cmd/builtin/who.c

/***********************************************************************
*                                                                      *
*               This software is part of the ast package               *
*          Copyright (c) 1992-2012 AT&T Intellectual Property          *
*                      and is licensed under the                       *
*                 Eclipse Public License, Version 1.0                  *
*                    by AT&T Intellectual Property                     *
*                                                                      *
*                A copy of the License is available at                 *
*          http://www.eclipse.org/org/documents/epl-v10.html           *
*         (with md5 checksum b35adb5213ca9657e911e9befb180842)         *
*                                                                      *
*              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
/*
 * who.c
 * Written by David Korn
 * Thu Aug 15 00:12:29 EDT 1996
 */

static const char usage[] =
"[-?\n@(#)$Id: who (AT&T Research) 2004-03-25 $\n]"
USAGE_LICENSE
"[+NAME?who - display who is on the system]"
"[+DESCRIPTION?\bwho\b displays various pieces of information about "
    "logged in users to standard output.]"
"[+?\bwho\b lists the user's name, terminal line, login time, and remote "
    "host name, if applicable, for each logged "
    "in user it reports.]"
"[+?The second form, \bwho am I\b is equivalent to \bwho -m\b.]"

"[i:idle?Also writes the idle time for each displayed user.  The idle time "
    "is the time since last activity on that line.]"
"[m?Write only information about the current terminal.]"
"[q:count?Writes only the login names and the number of users logged on.  "
    "This options overrides other options.]"
"[s?This option is ignored.]"
"[u:?Equivalent to \b-i\b.]"
"[w:writable?Equivalent to \b-T\b.]"
"[H:heading?Put a heading line in before of the output.]"
"[T:mesg?Specifies the state of the terminal as one of the following:]{"
    "[++?The terminal allows write access to other users.]"
    "[+-?The terminal denies write access to other users.]"
    "[+???The write access cannot be determined.]"
    "}"
"\n"
"\n[am I]\n"
"\n"
"[+EXIT STATUS]{"
    "[+0?Successful completion.]"
    "[+>0?One or more errors occurred.]"
"}"
"[+SEE ALSO?\bdate\b(1), \blogin\b(1)]"
;


#include    <cmd.h>
#include    <ls.h>
#include    <time.h>

#include "FEATURE/utmp"

#if _hdr_utmp
#   include <utmp.h>
#endif

#if _mem_ut_host_utmp && _mem_ut_type_utmp
#   undef   _hdr_utmpx
#endif

#if _hdr_utmpx
#   include <utmpx.h>
#   undef   _mem_ut_host_utmp
#   undef   _mem_ut_type_utmp
#   if _mem_ut_tv_utmpx
#       undef   ut_time
#       define  ut_time ut_tv.tv_sec
#   endif
#   if ! _mem_ut_user_utmpx
#       define ut_user ut_name
#   endif
#   ifdef UTMPX_FILE
#       define UTMP UTMPX_FILE
#   else
#       if _hdr_paths
#           include <paths.h>
#       endif
#       ifdef _PATH_UTMPX
#           define UTMP _PATH_UTMPX
#       else
#           ifdef UTMP_FILE
#               define UTMP UTMP_FILE
#           else
#               ifdef _PATH_UTMP
#                   define UTMP _PATH_UTMP
#               else
#                   define UTMP "/etc/utmpx"
#               endif
#           endif
#       endif
#   endif
#else
#   undef   _mem_ut_host_utmpx
#   undef   _mem_ut_type_utmpx
#   define utmpx    utmp
#   if _mem_ut_tv_utmp
#       undef   ut_time
#       define  ut_time ut_tv.tv_sec
#   endif
#   if ! _mem_ut_user_utmp
#       define ut_user ut_name
#   endif
#   ifdef UTMP_FILE
#       define UTMP UTMP_FILE
#   else
#       if _hdr_paths
#           include <paths.h>
#       endif
#       ifdef _PATH_UTMP
#           define UTMP _PATH_UTMP
#       else
#           define UTMP "/etc/utmp"
#       endif
#   endif
#endif

#ifdef  nonuser
#   define dead(ut) (nonuser(ut))
#else
#   if _mem_ut_type_utmp || _mem_ut_type_utmpx
#       ifdef USER_PROCESS
#           define dead(ut)     ((ut).ut_type != USER_PROCESS)
#       else
#           ifndef  DEAD_PROCESS
#               define DEAD_PROCESS 8
#           endif
#           define dead(ut)     ((ut).ut_type == DEAD_PROCESS)
#       endif
#   else
#       define dead(ut) 0
#   endif
#endif

#define skip(ut)    (!*ut.ut_user||!*ut.ut_line||dead(ut)|!strcasecmp(ut.ut_user,"login"))

typedef struct
{
    int flags;
    int siz_user;
    int siz_line;
    int siz_host;
} State_t;

