1 files changed, 675 insertions, 0 deletions

diff --git a/usr.sbin/jail/command.c b/usr.sbin/jail/command.c
new file mode 100644
index 0000000..437096a
--- /dev/null
+++ b/usr.sbin/jail/command.c
@@ -0,0 +1,675 @@
+/*-
+ * Copyright (c) 2010 James Gritton
+ * 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/types.h>
+#include <sys/event.h>
+#include <sys/stat.h>
+#include <sys/sysctl.h>
+#include <sys/user.h>
+#include <sys/wait.h>
+
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <kvm.h>
+#include <login_cap.h>
+#include <paths.h>
+#include <pwd.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "jailp.h"
+
+#define COMSTRING_DUMMY		((struct cfstring *)1)
+#define DEFAULT_STOP_TIMEOUT	10
+#define PHASH_SIZE		256
+
+LIST_HEAD(phhead, phash);
+
+struct phash {
+	LIST_ENTRY(phash)	le;
+	struct cfjail		*j;
+	pid_t			pid;
+};
+
+extern char **environ;
+
+static int get_user_info(struct cfjail *j, const char *username,
+    const struct passwd **pwdp, login_cap_t **lcapp);
+static void add_proc(struct cfjail *j, pid_t pid);
+static void clear_procs(struct cfjail *j);
+static struct cfjail *find_proc(pid_t pid);
+
+static struct cfjails sleeping = TAILQ_HEAD_INITIALIZER(sleeping);
+static struct cfjails runnable = TAILQ_HEAD_INITIALIZER(runnable);
+static struct phhead phash[PHASH_SIZE];
+static int kq;
+
+/*
+ * Run a command associated with a jail, possibly inside the jail.
+ */
+int
+run_command(struct cfjail *j, int *plimit, enum intparam comparam)
+{
+	const struct passwd *pwd;
+	struct cfstring *comstring, *s;
+	login_cap_t *lcap;
+	char **argv;
+	char *cs, *addr, *comcs;
+	const char *jidstr, *conslog, *path, *ruleset, *term, *username;
+	size_t comlen;
+	pid_t pid;
+	int argc, bg, clean, consfd, down, fib, i, injail, sjuser, timeout;
+
+	static char *cleanenv;
+
+	if (comparam) {
+		if (comparam == IP_MOUNT_DEVFS
+		    ? !bool_param(j->intparams[IP_MOUNT_DEVFS])
+		    : j->intparams[comparam] == NULL)
+			return 0;
+		j->comparam = comparam;
+		j->comstring = comparam == IP_MOUNT_DEVFS ? COMSTRING_DUMMY
+		    : STAILQ_FIRST(&j->intparams[comparam]->val);
+	} else {
+		comparam = j->comparam;
+		if (!(j->flags & JF_RUNQ))
+			j->comstring = j->comstring == COMSTRING_DUMMY
+			    ? NULL : STAILQ_NEXT(j->comstring, tq);
+	}
+	comstring = j->comstring;
+	if (comstring == NULL ||
+	    (comstring != COMSTRING_DUMMY && comstring->len == 0))
+		return 0;
+	if (plimit && *plimit == 0) {
+		j->flags |= JF_RUNQ;
+		requeue(j, &runnable);
+		return 1;
+	}
+	j->flags &= ~(JF_RUNQ | JF_BACKGROUND);
+	/*
+	 * Collect exec arguments.  Internal commands for network and
+	 * mounting build their own argument lists (XXX they should be
+	 * truly internal).
