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coreutils/src/who.c
Pádraig Brady aaba82431c maint: update all copyright year number ranges 
Run "make update-copyright" and then...

* gnulib: Update to latest with copyright year adjusted.
* tests/init.sh: Sync with gnulib to pick up copyright year.
* bootstrap: Likewise.
* tests/sample-test: Adjust to use the single most recent year.
2020-01-01 14:16:56 +00:00

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/* GNU's who.
Copyright (C) 1992-2020 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
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, see <https://www.gnu.org/licenses/>. */
/* Written by jla; revised by djm; revised again by mstone */
/* Output format:
name [state] line time [activity] [pid] [comment] [exit]
state: -T
name, line, time: not -q
idle: -u
*/
#include <config.h>
#include <getopt.h>
#include <stdio.h>
#include <assert.h>
#include <sys/types.h>
#include "system.h"
#include "c-ctype.h"
#include "canon-host.h"
#include "readutmp.h"
#include "die.h"
#include "error.h"
#include "hard-locale.h"
#include "quote.h"
#ifdef TTY_GROUP_NAME
# include <grp.h>
#endif
/* The official name of this program (e.g., no 'g' prefix). */
#define PROGRAM_NAME "who"
#define AUTHORS \
proper_name ("Joseph Arceneaux"), \
proper_name ("David MacKenzie"), \
proper_name ("Michael Stone")
#ifdef RUN_LVL
# define UT_TYPE_RUN_LVL(U) UT_TYPE_EQ (U, RUN_LVL)
#else
# define UT_TYPE_RUN_LVL(U) false
#endif
#ifdef INIT_PROCESS
# define UT_TYPE_INIT_PROCESS(U) UT_TYPE_EQ (U, INIT_PROCESS)
#else
# define UT_TYPE_INIT_PROCESS(U) false
#endif
#ifdef LOGIN_PROCESS
# define UT_TYPE_LOGIN_PROCESS(U) UT_TYPE_EQ (U, LOGIN_PROCESS)
#else
# define UT_TYPE_LOGIN_PROCESS(U) false
#endif
#ifdef DEAD_PROCESS
# define UT_TYPE_DEAD_PROCESS(U) UT_TYPE_EQ (U, DEAD_PROCESS)
#else
# define UT_TYPE_DEAD_PROCESS(U) false
#endif
#ifdef NEW_TIME
# define UT_TYPE_NEW_TIME(U) UT_TYPE_EQ (U, NEW_TIME)
#else
# define UT_TYPE_NEW_TIME(U) false
#endif
#define IDLESTR_LEN 6
#if HAVE_STRUCT_XTMP_UT_PID
# define PIDSTR_DECL_AND_INIT(Var, Utmp_ent) \
char Var[INT_STRLEN_BOUND (Utmp_ent->ut_pid) + 1]; \
sprintf (Var, "%ld", (long int) (Utmp_ent->ut_pid))
#else
# define PIDSTR_DECL_AND_INIT(Var, Utmp_ent) \
const char *Var = ""
#endif
#if HAVE_STRUCT_XTMP_UT_ID
# define UT_ID(U) ((U)->ut_id)
#else
# define UT_ID(U) "??"
#endif
/* If true, attempt to canonicalize hostnames via a DNS lookup. */
static bool do_lookup;
/* If true, display only a list of usernames and count of
the users logged on.
