/* 

 * compat.c - compatibility routines for the deprived

 *

 * This file is part of zsh, the Z shell.

 *

 * Copyright (c) 1992-1997 Paul Falstad

 * All rights reserved.

 *

 * Permission is hereby granted, without written agreement and without

 * license or royalty fees, to use, copy, modify, and distribute this

 * software and to distribute modified versions of this software for any

 * purpose, provided that the above copyright notice and the following

 * two paragraphs appear in all copies of this software.

 *

 * In no event shall Paul Falstad or the Zsh Development Group be liable

 * to any party for direct, indirect, special, incidental, or consequential

 * damages arising out of the use of this software and its documentation,

 * even if Paul Falstad and the Zsh Development Group have been advised of

 * the possibility of such damage.

 *

 * Paul Falstad and the Zsh Development Group specifically disclaim any

 * warranties, including, but not limited to, the implied warranties of

 * merchantability and fitness for a particular purpose.  The software

 * provided hereunder is on an "as is" basis, and Paul Falstad and the

 * Zsh Development Group have no obligation to provide maintenance,

 * support, updates, enhancements, or modifications.

 *

 */

#include "zsh.mdh"

#include "compat.pro"

/* Return pointer to first occurence of string t *

 * in string s.  Return NULL if not present.     */

#ifndef HAVE_STRSTR

char *

strstr(const char *s, const char *t)

{

    char *p1, *p2;

    for (; *s; s++) {

        for (p1 = s, p2 = t; *p2; p1++, p2++)

            if (*p1 != *p2)

                break;

        if (!*p2)

            return (char *)s;

    }

    return NULL;

}

#endif

#ifndef HAVE_GETHOSTNAME

int

gethostname(char *name, size_t namelen)

{

    struct utsname uts;

    uname(&uts);

    if(strlen(uts.nodename) >= namelen) {

	errno = EINVAL;

	return -1;

    }

    strcpy(name, uts.nodename);

    return 0;

}

#endif

#ifndef HAVE_GETTIMEOFDAY

int

gettimeofday(struct timeval *tv, struct timezone *tz)

{

    tv->tv_usec = 0;

    tv->tv_sec = (long)time((time_t) 0);

    return 0;

}

#endif

/* compute the difference between two calendar times */

#ifndef HAVE_DIFFTIME

double

difftime(time_t t2, time_t t1)

{

    return ((double)t2 - (double)t1);

}

#endif

#ifndef HAVE_STRERROR

extern char *sys_errlist[];

/* Get error message string associated with a particular  *

 * error number, and returns a pointer to that string.    *

 * This is not a particularly robust version of strerror. */

char *

strerror(int errnum)

{

    return (sys_errlist[errnum]);

}

#endif

#if 0

/* pathconf(_PC_PATH_MAX) is not currently useful to zsh.  The value *

 * returned varies depending on a number of factors, e.g. the amount *

 * of memory available to the operating system at a given time; thus *

 * it can't be used for buffer allocation, or even as an indication  *

 * of whether an attempt to use or create a given pathname may fail  *

 * at any future time.                                               *

 *                                                                   *

 * The call is also permitted to fail if the argument path is not an *

 * existing directory, so even to make sense of that one must search *

 * for a valid directory somewhere in the path and adjust.  Even if  *

 * it succeeds, the return value is relative to the input directory, *

 * and therefore potentially relative to the length of the shortest  *

 * path either to that directory or to our working directory.        *

 *                                                                   *

 * Finally, see the note below for glibc; detection of pathconf() is *

 * not by itself an indication that it works reliably.               */

/* The documentation for pathconf() says something like:             *

 *     The limit is returned, if one exists.  If the system  does    *

 *     not  have  a  limit  for  the  requested  resource,  -1 is    *

 *     returned, and errno is unchanged.  If there is  an  error,    *

 *     -1  is returned, and errno is set to reflect the nature of    *

 *     the error.                                                    *

 *                                                                   *

 * System calls are not permitted to set errno to 0; but we must (or *

 * some other flag value) in order to determine that the resource is *

 * unlimited.  What use is leaving errno unchanged?  Instead, define *

 * a wrapper that resets errno to 0 and returns 0 for "the system    *

 * does not have a limit," so that -1 always means a real error.     */

/**/

mod_export long

zpathmax(char *dir)

{

#ifdef HAVE_PATHCONF

    long pathmax;

    errno = 0;

    if ((pathmax = pathconf(dir, _PC_PATH_MAX)) >= 0) {

	/* Some versions of glibc pathconf return a hardwired value! */

	return pathmax;

