libcmd/common/pids.c

/***********************************************************************
*                                                                      *
*               This software is part of the ast package               *
*          Copyright (c) 1992-2010 AT&T Intellectual Property          *
*                      and is licensed under the                       *
*                  Common Public License, Version 1.0                  *
*                    by AT&T Intellectual Property                     *
*                                                                      *
*                A copy of the License is available at                 *
*            http://www.opensource.org/licenses/cpl1.0.txt             *
*         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
*                                                                      *
*              Information and Software Systems Research               *
*                            AT&T Research                             *
*                           Florham Park NJ                            *
*                                                                      *
*                 Glenn Fowler <gsf@research.att.com>                  *
*                  David Korn <dgk@research.att.com>                   *
*                                                                      *
***********************************************************************/
#pragma prototyped

#define FORMAT      "PID=%(pid)d PPID=%(ppid)d PGID=%(pgid)d TID=%(tid)d SID=%(sid)d"

static const char usage[] =
"[-?\n@(#)$Id: pids (AT&T Research) 2008-04-01 $\n]"
USAGE_LICENSE
"[+NAME?pids - list calling shell process ids]"
"[+DESCRIPTION?When invoked as a shell builtin, \bpids\b lists one or "
    "more of the calling process ids determined by \bgetpid\b(2), "
    "\bgetppid\b(2), \bgetpgrp\b(2), \btcgetpgrp\b(2) and \bgetsid\b(2). "
    "Unknown or invalid ids have the value \b-1\b.]"
"[f:format?List the ids specified by \aformat\a. \aformat\a follows "
    "\bprintf\b(3) conventions, except that \bsfio\b(3) inline ids are used "
    "instead of arguments: "
    "%[-+]][\awidth\a[.\aprecis\a[.\abase\a]]]]]](\aid\a)\achar\a. The "
    "supported \aid\as are:]:[format:=" FORMAT "]"
    "{"
        "[+pid?The process id.]"
        "[+pgid?The process group id.]"
        "[+ppid?The parent process id.]"
        "[+tid|tty?The controlling terminal id.]"
        "[+sid?The session id.]"
    "}"
"[+SEE ALSO?\bgetpid\b(2), \bgetppid\b(2), \bgetpgrp\b(2), "
    "\btcgetpgrp\b(2), \bgetsid\b(2)]"
;

#include <cmd.h>
#include <ast_tty.h>
#include <sfdisc.h>

/*
 * sfkeyprintf() lookup
 * handle==0 for heading
 */

static int
key(void* handle, Sffmt_t* fp, const char* arg, char** ps, Sflong_t* pn)
{
    register char*  s;
    int     fd;
    long        tid;

    if (!(s = fp->t_str) || streq(s, "pid"))
        *pn = getpid();
    else if (streq(s, "pgid"))
        *pn = getpgid(0);
    else if (streq(s, "ppid"))
        *pn = getppid();
    else if (streq(s, "tid") || streq(s, "tty"))
    {
        for (fd = 0; fd < 3; fd++)
            if ((tid = tcgetpgrp(fd)) >= 0)
                break;
        *pn = tid;
    }
    else if (streq(s, "sid"))
        *pn = getsid(0);
    else if (streq(s, "format"))
        *ps = (char*)handle;
    else
    {
        error(2, "%s: unknown format identifier", s);
        return 0;
    }
    return 1;
}

int
b_pids(int argc, char** argv, void* context)
{
    char*           format = 0;

    cmdinit(argc, argv, context, ERROR_CATALOG, 0);
    for (;;)
    {
        switch (optget(argv, usage))
        {
        case 'f':
            format = opt_info.arg;
            continue;
        case '?':
            error(ERROR_USAGE|4, "%s", opt_info.arg);
            continue;
        case ':':
            error(2, "%s", opt_info.arg);
            continue;
        }
        break;
    }
    argv += opt_info.index;
    if (error_info.errors || *argv)
        error(ERROR_USAGE|4, "%s", optusage(NiL));
    if (!format)
        format = FORMAT;
    sfkeyprintf(sfstdout, format, format, key, NiL);
    sfprintf(sfstdout, "\n");
    return 0;
}