Ignored for 'who am i'. */
static bool short_list;
/* If true, display only name, line, and time fields. */
static bool short_output;
/* If true, display the hours:minutes since each user has touched
the keyboard, or "." if within the last minute, or "old" if
not within the last day. */
static bool include_idle;
/* If true, display a line at the top describing each field. */
static bool include_heading;
/* If true, display a '+' for each user if mesg y, a '-' if mesg n,
or a '?' if their tty cannot be statted. */
static bool include_mesg;
/* If true, display process termination & exit status. */
static bool include_exit;
/* If true, display the last boot time. */
static bool need_boottime;
/* If true, display dead processes. */
static bool need_deadprocs;
/* If true, display processes waiting for user login. */
static bool need_login;
/* If true, display processes started by init. */
static bool need_initspawn;
/* If true, display the last clock change. */
static bool need_clockchange;
/* If true, display the current runlevel. */
static bool need_runlevel;
/* If true, display user processes. */
static bool need_users;
/* If true, display info only for the controlling tty. */
static bool my_line_only;
/* The strftime format to use for login times, and its expected
output width. */
static char const *time_format;
static int time_format_width;
/* for long options with no corresponding short option, use enum */
enum
{
LOOKUP_OPTION = CHAR_MAX + 1
};
static struct option const longopts[] =
{
{"all", no_argument, NULL, 'a'},
{"boot", no_argument, NULL, 'b'},
{"count", no_argument, NULL, 'q'},
{"dead", no_argument, NULL, 'd'},
{"heading", no_argument, NULL, 'H'},
{"login", no_argument, NULL, 'l'},
{"lookup", no_argument, NULL, LOOKUP_OPTION},
{"message", no_argument, NULL, 'T'},
{"mesg", no_argument, NULL, 'T'},
{"process", no_argument, NULL, 'p'},
{"runlevel", no_argument, NULL, 'r'},
{"short", no_argument, NULL, 's'},
{"time", no_argument, NULL, 't'},
{"users", no_argument, NULL, 'u'},
{"writable", no_argument, NULL, 'T'},
{GETOPT_HELP_OPTION_DECL},
{GETOPT_VERSION_OPTION_DECL},
{NULL, 0, NULL, 0}
};
/* Return a string representing the time between WHEN and now.
BOOTTIME is the time of last reboot.
FIXME: locale? */
static const char *
idle_string (time_t when, time_t boottime)
{
static time_t now = TYPE_MINIMUM (time_t);
if (now == TYPE_MINIMUM (time_t))
time (&now);
if (boottime < when && now - 24 * 60 * 60 < when && when <= now)
{
int seconds_idle = now - when;
if (seconds_idle < 60)
return " . ";
else
{
static char idle_hhmm[IDLESTR_LEN];
/* FIXME-in-2018: see if this assert is still required in order
to suppress gcc's unwarranted -Wformat-length= warning. */
assert (seconds_idle / (60 * 60) < 24);
sprintf (idle_hhmm, "%02d:%02d",
seconds_idle / (60 * 60),
(seconds_idle % (60 * 60)) / 60);
return idle_hhmm;
}
}
return _(" old ");
}
/* Return a time string. */
static const char *
time_string (const STRUCT_UTMP *utmp_ent)
{
static char buf[INT_STRLEN_BOUND (intmax_t) + sizeof "-%m-%d %H:%M"];
/* Don't take the address of UT_TIME_MEMBER directly.
Ulrich Drepper wrote:
"... GNU libc (and perhaps other libcs as well) have extended
utmp file formats which do not use a simple time_t ut_time field.
