- Commit work from libprocstat project. These patches add support for runtime

  file and processes information retrieval from the running kernel via sysctl
  in the form of new library, libprocstat.  The library also supports KVM backend
  for analyzing memory crash dumps.  Both procstat(1) and fstat(1) utilities have
  been modified to take advantage of the library (as the bonus point the fstat(1)
  utility no longer need superuser privileges to operate), and the procstat(1)
  utility is now able to display information from memory dumps as well.

  The newly introduced fuser(1) utility also uses this library and able to operate
  via sysctl and kvm backends.

  The library is by no means complete (e.g. KVM backend is missing vnode name
  resolution routines, and there're no manpages for the library itself) so I
  plan to improve it further.  I'm commiting it so it will get wider exposure
  and review.

  We won't be able to MFC this work as it relies on changes in HEAD, which
  was introduced some time ago, that break kernel ABI.  OTOH we may be able
  to merge the library with KVM backend if we really need it there.

Discussed with:	rwatson

1 files changed, 369 insertions, 0 deletions

diff --git a/usr.bin/fstat/fuser.c b/usr.bin/fstat/fuser.c
new file mode 100644
index 000000000000..02975b38c3da
--- /dev/null
+++ b/usr.bin/fstat/fuser.c
@@ -0,0 +1,369 @@
+/*-
+ * Copyright (c) 2005-2009 Stanislav Sedov <stas@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/queue.h>
+#include <sys/stat.h>
+#include <sys/sysctl.h>
+#include <sys/user.h>
+
+#include <assert.h>
+#include <ctype.h>
+#include <err.h>
+#include <fcntl.h>
+#include <libprocstat.h>
+#include <limits.h>
+#include <paths.h>
+#include <pwd.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sysexits.h>
+#include <unistd.h>
+
+#include "functions.h"
+
+/*
+ * File access mode flags table.
+ */
+struct {
+	int	flag;
+	char	ch;
+} fflags[] = {
+	{PS_FST_FFLAG_WRITE,	'w'},
+	{PS_FST_FFLAG_APPEND,	'a'},
+	{PS_FST_FFLAG_DIRECT,	'd'},
+	{PS_FST_FFLAG_SHLOCK,	's'},
+	{PS_FST_FFLAG_EXLOCK,	'e'}
+};
+#define	NFFLAGS	(sizeof(fflags) / sizeof(*fflags))
+
+/*
+ * Usage flags translation table.
+ */
+struct {
+	int	flag;
+	char	ch;
+} uflags[] = {
+	{PS_FST_UFLAG_RDIR,	'r'},
+	{PS_FST_UFLAG_CDIR,	'c'},
+	{PS_FST_UFLAG_JAIL,	'j'},
+	{PS_FST_UFLAG_TRACE,	't'},
+	{PS_FST_UFLAG_TEXT,	'x'},
+	{PS_FST_UFLAG_MMAP,	'm'},
+	{PS_FST_UFLAG_CTTY,	'y'}
+};
+#define	NUFLAGS	(sizeof(uflags) / sizeof(*uflags))
+
+struct consumer {
+	pid_t	pid;
+	uid_t	uid;
+	int	fd;
+	int	flags;
+	int	uflags;
+	STAILQ_ENTRY(consumer)	next;
+};
+struct reqfile {
+	uint32_t	fsid;
+	uint64_t	fileid;
+	const char	*name;
+	STAILQ_HEAD(, consumer) consumers;
+};
+
+/*
+ * Option flags.
+ */
+#define	UFLAG	0x01	/* -u flag: show users				*/
+#define	FFLAG	0x02	/* -f flag: specified files only		*/
+#define	CFLAG	0x04	/* -c flag: treat as mpoints			*/
+#define	MFLAG	0x10	/* -m flag: mmapped files too			*/
+#define	KFLAG	0x20	/* -k flag: send signal (SIGKILL by default)	*/
