Add [-J jid_file] option to write out a JidFile, similar to a PidFile,

containing the jailid, path, hostname, ip and the command used to start
the jail.

PR:		misc/89883
Submitted by:	L. Jason Godsey <lannygodsey -at- yahoo.com>
Reviewed by:	phk
MFC after:	1 week

2 files changed, 30 insertions, 6 deletions

diff --git a/usr.sbin/jail/jail.8 b/usr.sbin/jail/jail.8
index 0583f0e..bbdd336 100644
--- a/usr.sbin/jail/jail.8
+++ b/usr.sbin/jail/jail.8
@@ -42,6 +42,7 @@
 .Sh SYNOPSIS
 .Nm
 .Op Fl i
+.Op Fl J Ar jid_file
 .Op Fl l u Ar username | Fl U Ar username
 .Ar path hostname ip-number command ...
 .Sh DESCRIPTION
@@ -53,6 +54,9 @@ The options are as follows:
 .Bl -tag -width ".Fl u Ar username"
 .It Fl i
 Output the jail identifier of the newly created jail.
+.It Fl J Ar jid_file
+Write a JidFile, like a PidFile, containing jailid, path, hostname, ip and
+command used to start the jail.
 .It Fl l
 Run program in the clean environment.
 The environment is discarded except for
diff --git a/usr.sbin/jail/jail.c b/usr.sbin/jail/jail.c
index 84cab55..76bb01d 100644
--- a/usr.sbin/jail/jail.c
+++ b/usr.sbin/jail/jail.c
@@ -54,19 +54,25 @@ main(int argc, char **argv)
 	struct passwd *pwd = NULL;
 	struct in_addr in;
 	gid_t groups[NGROUPS];
-	int ch, i, iflag, lflag, ngroups, uflag, Uflag;
-	char path[PATH_MAX], *username;
+	int ch, i, iflag, Jflag, lflag, ngroups, uflag, Uflag;
+	char path[PATH_MAX], *username, *JidFile;
 	static char *cleanenv;
 	const char *shell, *p = NULL;
+	FILE *fp;
 
-	iflag = lflag = uflag = Uflag = 0;
-	username = cleanenv = NULL;
+	iflag = Jflag = lflag = uflag = Uflag = 0;
+	username = JidFile = cleanenv = NULL;
+	fp = NULL;
 
-	while ((ch = getopt(argc, argv, "ilu:U:")) != -1) {
+	while ((ch = getopt(argc, argv, "ilu:U:J:")) != -1) {
 		switch (ch) {
 		case 'i':
 			iflag = 1;
 			break;
+		case 'J':
+			JidFile = optarg;
+			Jflag = 1;
+			break;
 		case 'u':
 			username = optarg;
 			uflag = 1;
@@ -103,6 +109,11 @@ main(int argc, char **argv)
 	if (inet_aton(argv[2], &in) == 0)
 		errx(1, "Could not make sense of ip-number: %s", argv[2]);
 	j.ip_number = ntohl(in.s_addr);
+	if (Jflag) {
+		fp = fopen(JidFile, "w");
+		if (fp == NULL)
+			errx(1, "Could not create JidFile: %s", JidFile);
+	}
 	i = jail(&j);
 	if (i == -1)
 		err(1, "jail");
@@ -110,6 +121,15 @@ main(int argc, char **argv)
 		printf("%d\n", i);
 		fflush(stdout);
 	}
+	if (Jflag) {
+		if (fp != NULL) {
+			fprintf(fp, "%d\t%s\t%s\t%s\t%s\n",
+			    i, j.path, j.hostname, argv[2], argv[3]);
+			(void)fclose(fp);
+		} else {
+			errx(1, "Could not write JidFile: %s", JidFile);
+		}
+	}
 	if (username != NULL) {
 		if (Uflag)
 			GET_USER_INFO;
@@ -149,7 +169,7 @@ usage(void)
 {
 
 	(void)fprintf(stderr, "%s%s\n",
-	     "usage: jail [-i] [-l -u username | -U username]",
+	     "usage: jail [-i] [-J jid_file] [-l -u username | -U username]",
 	     " path hostname ip-number command ...");
 	exit(1);
 }