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Diffstat (limited to 'src/who.c')
| -rw-r--r-- | src/who.c | 836 |
1 files changed, 836 insertions, 0 deletions
diff --git a/src/who.c b/src/who.c new file mode 100644 index 0000000..abf3bc7 --- /dev/null +++ b/src/who.c @@ -0,0 +1,836 @@ +/* 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; +} |