    } else if (errno == EINVAL || errno == ENOENT || errno == ENOTDIR) {

	/* Work backward to find a directory, until we run out of path. */

	char *tail = strrchr(dir, '/');

	while (tail > dir && tail[-1] == '/')

	    --tail;

	if (tail > dir) {

	    *tail = 0;

	    pathmax = zpathmax(dir);

	    *tail = '/';

	} else {

	    errno = 0;

	    if (tail)

		pathmax = pathconf("/", _PC_PATH_MAX);

	    else

		pathmax = pathconf(".", _PC_PATH_MAX);

	}

	if (pathmax > 0) {

	    long taillen = (tail ? strlen(tail) : (strlen(dir) + 1));

	    if (taillen < pathmax)

		return pathmax - taillen;

	    else

		errno = ENAMETOOLONG;

	}

    }

    if (errno)

	return -1;

    else

	return 0; /* pathmax should be considered unlimited */

#else

    long dirlen = strlen(dir);

    /* The following is wrong if dir is not an absolute path. */

    return ((long) ((dirlen >= PATH_MAX) ?

		    ((errno = ENAMETOOLONG), -1) :

		    ((errno = 0), PATH_MAX - dirlen)));

#endif

}

#endif /* 0 */

#ifdef HAVE_SYSCONF

/* This is replaced by a macro from system.h if not HAVE_SYSCONF.    *

 * 0 is returned by sysconf if _SC_OPEN_MAX is unavailable;          *

 * -1 is returned on error                                           *

 *                                                                   *

 * Neither of these should happen, but resort to OPEN_MAX rather     *

 * than return 0 or -1 just in case.                                 */

/**/

mod_export long

zopenmax(void)

{

    static long openmax = 0;

    if (openmax < 1) {

	if ((openmax = sysconf(_SC_OPEN_MAX)) < 1) {

	    openmax = OPEN_MAX;

	} else if (openmax > OPEN_MAX) {

	    /* On some systems, "limit descriptors unlimited" or the  *

	     * equivalent will set openmax to a huge number.  Unless  *

	     * there actually is a file descriptor > OPEN_MAX already *

	     * open, nothing in zsh requires the true maximum, and in *

	     * fact it causes inefficiency elsewhere if we report it. *

	     * So, report the maximum of OPEN_MAX or the largest open *

	     * descriptor (is there a better way to find that?).      */

	    long i, j = OPEN_MAX;

	    for (i = j; i < openmax; i += (errno != EINTR)) {

		errno = 0;

		if (fcntl(i, F_GETFL, 0) < 0 &&

		    (errno == EBADF || errno == EINTR))

		    continue;

		j = i;

	    }

	    openmax = j;

	}

    }

    return (max_zsh_fd > openmax) ? max_zsh_fd : openmax;

}

#endif

/**/

mod_export char *

zgetdir(struct dirsav *d)

{

    char nbuf[PATH_MAX+3];

    char *buf;

    int bufsiz, pos;

    struct stat sbuf;

    ino_t pino;

    dev_t pdev;

#if !defined(__CYGWIN__) && !defined(USE_GETCWD)

    struct dirent *de;

    DIR *dir;

    dev_t dev;

    ino_t ino;

    int len;

#endif

    buf = zhalloc(bufsiz = PATH_MAX);

    pos = bufsiz - 1;

    buf[pos] = '\0';

    strcpy(nbuf, "../");

    if (stat(".", &sbuf) < 0) {

	if (d)

	    return NULL;

	buf[0] = '.';

	buf[1] = '\0';

	return buf;

    }

    pino = sbuf.st_ino;

    pdev = sbuf.st_dev;

    if (d)

	d->ino = pino, d->dev = pdev;

#ifdef HAVE_FCHDIR

    else

#endif

#if !defined(__CYGWIN__) && !defined(USE_GETCWD)

	holdintr();

    for (;;) {

	if (stat("..", &sbuf) < 0)

	    break;

	ino = pino;

	dev = pdev;

	pino = sbuf.st_ino;

	pdev = sbuf.st_dev;

	if (ino == pino && dev == pdev) {

	    /*if (!buf[pos])

		buf[--pos] = '\\';*/

	    if (d) {

#ifndef HAVE_FCHDIR

		zchdir(buf + pos);

		noholdintr();

#endif

		return d->dirname = ztrdup(buf + pos);

	    }

	    zchdir(buf + pos);

	    noholdintr();

	    return buf + pos;

