/* pathstat.c

Copyright (C) 2003 Anthony de Boer

This program is free software; you can redistribute it and/or modify
it under the terms of version 2 of the GNU General Public License as
published by the Free Software Foundation.

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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

I'm not including the usual "either version 2 of the License, or (at your
option) any later version" text since I want to reserve the chance to
read version 3 before using it, just to be sure it doesn't promise free
phone support or sexual favours from the program's author.

---

Usage:

 In ~/.profile, add everything plus the kitchen sink to $PATH, then
 `eval pathstat`.  It removes duplicates, nondirectories, dot, and such rot.

*/

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

struct spath {
	dev_t	p_dev;
	ino_t	p_ino;
	struct spath *p_nxt;
	};

void say(char *blurb) {
	write (1, blurb, strlen(blurb));
	}

void kvetch(char *blurb) {
	write (2, blurb, strlen(blurb));
	}

void barf(char *excuse) {
	kvetch(excuse);
	exit(1);
	}

int main(int argc, char **argv) {
	char *path, *npath;
	struct stat sbuf;
	struct spath *sptop, *spc;
	char *saypre;
	int verbose;

	if (argc == 2 && !strcmp(argv[1], "-v")) {
		verbose = 1;
		}
	else if (argc == 1) {
		verbose = 0;
		}
	else {
		barf("Usage: pathstat [-v]\n");
		}

	saypre = "PATH=";
	sptop = NULL;

	path = strdup(getenv("PATH"));
	if (!path || !*path) {
		barf("No PATH?\n");
		}

	while(path) {
		npath = strchr(path, ':');
		if (npath) {
			*npath++ = '\0';
			}

		if(!*path || *path != '/') {
			kvetch("Tossing \"");
			kvetch(path);
			kvetch("\" from PATH\n");
			goto LOOP;
			}
		if(stat(path, &sbuf)) {
			if (verbose) {
				perror(path);
				}
			goto LOOP;
			}
		if (!S_ISDIR(sbuf.st_mode)) {
			if (verbose) {
				kvetch(path);
				kvetch(" is not a directory\n");
				}
			goto LOOP;
			}

		spc = sptop;
		while(spc) {
			if (spc->p_dev == sbuf.st_dev && spc->p_ino == sbuf.st_ino) {
				if (verbose) {
					kvetch(path);
					kvetch(" already seen\n");
					}
				goto LOOP;
				}
			spc = spc->p_nxt;
			}

		spc = (struct spath *)malloc(sizeof(struct spath));
		if (spc == NULL) {
			barf("malloc failed\n");
			}
		spc->p_dev = sbuf.st_dev;
		spc->p_ino = sbuf.st_ino;
		spc->p_nxt = sptop;
		sptop = spc;

		say(saypre);
		say(path);

		saypre = ":";

		LOOP:
		path = npath;
		}
	
	say("\n");
	exit(0);
	return 0;
	}