HelenOS sources

root/uspace/lib/c/generic/io/io.c

DEFINITIONS

1. __stdio_init
2. __stdio_done
3. parse_mode
4. setvbuf
5. setbuf
6. _setvbuf
7. _fallocbuf
8. fopen
9. fdopen
10. _fclose_nofree
11. fclose
12. freopen
13. _fread
14. _fwrite
15. _ffillbuf
16. _fflushbuf
17. fread
18. fwrite
19. fputwc
20. fputuc
21. putwchar
22. putuchar
23. fputc
24. putchar
25. fputs
26. puts
27. fgetc
28. fgets
29. getchar
30. ungetc
31. fseek64
32. ftell64
33. fseek
34. ftell
35. rewind
36. fflush
37. feof
38. ferror
39. clearerr
40. fileno
41. vfs_fsession
42. vfs_fhandle
43. stdio_kio_read
44. stdio_kio_write
45. stdio_kio_flush
46. stdio_vfs_read
47. stdio_vfs_write
48. stdio_vfs_flush

/*
 * Copyright (c) 2005 Martin Decky
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup libc
 * @{
 */
/** @file
 */

#include <stdio.h>
#include <assert.h>
#include <str.h>
#include <errno.h>
#include <limits.h>
#include <stdbool.h>
#include <stdlib.h>
#include <async.h>
#include <io/kio.h>
#include <vfs/vfs.h>
#include <vfs/vfs_sess.h>
#include <vfs/inbox.h>
#include <ipc/loc.h>
#include <adt/list.h>
#include <wchar.h>
#include <uchar.h>
#include "../private/io.h"
#include "../private/stdio.h"

static void _ffillbuf(FILE *stream);
static void _fflushbuf(FILE *stream);

static size_t stdio_kio_read(void *, size_t, size_t, FILE *);
static size_t stdio_kio_write(const void *, size_t, size_t, FILE *);
static int stdio_kio_flush(FILE *);

static size_t stdio_vfs_read(void *, size_t, size_t, FILE *);
static size_t stdio_vfs_write(const void *, size_t, size_t, FILE *);

static int stdio_vfs_flush(FILE *);

/** KIO stream ops */
static __stream_ops_t stdio_kio_ops = {
        .read = stdio_kio_read,
        .write = stdio_kio_write,
        .flush = stdio_kio_flush
};

/** VFS stream ops */
static __stream_ops_t stdio_vfs_ops = {
        .read = stdio_vfs_read,
        .write = stdio_vfs_write,
        .flush = stdio_vfs_flush
};

static FILE stdin_null = {
        .fd = -1,
        .pos = 0,
        .error = true,
        .eof = true,
        .ops = &stdio_vfs_ops,
        .arg = NULL,
        .sess = NULL,
        .btype = _IONBF,
        .buf = NULL,
        .buf_size = 0,
        .buf_head = NULL,
        .buf_tail = NULL,
        .buf_state = _bs_empty
};

static FILE stdout_kio = {
        .fd = -1,
        .pos = 0,
        .error = false,
        .eof = false,
        .ops = &stdio_kio_ops,
        .arg = NULL,
        .sess = NULL,
        .btype = _IOLBF,
        .buf = NULL,
        .buf_size = BUFSIZ,
        .buf_head = NULL,
        .buf_tail = NULL,
        .buf_state = _bs_empty
};

static FILE stderr_kio = {
        .fd = -1,
        .pos = 0,
        .error = false,
        .eof = false,
        .ops = &stdio_kio_ops,
        .arg = NULL,
        .sess = NULL,
        .btype = _IONBF,
        .buf = NULL,
        .buf_size = 0,
        .buf_head = NULL,
        .buf_tail = NULL,
        .buf_state = _bs_empty
};

FILE *stdin = NULL;
FILE *stdout = NULL;
FILE *stderr = NULL;

static LIST_INITIALIZE(files);

void __stdio_init(void)
{
        /*
         * The first three standard file descriptors are assigned for compatibility.
         * This will probably be removed later.
         */
        int infd = inbox_get("stdin");
        if (infd >= 0) {
                int stdinfd = -1;
                (void) vfs_clone(infd, -1, false, &stdinfd);
                assert(stdinfd == 0);
                vfs_open(stdinfd, MODE_READ);
                stdin = fdopen(stdinfd, "r");
        } else {
                stdin = &stdin_null;
                list_append(&stdin->link, &files);
        }

