xref: /illumos-gate/usr/src/cmd/w/w.c (revision 9b9d39d2a32ff806d2431dbcc50968ef1e6d46b2)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright (c) 2013 Gary Mills
23  *
24  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
25  * Use is subject to license terms.
26  *
27  * Copyright 2020 Joyent, Inc.
28  */
29 
30 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
31 /*	  All Rights Reserved	*/
32 
33 /*
34  * University Copyright- Copyright (c) 1982, 1986, 1988
35  * The Regents of the University of California
36  * All Rights Reserved
37  *
38  * University Acknowledgment- Portions of this document are derived from
39  * software developed by the University of California, Berkeley, and its
40  * contributors.
41  */
42 
43 /*
44  * This is the new w command which takes advantage of
45  * the /proc interface to gain access to the information
46  * of all the processes currently on the system.
47  *
48  * This program also implements 'uptime'.
49  *
50  * Maintenance note:
51  *
52  * Much of this code is replicated in whodo.c.  If you're
53  * fixing bugs here, then you should probably fix 'em there too.
54  */
55 
56 #include <sys/types.h>
57 #include <sys/loadavg.h>
58 #include <sys/queue.h>
59 #include <sys/stat.h>
60 #include <sys/sysmacros.h>
61 
62 #include <ctype.h>
63 #include <dirent.h>
64 #include <err.h>
65 #include <errno.h>
66 #include <fcntl.h>
67 #include <limits.h>
68 #include <locale.h>
69 #include <priv_utils.h>
70 #include <procfs.h>		/* /proc header file */
71 #include <stdarg.h>
72 #include <stdio.h>
73 #include <stdlib.h>
74 #include <string.h>
75 #include <time.h>
76 #include <unistd.h>
77 #include <utmpx.h>
78 
79 /*
80  * Use the full lengths from utmpx for user and line.
81  */
82 static struct utmpx dummy;
83 #define	NMAX		(sizeof (dummy.ut_user))
84 #define	LMAX		(sizeof (dummy.ut_line))
85 
86 /* Print minimum field widths. */
87 #define	LOGIN_WIDTH	8
88 #define	LINE_WIDTH	8
89 
90 #define	DIV60(t)	((t+30)/60)	/* x/60 rounded */
91 
92 #define	PROCDIR		"/proc"
93 #define	PRINTF(a)	if (printf a < 0) { \
94 		perror((gettext("%s: printf failed"), prog)); \
95 		exit(1); }
96 
97 struct uproc {
98 	pid_t	p_upid;			/* process id */
99 	dev_t   p_ttyd;			/* controlling tty of process */
100 	time_t  p_time;			/* seconds of user & system time */
101 	time_t	p_ctime;		/* seconds of child user & sys time */
102 	int	p_igintr;		/* 1 = ignores SIGQUIT and SIGINT */
103 	char    p_comm[PRARGSZ+1];	/* command */
104 	char    p_args[PRARGSZ+1];	/* command line arguments */
105 	STAILQ_ENTRY(uproc) uprocs;
106 };
107 STAILQ_HEAD(uprochead, uproc) uphead;
108 
109 static time_t	findidle(char *);
110 static void	clnarglist(char *);
111 static void	prttime(time_t, int);
112 static void	prtat(time_t *time);
113 
114 static int	priv_proc_open(const char *, int);
115 static int	priv_proc_openat(int, const char *, int);
116 static boolean_t do_proc_read(int, void *, size_t);
117 
118 static char	*prog;		/* pointer to invocation name */
119 static int	header = 1;	/* true if -h flag: don't print heading */
120 static int	lflag = 1;	/* set if -l flag; 0 for -s flag: short form */
121 static char	*sel_user;	/* login of particular user selected */
122 static char	firstchar;	/* first char of name of prog invoked as */
123 static int	login;		/* true if invoked as login shell */
124 static time_t	now;		/* current time of day */
125 static time_t	uptime;		/* time of last reboot & elapsed time since */
126 static int	nusers;		/* number of users logged in now */
127 
128 /*
129  * Basic privs we never need and can drop. This is likely not exhaustive,
130  * but should significantly reduce any potential attack surfaces.