+
+static int flags = 0;	/* Option flags. */
+
+static void	printflags(struct consumer *consumer);
+static int	str2sig(const char *str);
+static void	usage(void) __dead2;
+static int	addfile(const char *path, struct reqfile *reqfile);
+static void	dofiles(struct procstat *procstat, struct kinfo_proc *kp,
+    struct reqfile *reqfiles, size_t nfiles);
+
+static void
+usage(void)
+{
+
+	fprintf(stderr,
+"usage: fuser [-cfhkmu] [-M core] [-N system] [-s signal] file ...\n");
+	exit(EX_USAGE);
+}
+
+static void
+printflags(struct consumer *cons)
+{
+	unsigned int i;
+
+	assert(cons);
+	for (i = 0; i < NUFLAGS; i++)
+		if ((cons->uflags & uflags[i].flag) != 0)
+			fputc(uflags[i].ch, stderr);
+	for (i = 0; i < NFFLAGS; i++)
+		if ((cons->flags & fflags[i].flag) != 0)
+			fputc(fflags[i].ch, stderr);
+}
+
+/*
+ * Add file to the list.
+ */
+static int
+addfile(const char *path, struct reqfile *reqfile)
+{
+	struct stat sb;
+
+	assert(path);
+	if (stat(path, &sb) != 0) {
+		warn("%s", path);
+		return (1);
+	}
+	reqfile->fileid = sb.st_ino;
+	reqfile->fsid = sb.st_dev;
+	reqfile->name = path;
+	STAILQ_INIT(&reqfile->consumers);
+	return (0);
+}
+
+int
+do_fuser(int argc, char *argv[])
+{
+	struct consumer *consumer;
+	struct kinfo_proc *p, *procs;
+	struct procstat *procstat;
+	struct reqfile *reqfiles;
+	char *ep, *nlistf, *memf;
+	int ch, cnt, sig;
+	unsigned int i, nfiles;
+
+	sig = SIGKILL;	/* Default to kill. */
+	nlistf = NULL;
+	memf = NULL;
+	while ((ch = getopt(argc, argv, "M:N:cfhkms:u")) != -1)
+		switch(ch) {
+		case 'f':
+			if ((flags & CFLAG) != 0)
+				usage();
+			flags |= FFLAG;
+			break;
+		case 'c':
+			if ((flags & FFLAG) != 0)
+				usage();
+			flags |= CFLAG;
+			break;
+		case 'N':
+			nlistf = optarg;
+			break;
+		case 'M':
+			memf = optarg;
+			break;
+		case 'u':
+			flags |= UFLAG;
+			break;
+		case 'm':
+			flags |= MFLAG;
+			break;
+		case 'k':
+			flags |= KFLAG;
+			break;
+		case 's':
+			if (isdigit(*optarg)) {
+				sig = strtol(optarg, &ep, 10);
+				if (*ep != '\0' || sig < 0 || sig >= sys_nsig)
+					errx(EX_USAGE, "illegal signal number" ": %s",
+					    optarg);
+			} else {
+				sig = str2sig(optarg);
+				if (sig < 0)
+					errx(EX_USAGE, "illegal signal name: "
+					    "%s", optarg);
+			}
+			break;
+		case 'h':
+			/* PASSTHROUGH */
+		default:
+			usage();
+			/* NORETURN */
+		}
+	argv += optind;
+	argc -= optind;
+
+	assert(argc >= 0);
+	if (argc == 0)
+		usage();
+		/* NORETURN */
+
+	/*
+	 * Process named files.
+	 */
+	reqfiles = malloc(argc * sizeof(struct reqfile));
+	if (reqfiles == NULL)
+		err(EX_OSERR, "malloc()");
+	nfiles = 0;
+	while (argc--)
+		if (!addfile(*(argv++), &reqfiles[nfiles]))
+			nfiles++;
+	if (nfiles == 0)
+		errx(EX_IOERR, "files not accessible");
+
+	if (memf != NULL)
+		procstat = procstat_open_kvm(nlistf, memf);
+	else
+		procstat = procstat_open_sysctl();
+	if (procstat == NULL)
+		errx(1, "procstat_open()");
+	procs = procstat_getprocs(procstat, KERN_PROC_PROC, 0, &cnt);