        int outfd = inbox_get("stdout");
        if (outfd >= 0) {
                int stdoutfd = -1;
                (void) vfs_clone(outfd, -1, false, &stdoutfd);
                assert(stdoutfd <= 1);
                while (stdoutfd < 1)
                        (void) vfs_clone(outfd, -1, false, &stdoutfd);
                vfs_open(stdoutfd, MODE_APPEND);
                stdout = fdopen(stdoutfd, "a");
        } else {
                stdout = &stdout_kio;
                list_append(&stdout->link, &files);
        }

        int errfd = inbox_get("stderr");
        if (errfd >= 0) {
                int stderrfd = -1;
                (void) vfs_clone(errfd, -1, false, &stderrfd);
                assert(stderrfd <= 2);
                while (stderrfd < 2)
                        (void) vfs_clone(errfd, -1, false, &stderrfd);
                vfs_open(stderrfd, MODE_APPEND);
                stderr = fdopen(stderrfd, "a");
        } else {
                stderr = &stderr_kio;
                list_append(&stderr->link, &files);
        }
}

void __stdio_done(void)
{
        while (!list_empty(&files)) {
                FILE *file = list_get_instance(list_first(&files), FILE, link);
                fclose(file);
        }
}

static bool parse_mode(const char *fmode, int *mode, bool *create, bool *excl,
    bool *truncate)
{
        /* Parse mode except first character. */
        const char *mp = fmode;

        if (*mp++ == '\0') {
                errno = EINVAL;
                return false;
        }

        if ((*mp == 'b') || (*mp == 't'))
                mp++;

        bool plus;
        if (*mp == '+') {
                mp++;
                plus = true;
        } else {
                plus = false;
        }

        bool ex;
        if (*mp == 'x') {
                mp++;
                ex = true;
        } else {
                ex = false;
        }

        if (*mp != '\0') {
                errno = EINVAL;
                return false;
        }

        *create = false;
        *truncate = false;
        *excl = false;

        /* Parse first character of fmode and determine mode for vfs_open(). */
        switch (fmode[0]) {
        case 'r':
                *mode = plus ? MODE_READ | MODE_WRITE : MODE_READ;
                if (ex) {
                        errno = EINVAL;
                        return false;
                }
                break;
        case 'w':
                *mode = plus ? MODE_READ | MODE_WRITE : MODE_WRITE;
                *create = true;
                *excl = ex;
                if (!plus)
                        *truncate = true;
                break;
        case 'a':
                /* TODO: a+ must read from beginning, append to the end. */
                if (plus) {
                        errno = ENOTSUP;
                        return false;
                }

                if (ex) {
                        errno = EINVAL;
                        return false;
                }

                *mode = MODE_APPEND | (plus ? MODE_READ | MODE_WRITE : MODE_WRITE);
                *create = true;
                break;
        default:
                errno = EINVAL;
                return false;
        }

        return true;
}

/** Set stream buffer. */
int setvbuf(FILE *stream, void *buf, int mode, size_t size)
{
        if (mode != _IONBF && mode != _IOLBF && mode != _IOFBF)
                return -1;

        stream->btype = mode;
        stream->buf = buf;
        stream->buf_size = size;
        stream->buf_head = stream->buf;
        stream->buf_tail = stream->buf;
        stream->buf_state = _bs_empty;

        return 0;
}

/** Set stream buffer.
 *
 * When @p buf is NULL, the stream is set as unbuffered, otherwise
 * full buffering is enabled.
 */
void setbuf(FILE *stream, void *buf)
{
        if (buf == NULL) {
                setvbuf(stream, NULL, _IONBF, BUFSIZ);
        } else {
                setvbuf(stream, buf, _IOFBF, BUFSIZ);
        }
}

static void _setvbuf(FILE *stream)
{
        /* FIXME: Use more complex rules for setting buffering options. */

        switch (stream->fd) {
        case 1:
                setvbuf(stream, NULL, _IOLBF, BUFSIZ);
                break;
        case 0:
        case 2:
                setvbuf(stream, NULL, _IONBF, 0);
                break;
        default:
                setvbuf(stream, NULL, _IOFBF, BUFSIZ);
        }
}

/** Allocate stream buffer. */
static int _fallocbuf(FILE *stream)
{
        assert(stream->buf == NULL);

        stream->buf = malloc(stream->buf_size);
        if (stream->buf == NULL) {
                errno = ENOMEM;
                return EOF;
        }

        stream->buf_head = stream->buf;
        stream->buf_tail = stream->buf;
        return 0;
}