131  */
132 static const char *drop_privs[] = {
133 	PRIV_FILE_WRITE,
134 	PRIV_NET_ACCESS,
135 	PRIV_PROC_EXEC,
136 	PRIV_PROC_FORK,
137 	PRIV_FILE_LINK_ANY
138 };
139 
140 #if SIGQUIT > SIGINT
141 #define	ACTSIZE	SIGQUIT
142 #else
143 #define	ACTSIZE	SIGINT
144 #endif
145 
146 int
147 main(int argc, char *argv[])
148 {
149 	struct utmpx	*ut;
150 	struct utmpx	*utmpbegin;
151 	struct utmpx	*utmpend;
152 	struct utmpx	*utp;
153 	struct uproc	*up;
154 	struct psinfo	info;
155 	struct sigaction actinfo[ACTSIZE];
156 	struct pstatus	statinfo;
157 	struct stat	sbuf;
158 	DIR		*dirp;
159 	struct dirent	*dp;
160 	char		pname[PATH_MAX];
161 	int		procfd;
162 	int		dirfd;
163 	char		*cp;
164 	int		i;
165 	int		days, hrs, mins;
166 	int		entries;
167 	double		loadavg[3];
168 	priv_set_t	*pset;
169 
170 	if (__init_suid_priv(PU_CLEARLIMITSET, PRIV_PROC_OWNER, NULL) != 0) {
171 		err(EXIT_FAILURE, "failed to enable privilege bracketing");
172 	}
173 
174 	/*
175 	 * After setting up privilege bracketing, we can further reduce the
176 	 * privileges in use. The effective set is set to the basic set minus
177 	 * the privs in drop_privs. The permitted set is the effective set
178 	 * plus PRIV_PROC_OWNER (i.e. the privilege being bracketed).
179 	 */
180 	pset = priv_allocset();
181 	if (pset == NULL)
182 		err(EXIT_FAILURE, "priv_allocset failed");
183 
184 	priv_basicset(pset);
185 	for (i = 0; i < ARRAY_SIZE(drop_privs); i++) {
186 		if (priv_delset(pset, drop_privs[i]) != 0) {
187 			err(EXIT_FAILURE,
188 			    "failed to remove %s privilege from privilege set",
189 			    drop_privs[i]);
190 		}
191 	}
192 
193 	if (setppriv(PRIV_SET, PRIV_EFFECTIVE, pset) < 0)
194 		err(EXIT_FAILURE, "failed setting effective privilege set");
195 
196 	if (priv_addset(pset, PRIV_PROC_OWNER) != 0) {
197 		err(EXIT_FAILURE,
198 		    "failed to add PRIV_PROC_OWNER privilege to privilege set");
199 	}
200 
201 	if (setppriv(PRIV_SET, PRIV_PERMITTED, pset) < 0)
202 		err(EXIT_FAILURE, "failed to set permitted privilege set");
203 
204 	/*
205 	 * Unfortunately, when run as root, privilege bracketing is a no-op,
206 	 * so we have to add PRIV_PROC_OWNER into our effective set for things
207 	 * to work.
208 	 */
209 	if (getuid() == 0 && setppriv(PRIV_SET, PRIV_EFFECTIVE, pset) < 0) {
210 		err(EXIT_FAILURE, "failed to set effective privilege set");
211 	}
212 
213 	priv_freeset(pset);
214 	pset = NULL;
215 
216 	(void) setlocale(LC_ALL, "");
217 #if !defined(TEXT_DOMAIN)
218 #define	TEXT_DOMAIN "SYS_TEST"
219 #endif
220 	(void) textdomain(TEXT_DOMAIN);
221 
222 	login = (argv[0][0] == '-');
223 	cp = strrchr(argv[0], '/');
224 	firstchar = login ? argv[0][1] : (cp == 0) ? argv[0][0] : cp[1];
225 	prog = argv[0];
226 
227 	while (argc > 1) {
228 		if (argv[1][0] == '-') {
229 			for (i = 1; argv[1][i]; i++) {
230 				switch (argv[1][i]) {
231 
232 				case 'h':
233 					header = 0;
234 					break;
235 
236 				case 'l':
237 					lflag++;
238 					break;
239 				case 's':
240 					lflag = 0;
241 					break;
242 
243 				case 'u':
244 				case 'w':
245 					firstchar = argv[1][i];
246 					break;
247 
248 				default:
