source: mainline/uspace/lib/c/generic/io/io.c@ e86a617a

/*
 * 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 <unistd.h>
#include <fcntl.h>
#include <assert.h>
#include <str.h>
#include <errno.h>
#include <stdbool.h>
#include <malloc.h>
#include <async.h>
#include <io/kio.h>
#include <vfs/vfs.h>
#include <vfs/vfs_sess.h>
#include <ipc/loc.h>
#include <adt/list.h>
#include "../private/io.h"
#include "../private/stdio.h"

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

static FILE stdin_null = {
        .fd = -1,
        .error = true,
        .eof = true,
        .kio = false,
        .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,
        .error = false,
        .eof = false,
        .kio = true,
        .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,
        .error = false,
        .eof = false,
        .kio = true,
        .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(int filc)
{
        if (filc > 0) {
                stdin = fdopen(0, "r");
        } else {
                stdin = &stdin_null;
                list_append(&stdin->link, &files);
        }
        
        if (filc > 1) {
                stdout = fdopen(1, "w");
        } else {
                stdout = &stdout_kio;
                list_append(&stdout->link, &files);
        }
        
        if (filc > 2) {
                stderr = fdopen(2, "w");
        } 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 *mode, int *flags)
{
        /* Parse mode except first character. */
        const char *mp = mode;
        if (*mp++ == 0) {
                errno = EINVAL;
                return false;
        }
        
        if ((*mp == 'b') || (*mp == 't'))
                mp++;
        
        bool plus;
        if (*mp == '+') {
                mp++;
                plus = true;
        } else
                plus = false;
        
        if (*mp != 0) {
                errno = EINVAL;
                return false;
        }
        
        /* Parse first character of mode and determine flags for open(). */
        switch (mode[0]) {
        case 'r':
                *flags = plus ? O_RDWR : O_RDONLY;
                break;
        case 'w':
                *flags = (O_TRUNC | O_CREAT) | (plus ? O_RDWR : O_WRONLY);
                break;
        case 'a':
                /* TODO: a+ must read from beginning, append to the end. */
                if (plus) {
                        errno = ENOTSUP;
                        return false;
                }
                *flags = (O_APPEND | O_CREAT) | (plus ? O_RDWR : O_WRONLY);
                break;
        default:
                errno = EINVAL;
                return false;
        }
        
        return true;
}

/** Set stream buffer. */
void setvbuf(FILE *stream, void *buf, int mode, size_t size)
{
        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;
}

/** 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][+].
 *
 */
FILE *fopen(const char *path, const char *mode)
{
        int flags;
        if (!parse_mode(mode, &flags))
                return NULL;
        
        /* Open file. */
        FILE *stream = malloc(sizeof(FILE));
        if (stream == NULL) {
                errno = ENOMEM;
                return NULL;
        }
        
        stream->fd = open(path, flags, 0666);
        if (stream->fd < 0) {
                /* errno was set by open() */
                free(stream);
                return NULL;
        }
        
        stream->error = false;
        stream->eof = false;
        stream->kio = false;
        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->error = false;
        stream->eof = false;
        stream->kio = false;
        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)
{
        int rc = 0;
        
        fflush(stream);
        
        if (stream->sess != NULL)
                async_hangup(stream->sess);
        
        if (stream->fd >= 0)
                rc = close(stream->fd);
        
        list_remove(&stream->link);
        
        if (rc != 0) {
                /* errno was set by close() */
                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)
{
        size_t left, done;

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

        left = size * nmemb;
        done = 0;
        
        while ((left > 0) && (!stream->error) && (!stream->eof)) {
                ssize_t rd = read(stream->fd, buf + done, left);
                
                if (rd < 0) {
                        /* errno was set by read() */
                        stream->error = true;
                } else if (rd == 0) {
                        stream->eof = true;
                } else {
                        left -= rd;
                        done += rd;
                }
        }
        
        return (done / size);
}

/** 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 left;
        size_t done;
        int rc;

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

        left = size * nmemb;
        done = 0;

        while ((left > 0) && (!stream->error)) {
                ssize_t wr;
                size_t uwr;
                
                if (stream->kio) {
                        uwr = 0;
                        rc = kio_write(buf + done, left, &uwr);
                        if (rc != EOK)
                                errno = rc;
                } else {
                        wr = write(stream->fd, buf + done, left);
                        if (wr >= 0) {
                                uwr = (size_t)wr;
                                rc = EOK;
                        } else {
                                /* errno was set by write */
                                uwr = 0;
                                rc = errno;
                        }
                }
                
                if (rc != EOK) {
                        /* errno was set above */
                        stream->error = true;
                } else {
                        left -= uwr;
                        done += uwr;
                }
        }

        if (done > 0)
                stream->need_sync = true;
        
        return (done / size);
}

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

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

        rc = read(stream->fd, stream->buf, stream->buf_size);
        if (rc < 0) {
                /* errno was set by read() */
                stream->error = true;
                return;
        }

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

        stream->buf_head += rc;
        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) {
                off64_t rc;
                rc = lseek(stream->fd, - (ssize_t) bytes_used, SEEK_CUR);
                if (rc == (off64_t)-1) {
                        /* errno was set by lseek */
                        stream->error = 1;
                        return;
                }
        }

        /* 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);
}

int fputc(wchar_t c, FILE *stream)
{
        char buf[STR_BOUNDS(1)];
        size_t sz = 0;
        
        if (chr_encode(c, buf, &sz, STR_BOUNDS(1)) == EOK) {
                size_t wr = fwrite(buf, 1, sz, stream);
                
                if (wr < sz)
                        return EOF;
                
                return (int) c;
        }
        
        return EOF;
}

int putchar(wchar_t 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)
{
        return fputs(str, stdout);
}

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

        if (stream->error)
                return EOF;

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

        stream->ungetc_chars = 0;

        rc = lseek(stream->fd, offset, whence);
        if (rc == (off64_t) (-1)) {
                /* errno has been set by lseek() */
                return EOF;
        }

        stream->eof = false;
        return 0;
}

off64_t ftell(FILE *stream)
{
        off64_t pos;
        
        if (stream->error)
                return EOF;
        
        _fflushbuf(stream);
        if (stream->error) {
                /* errno was set by _fflushbuf() */
                return EOF;
        }

        pos = lseek(stream->fd, 0, SEEK_CUR);
        if (pos == (off64_t) -1) {
                /* errno was set by lseek */
                return (off64_t) -1;
        }
        
        return pos - stream->ungetc_chars;
}

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->kio) {
                kio_update();
                return 0;
        }
        
        if ((stream->fd >= 0) && (stream->need_sync)) {
                /**
                 * Better than syncing always, but probably still not the
                 * right thing to do.
                 */
                stream->need_sync = false;
                if (fsync(stream->fd) != 0) {
                        /* errno was set by fsync() */
                        return EOF;
                }

                return 0;
        }
        
        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->kio) {
                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;
}

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

/** @}
 */