Source Code 1992 March/Source_Code_CD-ROM_Walnut_Creek_March_1992.iso/usenet/altsrcs/2/2651

Internet Message Format | 1991-02-02 | 11KB

From: [e-mail] (Maarten Litmaath)
Newsgroups: alt.sources
Subject: which6 - successor of ... which5!
Message-ID: <[e-mail]>
Date: 2 Feb 91 10:40:58 GMT

Now multiple groups (see getgroups(2) on BSD-derivatives) are supported.
Enjoy.

: This is a shar archive.  Extract with sh, not csh.
: This archive ends with exit, so do not worry about trailing junk.
: --------------------------- cut here --------------------------
PATH=/bin:/usr/bin:/usr/ucb
echo Extracting 'which6.c'
sed 's/^X//' > 'which6.c' << '+ END-OF-FILE ''which6.c'
X/*
X * which [-i] [-a] [--] [<command>]
X * alias which alias !\$ \| /usr/local/bin/which -i !\*
X * alias which 'eval alias \$$# | /usr/local/bin/which -i ${1+"$@"}'
X * which()
X * {
X *    eval last=\"\$$#\"
X *    set | sed -n "/^$last(){$/,/^}$/p" |
X *        /usr/local/bin/which -i ${1+"$@"}
X * }
X *
X * Author: Maarten Litmaath @ VU University Amsterdam ([e-mail])
X *
X * First change:
X *    Emile LeBlanc ([e-mail]) notes
X *    the access() system call considering everything executable for
X *    root (!), so we give root a special treatment.  :-(
X *    `which', `which -i' and `which -a' with no further arguments now
X *    return the PATH environment variable, split up into its components.
X *    The aliases defined above are slightly different from the previous
X *    version - now it's the shell who's doing the alias checking.
X * Second change:
X *    Added support for shell functions and multiline aliases, added the
X *    `--' option, changed the source style.
X * Third change:
X *    To hell with access()!
X *    Now stat() is used to give the right answer even if the effective
X *    uid (gid) differs from the real uid (gid).
X *    We can't use setuid(geteuid()), because that's nonportable.  :-(
X * Fourth change:
X *    Jim Meyering <[e-mail]> notes convert() will clobber
X *    the stack if the PATH is longer than BUF_SIZE - 1 characters.
X *    I've changed convert() altogether to return a path vector (cf. argv),
X *    whose components are the respective directories in the PATH.
X *    Furthermore in printing the PATH there are no trailing colons anymore.
X * Fifth change:
X *    I've added support for multiple groups (see getgroups(2) on BSD-
X *    derivatives).
X *    Thanks to John M. Sellens <[e-mail]> (and
X *    Andy at the same site).
X *    Furthermore, if a matching executable is found in an unreadable
X *    directory, beside the warning on stderr the name is now printed on
X *    stdout as well.
X */
X
X#ifdef    MULTIPLE_GROUPS
X#include    <sys/param.h>
X#else
X#include    <sys/types.h>
X#endif    /* MULTIPLE_GROUPS */
X#include    <sys/stat.h>
X#include    <stdio.h>
X
X#define        BUF_SIZE    512
X#define        M_USR        0700
X#define        M_GRP        0070
X#define        M_OTH        0007
X#define        X_ALL        0111
X#define        R_ALL        0444
X
Xchar    Version[] =
X    "@(#)which 6.0 91/02/02 Maarten Litmaath @ VU Informatika Amsterdam";
Xchar    *Prog;
X
X
Xvoid    usage()
X{
X    fprintf(stderr, "Usage: %s [-i] [-a] [--] [<command>]\n", Prog);
X    exit(1);
X}
X
X
Xmain(argc, argv)
Xint    argc;
Xregister char    **argv;
X{
X    register char    *path, *s, **pathv, **p;
X    char    *strcpy(), *getenv(), *fgets(), buf[BUF_SIZE], **convert();
X    int    all = 0, inter = 0, stop = 0, found = 0, uid, gid, mask,
X        xmask, rmask;
X    struct    stat    st;
X    void    usage();
X
X
X    Prog = *argv++;
X    --argc;
X
X    while (!stop && (s = *argv) && (*s == '-')) {
X        ++argv;
X        --argc;
X        ++s;
X        while (*s)
X            switch (*s++) {
X            case 'a':
X                all = 1;
X                break;
X            case 'i':
X                inter = 1;
X                break;
X            case '-':
X                stop = 1;
X                break;
X            default:
X                usage();
X            }
X    }
X
X    if (argc > 1)
X        usage();
X
X    if (inter && *argv) {
X        while (fgets(buf, sizeof buf, stdin)) {
X            if (!found) {
X                printf("%s", *argv);
X                found = 1;
X            }
X            printf("\t%s", buf);
X        }
X        if (found && !all)
X            exit(0);
X    }
X
X    if (!(path = getenv("PATH"))) {
X        fprintf(stderr, "%s: no PATH in environment!\n", Prog);
X        exit(1);
X    }
X
X    if (!*path)
X        path = ".";        /* another dubious convention */
