLK:
            shutdown_blkfront(files[fd].blk.dev);
	    files[fd].type = FTYPE_NONE;
	    return 0;
	case FTYPE_KBD:
            shutdown_kbdfront(files[fd].kbd.dev);
            files[fd].type = FTYPE_NONE;
            return 0;
	case FTYPE_FB:
            shutdown_fbfront(files[fd].fb.dev);
            files[fd].type = FTYPE_NONE;
            return 0;
	case FTYPE_NONE:
	    break;
    }
    printk("close(%d): Bad descriptor\n", fd);
    errno = EBADF;
    return -1;
}

static void init_stat(struct stat *buf)
{
    memset(buf, 0, sizeof(*buf));
    buf->st_dev = 0;
    buf->st_ino = 0;
    buf->st_nlink = 1;
    buf->st_rdev = 0;
    buf->st_blksize = 4096;
    buf->st_blocks = 0;
}

static void stat_from_fs(struct stat *buf, struct fsif_stat_response *stat)
{
    buf->st_mode = stat->stat_mode;
    buf->st_uid = stat->stat_uid;
    buf->st_gid = stat->stat_gid;
    buf->st_size = stat->stat_size;
    buf->st_atime = stat->stat_atime;
    buf->st_mtime = stat->stat_mtime;
    buf->st_ctime = stat->stat_ctime;
}

int stat(const char *path, struct stat *buf)
{
    struct fsif_stat_response stat;
    int ret;
    int fs_fd;
    printk("stat(%s)\n", path);
    fs_fd = fs_open(fs_import, (char*) path);
    if (fs_fd < 0) {
	errno = EIO;
	ret = -1;
	goto out;
    }
    ret = fs_stat(fs_import, fs_fd, &stat);
    if (ret < 0) {
	errno = EIO;
	ret = -1;
	goto outfd;
    }
    init_stat(buf);
    stat_from_fs(buf, &stat);
    ret = 0;

outfd:
    fs_close(fs_import, fs_fd);
out:
    return ret;
}

int fstat(int fd, struct stat *buf)
{
    init_stat(buf);
    switch (files[fd].type) {
	case FTYPE_CONSOLE:
	case FTYPE_SOCKET: {
	    buf->st_mode = (files[fd].type == FTYPE_CONSOLE?S_IFCHR:S_IFSOCK) | S_IRUSR|S_IWUSR;
	    buf->st_uid = 0;
	    buf->st_gid = 0;
	    buf->st_size = 0;
	    buf->st_atime = 
	    buf->st_mtime = 
	    buf->st_ctime = time(NULL);
	    return 0;
	}
	case FTYPE_FILE: {
	    struct fsif_stat_response stat;
	    int ret;
	    ret = fs_stat(fs_import, files[fd].file.fd, &stat);
	    if (ret < 0) {
		errno = EIO;
		return -1;
	    }
	    /* The protocol is a bit evasive about this value */
	    stat_from_fs(buf, &stat);
	    return 0;
	}
	default:
	    break;
    }

    printk("statf(%d): Bad descriptor\n", fd);
    errno = EBADF;
    return -1;
}

int ftruncate(int fd, off_t length)
{
    switch (files[fd].type) {
	case FTYPE_FILE: {
            int ret;
            ret = fs_truncate(fs_import, files[fd].file.fd, length);
	    if (ret < 0) {
		errno = EIO;
		return -1;
	    }
	    return 0;
	}
	default:
	    break;
    }

    printk("ftruncate(%d): Bad descriptor\n", fd);
    errno = EBADF;
    return -1;
}

int remove(const char *pathname)
{
    int ret;
    printk("remove(%s)", pathname);
    ret = fs_remove(fs_import, (char*) pathname);
    if (ret < 0) {
        errno = EIO;
        return -1;
    }
    return 0;
}

int unlink(const char *pathname)
{
    return remove(pathname);
}

int rmdir(const char *pathname)
{
    return remove(pathname);
}

int fcntl(int fd, int cmd, ...)
{
    long arg;
    va_list ap;
    va_start(ap, cmd);
    arg = va_arg(ap, long);
    va_end(ap);

    switch (cmd) {
#ifdef HAVE_LWIP
	case F_SETFL:
	    if (files[fd].type == FTYPE_SOCKET && !(arg & ~O_NONBLOCK)) {
		/* Only flag supported: non-blocking mode */
		uint32_t nblock = !!(arg & O_NONBLOCK);
		return lwip_ioctl(files[fd].socket.fd, FIONBIO, &nblock);
	    }
	    /* Fallthrough */
#endif
	default:
	    printk("fcntl(%d, %d, %lx/%lo)\n", fd, cmd, arg, arg);
	    errno = ENOSYS;
	    return -1;
    }
}

