#include "lrqElib.h"
#include "lrqEdefs.h"
#include <fcntl.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>

#ifdef lrqEopen
# undef lrqEopen
#endif
#undef open

static char lrqEo_buf[1500]; /* for the "why" */
#define buf lrqEo_buf

#include <stdarg.h>

int
lrqEopen(const char *filename, int whatfor, ...)
{
    va_list ap;

    int creatmode = 0;

    int fd;
    int savsyserrno;
    char *otext, *mtext, *special;
    int ewhat;
    int writing = 0;
    char *what = "file"; /* file/fifo/device/directory */
    char *reason;

    if (whatfor & O_CREAT) {
	va_start(ap, whatfor);
	creatmode = va_arg(ap, int);
	va_end(ap);
    }

    errno = 0;

    if ((fd = open(filename, whatfor, creatmode)) >= 0) {
	return fd;
    }
    /* we have an error */

    /* Save the original error message */
    savsyserrno = errno;

    if (filename == (char *) 0) {
	lrqE_error(lrqE_EPROG, "read: called with null file name");
	return -1;
    } else if (errno == EFAULT) {
	ewhat = lrqE_EPROG;
	filename = "[corrupted filename]";
    }

    /**
     * can't %s \"%s\" for %s %s because %s
     * otext file mtext special reason
     */

    /* Make a description of what we tried to do.. */
    if (whatfor & O_CREAT) {
	otext = "create";
    } else {
	if (whatfor & O_TRUNC) {
	    otext = "open (truncate)";
	} else {
	    otext = "open";
	}
    }
    if (whatfor & O_RDWR) {
	mtext = "update";
	writing = 1;
    } else if (whatfor & O_WRONLY) {
	mtext = "writing";
	writing = 1;
    } else {
	mtext = "reading";
    }

    if (whatfor & O_EXCL) {
	special = "(for exclusive access) -- \n\t";
    } else {
	special = "-- ";
    }

    /** Try to figure out the problem... **/

    /* Some special cases: */
    switch (savsyserrno) {
    case EAGAIN:
	reason = "it already exists, and there are outstanding locks (EAGAIN)";
	ewhat = lrqE_EFATAL;
	break;
    case EEXIST:
	reason = "it already exists";
	ewhat = lrqE_EFATAL;
	break;
    case EFAULT:
	reason = "the filename was corrupt [EFAULT]";
	ewhat = lrqE_EFATAL;
	break;
    case EINTR:
	/* See if we can do it again this time! */
	if ((fd = open(filename, whatfor, creatmode)) >= 0) {
	    return fd;
	}
	reason = "a signal interrupted the system call.";
	ewhat = lrqE_EFATAL;
	break;
    case EIO:
	reason = "there was a hangup or STREAMS error";
	ewhat = lrqE_EFATAL;
	break;
    case EISDIR:
	reason = "can't alter directories";
	ewhat = lrqE_EFATAL;
	what = "directory";
	break;
    case EMFILE:
	reason = "too many files are already open";
	ewhat = lrqE_EFATAL;
	break;
#ifdef EMULTIHOP
    case EMULTIHOP:
	reason = "MULTIHOP bug in RFS; use NFS instead!";
	ewhat = lrqE_EFATAL;
	what = "remote file";
	break;
#endif
    case ENFILE:
	reason = "the system file table is full";
	ewhat = lrqE_EFATAL;
	break;
    case ENOENT:
	if (whatfor & O_CREAT) {
	    reason = "a directory in the path doesn't exist";
	} else {
	    reason = "it doesn't exist";
	}
	ewhat = lrqE_EFATAL;
	break;
#ifdef ENOLINK
    case ENOLINK:
	reason = "the remote machine it's is now unavailable";
	ewhat = lrqE_EFATAL;
	what = "remote file";
	break;
#endif
    case ENOMEM:
	reason = "the system has run out of memory [ENOMEM]";
	ewhat = lrqE_EFATAL;
	break;
    case ENOSPC:
	reason = "the file system has run out of i-nodes";
	ewhat = lrqE_EFATAL;
	break;
#ifdef ENOSR
    case ENOSR:
	reason = "no streams are available";
	ewhat = lrqE_EFATAL;
	what = "streams device";
	break;
#endif
    case ENOTDIR:
	/*NOTDONE: find out which! */
	{
	    extern char *lrqEcheckpath();

	    char *d = lrqEcheckpath(filename, "d");
	    if (d != (char *) 0) {
		reason = d;
	    } else {
		reason = "one of the path compnents isn't a directory.";
	    }
	    ewhat = lrqE_EFATAL;
	}
	break;
    case ENXIO:
	what = "special device";
	ewhat = lrqE_EFATAL;
	reason = "no kernel driver, or polluted stream [ENXIO]";
	break;
    case EROFS:
	reason = "the file system is mounted read-only";
	ewhat = lrqE_EFATAL;
	break;
    case ETXTBSY:
	what = "program text";
	reason = "the program is currently running";
	ewhat = lrqE_EFATAL;
	break;
    default:
	if (savsyserrno < sys_nerr) {
	    reason = sys_errlist[savsyserrno];
	} else {
	    (void) sprintf(buf, "unknown error %d -- see intro(2)",
		savsyserrno);
	    reason - buf;
	}
	ewhat = lrqE_EFATAL|lrqE_EINTERNAL;
	break;
    }

    lrqE_error(ewhat, "can't %s %s \"%s\" for %s %s\n\t%s",
		otext, what, filename, mtext, special, reason);
}