nstool: Replace "pid" subcommand with "info" subcommand

The new subcommand gives more information about the holder process and its
namespace, and may be further extended in future.  Add some options which
give the old behaviour for existing scripts.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 49 insertions, 11 deletions

diff --git a/test/nstool.c b/test/nstool.c
index b736e8f..345b908 100644
--- a/test/nstool.c
+++ b/test/nstool.c
@@ -14,6 +14,7 @@
 #include <stdbool.h>
 #include <errno.h>
 #include <unistd.h>
+#include <getopt.h>
 #include <sys/socket.h>
 #include <linux/un.h>
 
@@ -30,9 +31,11 @@ static void usage(void)
 	    "    Run within a set of namespaces, open a Unix domain socket\n"
 	    "    (the \"control socket\") at SOCK and wait for requests from\n"
 	    "    other nstool subcommands.\n"
-	    "  nstool pid SOCK\n"
-	    "    Print the pid of the nstool hold process with control socket\n"
-	    "    at SOCK, as seen in the caller's namespace.\n"
+	    "  nstool info [-pw] pid SOCK\n"
+	    "    Print information about the nstool hold process with control\n"
+	    "    socket at SOCK\n"
+	    "      -p    Print just the holder's PID as seen by the caller\n"
+	    "      -w    Retry connecting to SOCK until it is ready\n"
 	    "  nstool stop SOCK\n"
 	    "    Instruct the nstool hold with control socket at SOCK to\n"
 	    "    terminate.\n");
@@ -103,17 +106,45 @@ static void cmd_hold(int argc, char *argv[])
 	unlink(sockpath);
 }
 
-static void cmd_pid(int argc, char *argv[])
+static void cmd_info(int argc, char *argv[])
 {
-	const char *sockpath = argv[1];
+	const struct option options[] = {
+		{"pid",		no_argument, 	NULL,	'p' },
+		{"wait",	no_argument,	NULL,	'w' },
+		{ 0 },
+	};
+	bool pidonly = false, waitforsock = false;
 	struct ucred peercred;
 	socklen_t optlen = sizeof(peercred);
-	int fd, rc;
+	const char *optstring = "pw";
+	const char *sockpath;
+	int fd, rc, opt;
 
-	if (argc != 2)
+	do {
+		opt = getopt_long(argc, argv, optstring, options, NULL);
+
+		switch (opt) {
+		case 'p':
+			pidonly = true;
+			break;
+		case 'w':
+			waitforsock = true;
+			break;
+		case -1:
+			break;
+		default:
+			usage();
+		}
+	} while (opt != -1);
+
+	if (optind != argc - 1) {
+		fprintf(stderr, "B\n");
 		usage();
+	}
+
+	sockpath = argv[optind];
 
-	fd = connect_ctl(sockpath, true);
+	fd = connect_ctl(sockpath, waitforsock);
 
 	rc = getsockopt(fd, SOL_SOCKET, SO_PEERCRED,
 			&peercred, &optlen);
@@ -123,7 +154,14 @@ static void cmd_pid(int argc, char *argv[])
 
 	close(fd);
 
-	printf("%d\n", peercred.pid);
+	if (pidonly) {
+		printf("%d\n", peercred.pid);
+	} else {
+		printf("As seen from calling context:\n");
+		printf("\tPID:\t%d\n", peercred.pid);
+		printf("\tUID:\t%u\n", peercred.uid);
+		printf("\tGID:\t%u\n", peercred.gid);
+	}
 }
 
 static void cmd_stop(int argc, char *argv[])
@@ -158,8 +196,8 @@ int main(int argc, char *argv[])
 
 	if (strcmp(subcmd, "hold") == 0)
 		cmd_hold(argc - 1, argv + 1);
-	else if (strcmp(subcmd, "pid") == 0)
-		cmd_pid(argc - 1, argv + 1);
+	else if (strcmp(subcmd, "info") == 0)
+		cmd_info(argc - 1, argv + 1);
 	else if (strcmp(subcmd, "stop") == 0)
 		cmd_stop(argc - 1, argv + 1);
 	else