+	 */
+	bg = j->flags & JF_FAILED;
+	down = j->flags & (JF_STOP | JF_FAILED);
+	if (comparam == IP__IP4_IFADDR) {
+		argv = alloca(8 * sizeof(char *));
+		*(const char **)&argv[0] = _PATH_IFCONFIG;
+		if ((cs = strchr(comstring->s, '|'))) {
+			argv[1] = alloca(cs - comstring->s + 1);
+			strlcpy(argv[1], comstring->s, cs - comstring->s + 1);
+			addr = cs + 1;
+		} else {
+			*(const char **)&argv[1] =
+			    string_param(j->intparams[IP_INTERFACE]);
+			addr = comstring->s;
+		}
+		*(const char **)&argv[2] = "inet";
+		if (!(cs = strchr(addr, '/'))) {
+			argv[3] = addr;
+			*(const char **)&argv[4] = "netmask";
+			*(const char **)&argv[5] = "255.255.255.255";
+			argc = 6;
+		} else if (strchr(cs + 1, '.')) {
+			argv[3] = alloca(cs - addr + 1);
+			strlcpy(argv[3], addr, cs - addr + 1);
+			*(const char **)&argv[4] = "netmask";
+			*(const char **)&argv[5] = cs + 1;
+			argc = 6;
+		} else {
+			argv[3] = addr;
+			argc = 4;
+		}
+		*(const char **)&argv[argc] = down ? "-alias" : "alias";
+		argv[argc + 1] = NULL;
+		j->flags |= JF_IFUP;
+#ifdef INET6
+	} else if (comparam == IP__IP6_IFADDR) {
+		argv = alloca(8 * sizeof(char *));
+		*(const char **)&argv[0] = _PATH_IFCONFIG;
+		if ((cs = strchr(comstring->s, '|'))) {
+			argv[1] = alloca(cs - comstring->s + 1);
+			strlcpy(argv[1], comstring->s, cs - comstring->s + 1);
+			addr = cs + 1;
+		} else {
+			*(const char **)&argv[1] =
+			    string_param(j->intparams[IP_INTERFACE]);
+			addr = comstring->s;
+		}
+		*(const char **)&argv[2] = "inet6";
+		argv[3] = addr;
+		if (!(cs = strchr(addr, '/'))) {
+			*(const char **)&argv[4] = "prefixlen";
+			*(const char **)&argv[5] = "128";
+			argc = 6;
+		} else
+			argc = 4;
+		*(const char **)&argv[argc] = down ? "-alias" : "alias";
+		argv[argc + 1] = NULL;
+		j->flags |= JF_IFUP;
+#endif
+	} else if (comparam == IP_VNET_INTERFACE) {
+		argv = alloca(5 * sizeof(char *));
+		*(const char **)&argv[0] = _PATH_IFCONFIG;
+		argv[1] = comstring->s;
+		*(const char **)&argv[2] = down ? "-vnet" : "vnet";
+		jidstr = string_param(j->intparams[KP_JID]);
+		*(const char **)&argv[3] =
+			jidstr ? jidstr : string_param(j->intparams[KP_NAME]);
+		argv[4] = NULL;
+		j->flags |= JF_IFUP;
+	} else if (comparam == IP_MOUNT) {
+		argv = alloca(8 * sizeof(char *));
+		comcs = alloca(comstring->len + 1);
+		strcpy(comcs, comstring->s);
+		argc = 0;
+		for (cs = strtok(comcs, " \t\f\v\r\n"); cs && argc < 4;
+		     cs = strtok(NULL, " \t\f\v\r\n"))
+			argv[argc++] = cs;
+		if (argc < 3) {
+			jail_warnx(j, "mount: %s: missing information",
+			    comstring->s);
+			failed(j);
+			return -1;
+		}
+		if (down) {
+			argv[4] = NULL;
+			argv[3] = argv[1];
+			*(const char **)&argv[0] = "/sbin/umount";
+		} else {
+			if (argc == 4) {
+				argv[7] = NULL;
+				argv[6] = argv[1];
+				argv[5] = argv[0];
+				argv[4] = argv[3];
+				*(const char **)&argv[3] = "-o";
+			} else {
+				argv[5] = NULL;
+				argv[4] = argv[1];
+				argv[3] = argv[0];
+			}
+			*(const char **)&argv[0] = _PATH_MOUNT;
+		}
+		*(const char **)&argv[1] = "-t";
+		j->flags |= JF_MOUNTED;
+	} else if (comparam == IP_MOUNT_FSTAB) {
