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-rw-r--r--src/nspawn/nspawn.c158
1 files changed, 148 insertions, 10 deletions
diff --git a/src/nspawn/nspawn.c b/src/nspawn/nspawn.c
index 0d538c2543..edad1cbf42 100644
--- a/src/nspawn/nspawn.c
+++ b/src/nspawn/nspawn.c
@@ -107,6 +107,12 @@ typedef enum LinkJournal {
LINK_GUEST
} LinkJournal;
+typedef enum Volatile {
+ VOLATILE_NO,
+ VOLATILE_YES,
+ VOLATILE_STATE,
+} Volatile;
+
static char *arg_directory = NULL;
static char *arg_user = NULL;
static sd_id128_t arg_uuid = {};
@@ -159,6 +165,7 @@ static bool arg_network_veth = false;
static const char *arg_network_bridge = NULL;
static unsigned long arg_personality = 0xffffffffLU;
static const char *arg_image = NULL;
+static Volatile arg_volatile = VOLATILE_NO;
static int help(void) {
@@ -207,7 +214,8 @@ static int help(void) {
" --share-system Share system namespaces with host\n"
" --register=BOOLEAN Register container as machine\n"
" --keep-unit Do not register a scope for the machine, reuse\n"
- " the service unit nspawn is running in\n",
+ " the service unit nspawn is running in\n"
+ " --volatile[=MODE] Run the system in volatile mode\n",
program_invocation_short_name);
return 0;
@@ -235,6 +243,7 @@ static int parse_argv(int argc, char *argv[]) {
ARG_NETWORK_VETH,
ARG_NETWORK_BRIDGE,
ARG_PERSONALITY,
+ ARG_VOLATILE,
};
static const struct option options[] = {
@@ -267,6 +276,7 @@ static int parse_argv(int argc, char *argv[]) {
{ "network-bridge", required_argument, NULL, ARG_NETWORK_BRIDGE },
{ "personality", required_argument, NULL, ARG_PERSONALITY },
{ "image", required_argument, NULL, 'i' },
+ { "volatile", optional_argument, NULL, ARG_VOLATILE },
{}
};
@@ -559,6 +569,25 @@ static int parse_argv(int argc, char *argv[]) {
break;
+ case ARG_VOLATILE:
+
+ if (!optarg)
+ arg_volatile = VOLATILE_YES;
+ else {
+ r = parse_boolean(optarg);
+ if (r < 0) {
+ if (streq(optarg, "state"))
+ arg_volatile = VOLATILE_STATE;
+ else {
+ log_error("Failed to parse --volatile= argument: %s", optarg);
+ return r;
+ }
+ } else
+ arg_volatile = r ? VOLATILE_YES : VOLATILE_NO;
+ }
+
+ break;
+
case '?':
return -EINVAL;
@@ -585,6 +614,11 @@ static int parse_argv(int argc, char *argv[]) {
return -EINVAL;
}
+ if (arg_volatile != VOLATILE_NO && arg_read_only) {
+ log_error("Cannot combine --read-only with --volatile. Note that --volatile already implies a read-only base hierarchy.");
+ return -EINVAL;
+ }
+
arg_retain = (arg_retain | plus | (arg_private_network ? 1ULL << CAP_NET_ADMIN : 0)) & ~minus;
return 1;
@@ -712,7 +746,7 @@ static int mount_binds(const char *dest, char **l, bool ro) {
}
/* Create the mount point, but be conservative -- refuse to create block
- * and char devices. */
+ * and char devices. */
if (S_ISDIR(source_st.st_mode))
mkdir_label(where, 0755);
else if (S_ISFIFO(source_st.st_mode))
@@ -796,7 +830,6 @@ static int setup_timezone(const char *dest) {
if (!y)
y = path_startswith(q, "/usr/share/zoneinfo/");
-
/* Already pointing to the right place? Then do nothing .. */
if (y && streq(y, z))
return 0;
@@ -815,7 +848,9 @@ static int setup_timezone(const char *dest) {
if (!what)
return log_oom();
+ mkdir_parents(where, 0755);
unlink(where);
+
if (symlink(what, where) < 0) {
log_error("Failed to correct timezone of container: %m");
return 0;
@@ -839,11 +874,105 @@ static int setup_resolv_conf(const char *dest) {
/* We don't really care for the results of this really. If it
