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-rw-r--r--test/nstool.c139
1 files changed, 139 insertions, 0 deletions
diff --git a/test/nstool.c b/test/nstool.c
new file mode 100644
index 0000000..9d6ee0c
--- /dev/null
+++ b/test/nstool.c
@@ -0,0 +1,139 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+/* nstool - maintain a namespace to be entered by other processes
+ *
+ * Copyright Red Hat
+ * Author: David Gibson <david@gibson.dropbear.id.au>
+ *
+ * Can run in 3 modes:
+ *
+ * nstool <path> hold
+ * Designed to be run inside a namespace, opens a Unix domain
+ * control socket at <path> and waits until instructed to stop
+ * with "nstool <path> stop"
+ * nstool <path> pid
+ * Prints the PID of the nstool hold process with control
+ * socket <path>. This is given in the PID namespace where
+ * nstool pid is executed, not the one where nstool hold is
+ * running
+ * nstool <path> stop
+ * Instruct the nstool hold with control socket at <path> to exit.
+ */
+
+#define _GNU_SOURCE
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+#include <sys/socket.h>
+#include <linux/un.h>
+
+#define die(...) \
+ do { \
+ fprintf(stderr, __VA_ARGS__); \
+ exit(1); \
+ } while (0)
+
+static void usage(void)
+{
+ die("Usage: nstool <socket path> hold|pid\n");
+}
+
+static void hold(int fd, const struct sockaddr_un *addr)
+{
+ int rc;
+
+ rc = bind(fd, (struct sockaddr *)addr, sizeof(*addr));
+ if (rc < 0)
+ die("bind(): %s\n", strerror(errno));
+
+ rc = listen(fd, 0);
+ if (rc < 0)
+ die("listen(): %s\n", strerror(errno));
+
+ printf("nstool: local PID=%d local UID=%u local GID=%u\n",
+ getpid(), getuid(), getgid());
+ do {
+ int afd = accept(fd, NULL, NULL);
+ char buf;
+
+ if (afd < 0)
+ die("accept(): %s\n", strerror(errno));
+
+ rc = read(afd, &buf, sizeof(buf));
+ if (rc < 0)
+ die("read(): %s\n", strerror(errno));
+ } while (rc == 0);
+
+ unlink(addr->sun_path);
+}
+
+static void pid(int fd, const struct sockaddr_un *addr)
+{
+ int rc;
+ struct ucred peercred;
+ socklen_t optlen = sizeof(peercred);
+
+ do {
+ rc = connect(fd, (struct sockaddr *)addr, sizeof(*addr));
+ if (rc < 0 && errno != ENOENT && errno != ECONNREFUSED)
+ die("connect(): %s\n", strerror(errno));
+ } while (rc < 0);
+
+ rc = getsockopt(fd, SOL_SOCKET, SO_PEERCRED,
+ &peercred, &optlen);
+ if (rc < 0)
+ die("getsockopet(SO_PEERCRED): %s\n", strerror(errno));
+
+ close(fd);
+
+ printf("%d\n", peercred.pid);
+}
+
+static void stop(int fd, const struct sockaddr_un *addr)
+{
+ int rc;
+ char buf = 'Q';
+
+ rc = connect(fd, (struct sockaddr *)addr, sizeof(*addr));
+ if (rc < 0)
+ die("connect(): %s\n", strerror(errno));
+
+ rc = write(fd, &buf, sizeof(buf));
+ if (rc < 0)
+ die("write(): %s\n", strerror(errno));
+
+ close(fd);
+}
+
+int main(int argc, char *argv[])
+{
+ int fd;
+ const char *sockname;
+ struct sockaddr_un sockaddr = {
+ .sun_family = AF_UNIX,
+ };
+
+ if (argc != 3)
+ usage();
+
+ sockname = argv[1];
+ strncpy(sockaddr.sun_path, sockname, UNIX_PATH_MAX);
+
+ fd = socket(AF_UNIX, SOCK_STREAM, PF_UNIX);
+ if (fd < 0)
+ die("socket(): %s\n", strerror(errno));
+
+ if (strcmp(argv[2], "hold") == 0)
+ hold(fd, &sockaddr);
+ else if (strcmp(argv[2], "pid") == 0)
+ pid(fd, &sockaddr);
+ else if (strcmp(argv[2], "stop") == 0)
+ stop(fd, &sockaddr);
+ else
+ usage();
+
+ exit(0);
+}