+		argv = alloca(4 * sizeof(char *));
+		*(const char **)&argv[0] = down ? "/sbin/umount" : _PATH_MOUNT;
+		*(const char **)&argv[1] = "-aF";
+		argv[2] = comstring->s;
+		argv[3] = NULL;
+		j->flags |= JF_MOUNTED;
+	} else if (comparam == IP_MOUNT_DEVFS) {
+		path = string_param(j->intparams[KP_PATH]);
+		if (path == NULL) {
+			jail_warnx(j, "mount.devfs: no path");
+			failed(j);
+			return -1;
+		}
+		if (down) {
+			argv = alloca(3 * sizeof(char *));
+			*(const char **)&argv[0] = "/sbin/umount";
+			argv[1] = alloca(strlen(path) + 5);
+			sprintf(argv[1], "%s/dev", path);
+			argv[2] = NULL;
+		} else {
+			argv = alloca(4 * sizeof(char *));
+			*(const char **)&argv[0] = _PATH_BSHELL;
+			*(const char **)&argv[1] = "-c";
+			ruleset = string_param(j->intparams
+			    [IP_MOUNT_DEVFS_RULESET]);
+			argv[2] = alloca(strlen(path) +
+			    (ruleset ? strlen(ruleset) + 1 : 0) + 56);
+			sprintf(argv[2], ". /etc/rc.subr; load_rc_config .; "
+			    "devfs_mount_jail %s/dev%s%s", path,
+			    ruleset ? " " : "", ruleset ? ruleset : "");
+			argv[3] = NULL;
+		}
+		j->flags |= JF_MOUNTED;
+	} else if (comparam == IP_COMMAND && j->name == NULL) {
+		argc = 0;
+		STAILQ_FOREACH(s, &j->intparams[IP_COMMAND]->val, tq)
+			argc++;
+		argv = alloca((argc + 1) * sizeof(char *));
+		argc = 0;
+		STAILQ_FOREACH(s, &j->intparams[IP_COMMAND]->val, tq)
+			argv[argc++] = s->s;
+		argv[argc] = NULL;
+		j->comstring = NULL;
+	} else if ((cs = strpbrk(comstring->s, "!\"$&'()*;<>?[\\]`{|}~")) &&
+		   !(cs[0] == '&' && cs[1] == '\0')) {
+		argv = alloca(4 * sizeof(char *));
+		*(const char **)&argv[0] = _PATH_BSHELL;
+		*(const char **)&argv[1] = "-c";
+		argv[2] = comstring->s;
+		argv[3] = NULL;
+	} else {
+		if (cs) {
+			*cs = 0;
+			bg = 1;
+		}
+		comcs = alloca(comstring->len + 1);
+		strcpy(comcs, comstring->s);	
+		argc = 0;
+		for (cs = strtok(comcs, " \t\f\v\r\n"); cs;
+		     cs = strtok(NULL, " \t\f\v\r\n"))
+			argc++;
+		argv = alloca((argc + 1) * sizeof(char *));
+		strcpy(comcs, comstring->s);	
+		argc = 0;
+		for (cs = strtok(comcs, " \t\f\v\r\n"); cs;
+		     cs = strtok(NULL, " \t\f\v\r\n"))
+			argv[argc++] = cs;
+		argv[argc] = NULL;
+	}
+	if (argv[0] == NULL)
+		return 0;
+
+	j->pstatus = 0;
+	if (int_param(j->intparams[IP_EXEC_TIMEOUT], &timeout) &&
+	    timeout != 0) {
+		clock_gettime(CLOCK_REALTIME, &j->timeout);
+		j->timeout.tv_sec += timeout;
+	} else
+		j->timeout.tv_sec = 0;
+
+	injail = comparam == IP_EXEC_START || comparam == IP_COMMAND ||
+	    comparam == IP_EXEC_STOP;
+	clean = bool_param(j->intparams[IP_EXEC_CLEAN]);
+	username = string_param(j->intparams[injail
+	    ? IP_EXEC_JAIL_USER : IP_EXEC_SYSTEM_USER]);
+	sjuser = bool_param(j->intparams[IP_EXEC_SYSTEM_JAIL_USER]);
+
+	consfd = 0;
+	if (injail &&
+	    (conslog = string_param(j->intparams[IP_EXEC_CONSOLELOG]))) {
+		consfd =
+		    open(conslog, O_WRONLY | O_CREAT | O_APPEND, DEFFILEMODE);
+		if (consfd < 0) {
+			jail_warnx(j, "open %s: %s", conslog, strerror(errno));
+			failed(j);
+			return -1;
+		}
+	}
+
+	comlen = 0;
+	for (i = 0; argv[i]; i++)
+		comlen += strlen(argv[i]) + 1;