In glibc, ut_time is a macro which selects for backward compatibility
the tv_sec member of a struct timeval value." */
time_t t = UT_TIME_MEMBER (utmp_ent);
struct tm *tmp = localtime (&t);
if (tmp)
{
strftime (buf, sizeof buf, time_format, tmp);
return buf;
}
else
return timetostr (t, buf);
}
/* Print formatted output line. Uses mostly arbitrary field sizes, probably
will need tweaking if any of the localization stuff is done, or for 64 bit
pids, etc. */
static void
print_line (int userlen, const char *user, const char state,
int linelen, const char *line,
const char *time_str, const char *idle, const char *pid,
const char *comment, const char *exitstr)
{
static char mesg[3] = { ' ', 'x', '\0' };
char *buf;
char x_idle[1 + IDLESTR_LEN + 1];
char x_pid[1 + INT_STRLEN_BOUND (pid_t) + 1];
char *x_exitstr;
int err;
mesg[1] = state;
if (include_idle && !short_output && strlen (idle) < sizeof x_idle - 1)
sprintf (x_idle, " %-6s", idle);
else
*x_idle = '\0';
if (!short_output && strlen (pid) < sizeof x_pid - 1)
sprintf (x_pid, " %10s", pid);
else
*x_pid = '\0';
x_exitstr = xmalloc (include_exit ? 1 + MAX (12, strlen (exitstr)) + 1 : 1);
if (include_exit)
sprintf (x_exitstr, " %-12s", exitstr);
else
*x_exitstr = '\0';
err = asprintf (&buf,
"%-8.*s"
"%s"
" %-12.*s"
" %-*s"
"%s"
"%s"
" %-8s"
"%s"
,
userlen, user ? user : " .",
include_mesg ? mesg : "",
linelen, line,
time_format_width,
time_str,
x_idle,
x_pid,
/* FIXME: it's not really clear whether the following
field should be in the short_output. A strict reading
of SUSv2 would suggest not, but I haven't seen any
implementations that actually work that way... */
comment,
x_exitstr
);
if (err == -1)
xalloc_die ();
{
/* Remove any trailing spaces. */
char *p = buf + strlen (buf);
while (*--p == ' ')
/* empty */;
*(p + 1) = '\0';
}
puts (buf);
free (buf);
free (x_exitstr);
}
/* Return true if a terminal device given as PSTAT allows other users
to send messages to; false otherwise */
static bool
is_tty_writable (struct stat const *pstat)
{
#ifdef TTY_GROUP_NAME
/* Ensure the group of the TTY device matches TTY_GROUP_NAME, more info at
https://bugzilla.redhat.com/454261 */
struct group *ttygr = getgrnam (TTY_GROUP_NAME);
if (!ttygr || (pstat->st_gid != ttygr->gr_gid))
return false;
#endif
return pstat->st_mode & S_IWGRP;
}
/* Send properly parsed USER_PROCESS info to print_line. The most
recent boot time is BOOTTIME. */
static void
print_user (const STRUCT_UTMP *utmp_ent, time_t boottime)
{
struct stat stats;
time_t last_change;
char mesg;
char idlestr[IDLESTR_LEN + 1];
static char *hoststr;
#if HAVE_UT_HOST
static size_t hostlen;
#endif
#define DEV_DIR_WITH_TRAILING_SLASH "/dev/"
#define DEV_DIR_LEN (sizeof (DEV_DIR_WITH_TRAILING_SLASH) - 1)
char line[sizeof (utmp_ent->ut_line) + DEV_DIR_LEN + 1];
char *p = line;
PIDSTR_DECL_AND_INIT (pidstr, utmp_ent);
/* Copy ut_line into LINE, prepending '/dev/' if ut_line is not
already an absolute file name. Some systems may put the full,
absolute file name in ut_line. */
if ( ! IS_ABSOLUTE_FILE_NAME (utmp_ent->ut_line))
