os-posix: Allow 'chroot' via '-run-with' and deprecate the old '-chroot' option

We recently introduced "-run-with" for options that influence the
runtime behavior of QEMU. This option has the big advantage that it
can group related options (so that it is easier for the users to spot
them) and that the options become introspectable via QMP this way.
So let's start moving more switches into this option group, starting
with "-chroot" now.

Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Message-Id: <20230703074447.17044-1-thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
index ddc1e48460fcfba0325aaea1b22345370ce287d3..02ea5a839fe1f466a45997a8d7969c4505716762 100644 (file)
--- a/docs/about/deprecated.rst
+++ b/docs/about/deprecated.rst
@@ -116,6 +116,11 @@ Use "whpx" (on Windows) or "hvf" (on macOS) instead.
 
 Use ``-run-with async-teardown=on`` instead.
 
+``-chroot`` (since 8.1)
+'''''''''''''''''''''''
+
+Use ``-run-with chroot=dir`` instead.
+
 ``-singlestep`` (since 8.1)
 '''''''''''''''''''''''''''
 

diff --git a/os-posix.c b/os-posix.c
index 90ea71725fb026e8dec8384267441ec427734fa3..cfcb96533c1b449ab96d651c01660ebc6ca62ad8 100644 (file)
--- a/os-posix.c
+++ b/os-posix.c
@@ -38,6 +38,7 @@
 #include "qemu/cutils.h"
 #include "qemu/config-file.h"
 #include "qemu/option.h"
+#include "qemu/module.h"
 
 #ifdef CONFIG_LINUX
 #include <sys/prctl.h>
@@ -148,6 +149,7 @@ int os_parse_cmd_args(int index, const char *optarg)
         }
         break;
     case QEMU_OPTION_chroot:
+        warn_report("option is deprecated, use '-run-with chroot=...' instead");
         chroot_dir = optarg;
         break;
     case QEMU_OPTION_daemonize:
@@ -158,18 +160,25 @@ int os_parse_cmd_args(int index, const char *optarg)
     case QEMU_OPTION_asyncteardown:
         init_async_teardown();
         break;
+#endif
     case QEMU_OPTION_run_with: {
+        const char *str;
         QemuOpts *opts = qemu_opts_parse_noisily(qemu_find_opts("run-with"),
                                                  optarg, false);
         if (!opts) {
             exit(1);
         }
+#if defined(CONFIG_LINUX)
         if (qemu_opt_get_bool(opts, "async-teardown", false)) {
             init_async_teardown();
         }
+#endif
+        str = qemu_opt_get(opts, "chroot");
+        if (str) {
+            chroot_dir = str;
+        }
         break;
     }
-#endif
     default:
         return -1;
     }
@@ -348,3 +357,27 @@ int os_mlock(void)
     return -ENOSYS;
 #endif
 }
+
+static QemuOptsList qemu_run_with_opts = {
+    .name = "run-with",
+    .head = QTAILQ_HEAD_INITIALIZER(qemu_run_with_opts.head),
+    .desc = {
+#if defined(CONFIG_LINUX)
+        {
+            .name = "async-teardown",
+            .type = QEMU_OPT_BOOL,
+        },
+#endif
+        {
+            .name = "chroot",
+            .type = QEMU_OPT_STRING,
+        },
+        { /* end of list */ }
+    },
+};
+
+static void register_runwith(void)
+{
+    qemu_add_opts(&qemu_run_with_opts);
+}
+opts_init(register_runwith);

diff --git a/qemu-options.hx b/qemu-options.hx
index 96087505b29b0c63e40e99615ff434863b4f36c7..f8f384e55181b3051597f63bd0f522f1668d6f54 100644 (file)
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -4677,11 +4677,12 @@ ERST
 
 #ifndef _WIN32
 DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \
-    "-chroot dir     chroot to dir just before starting the VM\n",
+    "-chroot dir     chroot to dir just before starting the VM (deprecated)\n",
     QEMU_ARCH_ALL)
 #endif
 SRST
 ``-chroot dir``
+    Deprecated, use '-run-with chroot=...' instead.
     Immediately before starting guest execution, chroot to the specified
     directory. Especially useful in combination with -runas.
 ERST
@@ -4868,13 +4869,16 @@ SRST
     This option is deprecated and should no longer be used. The new option
     ``-run-with async-teardown=on`` is a replacement.
 ERST
+#endif
+#ifdef CONFIG_POSIX
 DEF("run-with", HAS_ARG, QEMU_OPTION_run_with,
-    "-run-with async-teardown[=on|off]\n"
-    "                misc QEMU process lifecycle options\n"
-    "                async-teardown=on enables asynchronous teardown\n",
+    "-run-with [async-teardown=on|off][,chroot=dir]\n"
+    "                Set miscellaneous QEMU process lifecycle options:\n"
+    "                async-teardown=on enables asynchronous teardown (Linux only)\n"
+    "                chroot=dir chroot to dir just before starting the VM\n",
     QEMU_ARCH_ALL)
 SRST
-``-run-with``
+``-run-with [async-teardown=on|off][,chroot=dir]``
     Set QEMU process lifecycle options.
 
     ``async-teardown=on`` enables asynchronous teardown. A new process called
@@ -4887,6 +4891,10 @@ SRST
     performed correctly. This only works if the cleanup process is not
     forcefully killed with SIGKILL before the main QEMU process has
     terminated completely.
+
+    ``chroot=dir`` can be used for doing a chroot to the specified directory
+    immediately before starting the guest execution. This is especially useful
+    in combination with -runas.
 ERST
 #endif
 

diff --git a/util/async-teardown.c b/util/async-teardown.c
index 3ab19c8740cdf85222ad72dd7f7f722cdb99f1ce..62cdeb0f20a2500e02e51895e7c90ab9a62170ac 100644 (file)
--- a/util/async-teardown.c
+++ b/util/async-teardown.c
@@ -12,9 +12,6 @@
  */
 
 #include "qemu/osdep.h"
-#include "qemu/config-file.h"
-#include "qemu/option.h"
-#include "qemu/module.h"
 #include <dirent.h>
 #include <sys/prctl.h>
 #include <sched.h>
@@ -147,21 +144,3 @@ void init_async_teardown(void)
     clone(async_teardown_fn, new_stack_for_clone(), CLONE_VM, NULL);
     sigprocmask(SIG_SETMASK, &old_signals, NULL);
 }
-
-static QemuOptsList qemu_run_with_opts = {
-    .name = "run-with",
-    .head = QTAILQ_HEAD_INITIALIZER(qemu_run_with_opts.head),
-    .desc = {
-        {
-            .name = "async-teardown",
-            .type = QEMU_OPT_BOOL,
-        },
-        { /* end of list */ }
-    },
-};
-
-static void register_teardown(void)
-{
-    qemu_add_opts(&qemu_run_with_opts);
-}
-opts_init(register_teardown);