DIR *opendir(const char *name)
{
    DIR *ret;
    ret = malloc(sizeof(*ret));
    ret->name = strdup(name);
    ret->offset = 0;
    ret->entries = NULL;
    ret->curentry = -1;
    ret->nbentries = 0;
    ret->has_more = 1;
    return ret;
}

struct dirent *readdir(DIR *dir)
{
    if (dir->curentry >= 0) {
        free(dir->entries[dir->curentry]);
        dir->entries[dir->curentry] = NULL;
    }
    dir->curentry++;
    if (dir->curentry >= dir->nbentries) {
        dir->offset += dir->nbentries;
        free(dir->entries);
        dir->curentry = -1;
        dir->nbentries = 0;
        if (!dir->has_more)
            return NULL;
        dir->entries = fs_list(fs_import, dir->name, dir->offset, &dir->nbentries, &dir->has_more);
        if (!dir->entries || !dir->nbentries)
            return NULL;
        dir->curentry = 0;
    }
    dir->dirent.d_name = dir->entries[dir->curentry];
    return &dir->dirent;
} 
int closedir(DIR *dir)
{
    int i;
    for (i=0; i<dir->nbentries; i++)
        free(dir->entries[i]);
    free(dir->entries);
    free(dir->name);
    free(dir);
    return 0;
}

/* We assume that only the main thread calls select(). */

static const char file_types[] = {
    [FTYPE_NONE]	= 'N',
    [FTYPE_CONSOLE]	= 'C',
    [FTYPE_FILE]	= 'F',
    [FTYPE_XENBUS]	= 'S',
    [FTYPE_XC]		= 'X',
    [FTYPE_EVTCHN]	= 'E',
    [FTYPE_SOCKET]	= 's',
    [FTYPE_TAP]		= 'T',
    [FTYPE_BLK]		= 'B',
    [FTYPE_KBD]		= 'K',
    [FTYPE_FB]		= 'G',
};
#ifdef LIBC_DEBUG
static void dump_set(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout)
{
    int i, comma;
#define printfds(set) do {\
    comma = 0; \
    for (i = 0; i < nfds; i++) { \
	if (FD_ISSET(i, set)) { \
	    if (comma) \
		printk(", "); \
	    printk("%d(%c)", i, file_types[files[i].type]); \
	    comma = 1; \
	} \
    } \
} while (0)

    printk("[");
    if (readfds)
	printfds(readfds);
    printk("], [");
    if (writefds)
	printfds(writefds);
    printk("], [");
    if (exceptfds)
	printfds(exceptfds);
    printk("], ");
    if (timeout)
	printk("{ %ld, %ld }", timeout->tv_sec, timeout->tv_usec);
}
#else
#define dump_set(nfds, readfds, writefds, exceptfds, timeout)
#endif

/* Just poll without blocking */
static int select_poll(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds)
{
    int i, n = 0;
#ifdef HAVE_LWIP
    int sock_n, sock_nfds = 0;
    fd_set sock_readfds, sock_writefds, sock_exceptfds;
    struct timeval timeout = { .tv_sec = 0, .tv_usec = 0};
#endif

#ifdef LIBC_VERBOSE
    static int nb;
    static int nbread[NOFILE], nbwrite[NOFILE], nbexcept[NOFILE];
    static s_time_t lastshown;

    nb++;
#endif

#ifdef HAVE_LWIP
    /* first poll network */
    FD_ZERO(&sock_readfds);
    FD_ZERO(&sock_writefds);
    FD_ZERO(&sock_exceptfds);
    for (i = 0; i < nfds; i++) {
	if (files[i].type == FTYPE_SOCKET) {
	    if (FD_ISSET(i, readfds)) {
		FD_SET(files[i].socket.fd, &sock_readfds);
		sock_nfds = i+1;
	    }
	    if (FD_ISSET(i, writefds)) {
		FD_SET(files[i].socket.fd, &sock_writefds);
		sock_nfds = i+1;
	    }
	    if (FD_ISSET(i, exceptfds)) {
		FD_SET(files[i].socket.fd, &sock_exceptfds);
		sock_nfds = i+1;
	    }
	}
    }
    DEBUG("lwip_select(");
    dump_set(nfds, &sock_readfds, &sock_writefds, &sock_exceptfds, &timeout);
    DEBUG("); -> ");
    sock_n = lwip_select(sock_nfds, &sock_readfds, &sock_writefds, &sock_exceptfds, &timeout);
    dump_set(nfds, &sock_readfds, &sock_writefds, &sock_exceptfds, &timeout);
    DEBUG("\n");
#endif