#define FLAG_M  1
#define FLAG_T  2
#define FLAG_U  4
#define FLAG_H  8
#define FLAG_Q  0x10

static void outline(Sfio_t *out,register struct utmpx *up,register State_t* sp)
{
    struct stat statb;
    time_t t = up->ut_time;
    char *date = ctime(&t);
    char line[sizeof(up->ut_line)+6];
    int r = 0;
    if(sp->flags&(FLAG_T|FLAG_U))
    {
        sfsprintf(line,sizeof(line),"/dev/%s\0",up->ut_line);
        r = stat(line,&statb);
    }
    if(sp->flags&FLAG_T)
    {
        int state = '?';
        if(r>=0)
            state = (statb.st_mode&S_IWOTH)?'+':'-';
        sfprintf(out,"%-*.*s %c %-*.*s %.12s ",sp->siz_user,sp->siz_user,up->ut_user,state,sp->siz_line,sp->siz_line,up->ut_line,date+4);
    }
    else
        sfprintf(out,"%-*.*s %-*.*s %.12s ",sp->siz_user,sp->siz_user,up->ut_user,sp->siz_line,sp->siz_line,up->ut_line,date+4);
    if(sp->flags&FLAG_U)
    {
        time_t t = time(0)-30;
        sfsprintf(line,sizeof(line),"/dev/%s\0",up->ut_line);
        if(r>=0 && statb.st_atime<t)
        {
            t = (t-(up->ut_time+30))/60;
            if(t>24*60)
                sfprintf(out," old  ");
            else
                sfprintf(out, "%.2d:%.2d ",t/60,t%60);
        }
        else
            sfprintf(out,"  .   ");
    }
#if _mem_ut_host_utmp || _mem_ut_host_utmpx
    if (*up->ut_host)
        sfprintf(out,"  %-*.*s\n",sp->siz_host,sp->siz_host,up->ut_host);
    else
#endif
    sfputc(out,'\n');
}

static int who(Sfio_t *in, Sfio_t *out, int flags)
{
    struct utmpx ut;
    char *line = 0;
    int count = 0;
    State_t state;
    state.flags = flags;
    state.siz_user = sizeof(ut.ut_user);
    if (state.siz_user > 24)
        state.siz_user = 24;
    state.siz_line = sizeof(ut.ut_line);
    if (state.siz_line > 8)
        state.siz_line = 8;
#if _mem_ut_host_utmp || _mem_ut_host_utmpx
    state.siz_host = sizeof(ut.ut_host);
    if (state.siz_host > 30)
        state.siz_host = 30;
#endif
    if(state.flags&FLAG_Q)
        state.flags = FLAG_Q;
    if((state.flags&FLAG_M) && ((line=ttyname(0)) || (line=ttyname(2))))
        line += 5;
    if(state.flags&FLAG_H)
    {
        char *t = "";
        if(state.flags&FLAG_T)
            t = "MESG";
        if(state.flags&FLAG_U)
            sfprintf(out,"%-*.*s %2s %-*.*s %.12s %6s     %s\n",state.siz_user-3,state.siz_user-3,"USER",t,state.siz_line,state.siz_line,"LINE","LOGIN-TIME","IDLE","FROM");
        else
            sfprintf(out,"%-*.*s %2s %-*.*s %.12s     %s\n",state.siz_user-3,state.siz_user-3,"USER",t,state.siz_line,state.siz_line,"LINE","LOGIN-TIME","FROM");
    }
    while(sfread(in,&ut,sizeof(struct utmpx))>0)
    {
        if(skip(ut))
            continue;
        if(line && strcmp(line,ut.ut_line))
            continue;
        if(state.flags&FLAG_Q)
        {
            if(count)
                sfputc(out,' ');
            sfprintf(out,"%s",ut.ut_user);
        }
        else
            outline(out,&ut,&state);
        count++;
    }
    if(state.flags&FLAG_Q)
        sfprintf(out,"\n# users=%d\n",count);
    return(0);
}

int b_who(int argc, char** argv, Shbltin_t* context)
{
    register int n, flags=0;
    Sfio_t *sp;

    cmdinit(argc, argv, context, ERROR_CATALOG, 0);
    while (n = optget(argv, usage)) switch (n)
    {
        case 'm':
        flags |= FLAG_M;
        break;
        case 'H':
        flags |= FLAG_H;
        break;
        case 'T': case 'w':
        flags |= FLAG_T;
        break;
        case 'q':
        flags |= FLAG_Q;
        break;
        case 's':
        break;
        case 'i':
        case 'u':
        flags |= FLAG_U;
        break;
        case ':':
        error(2, opt_info.arg);
        break;
        case '?':
        error(ERROR_usage(2), "%s", opt_info.arg);
        break;
    }
    argv += opt_info.index;
    argc -= opt_info.index;
    if(argc==2)
    {
        flags |= FLAG_M;
        argc = 0;
    }
    if(error_info.errors || argc)
        error(ERROR_usage(2),"%s", optusage((char*)0));
    if(!(sp = sfopen((Sfio_t*)0,UTMP,"r")))
        error(ERROR_system(1),"%s: cannot open",UTMP);
    who(sp,sfstdout,flags);
    sfclose(sp);
    return(error_info.errors);
}