/** Open a stream.
 *
 * @param path Path of the file to open.
 * @param mode Mode string, (r|w|a)[b|t][+][x].
 *
 */
FILE *fopen(const char *path, const char *fmode)
{
        int mode;
        bool create;
        bool excl;
        bool truncate;

        if (!parse_mode(fmode, &mode, &create, &excl, &truncate))
                return NULL;

        /* Open file. */
        FILE *stream = malloc(sizeof(FILE));
        if (stream == NULL) {
                errno = ENOMEM;
                return NULL;
        }

        int flags = WALK_REGULAR;
        if (create && excl)
                flags |= WALK_MUST_CREATE;
        else if (create)
                flags |= WALK_MAY_CREATE;
        int file;
        errno_t rc = vfs_lookup(path, flags, &file);
        if (rc != EOK) {
                errno = rc;
                free(stream);
                return NULL;
        }

        rc = vfs_open(file, mode);
        if (rc != EOK) {
                errno = rc;
                vfs_put(file);
                free(stream);
                return NULL;
        }

        if (truncate) {
                rc = vfs_resize(file, 0);
                if (rc != EOK) {
                        errno = rc;
                        vfs_put(file);
                        free(stream);
                        return NULL;
                }
        }

        stream->fd = file;
        stream->pos = 0;
        stream->error = false;
        stream->eof = false;
        stream->ops = &stdio_vfs_ops;
        stream->arg = NULL;
        stream->sess = NULL;
        stream->need_sync = false;
        _setvbuf(stream);
        stream->ungetc_chars = 0;

        list_append(&stream->link, &files);

        return stream;
}

FILE *fdopen(int fd, const char *mode)
{
        /* Open file. */
        FILE *stream = malloc(sizeof(FILE));
        if (stream == NULL) {
                errno = ENOMEM;
                return NULL;
        }

        stream->fd = fd;
        stream->pos = 0;
        stream->error = false;
        stream->eof = false;
        stream->ops = &stdio_vfs_ops;
        stream->arg = NULL;
        stream->sess = NULL;
        stream->need_sync = false;
        _setvbuf(stream);
        stream->ungetc_chars = 0;

        list_append(&stream->link, &files);

        return stream;
}

static int _fclose_nofree(FILE *stream)
{
        errno_t rc = 0;

        fflush(stream);

        if (stream->sess != NULL)
                async_hangup(stream->sess);

        if (stream->fd >= 0)
                rc = vfs_put(stream->fd);

        list_remove(&stream->link);

        if (rc != EOK) {
                errno = rc;
                return EOF;
        }

        return 0;
}

int fclose(FILE *stream)
{
        int rc = _fclose_nofree(stream);

        if ((stream != &stdin_null) &&
            (stream != &stdout_kio) &&
            (stream != &stderr_kio))
                free(stream);

        return rc;
}

FILE *freopen(const char *path, const char *mode, FILE *stream)
{
        FILE *nstr;

        if (path == NULL) {
                /* Changing mode is not supported */
                return NULL;
        }

        (void) _fclose_nofree(stream);
        nstr = fopen(path, mode);
        if (nstr == NULL) {
                free(stream);
                return NULL;
        }

        list_remove(&nstr->link);
        *stream = *nstr;
        list_append(&stream->link, &files);

        free(nstr);

        return stream;
}

/** Read from a stream (unbuffered).
 *
 * @param buf    Destination buffer.
 * @param size   Size of each record.
 * @param nmemb  Number of records to read.
 * @param stream Pointer to the stream.
 *
 * @return Number of elements successfully read. On error this is less than
 *         nmemb, stream error indicator is set and errno is set.
 */
static size_t _fread(void *buf, size_t size, size_t nmemb, FILE *stream)
{
        return stream->ops->read(buf, size, nmemb, stream);
}

