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-rw-r--r--man/systemd-nspawn.xml24
-rw-r--r--src/nspawn/nspawn.c94
2 files changed, 105 insertions, 13 deletions
diff --git a/man/systemd-nspawn.xml b/man/systemd-nspawn.xml
index ccd3436d42..d6687038af 100644
--- a/man/systemd-nspawn.xml
+++ b/man/systemd-nspawn.xml
@@ -504,6 +504,30 @@
</varlistentry>
<varlistentry>
+ <term><option>--tmpfs=</option></term>
+
+ <listitem><para>Mount a tmpfs file
+ system into the container. Takes a
+ single absolute path argument that
+ specifies where to mount the tmpfs
+ instance to (in which case the
+ directory access mode will be chosen
+ as 0755, owned by root/root), or
+ optionally a colon-separated pair of
+ path and mount option string, that is
+ used for mounting (in which case the
+ kernel default for access mode and
+ owner will be chosen, unless otherwise
+ specified). This option is
+ particularly useful for mounting
+ directories such as
+ <filename>/var</filename> as tmpfs, to
+ allow state-less systems, in
+ particular when combined with
+ <option>--read-only</option>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
<term><option>--setenv=</option></term>
<listitem><para>Specifies an
diff --git a/src/nspawn/nspawn.c b/src/nspawn/nspawn.c
index 867cf19267..29ddfbb1ff 100644
--- a/src/nspawn/nspawn.c
+++ b/src/nspawn/nspawn.c
@@ -146,6 +146,7 @@ static uint64_t arg_retain =
(1ULL << CAP_MKNOD);
static char **arg_bind = NULL;
static char **arg_bind_ro = NULL;
+static char **arg_tmpfs = NULL;
static char **arg_setenv = NULL;
static bool arg_quiet = false;
static bool arg_share_system = false;
@@ -200,6 +201,7 @@ static int help(void) {
" --bind=PATH[:PATH] Bind mount a file or directory from the host into\n"
" the container\n"
" --bind-ro=PATH[:PATH] Similar, but creates a read-only bind mount\n"
+ " --tmpfs=PATH:[OPTIONS] Mount an empty tmpfs to the specified directory\n"
" --setenv=NAME=VALUE Pass an environment variable to PID 1\n"
" --share-system Share system namespaces with host\n"
" --register=BOOLEAN Register container as machine\n"
@@ -222,6 +224,7 @@ static int parse_argv(int argc, char *argv[]) {
ARG_LINK_JOURNAL,
ARG_BIND,
ARG_BIND_RO,
+ ARG_TMPFS,
ARG_SETENV,
ARG_SHARE_SYSTEM,
ARG_REGISTER,
@@ -247,6 +250,7 @@ static int parse_argv(int argc, char *argv[]) {
{ "link-journal", required_argument, NULL, ARG_LINK_JOURNAL },
{ "bind", required_argument, NULL, ARG_BIND },
{ "bind-ro", required_argument, NULL, ARG_BIND_RO },
+ { "tmpfs", required_argument, NULL, ARG_TMPFS },
{ "machine", required_argument, NULL, 'M' },
{ "slice", required_argument, NULL, 'S' },
{ "setenv", required_argument, NULL, ARG_SETENV },
@@ -469,6 +473,42 @@ static int parse_argv(int argc, char *argv[]) {
break;
}
+ case ARG_TMPFS: {
+ _cleanup_free_ char *a = NULL, *b = NULL;
+ char *e;
+
+ e = strchr(optarg, ':');
+ if (e) {
+ a = strndup(optarg, e - optarg);
+ b = strdup(e + 1);
+ } else {
+ a = strdup(optarg);
+ b = strdup("mode=0755");
+ }
+
+ if (!a || !b)
+ return log_oom();
+
+ if (!path_is_absolute(a)) {
+ log_error("Invalid tmpfs specification: %s", optarg);
+ return -EINVAL;
+ }
+
+ r = strv_push(&arg_tmpfs, a);
+ if (r < 0)
+ return log_oom();
+
+ a = NULL;
+
+ r = strv_push(&arg_tmpfs, b);
+ if (r < 0)
+ return log_oom();
+
+ b = NULL;
+
+ break;
+ }
+
case ARG_SETENV: {
char **n;
@@ -561,17 +601,17 @@ static int mount_all(const char *dest) {
} MountPoint;
static const MountPoint mount_table[] = {
- { "proc", "/proc", "proc", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, true },
- { "/proc/sys", "/proc/sys", NULL, NULL, MS_BIND, true }, /* Bind mount first */
- { NULL, "/proc/sys", NULL, NULL, MS_BIND|MS_RDONLY|MS_REMOUNT, true }, /* Then, make it r/o */
