/***********************************************************

Copyright 1991-1995 by Stichting Mathematisch Centrum, Amsterdam,

The Netherlands.

                        All Rights Reserved

Permission to use, copy, modify, and distribute this software and its

documentation for any purpose and without fee is hereby granted,

provided that the above copyright notice appear in all copies and that

both that copyright notice and this permission notice appear in

supporting documentation, and that the names of Stichting Mathematisch

Centrum or CWI or Corporation for National Research Initiatives or

CNRI not be used in advertising or publicity pertaining to

distribution of the software without specific, written prior

permission.

While CWI is the initial source for this software, a modified version

is made available by the Corporation for National Research Initiatives

(CNRI) at the Internet address ftp://ftp.python.org.

STICHTING MATHEMATISCH CENTRUM AND CNRI DISCLAIM ALL WARRANTIES WITH

REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF

MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH

CENTRUM OR CNRI BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL

DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR

PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER

TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR

PERFORMANCE OF THIS SOFTWARE.

******************************************************************/

/* A special version for minimal installs, where

   the bootstrap path is the directory in which

   the executable lives.

   Gordon McMillan, McMillan Enterprises, Inc. */

/* Return the initial module search path. */

#include "Python.h"

#include "osdefs.h"

#include <sys/types.h>

#include <sys/stat.h>

#include <string.h>

#if HAVE_UNISTD_H

#include <unistd.h>

#endif /* HAVE_UNISTD_H */

#ifdef WITH_NEXT_FRAMEWORK

#include <mach-o/dyld.h>

#endif

static char prefix[MAXPATHLEN+1];

static char *exec_prefix;

static char progpath[MAXPATHLEN+1];

static char *module_search_path = NULL;

static void

reduce(char *dir)

{

	int i = strlen(dir);

	while (i > 0 && dir[i] != SEP)

		--i;

	dir[i] = '\0';

}

#ifndef S_ISREG

#define S_ISREG(x) (((x) & S_IFMT) == S_IFREG)

#endif

#ifndef S_ISDIR

#define S_ISDIR(x) (((x) & S_IFMT) == S_IFDIR)

#endif

#if 0

static int

isfile(char *filename)		/* Is file, not directory */

{

	struct stat buf;

	if (stat(filename, &buf) != 0)

		return 0;

	if (!S_ISREG(buf.st_mode))

		return 0;

	return 1;

}

#endif

#if 0

static int

ismodule(char *filename)		/* Is module -- check for .pyc/.pyo too */

{

	if (isfile(filename))

		return 1;

	/* Check for the compiled version of prefix. */

	if (strlen(filename) < MAXPATHLEN) {

		strcat(filename, Py_OptimizeFlag ? "o" : "c");

		if (isfile(filename))

			return 1;

	}

	return 0;

}

#endif

static int

isxfile(char *filename)		/* Is executable file */

{

	struct stat buf;

	if (stat(filename, &buf) != 0)

		return 0;

	if (!S_ISREG(buf.st_mode))

		return 0;

	if ((buf.st_mode & 0111) == 0)

		return 0;

	return 1;

}

#if 0

static int

isdir(char *filename)			/* Is directory */

{

	struct stat buf;

	if (stat(filename, &buf) != 0)

		return 0;

	if (!S_ISDIR(buf.st_mode))

		return 0;

	return 1;

}

#endif

static void

joinpath(char *buffer, char *stuff)

{

	int n, k;

	if (stuff[0] == SEP)

		n = 0;

	else {

		n = strlen(buffer);

		if (n > 0 && buffer[n-1] != SEP && n < MAXPATHLEN)

			buffer[n++] = SEP;

	}

	k = strlen(stuff);

	if (n + k > MAXPATHLEN)

		k = MAXPATHLEN - n;

	strncpy(buffer+n, stuff, k);

	buffer[n+k] = '\0';

}

static void

calculate_path(void)

{

	char *prog = Py_GetProgramName();	/* use Py_SetProgramName(argv[0]) before Py_Initialize() */

	char argv0_path[MAXPATHLEN+1];

	char *epath;

	char *path = NULL;

	char *ppath = NULL;

        int  numchars;

	if (strchr(prog, SEP))

		strcpy(progpath, prog);

	else {

#if HAVE_READLINK

            sprintf(argv0_path, "/proc/%d/exe", getpid());

            numchars = readlink(argv0_path, progpath, MAXPATHLEN);

            if (numchars > 0) 

                progpath[numchars] = '\0';

            else {

#endif

		epath = getenv("PATH");

                if (epath) 

                    path = malloc(strlen(epath)+3);

		if (path) {

                    strcpy(path, ".:");

                    strcat(path, epath);

		    ppath = path;

	    	    while (1) {

				char *delim = strchr(ppath, DELIM);

				if (delim) {

					int len = delim - ppath;

					strncpy(progpath, ppath, len);

					*(progpath + len) = '\0';

				}

				else

					strcpy(progpath, ppath);

				joinpath(progpath, prog);

				if (isxfile(progpath))

					break;

				if (!delim) {

					progpath[0] = '\0';

					break;

				}

				ppath = delim + 1;

		    }

                    free(path);

		}

		else

			progpath[0] = '\0';

#if HAVE_READLINK

            }

#endif

	}

	/* at this point progpath includes the executable */

	strcpy(argv0_path, progpath);

#if HAVE_READLINK

	{

		char tmpbuffer[MAXPATHLEN+1];

		int linklen = readlink(progpath, tmpbuffer, MAXPATHLEN);

		while (linklen != -1) {

			/* It's not null terminated! */

			tmpbuffer[linklen] = '\0';

			if (tmpbuffer[0] == SEP)

				strcpy(argv0_path, tmpbuffer);

			else {

				/* Interpret relative to progpath */

				reduce(argv0_path);

				joinpath(argv0_path, tmpbuffer);

			}

			linklen = readlink(argv0_path, tmpbuffer, MAXPATHLEN);

		}

                strcpy(progpath, argv0_path);

	}

#endif /* HAVE_READLINK */

	reduce(argv0_path);

	/* now argv0_path is the directory of the executable */

	strcpy(prefix, argv0_path);

	exec_prefix = prefix;

	module_search_path = malloc(strlen(prefix)+1);

	strcpy(module_search_path, prefix);

}

/* External interface */

char *

Py_GetPath(void)

{

	if (!module_search_path)

		calculate_path();

	return module_search_path;

}

char *

Py_GetPrefix(void)

{

	if (!module_search_path)

		calculate_path();

	return prefix;

}

char *

Py_GetExecPrefix(void)

{

	if (!module_search_path)

		calculate_path();

	return exec_prefix;

}

char *

Py_GetProgramFullPath(void)

{

	if (!module_search_path)

		calculate_path();

	return progpath;

}