p = stpcpy (p, DEV_DIR_WITH_TRAILING_SLASH);
stzncpy (p, utmp_ent->ut_line, sizeof (utmp_ent->ut_line));
if (stat (line, &stats) == 0)
{
mesg = is_tty_writable (&stats) ? '+' : '-';
last_change = stats.st_atime;
}
else
{
mesg = '?';
last_change = 0;
}
if (last_change)
sprintf (idlestr, "%.*s", IDLESTR_LEN, idle_string (last_change, boottime));
else
sprintf (idlestr, " ?");
#if HAVE_UT_HOST
if (utmp_ent->ut_host[0])
{
char ut_host[sizeof (utmp_ent->ut_host) + 1];
char *host = NULL;
char *display = NULL;
/* Copy the host name into UT_HOST, and ensure it's nul terminated. */
stzncpy (ut_host, utmp_ent->ut_host, sizeof (utmp_ent->ut_host));
/* Look for an X display. */
display = strchr (ut_host, ':');
if (display)
*display++ = '\0';
if (*ut_host && do_lookup)
{
/* See if we can canonicalize it. */
host = canon_host (ut_host);
}
if (! host)
host = ut_host;
if (display)
{
if (hostlen < strlen (host) + strlen (display) + 4)
{
hostlen = strlen (host) + strlen (display) + 4;
free (hoststr);
hoststr = xmalloc (hostlen);
}
sprintf (hoststr, "(%s:%s)", host, display);
}
else
{
if (hostlen < strlen (host) + 3)
{
hostlen = strlen (host) + 3;
free (hoststr);
hoststr = xmalloc (hostlen);
}
sprintf (hoststr, "(%s)", host);
}
if (host != ut_host)
free (host);
}
else
{
if (hostlen < 1)
{
hostlen = 1;
free (hoststr);
hoststr = xmalloc (hostlen);
}
*hoststr = '\0';
}
#endif
print_line (sizeof UT_USER (utmp_ent), UT_USER (utmp_ent), mesg,
sizeof utmp_ent->ut_line, utmp_ent->ut_line,
time_string (utmp_ent), idlestr, pidstr,
hoststr ? hoststr : "", "");
}
static void
print_boottime (const STRUCT_UTMP *utmp_ent)
{
print_line (-1, "", ' ', -1, _("system boot"),
time_string (utmp_ent), "", "", "", "");
}
static char *
make_id_equals_comment (STRUCT_UTMP const *utmp_ent)
{
size_t utmpsize = sizeof UT_ID (utmp_ent);
char *comment = xmalloc (strlen (_("id=")) + utmpsize + 1);
strcpy (comment, _("id="));
strncat (comment, UT_ID (utmp_ent), utmpsize);
return comment;
}
static void
print_deadprocs (const STRUCT_UTMP *utmp_ent)
{
static char *exitstr;
char *comment = make_id_equals_comment (utmp_ent);
PIDSTR_DECL_AND_INIT (pidstr, utmp_ent);
if (!exitstr)
exitstr = xmalloc (strlen (_("term="))
+ INT_STRLEN_BOUND (UT_EXIT_E_TERMINATION (utmp_ent)) + 1
+ strlen (_("exit="))
+ INT_STRLEN_BOUND (UT_EXIT_E_EXIT (utmp_ent))
+ 1);
sprintf (exitstr, "%s%d %s%d", _("term="), UT_EXIT_E_TERMINATION (utmp_ent),
_("exit="), UT_EXIT_E_EXIT (utmp_ent));
/* FIXME: add idle time? */
print_line (-1, "", ' ', sizeof utmp_ent->ut_line, utmp_ent->ut_line,
time_string (utmp_ent), "", pidstr, comment, exitstr);
free (comment);
}
static void
print_login (const STRUCT_UTMP *utmp_ent)
{
char *comment = make_id_equals_comment (utmp_ent);
PIDSTR_DECL_AND_INIT (pidstr, utmp_ent);
/* FIXME: add idle time? */
print_line (-1, _("LOGIN"), ' ', sizeof utmp_ent->ut_line, utmp_ent->ut_line,
time_string (utmp_ent), "", pidstr, comment, "");
free (comment);
}
static void
print_initspawn (const STRUCT_UTMP *utmp_ent)
{
char *comment = make_id_equals_comment (utmp_ent);