- { "sysfs", "/sys", "sysfs", NULL, MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV, true },
- { "tmpfs", "/dev", "tmpfs", "mode=755", MS_NOSUID|MS_STRICTATIME, true },
+ { "proc", "/proc", "proc", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, true },
+ { "/proc/sys", "/proc/sys", NULL, NULL, MS_BIND, true }, /* Bind mount first */
+ { NULL, "/proc/sys", NULL, NULL, MS_BIND|MS_RDONLY|MS_REMOUNT, true }, /* Then, make it r/o */
+ { "sysfs", "/sys", "sysfs", NULL, MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV, true },
+ { "tmpfs", "/dev", "tmpfs", "mode=755", MS_NOSUID|MS_STRICTATIME, true },
{ "devpts", "/dev/pts", "devpts","newinstance,ptmxmode=0666,mode=620,gid=" STRINGIFY(TTY_GID), MS_NOSUID|MS_NOEXEC, true },
- { "tmpfs", "/dev/shm", "tmpfs", "mode=1777", MS_NOSUID|MS_NODEV|MS_STRICTATIME, true },
- { "tmpfs", "/run", "tmpfs", "mode=755", MS_NOSUID|MS_NODEV|MS_STRICTATIME, true },
+ { "tmpfs", "/dev/shm", "tmpfs", "mode=1777", MS_NOSUID|MS_NODEV|MS_STRICTATIME, true },
+ { "tmpfs", "/run", "tmpfs", "mode=755", MS_NOSUID|MS_NODEV|MS_STRICTATIME, true },
#ifdef HAVE_SELINUX
- { "/sys/fs/selinux", "/sys/fs/selinux", NULL, NULL, MS_BIND, false }, /* Bind mount first */
- { NULL, "/sys/fs/selinux", NULL, NULL, MS_BIND|MS_RDONLY|MS_REMOUNT, false }, /* Then, make it r/o */
+ { "/sys/fs/selinux", "/sys/fs/selinux", NULL, NULL, MS_BIND, false }, /* Bind mount first */
+ { NULL, "/sys/fs/selinux", NULL, NULL, MS_BIND|MS_RDONLY|MS_REMOUNT, false }, /* Then, make it r/o */
#endif
};
@@ -640,7 +680,7 @@ static int mount_binds(const char *dest, char **l, bool ro) {
char **x, **y;
STRV_FOREACH_PAIR(x, y, l) {
- char *where;
+ _cleanup_free_ char *where = NULL;
struct stat source_st, dest_st;
int r;
@@ -649,12 +689,14 @@ static int mount_binds(const char *dest, char **l, bool ro) {
return -errno;
}
- where = strappenda(dest, *y);
+ where = strappend(dest, *y);
+ if (!where)
+ return log_oom();
+
r = stat(where, &dest_st);
if (r == 0) {
if ((source_st.st_mode & S_IFMT) != (dest_st.st_mode & S_IFMT)) {
- log_error("The file types of %s and %s do not match. Refusing bind mount",
- *x, where);
+ log_error("The file types of %s and %s do not match. Refusing bind mount", *x, where);
return -EINVAL;
}
} else if (errno == ENOENT) {
@@ -667,6 +709,7 @@ static int mount_binds(const char *dest, char **l, bool ro) {
log_error("Failed to bind mount %s: %m", *x);
return -errno;
}
+
/* Create the mount point, but be conservative -- refuse to create block
* and char devices. */
if (S_ISDIR(source_st.st_mode))
@@ -699,6 +742,27 @@ static int mount_binds(const char *dest, char **l, bool ro) {
return 0;
}
+static int mount_tmpfs(const char *dest) {
+ char **i, **o;
+
+ STRV_FOREACH_PAIR(i, o, arg_tmpfs) {
+ _cleanup_free_ char *where = NULL;
+
+ where = strappend(dest, *i);
+ if (!where)
+ return log_oom();
+
+ mkdir_label(where, 0755);
+
+ if (mount("tmpfs", where, "tmpfs", MS_NODEV|MS_STRICTATIME, *o) < 0) {
+ log_error("tmpfs mount to %s failed: %m", where);
+ return -errno;
+ }
+ }
+
+ return 0;
+}
+
static int setup_timezone(const char *dest) {
_cleanup_free_ char *where = NULL, *p = NULL, *q = NULL, *check = NULL, *what = NULL;
char *z, *y;
@@ -2998,6 +3062,9 @@ int main(int argc, char *argv[]) {
if (mount_binds(arg_directory, arg_bind_ro, true) < 0)
goto child_fail;
+ if (mount_tmpfs(arg_directory) < 0)
+ goto child_fail;
+
if (setup_kdbus(arg_directory, kdbus_domain) < 0)
goto child_fail;
@@ -3248,6 +3315,7 @@ finish:
strv_free(arg_network_macvlan);
strv_free(arg_bind);
strv_free(arg_bind_ro);
+ strv_free(arg_tmpfs);
return r;
}
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-11 21:43:29 +0000