	}

	if (!(dir = opendir("..")))

	    break;

	while ((de = readdir(dir))) {

	    char *fn = de->d_name;

	    /* Ignore `.' and `..'. */

	    if (fn[0] == '.' &&

		(fn[1] == '\0' ||

		 (fn[1] == '.' && fn[2] == '\0')))

		continue;

#ifdef HAVE_STRUCT_DIRENT_D_STAT

	    if(de->d_stat.st_dev == dev && de->d_stat.st_ino == ino) {

		strncpy(nbuf + 3, fn, PATH_MAX);

		break;

	    }

#else /* !HAVE_STRUCT_DIRENT_D_STAT */

# ifdef HAVE_STRUCT_DIRENT_D_INO

	    if (dev != pdev || (ino_t) de->d_ino == ino)

# endif /* HAVE_STRUCT_DIRENT_D_INO */

	    {

		strncpy(nbuf + 3, fn, PATH_MAX);

		lstat(nbuf, &sbuf);

		if (sbuf.st_dev == dev && sbuf.st_ino == ino)

		    break;

	    }

#endif /* !HAVE_STRUCT_DIRENT_D_STAT */

	}

	closedir(dir);

	if (!de)

	    break;

	len = strlen(nbuf + 2);

	pos -= len;

	while (pos <= 1) {

	    char *newbuf = zhalloc(2*bufsiz);

	    memcpy(newbuf + bufsiz, buf, bufsiz);

	    buf = newbuf;

	    pos += bufsiz;

	    bufsiz *= 2;

	}

	memcpy(buf + pos, nbuf + 2, len);

#ifdef HAVE_FCHDIR

	if (d)

	    return d->dirname = ztrdup(buf + pos + 1);

#endif

	if (chdir(".."))

	    break;

    }

    if (d) {

#ifndef HAVE_FCHDIR

	if (*buf)

	    zchdir(buf + pos + 1);

	noholdintr();

#endif

	return NULL;

    }

    if (*buf)

	zchdir(buf + pos + 1);

    noholdintr();

#else  /* __CYGWIN__, USE_GETCWD cases */

    if (!getcwd(buf, bufsiz)) {

	if (d) {

	    return NULL;

	}

    } else {

	if (d) {

	    return d->dirname = ztrdup(buf);

	}

	return buf;

    }

#endif

    buf[0] = '.';

    buf[1] = '\0';

    return buf;

}

/**/

char *

zgetcwd(void)

{

    return zgetdir(NULL);

}

/* chdir with arbitrary long pathname.  Returns 0 on success, -1 on normal *

 * failure and -2 when chdir failed and the current directory is lost.  */

/**/

mod_export int

zchdir(char *dir)

{

    char *s;

    int currdir = -2;

#ifdef __SYMBIAN32__

	if(dir==NULL || !*dir)

		{

		return -1; //denote failure	

		}

#endif		

    for (;;) {

	if (!*dir || chdir(dir) == 0) {

#ifdef HAVE_FCHDIR

           if (currdir >= 0)

               close(currdir);

#endif

	    return 0;

	}

	if ((errno != ENAMETOOLONG && errno != ENOMEM) ||

	    strlen(dir) < PATH_MAX)

	    break;

	for (s = dir + PATH_MAX - 1; s > dir && *s != '/'; s--)

	    ;

	if (s == dir)

	    break;

#ifdef HAVE_FCHDIR

	if (currdir == -2)

	    currdir = open(".", O_RDONLY|O_NOCTTY);

#endif

	*s = '\0';

	if (chdir(dir) < 0) {

	    *s = '/';

	    break;

	}

#ifndef HAVE_FCHDIR

	currdir = -1;

#endif

	*s = '/';

	while (*++s == '/')

	    ;

	dir = s;

    }

#ifdef HAVE_FCHDIR

    if (currdir >= 0) {

	if (fchdir(currdir) < 0) {

	    close(currdir);

	    return -2;

	}

	close(currdir);

	return -1;

    }

#endif

    return currdir == -2 ? -1 : -2;

}

/*

 * How to print out a 64 bit integer.  This isn't needed (1) if longs

 * are 64 bit, since ordinary %ld will work (2) if we couldn't find a

 * 64 bit type anyway.

 */

/**/

#ifdef ZSH_64_BIT_TYPE

/**/

mod_export char *

output64(zlong val)

{

    static char llbuf[DIGBUFSIZE];

    convbase(llbuf, val, 0);

    return llbuf;

}

/**/

#endif /* ZSH_64_BIT_TYPE */