+	if (procs == NULL)
+		 errx(1, "procstat_getprocs()");
+
+	/*
+	 * Walk through process table and look for matching files.
+	 */
+	p = procs;
+	while(cnt--)
+		if (p->ki_stat != SZOMB)
+			dofiles(procstat, p++, reqfiles, nfiles);
+
+	for (i = 0; i < nfiles; i++) {
+		fprintf(stderr, "%s:", reqfiles[i].name);
+		fflush(stderr);
+		STAILQ_FOREACH(consumer, &reqfiles[i].consumers, next) {
+			if (consumer->flags != 0) {
+				fprintf(stdout, "%6d", consumer->pid);
+				fflush(stdout);
+				printflags(consumer);
+				if ((flags & UFLAG) != 0)
+					fprintf(stderr, "(%s)",
+					    user_from_uid(consumer->uid, 0));
+				if ((flags & KFLAG) != 0)
+					kill(consumer->pid, sig);
+				fflush(stderr);
+			}
+		}
+		(void)fprintf(stderr, "\n");
+	}
+	procstat_freeprocs(procstat, procs);
+	procstat_close(procstat);
+	free(reqfiles);
+	return (0);
+}
+
+static void
+dofiles(struct procstat *procstat, struct kinfo_proc *kp,
+    struct reqfile *reqfiles, size_t nfiles)
+{
+	struct vnstat vn;
+	struct consumer *cons;
+	struct filestat *fst;
+	struct filestat_list *head;
+	int error, match;
+	unsigned int i;
+	char errbuf[_POSIX2_LINE_MAX];
+	
+	head = procstat_getfiles(procstat, kp, flags & MFLAG);
+	if (head == NULL)
+		return;
+	STAILQ_FOREACH(fst, head, next) {
+		if (fst->fs_type != PS_FST_TYPE_VNODE)
+			continue;
+		error = procstat_get_vnode_info(procstat, fst, &vn, errbuf);
+		if (error != 0)
+			continue;
+		for (i = 0; i < nfiles; i++) {
+			if (flags & CFLAG && reqfiles[i].fsid == vn.vn_fsid) {
+				break;
+			}
+			else if (reqfiles[i].fsid == vn.vn_fsid &&
+			    reqfiles[i].fileid == vn.vn_fileid) {
+				break;
+			}
+			else if (!(flags & FFLAG) &&
+			    (vn.vn_type == PS_FST_VTYPE_VCHR ||
+			    vn.vn_type == PS_FST_VTYPE_VBLK) &&
+			    vn.vn_fsid == reqfiles[i].fileid) {
+				break;
+			}
+		}
+		if (i == nfiles)
+			continue;	/* No match. */
+
+		/*
+		 * Look for existing entries.
+		 */
+		match = 0;
+		STAILQ_FOREACH(cons, &reqfiles[i].consumers, next)
+			if (cons->pid == kp->ki_pid) {
+				match = 1;
+				break;
+			}
+		if (match == 1) {	/* Use old entry. */
+			cons->flags |= fst->fs_fflags;
+			cons->uflags |= fst->fs_uflags;
+		} else {
+			/*
+			 * Create new entry in the consumer chain.
+			 */
+			cons = calloc(1, sizeof(struct consumer));
+			if (cons == NULL) {
+				warn("malloc()");
+				continue;
+			}
+			cons->uid = kp->ki_uid;
+			cons->pid = kp->ki_pid;
+			cons->uflags = fst->fs_uflags;
+			cons->flags = fst->fs_fflags;
+			STAILQ_INSERT_TAIL(&reqfiles[i].consumers, cons, next);
+		}
+	}
+	procstat_freefiles(procstat, head);
+}
+
+/*
+ * Returns signal number for it's string representation.
+ */
+static int
+str2sig(const char *str)
+{
+	int i;
+
+#define	SIGPREFIX	"sig"
+	if (!strncasecmp(str, SIGPREFIX, sizeof(SIGPREFIX)))
+		str += sizeof(SIGPREFIX);
+	for (i = 1; i < sys_nsig; i++) {
+                if (!strcasecmp(sys_signame[i], str))
+                        return (i);
+        }
+        return (-1);
+}