+	j->comline = cs = emalloc(comlen);
+	for (i = 0; argv[i]; i++) {
+		strcpy(cs, argv[i]);
+		if (argv[i + 1]) {
+			cs += strlen(argv[i]) + 1;
+			cs[-1] = ' ';
+		}
+	}
+	if (verbose > 0)
+		jail_note(j, "run command%s%s%s: %s\n",
+		    injail ? " in jail" : "", username ? " as " : "",
+		    username ? username : "", j->comline);
+
+	pid = fork();
+	if (pid < 0)
+		err(1, "fork");
+	if (pid > 0) {
+		if (bg) {
+			j->flags |= JF_BACKGROUND;
+			requeue(j, &ready);
+		} else {
+			--*plimit;
+			add_proc(j, pid);
+		}
+		return 1;
+	}
+	if (bg)
+		setsid();
+
+	pwd = NULL;
+	lcap = NULL;
+	if ((clean || username) && injail && sjuser &&
+	    get_user_info(j, username, &pwd, &lcap) < 0)
+		exit(1);
+	if (injail) {
+		/* jail_attach won't chdir along with its chroot. */
+		path = string_param(j->intparams[KP_PATH]);
+		if (path && chdir(path) < 0) {
+			jail_warnx(j, "chdir %s: %s", path, strerror(errno));
+			exit(1);
+		}
+		if (int_param(j->intparams[IP_EXEC_FIB], &fib) &&
+		    setfib(fib) < 0) {
+			jail_warnx(j, "setfib: %s", strerror(errno));
+			exit(1);
+		}
+		if (jail_attach(j->jid) < 0) {
+			jail_warnx(j, "jail_attach: %s", strerror(errno));
+			exit(1);
+		}
+	}
+	if (clean || username) {
+		if (!(injail && sjuser) &&
+		    get_user_info(j, username, &pwd, &lcap) < 0)
+			exit(1);
+		if (clean) {
+			term = getenv("TERM");
+			environ = &cleanenv;
+			setenv("PATH", "/bin:/usr/bin", 0);
+			setenv("TERM", term, 1);
+		}
+		if (setusercontext(lcap, pwd, pwd->pw_uid, username
+		    ? LOGIN_SETALL & ~LOGIN_SETGROUP & ~LOGIN_SETLOGIN
+		    : LOGIN_SETPATH | LOGIN_SETENV) < 0) {
+			jail_warnx(j, "setusercontext %s: %s", pwd->pw_name,
+			    strerror(errno));
+			exit(1);
+		}
+		login_close(lcap);
+		setenv("USER", pwd->pw_name, 1);
+		setenv("HOME", pwd->pw_dir, 1);
+		setenv("SHELL",
+		    *pwd->pw_shell ? pwd->pw_shell : _PATH_BSHELL, 1);
+		if (clean && chdir(pwd->pw_dir) < 0) {
+			jail_warnx(j, "chdir %s: %s",
+			    pwd->pw_dir, strerror(errno));
+			exit(1);
+		}
+		endpwent();
+	}
+
+	if (consfd != 0 && (dup2(consfd, 1) < 0 || dup2(consfd, 2) < 0)) {
+		jail_warnx(j, "exec.consolelog: %s", strerror(errno));
+		exit(1);
+	}
+	closefrom(3);
+	execvp(argv[0], argv);
+	jail_warnx(j, "exec %s: %s", argv[0], strerror(errno));
+	exit(1);
+}
+
+/*
+ * Check command exit status
+ */
+int
+finish_command(struct cfjail *j, int *plimit)
+{
+	int error;
+
+	if (j->flags & (JF_RUNQ | JF_BACKGROUND))
+		return 0;
+	++*plimit;
+	if (!TAILQ_EMPTY(&runnable))
+		requeue(TAILQ_FIRST(&runnable), &ready);
+	error = 0;
+	if (j->flags & JF_TIMEOUT) {
+		j->flags &= ~JF_TIMEOUT;
+		if (j->comparam != IP_STOP_TIMEOUT) {
+			jail_warnx(j, "%s: timed out", j->comline);
+			failed(j);
+			error = -1;
+		} else if (verbose > 0)
+			jail_note(j, "timed out\n");
+	} else if (j->pstatus != 0) {
+		if (WIFSIGNALED(j->pstatus))
+			jail_warnx(j, "%s: exited on signal %d",
+			    j->comline, WTERMSIG(j->pstatus));
+		else
+			jail_warnx(j, "%s: failed", j->comline);
+		failed(j);
+		error = -1;
+	}
+	free(j->comline);
+	return error;
+}
+
+/*
+ * Check for finished processed or timeouts.
