source: mainline/uspace/lib/posix/src/stdio.c@ 460ea7e

/*
 * Copyright (c) 2011 Jiri Zarevucky
 * Copyright (c) 2011 Petr Koupy
 * Copyright (c) 2018 Jiri Svoboda
 * 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 libposix
 * @{
 */
/** @file Standard buffered input/output.
 */

#include "internal/common.h"
#include <stdio.h>

#include <assert.h>
#include <errno.h>
#include <stdbool.h>
#include <tmpfile.h>

#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

#include <io/printf_core.h>
#include <str.h>
#include <malloc.h>
#include <adt/list.h>

/**
 * Generate a pathname for the controlling terminal.
 *
 * @param s Allocated buffer to which the pathname shall be put.
 * @return Either s or static location filled with the requested pathname.
 */
char *ctermid(char *s)
{
        /* Currently always returns an error value (empty string). */
        // TODO: return a real terminal path

        static char dummy_path[L_ctermid] = { '\0' };

        if (s == NULL) {
                return dummy_path;
        }

        s[0] = '\0';
        return s;
}

/**
 * Read a stream until the delimiter (or EOF) is encountered.
 *
 * @param lineptr Pointer to the output buffer in which there will be stored
 *     nul-terminated string together with the delimiter (if encountered).
 *     Will be resized if necessary.
 * @param n Pointer to the size of the output buffer. Will be increased if
 *     necessary.
 * @param delimiter Delimiter on which to finish reading the stream.
 * @param stream Input stream.
 * @return Number of fetched characters (including delimiter if encountered)
 *     or -1 on error (set in errno).
 */
ssize_t getdelim(char **restrict lineptr, size_t *restrict n,
    int delimiter, FILE *restrict stream)
{
        /* Check arguments for sanity. */
        if (!lineptr || !n) {
                errno = EINVAL;
                return -1;
        }

        size_t alloc_step = 80; /* Buffer size gain during reallocation. */
        char *pos = *lineptr; /* Next free byte of the output buffer. */
        size_t cnt = 0; /* Number of fetched characters. */
        int c = fgetc(stream); /* Current input character. Might be EOF. */

        do {
                /* Mask EOF as NUL to terminate string. */
                if (c == EOF) {
                        c = '\0';
                }

                /* Ensure there is still space left in the buffer. */
                if (pos == *lineptr + *n) {
                        *lineptr = realloc(*lineptr, *n + alloc_step);
                        if (*lineptr) {
                                pos = *lineptr + *n;
                                *n += alloc_step;
                        } else {
                                errno = ENOMEM;
                                return -1;
                        }
                }

                /* Store the fetched character. */
                *pos = c;

                /* Fetch the next character according to the current character. */
                if (c != '\0') {
                        ++pos;
                        ++cnt;
                        if (c == delimiter) {
                                /*
                                 * Delimiter was just stored. Provide EOF as the next
                                 * character - it will be masked as NUL and output string
                                 * will be properly terminated.
                                 */
                                c = EOF;
                        } else {
                                /*
                                 * Neither delimiter nor EOF were encountered. Just fetch
                                 * the next character from the stream.
                                 */
                                c = fgetc(stream);
                        }
                }
        } while (c != '\0');

        if (errno == EOK && cnt > 0) {
                return cnt;
        } else {
                /* Either some error occured or the stream was already at EOF. */
                return -1;
        }
}

/**
 * Read a stream until the newline (or EOF) is encountered.
 *
 * @param lineptr Pointer to the output buffer in which there will be stored
 *     nul-terminated string together with the delimiter (if encountered).
 *     Will be resized if necessary.
 * @param n Pointer to the size of the output buffer. Will be increased if
 *     necessary.
 * @param stream Input stream.
 * @return Number of fetched characters (including newline if encountered)
 *     or -1 on error (set in errno).
 */
ssize_t getline(char **restrict lineptr, size_t *restrict n,
    FILE *restrict stream)
{
        return getdelim(lineptr, n, '\n', stream);
}

/**
 * Reposition a file-position indicator in a stream.
 *
 * @param stream Stream to seek in.
 * @param offset Direction and amount of bytes to seek.
 * @param whence From where to seek.
 * @return Zero on success, -1 otherwise.
 */
int fseeko(FILE *stream, off_t offset, int whence)
{
        return fseek64(stream, offset, whence);
}

/**
 * Discover current file offset in a stream.
 *
 * @param stream Stream for which the offset shall be retrieved.
 * @return Current offset or -1 if not possible.
 */
off_t ftello(FILE *stream)
{
        return ftell64(stream);
}

/**
 * Print formatted output to the opened file.
 *
 * @param fildes File descriptor of the opened file.
 * @param format Format description.
 * @return Either the number of printed characters or negative value on error.
 */
int dprintf(int fildes, const char *restrict format, ...)
{
        va_list list;
        va_start(list, format);
        int result = vdprintf(fildes, format, list);
        va_end(list);
        return result;
}