/** Write to a stream (unbuffered).
 *
 * @param buf    Source buffer.
 * @param size   Size of each record.
 * @param nmemb  Number of records to write.
 * @param stream Pointer to the stream.
 *
 * @return Number of elements successfully written. On error this is less than
 *         nmemb, stream error indicator is set and errno is set.
 */
static size_t _fwrite(const void *buf, size_t size, size_t nmemb, FILE *stream)
{
        size_t nwritten;

        if (size == 0 || nmemb == 0)
                return 0;

        nwritten = stream->ops->write(buf, size, nmemb, stream);

        if (nwritten > 0)
                stream->need_sync = true;

        return (nwritten / size);
}

/** Read some data in stream buffer.
 *
 * On error, stream error indicator is set and errno is set.
 */
static void _ffillbuf(FILE *stream)
{
        errno_t rc;
        size_t nread;

        stream->buf_head = stream->buf_tail = stream->buf;

        rc = vfs_read(stream->fd, &stream->pos, stream->buf, stream->buf_size,
            &nread);
        if (rc != EOK) {
                errno = rc;
                stream->error = true;
                return;
        }

        if (nread == 0) {
                stream->eof = true;
                return;
        }

        stream->buf_head += nread;
        stream->buf_state = _bs_read;
}

/** Write out stream buffer, do not sync stream. */
static void _fflushbuf(FILE *stream)
{
        size_t bytes_used;

        if ((!stream->buf) || (stream->btype == _IONBF) || (stream->error))
                return;

        bytes_used = stream->buf_head - stream->buf_tail;

        /* If buffer has prefetched read data, we need to seek back. */
        if (bytes_used > 0 && stream->buf_state == _bs_read)
                stream->pos -= bytes_used;

        /* If buffer has unwritten data, we need to write them out. */
        if (bytes_used > 0 && stream->buf_state == _bs_write) {
                (void) _fwrite(stream->buf_tail, 1, bytes_used, stream);
                /* On error stream error indicator and errno are set by _fwrite */
                if (stream->error)
                        return;
        }

        stream->buf_head = stream->buf;
        stream->buf_tail = stream->buf;
        stream->buf_state = _bs_empty;
}

/** Read from a stream.
 *
 * @param dest   Destination buffer.
 * @param size   Size of each record.
 * @param nmemb  Number of records to read.
 * @param stream Pointer to the stream.
 *
 */
size_t fread(void *dest, size_t size, size_t nmemb, FILE *stream)
{
        uint8_t *dp;
        size_t bytes_left;
        size_t now;
        size_t data_avail;
        size_t total_read;
        size_t i;

        if (size == 0 || nmemb == 0)
                return 0;

        bytes_left = size * nmemb;
        total_read = 0;
        dp = (uint8_t *) dest;

        /* Bytes from ungetc() buffer */
        while (stream->ungetc_chars > 0 && bytes_left > 0) {
                *dp++ = stream->ungetc_buf[--stream->ungetc_chars];
                ++total_read;
                --bytes_left;
        }

        /* If not buffered stream, read in directly. */
        if (stream->btype == _IONBF) {
                total_read += _fread(dest, 1, bytes_left, stream);
                return total_read / size;
        }

        /* Make sure no data is pending write. */
        if (stream->buf_state == _bs_write)
                _fflushbuf(stream);

        /* Perform lazy allocation of stream buffer. */
        if (stream->buf == NULL) {
                if (_fallocbuf(stream) != 0)
                        return 0; /* Errno set by _fallocbuf(). */
        }

        while ((!stream->error) && (!stream->eof) && (bytes_left > 0)) {
                if (stream->buf_head == stream->buf_tail)
                        _ffillbuf(stream);

                if (stream->error || stream->eof) {
                        /* On error errno was set by _ffillbuf() */
                        break;
                }

                data_avail = stream->buf_head - stream->buf_tail;

                if (bytes_left > data_avail)
                        now = data_avail;
                else
                        now = bytes_left;

                for (i = 0; i < now; i++) {
                        dp[i] = stream->buf_tail[i];
                }

                dp += now;
                stream->buf_tail += now;
                bytes_left -= now;
                total_read += now;
        }

        return (total_read / size);
}

/** Write to a stream.
 *
 * @param buf    Source buffer.
 * @param size   Size of each record.
 * @param nmemb  Number of records to write.
 * @param stream Pointer to the stream.
 *
 */
size_t fwrite(const void *buf, size_t size, size_t nmemb, FILE *stream)
{
        uint8_t *data;
        size_t bytes_left;
        size_t now;
        size_t buf_free;
        size_t total_written;
        size_t i;
        uint8_t b;
        bool need_flush;

        if (size == 0 || nmemb == 0)
                return 0;

        /* If not buffered stream, write out directly. */
        if (stream->btype == _IONBF) {
                now = _fwrite(buf, size, nmemb, stream);
                fflush(stream);
                return now;
        }