X
X    pathv = convert(path);        /* convert path string to vector */
X
X    if (!*argv) {            /* print path if no more arguments */
X        while (*pathv)
X            puts(*pathv++);
X        exit(0);
X    }
X
X    uid = geteuid();
X    gid = getegid();
X    if (uid == 0) {
X        xmask = X_ALL;
X        rmask = R_ALL;
X    }
X
X    for (p = pathv; path = *p++; ) {    /* try every component */
X        s = buf;
X        while (*s++ = *path++)
X            ;
X        (void) strcpy(s, *argv);
X        *--s = '/';
X
X        if (stat(buf, &st) != 0 || (st.st_mode & S_IFMT) != S_IFREG)
X            continue;
X
X        /* file exists and is regular */
X
X        if (uid != 0) {
X            mask = st.st_uid == uid ? M_USR :
X                st.st_gid == gid ? M_GRP :
X#ifdef    MULTIPLE_GROUPS
X                groups_member(st.st_gid) ? M_GRP :
X#endif    /* MULTIPLE_GROUPS */
X                M_OTH;
X            xmask = X_ALL & mask;
X            rmask = R_ALL & mask;
X        }
X
X        if (!(st.st_mode & xmask))
X            continue;
X
X        /* file is executable */
X
X        *s = 0;
X        if (stat(buf, &st) != 0) {
X            perror(buf);
X            continue;
X        }
X
X        /* warn user if the directory is unreadable */
X
X        if (!(st.st_mode & rmask))
X            fprintf(stderr,
X                "%s: %s found in unreadable directory `%s'!\n",
X                Prog, *argv, buf);
X
X        *s = '/';
X        puts(buf);
X        if (!all)
X            exit(0);
X        found = 1;
X    }
X
X    if (found)
X        exit(0);
X
X    fprintf(stderr, "%s not found in:\n", *argv);
X    while (*pathv)
X        fprintf(stderr, "%s\n", *pathv++);
X    exit(1);
X    /* NOTREACHED */
X}
X
X
Xchar    **convert(path)
Xchar    *path;
X{
X    register char    *s, c;
X    register int    pathc;        /* the length of the path vector */
X    char    **v, **pathv, *malloc();
X
X    for (s = path, pathc = 2; c = *s++; )
X        if (c == ':')
X            ++pathc;
X
X    if (!(pathv = (char **) malloc(pathc * sizeof(char *)))) {
X        perror("malloc");
X        exit(1);
X    }
X
X    for (s = path, v = pathv; (c = *s) != '\0'; ) {
X        if (c == ':') {
X            /*
X             * This colon is spurious.  According to some
X             * dubious convention it is made equivalent to a dot.
X             */
X            *v++ = ".";
X            if (*++s == '\0')
X                *v++ = ".";
X                /*
X                 * The PATH ended in a spurious colon.
X                 * To be consistent we add another dot
X                 * to the path vector.  One day you'll
X                 * be glad we did.
X                 */
X        } else {
X            *v++ = s;
X            while ((c = *++s) != '\0')
X                if (c == ':') {
X                    *s++ = '\0';
X                    if (*s == '\0')
X                        *v++ = ".";
X                        /*
X                         * The PATH ended in a
X                         * (spurious) colon, so
X                         * add dot to the vector.
X                         */
X                    break;
X                }
X        }
X    }
X
X    *v = 0;        /* Signal the end of the path vector. */
X
X    return pathv;
X}
X
X
X#ifdef    MULTIPLE_GROUPS
Xint    groups_member(gid)
Xint    gid;
X{
X    register
X    int    *p, ngroups;
X    int    groups[NGROUPS];
X
X    if ((ngroups = getgroups(NGROUPS, groups)) < 0)
X        return 0;
X    p = groups;
X        while (--ngroups >= 0)
X        if (*p++ == gid)
X            return 1;
X    return 0;
X}
X#endif    /* MULTIPLE_GROUPS */
+ END-OF-FILE which6.c
chmod 'u=rw,g=r,o=r' 'which6.c'
set `wc -c 'which6.c'`
count=$1
case $count in
5970)    :;;
*)    echo 'Bad character count in ''which6.c' >&2
        echo 'Count should be 5970' >&2
esac
echo Extracting 'which.1'
sed 's/^X//' > 'which.1' << '+ END-OF-FILE ''which.1'
X.TH WHICH 1 Apr\ 04\ 1990
X.SH NAME
Xwhich \- give alias, function or path expansion of command
X.SH SYNOPSIS
X.B which
X[
X.B \-i
X] [
X.B \-a
X] [
X.B \-\-
X] [
X.I command
X]
X.SH DESCRIPTION
X.I Which
Xprovides the user with the full expansion of the
X.I command
Xargument, be it either an \fIalias\fR, a \fIshell function\fR
Xor an executable file (default). To enable search for
X.I aliases
Xand \fIshell functions\fR
Xthe user should supply the `\fI\-i\fR'
X(= interactive) flag. In that case
X.I which
Xexpects as standard input the expansion of the \fIalias\fR
Xor \fIshell function\fR.