PIDSTR_DECL_AND_INIT (pidstr, utmp_ent);
print_line (-1, "", ' ', sizeof utmp_ent->ut_line, utmp_ent->ut_line,
time_string (utmp_ent), "", pidstr, comment, "");
free (comment);
}
static void
print_clockchange (const STRUCT_UTMP *utmp_ent)
{
/* FIXME: handle NEW_TIME & OLD_TIME both */
print_line (-1, "", ' ', -1, _("clock change"),
time_string (utmp_ent), "", "", "", "");
}
static void
print_runlevel (const STRUCT_UTMP *utmp_ent)
{
static char *runlevline, *comment;
unsigned char last = UT_PID (utmp_ent) / 256;
unsigned char curr = UT_PID (utmp_ent) % 256;
if (!runlevline)
runlevline = xmalloc (strlen (_("run-level")) + 3);
sprintf (runlevline, "%s %c", _("run-level"), curr);
if (!comment)
comment = xmalloc (strlen (_("last=")) + 2);
sprintf (comment, "%s%c", _("last="), (last == 'N') ? 'S' : last);
print_line (-1, "", ' ', -1, runlevline, time_string (utmp_ent),
"", "", c_isprint (last) ? comment : "", "");
return;
}
/* Print the username of each valid entry and the number of valid entries
in UTMP_BUF, which should have N elements. */
static void
list_entries_who (size_t n, const STRUCT_UTMP *utmp_buf)
{
unsigned long int entries = 0;
char const *separator = "";
while (n--)
{
if (IS_USER_PROCESS (utmp_buf))
{
char *trimmed_name;
trimmed_name = extract_trimmed_name (utmp_buf);
printf ("%s%s", separator, trimmed_name);
free (trimmed_name);
separator = " ";
entries++;
}
utmp_buf++;
}
printf (_("\n# users=%lu\n"), entries);
}
static void
print_heading (void)
{
print_line (-1, _("NAME"), ' ', -1, _("LINE"), _("TIME"), _("IDLE"),
_("PID"), _("COMMENT"), _("EXIT"));
}
/* Display UTMP_BUF, which should have N entries. */
static void
scan_entries (size_t n, const STRUCT_UTMP *utmp_buf)
{
char *ttyname_b IF_LINT ( = NULL);
time_t boottime = TYPE_MINIMUM (time_t);
if (include_heading)
print_heading ();
if (my_line_only)
{
ttyname_b = ttyname (STDIN_FILENO);
if (!ttyname_b)
return;
if (STRNCMP_LIT (ttyname_b, DEV_DIR_WITH_TRAILING_SLASH) == 0)
ttyname_b += DEV_DIR_LEN; /* Discard /dev/ prefix. */
}
while (n--)
{
if (!my_line_only
|| STREQ_LEN (ttyname_b, utmp_buf->ut_line,
sizeof (utmp_buf->ut_line)))
{
if (need_users && IS_USER_PROCESS (utmp_buf))
print_user (utmp_buf, boottime);
else if (need_runlevel && UT_TYPE_RUN_LVL (utmp_buf))
print_runlevel (utmp_buf);
else if (need_boottime && UT_TYPE_BOOT_TIME (utmp_buf))
print_boottime (utmp_buf);
/* I've never seen one of these, so I don't know what it should
look like :^)
FIXME: handle OLD_TIME also, perhaps show the delta? */
else if (need_clockchange && UT_TYPE_NEW_TIME (utmp_buf))
print_clockchange (utmp_buf);
else if (need_initspawn && UT_TYPE_INIT_PROCESS (utmp_buf))
print_initspawn (utmp_buf);
else if (need_login && UT_TYPE_LOGIN_PROCESS (utmp_buf))
print_login (utmp_buf);
else if (need_deadprocs && UT_TYPE_DEAD_PROCESS (utmp_buf))
print_deadprocs (utmp_buf);
}
if (UT_TYPE_BOOT_TIME (utmp_buf))
boottime = UT_TIME_MEMBER (utmp_buf);
utmp_buf++;
}
}
/* Display a list of who is on the system, according to utmp file FILENAME.