        /* Make sure buffer contains no prefetched data. */
        if (stream->buf_state == _bs_read)
                _fflushbuf(stream);

        /* Perform lazy allocation of stream buffer. */
        if (stream->buf == NULL) {
                if (_fallocbuf(stream) != 0)
                        return 0; /* Errno set by _fallocbuf(). */
        }

        data = (uint8_t *) buf;
        bytes_left = size * nmemb;
        total_written = 0;
        need_flush = false;

        while ((!stream->error) && (bytes_left > 0)) {
                buf_free = stream->buf_size - (stream->buf_head - stream->buf);
                if (bytes_left > buf_free)
                        now = buf_free;
                else
                        now = bytes_left;

                for (i = 0; i < now; i++) {
                        b = data[i];
                        stream->buf_head[i] = b;

                        if ((b == '\n') && (stream->btype == _IOLBF))
                                need_flush = true;
                }

                data += now;
                stream->buf_head += now;
                buf_free -= now;
                bytes_left -= now;
                total_written += now;
                stream->buf_state = _bs_write;

                if (buf_free == 0) {
                        /* Only need to drain buffer. */
                        _fflushbuf(stream);
                        if (!stream->error)
                                need_flush = false;
                }
        }

        if (need_flush)
                fflush(stream);

        return (total_written / size);
}

wint_t fputwc(wchar_t wc, FILE *stream)
{
        char buf[STR_BOUNDS(1)];
        size_t sz = 0;

        if (chr_encode(wc, buf, &sz, STR_BOUNDS(1)) != EOK) {
                errno = EILSEQ;
                return WEOF;
        }

        size_t wr = fwrite(buf, 1, sz, stream);
        if (wr < sz)
                return WEOF;

        return wc;
}

wint_t fputuc(char32_t wc, FILE *stream)
{
        char buf[STR_BOUNDS(1)];
        size_t sz = 0;

        if (chr_encode(wc, buf, &sz, STR_BOUNDS(1)) != EOK) {
                errno = EILSEQ;
                return WEOF;
        }

        size_t wr = fwrite(buf, 1, sz, stream);
        if (wr < sz)
                return WEOF;

        return wc;
}

wint_t putwchar(wchar_t wc)
{
        return fputwc(wc, stdout);
}

wint_t putuchar(char32_t wc)
{
        return fputuc(wc, stdout);
}

int fputc(int c, FILE *stream)
{
        unsigned char b;
        size_t wr;

        b = (unsigned char) c;
        wr = fwrite(&b, sizeof(b), 1, stream);
        if (wr < 1)
                return EOF;

        return b;
}

int putchar(int c)
{
        return fputc(c, stdout);
}

int fputs(const char *str, FILE *stream)
{
        (void) fwrite(str, str_size(str), 1, stream);
        if (ferror(stream))
                return EOF;
        return 0;
}

int puts(const char *str)
{
        if (fputs(str, stdout) < 0)
                return EOF;
        return putchar('\n');
}

int fgetc(FILE *stream)
{
        char c;

        /* This could be made faster by only flushing when needed. */
        if (stdout)
                fflush(stdout);
        if (stderr)
                fflush(stderr);

        if (fread(&c, sizeof(char), 1, stream) < sizeof(char))
                return EOF;

        return (int) c;
}

char *fgets(char *str, int size, FILE *stream)
{
        int c;
        int idx;

        idx = 0;
        while (idx < size - 1) {
                c = fgetc(stream);
                if (c == EOF)
                        break;

                str[idx++] = c;

                if (c == '\n')
                        break;
        }

        if (ferror(stream))
                return NULL;

        if (idx == 0)
                return NULL;

        str[idx] = '\0';
        return str;
}

int getchar(void)
{
        return fgetc(stdin);
}

int ungetc(int c, FILE *stream)
{
        if (c == EOF)
                return EOF;

        if (stream->ungetc_chars >= UNGETC_MAX)
                return EOF;

        stream->ungetc_buf[stream->ungetc_chars++] =
            (uint8_t)c;

        stream->eof = false;
        return (uint8_t)c;
}

int fseek64(FILE *stream, off64_t offset, int whence)
{
        errno_t rc;

        if (stream->error)
                return -1;