249 					(void) fprintf(stderr, gettext(
250 					    "%s: bad flag %s\n"),
251 					    prog, argv[1]);
252 					exit(1);
253 				}
254 			}
255 		} else {
256 			if (!isalnum(argv[1][0]) || argc > 2) {
257 				(void) fprintf(stderr, gettext(
258 				    "usage: %s [ -hlsuw ] [ user ]\n"), prog);
259 				exit(1);
260 			} else
261 				sel_user = argv[1];
262 		}
263 		argc--; argv++;
264 	}
265 
266 	/*
267 	 * read the UTMPX_FILE (contains information about each logged in user)
268 	 */
269 	if (stat(UTMPX_FILE, &sbuf) < 0)
270 		err(EXIT_FAILURE, gettext("stat error of %s"), UTMPX_FILE);
271 
272 	entries = sbuf.st_size / sizeof (struct futmpx);
273 	if ((ut = calloc(entries, sizeof (struct utmpx))) == NULL)
274 		err(EXIT_FAILURE, gettext("calloc error of %s"), UTMPX_FILE);
275 
276 	(void) utmpxname(UTMPX_FILE);
277 
278 	utmpbegin = ut;
279 	utmpend = utmpbegin + entries;
280 
281 	setutxent();
282 	while ((ut < utmpend) && ((utp = getutxent()) != NULL))
283 		(void) memcpy(ut++, utp, sizeof (*ut));
284 	endutxent();
285 
286 	(void) time(&now);	/* get current time */
287 
288 	if (header) {	/* print a header */
289 		prtat(&now);
290 		for (ut = utmpbegin; ut < utmpend; ut++) {
291 			if (ut->ut_type == USER_PROCESS) {
292 				if (!nonuserx(*ut))
293 					nusers++;
294 			} else if (ut->ut_type == BOOT_TIME) {
295 				uptime = now - ut->ut_xtime;
296 				uptime += 30;
297 				days = uptime / (60*60*24);
298 				uptime %= (60*60*24);
299 				hrs = uptime / (60*60);
300 				uptime %= (60*60);
301 				mins = uptime / 60;
302 
303 				PRINTF((gettext("up")));
304 				if (days > 0)
305 					PRINTF((gettext(
306 					    " %d day(s),"), days));
307 				if (hrs > 0 && mins > 0) {
308 					PRINTF((" %2d:%02d,", hrs, mins));
309 				} else {
310 					if (hrs > 0) {
311 						PRINTF((gettext(
312 						    " %d hr(s),"), hrs));
313 					} else { /* mins can be zero */
314 						PRINTF((gettext(
315 						    " %d min(s),"), mins));
316 					}
317 				}
318 			}
319 		}
320 
321 		ut = utmpbegin;	/* rewind utmp data */
322 		PRINTF((((nusers == 1) ?
323 		    gettext("  %d user") : gettext("  %d users")), nusers));
324 		/*
325 		 * Print 1, 5, and 15 minute load averages.
326 		 */
327 		(void) getloadavg(loadavg, 3);
328 		PRINTF((gettext(",  load average: %.2f, %.2f, %.2f\n"),
329 		    loadavg[LOADAVG_1MIN], loadavg[LOADAVG_5MIN],
330 		    loadavg[LOADAVG_15MIN]));
331 
332 		if (firstchar == 'u')	/* uptime command */
333 			exit(0);
334 
335 		if (lflag) {
336 			PRINTF((dcgettext(NULL, "User     tty      "
337 			    "login@         idle    JCPU    PCPU what\n",
338 			    LC_TIME)));
339 		} else {
340 			PRINTF((dcgettext(NULL,
341 			    "User     tty         idle what\n",
342 			    LC_TIME)));
343 		}
344 
345 		if (fflush(stdout) == EOF) {
346 			err(EXIT_FAILURE, "fflush failed");
347 		}
348 	}
349 
350 	/* Loop through /proc, reading info about each process */
351 	if ((dirp = opendir(PROCDIR)) == NULL)
352 		err(EXIT_FAILURE, gettext("could not open %s"), PROCDIR);
353 
354 	STAILQ_INIT(&uphead);
355 	while ((dp = readdir(dirp)) != NULL) {
356 		if (dp->d_name[0] == '.')