Use read_utmp OPTIONS to read the file. */
static void
who (const char *filename, int options)
{
size_t n_users;
STRUCT_UTMP *utmp_buf;
if (read_utmp (filename, &n_users, &utmp_buf, options) != 0)
die (EXIT_FAILURE, errno, "%s", quotef (filename));
if (short_list)
list_entries_who (n_users, utmp_buf);
else
scan_entries (n_users, utmp_buf);
free (utmp_buf);
}
void
usage (int status)
{
if (status != EXIT_SUCCESS)
emit_try_help ();
else
{
printf (_("Usage: %s [OPTION]... [ FILE | ARG1 ARG2 ]\n"), program_name);
fputs (_("\
Print information about users who are currently logged in.\n\
"), stdout);
fputs (_("\
\n\
-a, --all same as -b -d --login -p -r -t -T -u\n\
-b, --boot time of last system boot\n\
-d, --dead print dead processes\n\
-H, --heading print line of column headings\n\
"), stdout);
fputs (_("\
-l, --login print system login processes\n\
"), stdout);
fputs (_("\
--lookup attempt to canonicalize hostnames via DNS\n\
-m only hostname and user associated with stdin\n\
-p, --process print active processes spawned by init\n\
"), stdout);
fputs (_("\
-q, --count all login names and number of users logged on\n\
-r, --runlevel print current runlevel\n\
-s, --short print only name, line, and time (default)\n\
-t, --time print last system clock change\n\
"), stdout);
fputs (_("\
-T, -w, --mesg add user's message status as +, - or ?\n\
-u, --users list users logged in\n\
--message same as -T\n\
--writable same as -T\n\
"), stdout);
fputs (HELP_OPTION_DESCRIPTION, stdout);
fputs (VERSION_OPTION_DESCRIPTION, stdout);
printf (_("\
\n\
If FILE is not specified, use %s. %s as FILE is common.\n\
If ARG1 ARG2 given, -m presumed: 'am i' or 'mom likes' are usual.\n\
"), UTMP_FILE, WTMP_FILE);
emit_ancillary_info (PROGRAM_NAME);
}
exit (status);
}
int
main (int argc, char **argv)
{
int optc;
bool assumptions = true;
initialize_main (&argc, &argv);
set_program_name (argv[0]);
setlocale (LC_ALL, "");
bindtextdomain (PACKAGE, LOCALEDIR);
textdomain (PACKAGE);
atexit (close_stdout);
while ((optc = getopt_long (argc, argv, "abdlmpqrstuwHT", longopts, NULL))
!= -1)
{
switch (optc)
{
case 'a':
need_boottime = true;
need_deadprocs = true;
need_login = true;
need_initspawn = true;
need_runlevel = true;
need_clockchange = true;
need_users = true;
include_mesg = true;
include_idle = true;
include_exit = true;
assumptions = false;
break;
case 'b':
need_boottime = true;
assumptions = false;
break;
case 'd':
need_deadprocs = true;
include_idle = true;
include_exit = true;
assumptions = false;
break;
case 'H':
include_heading = true;
break;
case 'l':
need_login = true;
include_idle = true;
assumptions = false;
break;
case 'm':
my_line_only = true;
break;
case 'p':
need_initspawn = true;
assumptions = false;
break;
case 'q':
short_list = true;
break;
case 'r':
need_runlevel = true;
include_idle = true;
assumptions = false;
break;
case 's':
short_output = true;
break;
case 't':
need_clockchange = true;
assumptions = false;
break;
case 'T':
case 'w':
include_mesg = true;
break;
case 'u':
need_users = true;
include_idle = true;
assumptions = false;
break;
case LOOKUP_OPTION:
do_lookup = true;
break;
case_GETOPT_HELP_CHAR;
case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
default:
usage (EXIT_FAILURE);
}
}
if (assumptions)
{
need_users = true;
short_output = true;
}
if (include_exit)
{
short_output = false;
}
if (hard_locale (LC_TIME))
{
time_format = "%Y-%m-%d %H:%M";
time_format_width = 4 + 1 + 2 + 1 + 2 + 1 + 2 + 1 + 2;
}
else
{
time_format = "%b %e %H:%M";
time_format_width = 3 + 1 + 2 + 1 + 2 + 1 + 2;
}
switch (argc - optind)
{
case 2: /* who <blurf> <glop> */
my_line_only = true;
FALLTHROUGH;
case -1:
case 0: /* who */
who (UTMP_FILE, READ_UTMP_CHECK_PIDS);
break;
case 1: /* who <utmp file> */
who (argv[optind], 0);
break;
default: /* lose */
error (0, 0, _("extra operand %s"), quote (argv[optind + 2]));
usage (EXIT_FAILURE);
}
return EXIT_SUCCESS;
}
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