+ */
+struct cfjail *
+next_proc(int nonblock)
+{
+	struct kevent ke;
+	struct timespec ts;
+	struct timespec *tsp;
+	struct cfjail *j;
+
+	if (!TAILQ_EMPTY(&sleeping)) {
+	again:
+		tsp = NULL;
+		if ((j = TAILQ_FIRST(&sleeping)) && j->timeout.tv_sec) {
+			clock_gettime(CLOCK_REALTIME, &ts);
+			ts.tv_sec = j->timeout.tv_sec - ts.tv_sec;
+			ts.tv_nsec = j->timeout.tv_nsec - ts.tv_nsec;
+			if (ts.tv_nsec < 0) {
+				ts.tv_sec--;
+				ts.tv_nsec += 1000000000;
+			}
+			if (ts.tv_sec < 0 ||
+			    (ts.tv_sec == 0 && ts.tv_nsec == 0)) {
+				j->flags |= JF_TIMEOUT;
+				clear_procs(j);
+				return j;
+			}
+			tsp = &ts;
+		}
+		if (nonblock) {
+			ts.tv_sec = 0;
+			ts.tv_nsec = 0;
+			tsp = &ts;
+		}
+		switch (kevent(kq, NULL, 0, &ke, 1, tsp)) {
+		case -1:
+			if (errno != EINTR)
+				err(1, "kevent");
+			goto again;
+		case 0:
+			if (!nonblock) {
+				j = TAILQ_FIRST(&sleeping);
+				j->flags |= JF_TIMEOUT;
+				clear_procs(j);
+				return j;
+			}
+			break;
+		case 1:
+			(void)waitpid(ke.ident, NULL, WNOHANG);
+			if ((j = find_proc(ke.ident))) {
+				j->pstatus = ke.data;
+				return j;
+			}
+			goto again;
+		}
+	}
+	return NULL;
+}
+
+/*
+ * Send SIGTERM to all processes in a jail and wait for them to die.
+ */
+int
+term_procs(struct cfjail *j)
+{
+	struct kinfo_proc *ki;
+	int i, noted, pcnt, timeout;
+
+	static kvm_t *kd;
+
+	if (!int_param(j->intparams[IP_STOP_TIMEOUT], &timeout))
+		timeout = DEFAULT_STOP_TIMEOUT;
+	else if (timeout == 0)
+		return 0;
+
+	if (kd == NULL) {
+		kd = kvm_open(NULL, NULL, NULL, O_RDONLY, "jail");
+		if (kd == NULL)
+			exit(1);
+	}
+
+	ki = kvm_getprocs(kd, KERN_PROC_PROC, 0, &pcnt);
+	if (ki == NULL)
+		exit(1);
+	noted = 0;
+	for (i = 0; i < pcnt; i++)
+		if (ki[i].ki_jid == j->jid &&
+		    kill(ki[i].ki_pid, SIGTERM) == 0) {
+			add_proc(j, ki[i].ki_pid);
+			if (verbose > 0) {
+				if (!noted) {
+					noted = 1;
+					jail_note(j, "sent SIGTERM to:");
+				}
+				printf(" %d", ki[i].ki_pid);
+			}
+		}
+	if (noted)
+		printf("\n");
+	if (j->nprocs > 0) {
+		clock_gettime(CLOCK_REALTIME, &j->timeout);
+		j->timeout.tv_sec += timeout;
+		return 1;
+	}
+	return 0;
+}
+
+/*
+ * Add a process to the hash, tied to a jail.