357 			continue;
358 
359 		if (snprintf(pname, sizeof (pname), "%s/%s", PROCDIR,
360 		    dp->d_name) > sizeof (pname))
361 			continue;
362 
363 		dirfd = priv_proc_open(pname, O_RDONLY | O_DIRECTORY);
364 		if (dirfd < 0)
365 			continue;
366 
367 		procfd = priv_proc_openat(dirfd, "psinfo", O_RDONLY);
368 		if (procfd < 0) {
369 			(void) close(dirfd);
370 			continue;
371 		}
372 		if (!do_proc_read(procfd, &info, sizeof (info))) {
373 			warn(gettext("failed to read %s"), pname);
374 			(void) close(dirfd);
375 			continue;
376 		}
377 		(void) close(procfd);
378 
379 		/* Not interested in zombies */
380 		if (info.pr_nlwp == 0)
381 			continue;
382 		/* Not interested in processes without a terminal */
383 		if (info.pr_ttydev == NODEV)
384 			continue;
385 
386 		procfd = priv_proc_openat(dirfd, "status", O_RDONLY);
387 		if (procfd < 0) {
388 			(void) close(dirfd);
389 			continue;
390 		}
391 		if (!do_proc_read(procfd, &statinfo, sizeof (statinfo))) {
392 			warn(gettext("failed to read %s/status"), pname);
393 			(void) close(procfd);
394 			(void) close(dirfd);
395 			continue;
396 		}
397 		(void) close(procfd);
398 
399 		procfd = priv_proc_openat(dirfd, "sigact", O_RDONLY);
400 		if (procfd < 0) {
401 			(void) close(dirfd);
402 			continue;
403 		}
404 		if (!do_proc_read(procfd, actinfo, sizeof (actinfo))) {
405 			warn(gettext("failed to read %s/sigact"), pname);
406 			(void) close(procfd);
407 			(void) close(dirfd);
408 			continue;
409 		}
410 		(void) close(procfd);
411 		(void) close(dirfd);
412 
413 		up = calloc(1, sizeof (*up));
414 		if (up == NULL)
415 			err(EXIT_FAILURE, "calloc");
416 		up->p_upid = info.pr_pid;
417 		up->p_ttyd = info.pr_ttydev;
418 		up->p_time =
419 		    statinfo.pr_utime.tv_sec +
420 		    statinfo.pr_stime.tv_sec;
421 		up->p_ctime =
422 		    statinfo.pr_cutime.tv_sec +
423 		    statinfo.pr_cstime.tv_sec;
424 		up->p_igintr =
425 		    actinfo[SIGINT-1].sa_handler == SIG_IGN &&
426 		    actinfo[SIGQUIT-1].sa_handler == SIG_IGN;
427 		(void) strlcpy(up->p_comm, info.pr_fname, sizeof (up->p_comm));
428 		/* Process args */
429 		clnarglist(info.pr_psargs);
430 		(void) strlcpy(up->p_args, info.pr_psargs, sizeof (up->p_args));
431 		if (up->p_args[0] == 0 || up->p_args[0] == '?' ||
432 		    (up->p_args[0] == '-' && up->p_args[1] <= ' ')) {
433 			(void) strlcat(up->p_args, " (", sizeof (up->p_args));
434 			(void) strlcat(up->p_args, up->p_comm,
435 			    sizeof (up->p_args));
436 			(void) strlcat(up->p_args, ")", sizeof (up->p_args));
437 		}
438 		STAILQ_INSERT_TAIL(&uphead, up, uprocs);
439 	}
440 
441 	/* revert to non-privileged user after opening */
442 	__priv_relinquish();
443 	if (getuid() == 0) {
444 		/*
445 		 * Since the privilege bracketing functions are effectively
446 		 * no-ops when running as root, we must explicitly
447 		 * relinquish PRIV_PROC_OWNER ourselves.