XIf the standard input is empty or the `\fI\-i\fR' flag has not been
Xgiven, \fIwhich\fR will try to locate \fIcommand\fR
Xin the user's \fBPATH\fR.
XThe interactive mode is easily used by setting an
X.I alias
Xlike the following:
X.ft B
X.nf
X
X    alias    which    alias !\\$ \\| /usr/local/bin/which \-i !\\*
X
X.fi
X.ft R
Xin \fIcsh\fR, or
X.ft B
X.nf
X
X    alias    which    eval alias '\\"\\$$#\\" |' \\
X            /usr/local/bin/which \-i '${1+"$@"}'
X
X.fi
X.ft R
Xin shells which are supersets of
X.I sh
Xand which know \fIaliases\fR. If your shell has \fIshell functions\fR, you
Xcan use the following function:
X.ft B
X.nf
X
X    which()
X    {
X        eval last=\\"\\$$#\\"
X        set | sed \-n "/^$last(){$/,/^}$/p" |
X            /usr/local/bin/which \-i ${1+"$@"}
X    }
X
X.fi
X.ft R
XIf the `\fI\-a\fR' (= all) flag is given,
X.I which
Xwill not stop after the first `match', but search for all occurrences of
X.I command
Xin the user's
X.B PATH.
XThe `\fI\-\-\fR'
Xflag can be used to end the list of options: the next argument (if present)
Xwill be taken as \fIcommand\fR, even if it starts with a `\-'.
X\fIWhich [\-i] [\-a] [\-\-]\fR
Xwithout further arguments prints the user's
X.B PATH
Xbroken up into its components,
Xone per line.
X.PP
XThis new version of the
X.I which
Xcommand is not a
X.I csh
Xscript.
XBeing an executable it is much faster, and not sourcing
X.I .cshrc
Xit gives a true picture of one's
X.I aliases.
XFurthermore it will give the correct answers even if:
X.IP \-
Xthe \fIeffective uid\fR
X(\fIgid\fR) differs from the \fIreal\fR uid (gid)
X.IP \-
Xthe effective uid is 0 (\fIroot\fR).
X.SH EXAMPLE
X.ft B
X.nf
X% alias
Xwhich    alias !$ | /usr/local/bin/which \-i !*
X% which which
Xwhich    alias !$ | /usr/local/bin/which \-i !*
X% which \-a which
Xwhich    alias !$ | /usr/local/bin/which \-i !*
X/usr/local/bin/which
X/usr/ucb/which
X%
X.fi
X.ft R
X.SH AUTHOR
XMaarten Litmaath @ VU Informatika Amsterdam
+ END-OF-FILE which.1
chmod 'u=rw,g=r,o=r' 'which.1'
set `wc -c 'which.1'`
count=$1
case $count in
2384)    :;;
*)    echo 'Bad character count in ''which.1' >&2
        echo 'Count should be 2384' >&2
esac
echo Extracting 'Makefile'
sed 's/^X//' > 'Makefile' << '+ END-OF-FILE ''Makefile'
X# Makefile for /usr/local/bin/which
X# If your operating system does not support multiple groups (see getgroups(2)
X# on BSD-derivatives), comment out the next line.
XMULTIPLE_GROUPS=-DMULTIPLE_GROUPS
X
Xwhich:        which6.c
X        cc -O $(MULTIPLE_GROUPS) -o which which6.c
X
Xinstall:    which doc
X        /bin/mv -f which /usr/local/bin
X        /bin/mv -f which.man /usr/local/man/cat1/which.1
X        /bin/cp which.1 /usr/local/man/man1
X
Xdoc:
X        nroff -man which.1 > which.man
+ END-OF-FILE Makefile
chmod 'u=rw,g=r,o=r' 'Makefile'
set `wc -c 'Makefile'`
count=$1
case $count in
443)    :;;
*)    echo 'Bad character count in ''Makefile' >&2
        echo 'Count should be 443' >&2
esac
exit 0
--
"Salman Rushdie received a copy just as his latest novel was being published.
He ignored it and received myriads of death threats. He quickly decided to
send out twenty copies (some to the Ayatollah) and is still alive."
            (John Banagan <[e-mail]> in sci.skeptic)