    /* Then see others as well. */
    for (i = 0; i < nfds; i++) {
	switch(files[i].type) {
	default:
	    if (FD_ISSET(i, readfds) || FD_ISSET(i, writefds) || FD_ISSET(i, exceptfds))
		printk("bogus fd %d in select\n", i);
	    /* Fallthrough.  */
	case FTYPE_FILE:
	    FD_CLR(i, readfds);
	    FD_CLR(i, writefds);
	    FD_CLR(i, exceptfds);
	    break;
	case FTYPE_CONSOLE:
	    if (FD_ISSET(i, readfds)) {
                if (xencons_ring_avail())
		    n++;
		else
		    FD_CLR(i, readfds);
            }
	    if (FD_ISSET(i, writefds))
                n++;
	    FD_CLR(i, exceptfds);
	    break;
	case FTYPE_XENBUS:
	    if (FD_ISSET(i, readfds)) {
                if (files[i].xenbus.events)
		    n++;
		else
		    FD_CLR(i, readfds);
	    }
	    FD_CLR(i, writefds);
	    FD_CLR(i, exceptfds);
	    break;
	case FTYPE_EVTCHN:
	case FTYPE_TAP:
	case FTYPE_BLK:
	case FTYPE_KBD:
	case FTYPE_FB:
	    if (FD_ISSET(i, readfds)) {
		if (files[i].read)
		    n++;
		else
		    FD_CLR(i, readfds);
	    }
	    FD_CLR(i, writefds);
	    FD_CLR(i, exceptfds);
	    break;
#ifdef HAVE_LWIP
	case FTYPE_SOCKET:
	    if (FD_ISSET(i, readfds)) {
	        /* Optimize no-network-packet case.  */
		if (sock_n && FD_ISSET(files[i].socket.fd, &sock_readfds))
		    n++;
		else
		    FD_CLR(i, readfds);
	    }
            if (FD_ISSET(i, writefds)) {
		if (sock_n && FD_ISSET(files[i].socket.fd, &sock_writefds))
		    n++;
		else
		    FD_CLR(i, writefds);
            }
            if (FD_ISSET(i, exceptfds)) {
		if (sock_n && FD_ISSET(files[i].socket.fd, &sock_exceptfds))
		    n++;
		else
		    FD_CLR(i, exceptfds);
            }
	    break;
#endif
	}
#ifdef LIBC_VERBOSE
	if (FD_ISSET(i, readfds))
	    nbread[i]++;
	if (FD_ISSET(i, writefds))
	    nbwrite[i]++;
	if (FD_ISSET(i, exceptfds))
	    nbexcept[i]++;
#endif
    }
#ifdef LIBC_VERBOSE
    if (NOW() > lastshown + 1000000000ull) {
	lastshown = NOW();
	printk("%lu MB free, ", num_free_pages() / ((1 << 20) / PAGE_SIZE));
	printk("%d(%d): ", nb, sock_n);
	for (i = 0; i < nfds; i++) {
	    if (nbread[i] || nbwrite[i] || nbexcept[i])
		printk(" %d(%c):", i, file_types[files[i].type]);
	    if (nbread[i])
	    	printk(" %dR", nbread[i]);
	    if (nbwrite[i])
		printk(" %dW", nbwrite[i]);
	    if (nbexcept[i])
		printk(" %dE", nbexcept[i]);
	}
	printk("\n");
	memset(nbread, 0, sizeof(nbread));
	memset(nbwrite, 0, sizeof(nbwrite));
	memset(nbexcept, 0, sizeof(nbexcept));
	nb = 0;
    }
#endif
    return n;
}