448 		 */
449 		pset = priv_allocset();
450 		if (pset == NULL) {
451 			err(EXIT_FAILURE,
452 			    gettext("failed to allocate privilege set"));
453 		}
454 
455 		priv_emptyset(pset);
456 
457 		if (priv_addset(pset, PRIV_PROC_OWNER) != 0) {
458 			err(EXIT_FAILURE, gettext("failed to add "
459 			    "PRIV_PROC_OWNER to privilege set"));
460 		}
461 
462 		if (setppriv(PRIV_OFF, PRIV_PERMITTED, pset) != 0) {
463 			err(EXIT_FAILURE,
464 			    gettext("failed to set permitted privilege set"));
465 		}
466 
467 		priv_freeset(pset);
468 		pset = NULL;
469 	}
470 
471 	(void) closedir(dirp);
472 	(void) time(&now);	/* get current time */
473 
474 	/*
475 	 * loop through utmpx file, printing process info
476 	 * about each logged in user
477 	 */
478 	for (ut = utmpbegin; ut < utmpend; ut++) {
479 		struct uproc *upt;
480 		char linedev[PATH_MAX];
481 		char what[1024];
482 		time_t idle, jobtime, proctime;
483 		pid_t curpid;
484 
485 		if (ut->ut_type != USER_PROCESS)
486 			continue;
487 		if (sel_user != NULL &&
488 		    strncmp(ut->ut_name, sel_user, NMAX) != 0)
489 			continue;
490 
491 		/* print login name of the user */
492 		PRINTF(("%-*.*s ", LOGIN_WIDTH, NMAX, ut->ut_name));
493 
494 		/* print tty user is on */
495 		if (lflag) {
496 			PRINTF(("%-*.*s ", LINE_WIDTH, LMAX, ut->ut_line));
497 		} else {
498 			if (strncmp(ut->ut_line, "pts/", strlen("pts/")) == 0) {
499 				PRINTF(("%-*.*s ", LINE_WIDTH, LMAX,
500 				    &ut->ut_line[4]));
501 			} else {
502 				PRINTF(("%-*.*s ", LINE_WIDTH, LMAX,
503 				    ut->ut_line));
504 			}
505 		}
506 
507 		/* print when the user logged in */
508 		if (lflag) {
509 			time_t tim = ut->ut_xtime;
510 			prtat(&tim);
511 		}
512 
513 		/* print idle time */
514 		idle = findidle(ut->ut_line);
515 		prttime(idle, 8);
516 
517 		/*
518 		 * Go through the list of processes for this terminal,
519 		 * calculating job/process times, and look for the
520 		 * "most interesting" process.
521 		 */
522 		jobtime = 0;
523 		proctime = 0;
524 		curpid = -1;
525 		(void) strlcpy(what, "-", sizeof (what));
526 
527 		(void) snprintf(linedev, sizeof (linedev), "/dev/%s",
528 		    ut->ut_line);
529 		if (stat(linedev, &sbuf) == -1 ||
530 		    (sbuf.st_mode & S_IFMT) != S_IFCHR ||
531 		    sbuf.st_rdev == NODEV)
532 			goto skip;
533 
534 		STAILQ_FOREACH_SAFE(up, &uphead, uprocs, upt) {
535 			if (up->p_ttyd != sbuf.st_rdev)
536 				continue;
537 			jobtime += up->p_time + up->p_ctime;
538 			proctime += up->p_time;
539 			/*
540 			 * Check for "most interesting" process, currently
541 			 * the one having the highest PID.
542 			 */
543 			if (up->p_upid > curpid && !up->p_igintr) {
544 				curpid = up->p_upid;
545 				if (lflag) {
546 					(void) strlcpy(what, up->p_args,
547 					    sizeof (what));
548 				} else {
549 					(void) strlcpy(what, up->p_comm,
550 					    sizeof (what));
551 				}
552 			}
553 			STAILQ_REMOVE(&uphead, up, uproc, uprocs);
554 			free(up);
555 		}
556 
557 skip:
558 		if (lflag) {
559 			/* Print CPU time for all processes & children */
560 			prttime(jobtime, 8);
561 			/* Print cpu time for interesting process */
562 			prttime(proctime, 8);
563 		}
564 		/* "Most interesting" process */
565 		PRINTF(("%-.32s\n", what));
566 	}
567 
568 	if (fclose(stdout) == EOF)
569 		err(EXIT_FAILURE, gettext("fclose failed"));
570 
571 	return (0);
572 }
573 
574 #define	HR	(60 * 60)
575 #define	DAY	(24 * HR)
576 #define	MON	(30 * DAY)
577 
578 /*
579  * Prttime prints an elapsed time in hours, minutes, or seconds,
580  * right-justified with the rightmost column always blank.
581  * The second argument is the minimum field width.
582  */
583 static void
584 prttime(time_t tim, int width)
585 {
586 	char value[36];
587 
588 	if (tim >= 36 * 60) {
589 		(void) snprintf(value, sizeof (value), "%d:%02d:%02d",
590 		    (int)tim / HR, (int)(tim % HR) / 60, (int)tim % 60);
591 	} else if (tim >= 60) {
592 		(void) snprintf(value, sizeof (value), "%d:%02d",
593 		    (int)tim / 60, (int)tim % 60);
594 	} else if (tim > 0) {
595 		(void) snprintf(value, sizeof (value), "%d", (int)tim);
596 	} else {
597 		(void) strlcpy(value, "0", sizeof (value));
598 	}
599 	width = (width > 2) ? width - 1 : 1;
600 	PRINTF(("%*s ", width, value));
601 }
602 
603 /*
604  * Prints the ISO date or time given a pointer to a time of day,
605  * left-justfied in a 12-character expanding field with the
606  * rightmost column always blank.