* fails, it fails, but meh... */
+ mkdir_parents(where, 0755);
copy_file("/etc/resolv.conf", where, O_TRUNC|O_NOFOLLOW, 0644);
return 0;
}
+static int setup_volatile_state(const char *directory) {
+ const char *p;
+ int r;
+
+ assert(directory);
+
+ if (arg_volatile != VOLATILE_STATE)
+ return 0;
+
+ /* --volatile=state means we simply overmount /var
+ with a tmpfs, and the rest read-only. */
+
+ r = bind_remount_recursive(directory, true);
+ if (r < 0) {
+ log_error("Failed to remount %s read-only: %s", directory, strerror(-r));
+ return r;
+ }
+
+ p = strappenda(directory, "/var");
+ mkdir(p, 0755);
+
+ if (mount("tmpfs", p, "tmpfs", MS_STRICTATIME, "mode=755") < 0) {
+ log_error("Failed to mount tmpfs to /var: %m");
+ return -errno;
+ }
+
+ return 0;
+}
+
+static int setup_volatile(const char *directory) {
+ bool tmpfs_mounted = false, bind_mounted = false;
+ char template[] = "/tmp/nspawn-volatile-XXXXXX";
+ const char *f, *t;
+ int r;
+
+ assert(directory);
+
+ if (arg_volatile != VOLATILE_YES)
+ return 0;
+
+ /* --volatile=yes means we mount a tmpfs to the root dir, and
+ the original /usr to use inside it, and that read-only. */
+
+ if (!mkdtemp(template)) {
+ log_error("Failed to create temporary directory: %m");
+ return -errno;
+ }
+
+ if (mount("tmpfs", template, "tmpfs", MS_STRICTATIME, "mode=755") < 0) {
+ log_error("Failed to mount tmpfs for root directory: %m");
+ r = -errno;
+ goto fail;
+ }
+
+ tmpfs_mounted = true;
+
+ f = strappenda(directory, "/usr");
+ t = strappenda(template, "/usr");
+
+ mkdir(t, 0755);
+ if (mount(f, t, "bind", MS_BIND|MS_REC, NULL) < 0) {
+ log_error("Failed to create /usr bind mount: %m");
+ r = -errno;
+ goto fail;
+ }
+
+ bind_mounted = true;
+
+ r = bind_remount_recursive(t, true);
+ if (r < 0) {
+ log_error("Failed to remount %s read-only: %s", t, strerror(-r));
+ goto fail;
+ }
+
+ if (mount(template, directory, NULL, MS_MOVE, NULL) < 0) {
+ log_error("Failed to move root mount: %m");
+ r = -errno;
+ goto fail;
+ }
+
+ rmdir(template);
+
+ return 0;
+
+fail:
+ if (bind_mounted)
+ umount(t);
+ if (tmpfs_mounted)
+ umount(template);
+ rmdir(template);
+ return r;
+}
+
static char* id128_format_as_uuid(sd_id128_t id, char s[37]) {
snprintf(s, 37,
@@ -2868,7 +2997,11 @@ int main(int argc, char *argv[]) {
goto finish;
}
- r = dissect_image(image_fd, &root_device, &root_device_rw, &home_device, &home_device_rw, &srv_device, &srv_device_rw, &secondary);
+ r = dissect_image(image_fd,
+ &root_device, &root_device_rw,
+ &home_device, &home_device_rw,
+ &srv_device, &srv_device_rw,
+ &secondary);
if (r < 0)
goto finish;
}
@@ -3042,18 +3175,23 @@ int main(int argc, char *argv[]) {
srv_device, srv_device_rw) < 0)
goto child_fail;
- r = base_filesystem_create(arg_directory);
- if (r < 0) {
- log_error("Failed to create the base filesystem: %s", strerror(-r));
- goto child_fail;
- }
-
/* Turn directory into bind mount */
if (mount(arg_directory, arg_directory, "bind", MS_BIND|MS_REC, NULL) < 0) {
log_error("Failed to make bind mount: %m");
goto child_fail;
}
+ r = setup_volatile(arg_directory);
+ if (r < 0)
+ goto child_fail;
+
+ if (setup_volatile_state(arg_directory) < 0)
+ goto child_fail;
+
+ r = base_filesystem_create(arg_directory);
+ if (r < 0)
+ goto child_fail;
+
if (arg_read_only) {
k = bind_remount_recursive(arg_directory, true);
if (k < 0) {
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-09 18:13:40 +0000