/* The strategy is to
 * - announce that we will maybe sleep
 * - poll a bit ; if successful, return
 * - if timeout, return
 * - really sleep (except if somebody woke us in the meanwhile) */
int select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
	struct timeval *timeout)
{
    int n, ret;
    fd_set myread, mywrite, myexcept;
    struct thread *thread = get_current();
    s_time_t start = NOW(), stop;
    DEFINE_WAIT(w1);
    DEFINE_WAIT(w2);
    DEFINE_WAIT(w3);
    DEFINE_WAIT(w4);
    DEFINE_WAIT(w5);
    DEFINE_WAIT(w6);

    assert(thread == main_thread);

    DEBUG("select(%d, ", nfds);
    dump_set(nfds, readfds, writefds, exceptfds, timeout);
    DEBUG(");\n");

    if (timeout)
	stop = start + SECONDS(timeout->tv_sec) + timeout->tv_usec * 1000;
    else
	/* just make gcc happy */
	stop = start;

    /* Tell people we're going to sleep before looking at what they are
     * saying, hence letting them wake us if events happen between here and
     * schedule() */
    add_waiter(w1, netfront_queue);
    add_waiter(w2, event_queue);
    add_waiter(w3, blkfront_queue);
    add_waiter(w4, xenbus_watch_queue);
    add_waiter(w5, kbdfront_queue);
    add_waiter(w6, console_queue);

    if (readfds)
        myread = *readfds;
    else
        FD_ZERO(&myread);
    if (writefds)
        mywrite = *writefds;
    else
        FD_ZERO(&mywrite);
    if (exceptfds)
        myexcept = *exceptfds;
    else
        FD_ZERO(&myexcept);

    DEBUG("polling ");
    dump_set(nfds, &myread, &mywrite, &myexcept, timeout);
    DEBUG("\n");
    n = select_poll(nfds, &myread, &mywrite, &myexcept);

    if (n) {
	dump_set(nfds, readfds, writefds, exceptfds, timeout);
	if (readfds)
	    *readfds = myread;
	if (writefds)
	    *writefds = mywrite;
	if (exceptfds)
	    *exceptfds = myexcept;
	DEBUG(" -> ");
	dump_set(nfds, readfds, writefds, exceptfds, timeout);
	DEBUG("\n");
	wake(thread);
	ret = n;
	goto out;
    }
    if (timeout && NOW() >= stop) {
	if (readfds)
	    FD_ZERO(readfds);
	if (writefds)
	    FD_ZERO(writefds);
	if (exceptfds)
	    FD_ZERO(exceptfds);
	timeout->tv_sec = 0;
	timeout->tv_usec = 0;
	wake(thread);
	ret = 0;
	goto out;
    }

    if (timeout)
	thread->wakeup_time = stop;
    schedule();

    if (readfds)
        myread = *readfds;
    else
        FD_ZERO(&myread);
    if (writefds)
        mywrite = *writefds;
    else
        FD_ZERO(&mywrite);
    if (exceptfds)
        myexcept = *exceptfds;
    else
        FD_ZERO(&myexcept);

    n = select_poll(nfds, &myread, &mywrite, &myexcept);

    if (n) {
	if (readfds)
	    *readfds = myread;
	if (writefds)
	    *writefds = mywrite;
	if (exceptfds)
	    *exceptfds = myexcept;
	ret = n;
	goto out;
    }
    errno = EINTR;
    ret = -1;

out:
    remove_waiter(w1);
    remove_waiter(w2);
    remove_waiter(w3);
    remove_waiter(w4);
    remove_waiter(w5);
    remove_waiter(w6);
    return ret;
}

#ifdef HAVE_LWIP
int socket(int domain, int type, int protocol)
{
    int fd, res;
    fd = lwip_socket(domain, type, protocol);
    if (fd < 0)
	return -1;
    res = alloc_fd(FTYPE_SOCKET);
    printk("socket -> %d\n", res);
    files[res].socket.fd = fd;
    return res;
}

int accept(int s, struct sockaddr *addr, socklen_t *addrlen)
{
    int fd, res;
    if (files[s].type != FTYPE_SOCKET) {
	printk("accept(%d): Bad descriptor\n", s);
	errno = EBADF;
	return -1;
    }
    fd = lwip_accept(files[s].socket.fd, addr, addrlen);
    if (fd < 0)
	return -1;
    res = alloc_fd(FTYPE_SOCKET);
    files[res].socket.fd = fd;
    printk("accepted on %d -> %d\n", s, res);
    return res;
}