607  * Includes a dcgettext() override in case a message catalog is needed.
608  */
609 static void
610 prtat(time_t *time)
611 {
612 	struct tm	*p;
613 
614 	p = localtime(time);
615 	if (now - *time <= 18 * HR) {
616 		char timestr[50];
617 
618 		(void) strftime(timestr, sizeof (timestr),
619 		    dcgettext(NULL, "%T", LC_TIME), p);
620 		PRINTF(("%-11s ", timestr));
621 	} else if (now - *time <= 7 * DAY) {
622 		char weekdaytime[20];
623 
624 		(void) strftime(weekdaytime, sizeof (weekdaytime),
625 		    dcgettext(NULL, "%a %H:%M", LC_TIME), p);
626 		PRINTF(("%-11s ", weekdaytime));
627 	} else {
628 		char monthtime[20];
629 
630 		(void) strftime(monthtime, sizeof (monthtime),
631 		    dcgettext(NULL, "%F", LC_TIME), p);
632 		PRINTF(("%-11s ", monthtime));
633 	}
634 }
635 
636 /*
637  * find & return number of minutes current tty has been idle
638  */
639 static time_t
640 findidle(char *devname)
641 {
642 	struct stat stbuf;
643 	time_t lastaction, diff;
644 	char ttyname[64];
645 
646 	(void) strlcpy(ttyname, "/dev/", sizeof (ttyname));
647 	(void) strlcat(ttyname, devname, sizeof (ttyname));
648 	if (stat(ttyname, &stbuf) != -1) {
649 		lastaction = stbuf.st_atime;
650 		diff = now - lastaction;
651 		diff = DIV60(diff);
652 		if (diff < 0)
653 			diff = 0;
654 	} else
655 		diff = 0;
656 	return (diff);
657 }
658 
659 /*
660  * given a pointer to the argument string get rid of unsavory characters.
661  */
662 static void
663 clnarglist(char *arglist)
664 {
665 	char	*c;
666 	int	err = 0;
667 
668 	/* get rid of unsavory characters */
669 	for (c = arglist; *c != '\0'; c++) {
670 		if ((*c < ' ') || (*c > 0176)) {
671 			if (err++ > 5) {
672 				*arglist = '\0';
673 				break;
674 			}
675 			*c = '?';
676 		}
677 	}
678 }
679 
680 static int
681 priv_proc_open(const char *path, int oflag)
682 {
683 	int fd, errsave = 0;
684 
685 	if (__priv_bracket(PRIV_ON) != 0)
686 		err(EXIT_FAILURE, gettext("privilege bracketing failed"));
687 
688 	do {
689 		fd = open(path, oflag);
690 		if (fd < 0)
691 			errsave = errno;
692 	} while (fd < 0 && errno == EAGAIN);
693 
694 	if (__priv_bracket(PRIV_OFF) != 0)
695 		err(EXIT_FAILURE, gettext("privilege bracketing failed"));
696 
697 	if (fd < 0)
698 		errno = errsave;
699 
700 	return (fd);
701 }
702 
703 static int
704 priv_proc_openat(int dfd, const char *path, int mode)
705 {
706 	int fd, errsave = 0;
707 
708 	if (__priv_bracket(PRIV_ON) != 0)
709 		err(EXIT_FAILURE, gettext("privilege bracketing failed"));
710 
711 	do {
712 		fd = openat(dfd, path, mode);
713 		if (fd < 0)
714 			errsave = errno;
715 	} while (fd < 0 && errno == EAGAIN);
716 
717 	if (__priv_bracket(PRIV_OFF) != 0)
718 		err(EXIT_FAILURE, gettext("privilege bracketing failed"));
719 
720 	if (fd < 0)
721 		errno = errsave;
722 
723 	return (fd);
724 }
725 
726 static boolean_t
727 do_proc_read(int fd, void *buf, size_t bufsize)
728 {
729 	ssize_t n;
730 
731 	do {
732 		n = pread(fd, buf, bufsize, 0);
733 		if (n == bufsize)
734 			return (B_TRUE);
735 		/*
736 		 * Retry on a partial read or EAGAIN, otherwise fail
737 		 */
738 	} while (n >= 0 || errno == EAGAIN);
739 
740 	return (B_FALSE);
741 }
742