Linux Cubed Series 3: Developer Tools/Linux Cubed Series 3 - Developer Tools.iso/utils/file/managers/git-4.3/git-4/git-4.3.7/src/xio.c

C/C++ Source or Header | 1995-07-08 | 4.3 KB | 252 lines

/* xio.c -- safe versions of the system io primitives. It also includes a
   new version of the readlink system call that computes the number of
   characters required to hold the entire link. */

/* Copyright (C) 1993, 1994, 1995 Free Software Foundation, Inc.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */

/* Written by Tudor Hulubei and Andrei Pitis.  */


#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <sys/types.h>

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif /* HAVE_UNISTD_H */

#ifndef HAVE_GETCWD
#include <sys/param.h>
#ifdef MAXPATHLEN
#define MAXPATHSIZE MAXPATHLEN
#else
#ifdef PATH_MAX
#define MAXPATHSIZE PATH_MAX
#else
#define MAXPATHSIZE 1024
#endif /* PATH_MAX */
#endif /* MAXPATHLEN */
#endif /* HAVE_GETCWD */

#include <errno.h>

/* Not all systems declare ERRNO in errno.h... and some systems #define it! */
#if !defined (errno)
extern int errno;
#endif /* !errno */


#include "xmalloc.h"
#include "xio.h"


int
xread(fd, buf, count)
    int fd;
    char *buf;
    size_t count;
{
    int chars;
    int old_errno;

    if (count <= 0)
        return count;

#ifdef EINTR
    old_errno = errno;

    do
        chars = read(fd, buf, count);
    while (chars < 0 && errno == EINTR);

    errno = old_errno;
    return chars;
#else
    return read(fd, buf, count);
#endif
}


int
xwrite(fd, buf, count)
    int fd;
    char *buf;
    size_t count;
{
    int chars;
    int old_errno;

    if (count <= 0)
        return count;

#ifdef EINTR
    old_errno = errno;

    do
        chars = write(fd, buf, count);
    while (chars < 0 && errno == EINTR);

    errno = old_errno;
    return chars;
#else
    return write(fd, buf, count);
#endif
}


int
__xreadlink(path, buf, size)
    const char *path;
    char *buf;
    size_t size;
{
    int chars;
    int old_errno;

    if (size <= 0)
        return size;

#ifdef EINTR
    old_errno = errno;

    do
    {
        chars = readlink(path, buf, size);
        old_errno = size;
    }
    while (chars < 0 && errno == EINTR);

    errno = old_errno;
    return chars;
#else
    return read(fd, buf, count);
#endif
}


int
xreadlink(filename)
    const char *filename;
{
    int size = 100;

    for (;;)
    {
        char *buffer = xmalloc(size);
        int  nchars  = __xreadlink(filename, buffer, size);

        if (nchars < size)
        {
            xfree(buffer);
            return nchars;
        }

        xfree(buffer);
        size *= 2;
    }
}


int
xfstat(filedes, buf)
    int filedes;
    struct stat *buf;
{
    int result;

    do
        result = fstat(filedes, buf);
    while (result < 0 && errno == EINTR);

    return result;
}


int
xstat(filename, buf)
    const char *filename;
    struct stat *buf;
{
    int result;

    do
        result = stat(filename, buf);
    while (result < 0 && errno == EINTR);

    return result;
}


int
xlstat(filename, buf)
    const char *filename;
    struct stat *buf;
{
    int result;

    do
#ifdef HAVE_LSTAT
        result = lstat(filename, buf);
#else
        result = stat(filename, buf);
#endif /* HAVE_LSTAT */
    while (result < 0 && errno == EINTR);

    return result;
}


char *
xgetcwd()
{
    size_t size;
    char *result;
    char *cwd;

    errno = 0;

#ifdef HAVE_GETCWD
    cwd = xmalloc(size = 64);

    while ((result = getcwd(cwd, size)) == NULL && errno == ERANGE)
    {
        cwd = xrealloc(cwd, size += 64);
        errno = 0;
    }
#else
    /* No getcwd() -> getwd(): BSD style... bleah!  */

    cwd    = xmalloc(MAXPATHSIZE + 2);
    result = getwd(cwd);

    if (result)
        cwd = xrealloc(cwd, strlen(cwd) + 1);
#endif  /* HAVE_GETCWD */

    if (result == NULL)
    {
        int old_errno = errno;
        xfree(cwd);
        errno = old_errno;
        return NULL;
    }

    return cwd;
}