        _fflushbuf(stream);
        if (stream->error) {
                /* errno was set by _fflushbuf() */
                return -1;
        }

        stream->ungetc_chars = 0;

        vfs_stat_t st;
        switch (whence) {
        case SEEK_SET:
                stream->pos = offset;
                break;
        case SEEK_CUR:
                stream->pos += offset;
                break;
        case SEEK_END:
                rc = vfs_stat(stream->fd, &st);
                if (rc != EOK) {
                        errno = rc;
                        stream->error = true;
                        return -1;
                }
                stream->pos = st.size + offset;
                break;
        }

        stream->eof = false;
        return 0;
}

off64_t ftell64(FILE *stream)
{
        if (stream->error)
                return EOF;

        _fflushbuf(stream);
        if (stream->error) {
                /* errno was set by _fflushbuf() */
                return EOF;
        }

        return stream->pos - stream->ungetc_chars;
}

int fseek(FILE *stream, long offset, int whence)
{
        return fseek64(stream, offset, whence);
}

long ftell(FILE *stream)
{
        off64_t off = ftell64(stream);

        /* The native position is too large for the C99-ish interface. */
        if (off > LONG_MAX) {
                errno = EOVERFLOW;
                return -1;
        }

        return off;
}

void rewind(FILE *stream)
{
        (void) fseek(stream, 0, SEEK_SET);
}

int fflush(FILE *stream)
{
        if (stream->error)
                return EOF;

        _fflushbuf(stream);
        if (stream->error) {
                /* errno was set by _fflushbuf() */
                return EOF;
        }

        if (stream->need_sync) {
                /**
                 * Better than syncing always, but probably still not the
                 * right thing to do.
                 */
                if (stream->ops->flush(stream) == EOF)
                        return EOF;

                stream->need_sync = false;
        }

        return 0;
}

int feof(FILE *stream)
{
        return stream->eof;
}

int ferror(FILE *stream)
{
        return stream->error;
}

void clearerr(FILE *stream)
{
        stream->eof = false;
        stream->error = false;
}

int fileno(FILE *stream)
{
        if (stream->ops != &stdio_vfs_ops) {
                errno = EBADF;
                return EOF;
        }

        return stream->fd;
}

async_sess_t *vfs_fsession(FILE *stream, iface_t iface)
{
        if (stream->fd >= 0) {
                if (stream->sess == NULL)
                        stream->sess = vfs_fd_session(stream->fd, iface);

                return stream->sess;
        }

        return NULL;
}

errno_t vfs_fhandle(FILE *stream, int *handle)
{
        if (stream->fd >= 0) {
                *handle = stream->fd;
                return EOK;
        }

        return ENOENT;
}

/** Read from KIO stream. */
static size_t stdio_kio_read(void *buf, size_t size, size_t nmemb, FILE *stream)
{
        stream->eof = true;
        return 0;
}

/** Write to KIO stream. */
static size_t stdio_kio_write(const void *buf, size_t size, size_t nmemb,
    FILE *stream)
{
        errno_t rc;
        size_t nwritten;

        rc = kio_write(buf, size * nmemb, &nwritten);
        if (rc != EOK) {
                stream->error = true;
                nwritten = 0;
        }

        return nwritten / size;
}

/** Flush KIO stream. */
static int stdio_kio_flush(FILE *stream)
{
        kio_update();
        return 0;
}

/** Read from VFS stream. */
static size_t stdio_vfs_read(void *buf, size_t size, size_t nmemb, FILE *stream)
{
        errno_t rc;
        size_t nread;

        if (size == 0 || nmemb == 0)
                return 0;

        rc = vfs_read(stream->fd, &stream->pos, buf, size * nmemb, &nread);
        if (rc != EOK) {
                errno = rc;
                stream->error = true;
        } else if (nread == 0) {
                stream->eof = true;
        }

        return (nread / size);
}

/** Write to VFS stream. */
static size_t stdio_vfs_write(const void *buf, size_t size, size_t nmemb,
    FILE *stream)
{
        errno_t rc;
        size_t nwritten;

        rc = vfs_write(stream->fd, &stream->pos, buf, size * nmemb, &nwritten);
        if (rc != EOK) {
                errno = rc;
                stream->error = true;
        }

        return nwritten / size;
}

/** Flush VFS stream. */
static int stdio_vfs_flush(FILE *stream)
{
        errno_t rc;

        rc = vfs_sync(stream->fd);
        if (rc != EOK) {
                errno = rc;
                return EOF;
        }

        return 0;
}

/** @}
 */