/**
 * Write ordinary string to the opened file.
 *
 * @param str String to be written.
 * @param size Size of the string (in bytes)..
 * @param fd File descriptor of the opened file.
 * @return The number of written characters.
 */
static int _dprintf_str_write(const char *str, size_t size, void *fd)
{
        const int fildes = *(int *) fd;
        size_t wr;
        if (failed(vfs_write(fildes, &posix_pos[fildes], str, size, &wr)))
                return -1;
        return str_nlength(str, wr);
}

/**
 * Write wide string to the opened file.
 *
 * @param str String to be written.
 * @param size Size of the string (in bytes).
 * @param fd File descriptor of the opened file.
 * @return The number of written characters.
 */
static int _dprintf_wstr_write(const wchar_t *str, size_t size, void *fd)
{
        size_t offset = 0;
        size_t chars = 0;
        size_t sz;
        char buf[4];

        while (offset < size) {
                sz = 0;
                if (chr_encode(str[chars], buf, &sz, sizeof(buf)) != EOK) {
                        break;
                }

                const int fildes = *(int *) fd;
                size_t nwr;
                if (vfs_write(fildes, &posix_pos[fildes], buf, sz, &nwr) != EOK)
                        break;

                chars++;
                offset += sizeof(wchar_t);
        }

        return chars;
}

/**
 * Print formatted output to the opened file.
 *
 * @param fildes File descriptor of the opened file.
 * @param format Format description.
 * @param ap Print arguments.
 * @return Either the number of printed characters or negative value on error.
 */
int vdprintf(int fildes, const char *restrict format, va_list ap)
{
        printf_spec_t spec = {
                .str_write = _dprintf_str_write,
                .wstr_write = _dprintf_wstr_write,
                .data = &fildes
        };

        return printf_core(format, &spec, ap);
}

/**
 * Acquire file stream for the thread.
 *
 * @param file File stream to lock.
 */
void flockfile(FILE *file)
{
        /* dummy */
}

/**
 * Acquire file stream for the thread (non-blocking).
 *
 * @param file File stream to lock.
 * @return Zero for success and non-zero if the lock cannot be acquired.
 */
int ftrylockfile(FILE *file)
{
        /* dummy */
        return 0;
}

/**
 * Relinquish the ownership of the locked file stream.
 *
 * @param file File stream to unlock.
 */
void funlockfile(FILE *file)
{
        /* dummy */
}

/**
 * Get a byte from a stream (thread-unsafe).
 *
 * @param stream Input file stream.
 * @return Either read byte or EOF.
 */
int getc_unlocked(FILE *stream)
{
        return getc(stream);
}

/**
 * Get a byte from the standard input stream (thread-unsafe).
 *
 * @return Either read byte or EOF.
 */
int getchar_unlocked(void)
{
        return getchar();
}

/**
 * Put a byte on a stream (thread-unsafe).
 *
 * @param c Byte to output.
 * @param stream Output file stream.
 * @return Either written byte or EOF.
 */
int putc_unlocked(int c, FILE *stream)
{
        return putc(c, stream);
}

/**
 * Put a byte on the standard output stream (thread-unsafe).
 *
 * @param c Byte to output.
 * @return Either written byte or EOF.
 */
int putchar_unlocked(int c)
{
        return putchar(c);
}

/** Determine if directory is an 'appropriate' temporary directory.
 *
 * @param dir Directory path
 * @return @c true iff directory is appropriate.
 */
static bool is_appropriate_tmpdir(const char *dir)
{
        struct stat sbuf;

        /* Must not be NULL */
        if (dir == NULL)
                return false;

        /* Must not be empty */
        if (dir[0] == '\0')
                return false;

        if (stat(dir, &sbuf) != 0)
                return false;

        /* Must be a directory */
        if ((sbuf.st_mode & S_IFMT) != S_IFDIR)
                return false;

        /* Must be writable */
        if (access(dir, W_OK) != 0)
                return false;

        return true;
}

/** Construct unique file name.
 *
 * Never use this function.
 *
 * @param dir Path to directory, where the file should be created.
 * @param pfx Optional prefix up to 5 characters long.
 * @return Newly allocated unique path for temporary file. NULL on failure.
 */
char *tempnam(const char *dir, const char *pfx)
{
        const char *dpref;
        char *d;
        char *buf;
        int rc;

        d = getenv("TMPDIR");
        if (is_appropriate_tmpdir(d))
                dpref = d;
        else if (is_appropriate_tmpdir(dir))
                dpref = dir;
        else if (is_appropriate_tmpdir(P_tmpdir))
                dpref = P_tmpdir;
        else
                dpref = "/";

        if (dpref[strlen(dpref) - 1] != '/')
                rc = asprintf(&buf, "%s/%sXXXXXX", dpref, pfx);
        else
                rc = asprintf(&buf, "%s%sXXXXXX", dpref, pfx);

        if (rc < 0)
                return NULL;

        rc = __tmpfile_templ(buf, false);
        if (rc != 0) {
                free(buf);
                return NULL;
        }

        return buf;
}

/** @}
 */