Date: Fri, 14 Dec 2001 19:22:42 -0700 From: Peter Sanchez <fut0n@linuxforlesbians.org> To: Dag-Erling Smorgrav <des@ofug.org> Cc: freebsd-bugs@freebsd.org Subject: Re: bin/32807: which utility replacement in C Message-ID: <20011214192242.C38914@sushi.linuxforlesbians.org> In-Reply-To: <xzpzo4lwer4.fsf@flood.ping.uio.no>; from des@ofug.org on Sat, Dec 15, 2001 at 12:42:07AM %2B0100 References: <200112132100.fBDL01r64612@freefall.freebsd.org> <Pine.NEB.3.96L.1011214061809.83145A-100000@fledge.watson.org> <20011214070038.B38914@sushi.linuxforlesbians.org> <xzpd71hyhfi.fsf@flood.ping.uio.no> <20011214143727.A41700@sushi.linuxforlesbians.org> <xzpzo4lwer4.fsf@flood.ping.uio.no>
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heh, old habits die hard. Here is the final copy :) *whew* and I thought
this was gonna be easy heh.
Peter
/*
* which - a which utility for Unix
*
* SYNOPSIS: For FreeBSD-4.x and later
*
* DESCRIPTION:
* Utility to get the full system path of an executable in the=20
* users PATH environment variable.
*
* Works for:
* FreeBSD 4.x and probably most earlier versions
*
* AUTHOR: Peter Sanchez <psanchez@packet-addiction.org>
*/
#ifndef lint
static const char rcsid[] =3D "$FreeBSD$";
#endif /* not lint */
#include <sys/types.h>
#include <sys/stat.h>
#include <err.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <pwd.h>
#include <sysexits.h>
#define NGROUPS 15
struct pathinfo {
struct pathinfo *next;
char *path;
};
struct pathinfo *all =3D NULL;
int found =3D 1;
void
usage(void)
{
(void)fprintf(stderr, "usage: which [-a] [-s] program ...\n");
exit(EX_USAGE);
}
int
file_exists(char *file)
{
struct stat info;
int check;
check =3D stat(file, &info);
if (check =3D=3D -1)
return check; /* file doesnt exist */
return (info.st_mode & S_IFREG && access(file, X_OK) =3D=3D 0) ? ch=
eck : -1;
}
void
losepath(void)
{
struct pathinfo *tmp;
while (all !=3D NULL) {
tmp =3D all->next;
free(all);
all =3D tmp;
}
}
void
findpath(void)
{
struct pathinfo *cur =3D NULL;
char *userpath =3D getenv("PATH");
=20
if (userpath =3D=3D NULL || strlen(userpath) =3D=3D 0)
errx(EX_OSERR, "No PATH variable.");
all =3D (struct pathinfo *)malloc(sizeof(struct pathinfo));
if (all =3D=3D NULL)
err(EX_OSERR, (char *)NULL);
/* NOTREACHED */
cur =3D all;
while ((cur->path =3D strsep(&userpath, ":")) !=3D NULL) {
cur->next =3D (struct pathinfo *)malloc(sizeof(struct pathi=
nfo));
if (cur->next =3D=3D NULL) {
losepath();
err(EX_OSERR, (char *)NULL);
/* NOTREACHED */
}
if (strlen(cur->path) =3D=3D 0)
warnx("PATH element of 0 length.");
cur =3D cur->next;
}
cur->next =3D NULL;
cur =3D all;
}
void
findprog(char *prog, int aflag, int sflag)
{
struct pathinfo *tmp;
char *tmpbuf;
tmp =3D all;
while (all !=3D NULL) {
if (all->path =3D=3D NULL)
break;
if (strchr(prog, '/'))
tmpbuf =3D strdup(prog);
else {
tmpbuf =3D malloc(sizeof(char) * (strlen(all->path)=
+ strlen(prog) + 1));
if (tmpbuf =3D=3D NULL) {
losepath();
err(EX_OSERR, (char *)NULL);
/* NOTREACHED */
}
sprintf(tmpbuf,"%s/%s",all->path,prog);
}
if (file_exists(tmpbuf) =3D=3D 0) {
found =3D 0;
if (sflag && aflag) ;
else if (sflag && !aflag) {
all =3D tmp;
free(tmpbuf);
return;
}
else if (aflag && !sflag)
(void)printf("%s\n", tmpbuf);
else {
(void)printf("%s\n", tmpbuf);
all =3D tmp;
free(tmpbuf);
return;
}
}
all =3D all->next;
free(tmpbuf);
}
all =3D tmp;
}
int
main(int argc, char *argv[])
{
char ch;
int aflag, sflag, i;
aflag =3D sflag =3D 0;
if (argc < 2)
exit(EX_USAGE);
=20
while ((ch =3D getopt(argc, argv, "ash?")) !=3D -1) {
switch (ch) {
case 'a':
aflag =3D 1;
break;
case 's':
sflag =3D 1;
break;
case 'h':
case '?':
default:
usage();
/* NOTREACHED */
}
}
argc -=3D optind;
argv +=3D optind;
=20
findpath();
for (i =3D 0; i < argc; i++)
findprog(argv[i], aflag, sflag);
=20
losepath();
return sflag ? found : 0;
}
On Sat, Dec 15, 2001 at 12:42:07AM +0100, Dag-Erling Smorgrav wrote:
> Peter Sanchez <fut0n@linuxforlesbians.org> writes:
> > Struct rules, but understandable. I like the style(9) format, makes it
> > look much more structured and readable. Here ya go, I hope this is what
> > you had in mind.
>=20
> Yes, much better! Though the explicit "return" from void functions
> isn't necessary.
>=20
> DES
> --=20
> Dag-Erling Smorgrav - des@ofug.org
--=20
Peter Sanchez, aka fut0n | "The ability to read is what
- fut0n@linuxforlesbians.org | distinguishes Unix users from
- www.linuxforlesbians.org | those of more popular platforms."
- FreeBSD or DIE | - John Lasser
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