+ */
+static void
+add_proc(struct cfjail *j, pid_t pid)
+{
+	struct kevent ke;
+	struct cfjail *tj;
+	struct phash *ph;
+
+	if (!kq && (kq = kqueue()) < 0)
+		err(1, "kqueue");
+	EV_SET(&ke, pid, EVFILT_PROC, EV_ADD, NOTE_EXIT, 0, NULL);
+	if (kevent(kq, &ke, 1, NULL, 0, NULL) < 0)
+		err(1, "kevent");
+	ph = emalloc(sizeof(struct phash));
+	ph->j = j;
+	ph->pid = pid;
+	LIST_INSERT_HEAD(&phash[pid % PHASH_SIZE], ph, le);
+	j->nprocs++;
+	if (j->timeout.tv_sec) {
+		TAILQ_REMOVE(j->queue, j, tq);
+		TAILQ_FOREACH(tj, &sleeping, tq) {
+			if (!tj->timeout.tv_sec ||
+			    j->timeout.tv_sec < tj->timeout.tv_sec ||
+			    (j->timeout.tv_sec == tj->timeout.tv_sec &&
+			    j->timeout.tv_nsec <= tj->timeout.tv_nsec)) {
+				TAILQ_INSERT_BEFORE(tj, j, tq);
+				break;
+			}
+		}
+		if (tj == NULL)
+			TAILQ_INSERT_TAIL(&sleeping, j, tq);
+		j->queue = &sleeping;
+	} else
+		requeue(j, &sleeping);
+}
+
+/*
+ * Remove any processes from the hash that correspond to a jail.
+ */
+static void
+clear_procs(struct cfjail *j)
+{
+	struct kevent ke;
+	struct phash *ph, *tph;
+	int i;
+
+	j->nprocs = 0;
+	for (i = 0; i < PHASH_SIZE; i++)
+		LIST_FOREACH_SAFE(ph, &phash[i], le, tph)
+			if (ph->j == j) {
+				EV_SET(&ke, ph->pid, EVFILT_PROC, EV_DELETE,
+				    NOTE_EXIT, 0, NULL);
+				(void)kevent(kq, &ke, 1, NULL, 0, NULL);
+				LIST_REMOVE(ph, le);
+				free(ph);
+			}
+}
+
+/*
+ * Find the jail that corresponds to an exited process.
+ */
+static struct cfjail *
+find_proc(pid_t pid)
+{
+	struct cfjail *j;
+	struct phash *ph;
+
+	LIST_FOREACH(ph, &phash[pid % PHASH_SIZE], le)
+		if (ph->pid == pid) {
+			j = ph->j;
+			LIST_REMOVE(ph, le);
+			free(ph);
+			return --j->nprocs ? NULL : j;
+		}
+	return NULL;
+}
+
+/*
+ * Look up a user in the passwd and login.conf files.
+ */
+static int
+get_user_info(struct cfjail *j, const char *username,
+    const struct passwd **pwdp, login_cap_t **lcapp)
+{
+	const struct passwd *pwd;
+
+	*pwdp = pwd = username ? getpwnam(username) : getpwuid(getuid());
+	if (pwd == NULL) {
+		if (errno)
+			jail_warnx(j, "getpwnam%s%s: %s", username ? " " : "",
+			    username ? username : "", strerror(errno));
+		else if (username)
+			jail_warnx(j, "%s: no such user", username);
+		else
+			jail_warnx(j, "unknown uid %d", getuid());
+		return -1;
+	}
+	*lcapp = login_getpwclass(pwd);
+	if (*lcapp == NULL) {
+		jail_warnx(j, "getpwclass %s: %s", pwd->pw_name,
+		    strerror(errno));
+		return -1;
+	}
+	/* Set the groups while the group file is still available */
+	if (initgroups(pwd->pw_name, pwd->pw_gid) < 0) {
+		jail_warnx(j, "initgroups %s: %s", pwd->pw_name,
+		    strerror(errno));
+		return -1;
+	}
+	return 0;
+}