#define LWIP_STUB(ret, name, proto, args) \
ret name proto \
{ \
    if (files[s].type != FTYPE_SOCKET) { \
	printk(#name "(%d): Bad descriptor\n", s); \
	errno = EBADF; \
	return -1; \
    } \
    s = files[s].socket.fd; \
    return lwip_##name args; \
}

LWIP_STUB(int, bind, (int s, struct sockaddr *my_addr, socklen_t addrlen), (s, my_addr, addrlen))
LWIP_STUB(int, getsockopt, (int s, int level, int optname, void *optval, socklen_t *optlen), (s, level, optname, optval, optlen))
LWIP_STUB(int, setsockopt, (int s, int level, int optname, void *optval, socklen_t optlen), (s, level, optname, optval, optlen))
LWIP_STUB(int, connect, (int s, struct sockaddr *serv_addr, socklen_t addrlen), (s, serv_addr, addrlen))
LWIP_STUB(int, listen, (int s, int backlog), (s, backlog));
LWIP_STUB(ssize_t, recv, (int s, void *buf, size_t len, int flags), (s, buf, len, flags))
LWIP_STUB(ssize_t, recvfrom, (int s, void *buf, size_t len, int flags, struct sockaddr *from, socklen_t *fromlen), (s, buf, len, flags, from, fromlen))
LWIP_STUB(ssize_t, send, (int s, void *buf, size_t len, int flags), (s, buf, len, flags))
LWIP_STUB(ssize_t, sendto, (int s, void *buf, size_t len, int flags, struct sockaddr *to, socklen_t tolen), (s, buf, len, flags, to, tolen))
LWIP_STUB(int, getsockname, (int s, struct sockaddr *name, socklen_t *namelen), (s, name, namelen))
#endif

int nanosleep(const struct timespec *req, struct timespec *rem)
{
    s_time_t start = NOW();
    s_time_t stop = start + SECONDS(req->tv_sec) + req->tv_nsec;
    s_time_t stopped;
    struct thread *thread = get_current();

    thread->wakeup_time = stop;
    clear_runnable(thread);
    schedule();
    stopped = NOW();

    if (rem)
    {
	s_time_t remaining = stop - stopped;
	if (remaining > 0)
	{
	    rem->tv_nsec = remaining % 1000000000ULL;
	    rem->tv_sec  = remaining / 1000000000ULL;
	} else memset(rem, 0, sizeof(*rem));
    }

    return 0;
}

int usleep(useconds_t usec)
{
    /* "usec shall be less than one million."  */
    struct timespec req;
    req.tv_nsec = usec * 1000;
    req.tv_sec = 0;

    if (nanosleep(&req, NULL))
	return -1;

    return 0;
}

unsigned int sleep(unsigned int seconds)
{
    struct timespec req, rem;
    req.tv_sec = seconds;
    req.tv_nsec = 0;

    if (nanosleep(&req, &rem))
	return -1;

    if (rem.tv_nsec > 0)
	rem.tv_sec++;

    return rem.tv_sec;
}

int clock_gettime(clockid_t clk_id, struct timespec *tp)
{
    switch (clk_id) {
	case CLOCK_MONOTONIC:
	{
	    struct timeval tv;

	    gettimeofday(&tv, NULL);

	    tp->tv_sec = tv.tv_sec;
	    tp->tv_nsec = tv.tv_usec * 1000;

	    break;
	}
	case CLOCK_REALTIME:
	{
	    u64 nsec = monotonic_clock();

	    tp->tv_sec = nsec / 1000000000ULL;
	    tp->tv_nsec = nsec % 1000000000ULL;

	    break;
	}
	default:
	    print_unsupported("clock_gettime(%d)", clk_id);
	    errno = EINVAL;
	    return -1;
    }

    return 0;
}

size_t getpagesize(void)
{
    return PAGE_SIZE;
}

void *mmap(void *start, size_t length, int prot, int flags, int fd, off_t offset)
{
    unsigned long n = (length + PAGE_SIZE - 1) / PAGE_SIZE;

