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

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

[Thomas Huth]

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.

Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 docs/about/deprecated.rst |  5 +++++
 os-posix.c                | 35 ++++++++++++++++++++++++++++++++++-
 util/async-teardown.c     | 21 ---------------------
 qemu-options.hx           | 18 +++++++++++++-----
 4 files changed, 52 insertions(+), 27 deletions(-)

diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
index 0743459862..1cf53b86ce 100644
--- 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 90ea71725f..0ae1fb2347 100644
--- 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_teardown(void)
+{
+    qemu_add_opts(&qemu_run_with_opts);
+}
+opts_init(register_teardown);
diff --git a/util/async-teardown.c b/util/async-teardown.c
index 3ab19c8740..62cdeb0f20 100644
--- 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);
diff --git a/qemu-options.hx b/qemu-options.hx
index b57489d7ca..f49d4c0e3c 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -4670,11 +4670,12 @@ 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
@@ -4861,13 +4862,16 @@ 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
@@ -4880,6 +4884,10 @@ 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
 
-- 
2.39.3

Re: [PATCH] os-posix: Allow 'chroot' via '-run-with' and deprecate the old '-chroot' option

[Claudio Imbrenda]

On Fri, 30 Jun 2023 17:01:12 +0200
Thomas Huth <thuth@redhat.com> wrote:

> 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.
> 
> Signed-off-by: Thomas Huth <thuth@redhat.com>

Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>

> ---
>  docs/about/deprecated.rst |  5 +++++
>  os-posix.c                | 35 ++++++++++++++++++++++++++++++++++-
>  util/async-teardown.c     | 21 ---------------------
>  qemu-options.hx           | 18 +++++++++++++-----
>  4 files changed, 52 insertions(+), 27 deletions(-)
> 
> diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
> index 0743459862..1cf53b86ce 100644
> --- 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 90ea71725f..0ae1fb2347 100644
> --- 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_teardown(void)
> +{
> +    qemu_add_opts(&qemu_run_with_opts);
> +}
> +opts_init(register_teardown);
> diff --git a/util/async-teardown.c b/util/async-teardown.c
> index 3ab19c8740..62cdeb0f20 100644
> --- 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);
> diff --git a/qemu-options.hx b/qemu-options.hx
> index b57489d7ca..f49d4c0e3c 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -4670,11 +4670,12 @@ 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
> @@ -4861,13 +4862,16 @@ 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
> @@ -4880,6 +4884,10 @@ 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
>  

Re: [PATCH] os-posix: Allow 'chroot' via '-run-with' and deprecate the old '-chroot' option

[Michael Tokarev]

30.06.2023 18:01, Thomas Huth wrote:
> 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.
...
> +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_teardown(void)
> +{
> +    qemu_add_opts(&qemu_run_with_opts);
> +}
> +opts_init(register_teardown);

Hmm.. Is it still register_teardown? :)

Other than that,

Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>

/mjt

Re: [PATCH] os-posix: Allow 'chroot' via '-run-with' and deprecate the old '-chroot' option

[Thomas Huth]

On 30/06/2023 17.56, Michael Tokarev wrote:
> 30.06.2023 18:01, Thomas Huth wrote:
>> 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.
> ...
>> +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_teardown(void)
>> +{
>> +    qemu_add_opts(&qemu_run_with_opts);
>> +}
>> +opts_init(register_teardown);
> 
> Hmm.. Is it still register_teardown? :)

Drat. Should be something like "register_runwith" now, of course. Thanks for 
spotting it!

  Thomas

> Other than that,
> 
> Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
> 
> /mjt
> 

Re: [PATCH] os-posix: Allow 'chroot' via '-run-with' and deprecate the old '-chroot' option

[Ján Tomko]

[-- Attachment #1: Type: text/plain, Size: 816 bytes --]

On a Friday in 2023, Thomas Huth wrote:
>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.
>
>Signed-off-by: Thomas Huth <thuth@redhat.com>
>---
> docs/about/deprecated.rst |  5 +++++
> os-posix.c                | 35 ++++++++++++++++++++++++++++++++++-
> util/async-teardown.c     | 21 ---------------------
> qemu-options.hx           | 18 +++++++++++++-----
> 4 files changed, 52 insertions(+), 27 deletions(-)
>

For libvirt:

Reviewed-by: Ján Tomko <jtomko@redhat.com>

Jano

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