    ASSERT(!start);
    ASSERT(prot == (PROT_READ|PROT_WRITE));
    ASSERT((fd == -1 && (flags == (MAP_SHARED|MAP_ANON) || flags == (MAP_PRIVATE|MAP_ANON)))
        || (fd != -1 && flags == MAP_SHARED));
    ASSERT(offset == 0);

    if (fd == -1)
        return map_zero(n, 1);
    else if (files[fd].type == FTYPE_XC) {
        unsigned long zero = 0;
        return map_frames_ex(&zero, n, 0, 0, 1, DOMID_SELF, 0, 0);
    } else ASSERT(0);
}
#if defined(__x86_64__) || defined(__ia64__)
__typeof__(mmap) mmap64 __attribute__((__alias__("mmap")));
#endif

int munmap(void *start, size_t length)
{
    int i, n = length / PAGE_SIZE;
    multicall_entry_t call[n];
    unsigned char (*data)[PAGE_SIZE] = start;
    int ret;
    ASSERT(!((unsigned long)start & ~PAGE_MASK));
    ASSERT(!(length & ~PAGE_MASK));

    for (i = 0; i < n; i++) {
	call[i].op = __HYPERVISOR_update_va_mapping;
	call[i].args[0] = (unsigned long) &data[i];
	call[i].args[1] = 0;
	call[i].args[2] = 0;
	call[i].args[3] = UVMF_INVLPG;
    }

    ret = HYPERVISOR_multicall(call, n);
    if (ret) {
	errno = -ret;
	return -1;
    }

    for (i = 0; i < n; i++) {
	if (call[i].result) {
	    errno = call[i].result;
	    return -1;
	}
    }
    return 0;
}

void sparse(unsigned long data, size_t size)
{
    unsigned long newdata;
    xen_pfn_t *mfns;
    int i, n;

    newdata = (data + PAGE_SIZE - 1) & PAGE_MASK;
    if (newdata - data > size)
        return;
    size -= newdata - data;
    data = newdata;
    n = size / PAGE_SIZE;
    size = n * PAGE_SIZE;

    mfns = malloc(n * sizeof(*mfns));
    for (i = 0; i < n; i++) {
#ifdef LIBC_DEBUG
        int j;
        for (j=0; j<PAGE_SIZE; j++)
            if (((char*)data + i * PAGE_SIZE)[j]) {
                printk("%lx is not zero!\n", data + i * PAGE_SIZE + j);
                exit(1);
            }
#endif
        mfns[i] = virtual_to_mfn(data + i * PAGE_SIZE);
    }

    printk("sparsing %ldMB at %lx\n", size >> 20, data);

    munmap((void *) data, size);
    free_physical_pages(mfns, n);
    do_map_zero(data, n);
}


/* Not supported by FS yet.  */
unsupported_function_crash(link);
unsupported_function(int, readlink, -1);
unsupported_function_crash(umask);

/* We could support that.  */
unsupported_function_log(int, chdir, -1);

/* No dynamic library support.  */ 
unsupported_function_log(void *, dlopen, NULL);
unsupported_function_log(void *, dlsym, NULL);
unsupported_function_log(char *, dlerror, NULL);
unsupported_function_log(int, dlclose, -1);

/* We don't raise signals anyway.  */
unsupported_function(int, sigemptyset, -1);
unsupported_function(int, sigfillset, -1);
unsupported_function(int, sigaddset, -1);
unsupported_function(int, sigdelset, -1);
unsupported_function(int, sigismember, -1);
unsupported_function(int, sigprocmask, -1);
unsupported_function(int, sigaction, -1);
unsupported_function(int, __sigsetjmp, 0);
unsupported_function(int, sigaltstack, -1);
unsupported_function_crash(kill);

/* Unsupported */
unsupported_function_crash(pipe);
unsupported_function_crash(fork);
unsupported_function_crash(execv);
unsupported_function_crash(execve);
unsupported_function_crash(waitpid);
unsupported_function_crash(wait);
unsupported_function_crash(lockf);
unsupported_function_crash(sysconf);
unsupported_function(int, tcsetattr, -1);
unsupported_function(int, tcgetattr, 0);

/* Linuxish abi for the Caml runtime, don't support */
unsupported_function_log(struct dirent *, readdir64, NULL);
unsupported_function_log(int, getrusage, -1);
unsupported_function_log(int, getrlimit, -1);
unsupported_function_log(int, getrlimit64, -1);
unsupported_function_log(int, __xstat64, -1);
unsupported_function_log(long, __strtol_internal, LONG_MIN);
unsupported_function_log(double, __strtod_internal, HUGE_VAL);
#endif