Why we need args?
When plugin outputs log files, only binary path can't distinguish multiple
runs if the binary passed with different args.
This is bad for CI using plugin.

Signed-off-by: demin.han <demin.han@starfivetech.com>
---
 include/qemu/qemu-plugin.h   | 11 +++++++++++
 plugins/api.c                | 16 ++++++++++++++++
 plugins/qemu-plugins.symbols |  1 +
 3 files changed, 28 insertions(+)

diff --git a/include/qemu/qemu-plugin.h b/include/qemu/qemu-plugin.h
index 622c9a0232..daf75c9f5a 100644
--- a/include/qemu/qemu-plugin.h
+++ b/include/qemu/qemu-plugin.h
@@ -837,6 +837,17 @@ bool qemu_plugin_bool_parse(const char *name, const char *val, bool *ret);
 QEMU_PLUGIN_API
 const char *qemu_plugin_path_to_binary(void);
 
+/**
+ * qemu_plugin_argv_to_binary() - argv to binary file being executed
+ *
+ * Return a string array representing the argv to the binary. For user-mode
+ * this is the main executable's argv. For system emulation we currently
+ * return NULL. The user should g_free() the string array once no longer
+ * needed.
+ */
+QEMU_PLUGIN_API
+const char **qemu_plugin_argv_to_binary(void);
+
 /**
  * qemu_plugin_start_code() - returns start of text segment
  *
diff --git a/plugins/api.c b/plugins/api.c
index 24ea64e2de..fa2735db03 100644
--- a/plugins/api.c
+++ b/plugins/api.c
@@ -485,6 +485,22 @@ const char *qemu_plugin_path_to_binary(void)
     return path;
 }
 
+const char **qemu_plugin_argv_to_binary(void)
+{
+    const char **argv = NULL;
+#ifdef CONFIG_USER_ONLY
+    int i, argc;
+    TaskState *ts = get_task_state(current_cpu);
+    argc = ts->bprm->argc;
+    argv = g_malloc(sizeof(char *) * (argc + 1));
+    for (i = 0; i < argc; ++i) {
+        argv[i] = g_strdup(ts->bprm->argv[i]);
+    }
+    argv[argc] = NULL;
+#endif
+    return argv;
+}
+
 uint64_t qemu_plugin_start_code(void)
 {
     uint64_t start = 0;
diff --git a/plugins/qemu-plugins.symbols b/plugins/qemu-plugins.symbols
index 032661f9ea..532582effe 100644
--- a/plugins/qemu-plugins.symbols
+++ b/plugins/qemu-plugins.symbols
@@ -1,4 +1,5 @@
 {
+  qemu_plugin_argv_to_binary;
   qemu_plugin_bool_parse;
   qemu_plugin_end_code;
   qemu_plugin_entry_code;
-- 
2.46.1

"demin.han" <demin.han@starfivetech.com> writes:

> Why we need args?
> When plugin outputs log files, only binary path can't distinguish multiple
> runs if the binary passed with different args.
> This is bad for CI using plugin.

New APIs should come with an example use case for testing. However for
this use case why isn't the plugin using getpid() or gettid() a suitable
solution?

Some additional comments bellow...

> Signed-off-by: demin.han <demin.han@starfivetech.com>
> ---
>  include/qemu/qemu-plugin.h   | 11 +++++++++++
>  plugins/api.c                | 16 ++++++++++++++++
>  plugins/qemu-plugins.symbols |  1 +
>  3 files changed, 28 insertions(+)
>
> diff --git a/include/qemu/qemu-plugin.h b/include/qemu/qemu-plugin.h
> index 622c9a0232..daf75c9f5a 100644
> --- a/include/qemu/qemu-plugin.h
> +++ b/include/qemu/qemu-plugin.h
> @@ -837,6 +837,17 @@ bool qemu_plugin_bool_parse(const char *name, const char *val, bool *ret);
>  QEMU_PLUGIN_API
>  const char *qemu_plugin_path_to_binary(void);
>  
> +/**
> + * qemu_plugin_argv_to_binary() - argv to binary file being executed
> + *
> + * Return a string array representing the argv to the binary. For user-mode
> + * this is the main executable's argv. For system emulation we currently
> + * return NULL.

Maybe more explicit:

qemu_plugin_get_user_argv() and be clear it is user mode only.

Although I suspect a qemu_plugin_get_user_env() might be a more useful
helper depending on the use case.

> The user should g_free() the string array once no longer
> + * needed.
> + */
> +QEMU_PLUGIN_API
> +const char **qemu_plugin_argv_to_binary(void);
> +
>  /**
>   * qemu_plugin_start_code() - returns start of text segment
>   *
> diff --git a/plugins/api.c b/plugins/api.c
> index 24ea64e2de..fa2735db03 100644
> --- a/plugins/api.c
> +++ b/plugins/api.c
> @@ -485,6 +485,22 @@ const char *qemu_plugin_path_to_binary(void)
>      return path;
>  }
>  
> +const char **qemu_plugin_argv_to_binary(void)
> +{
> +    const char **argv = NULL;
> +#ifdef CONFIG_USER_ONLY
> +    int i, argc;
> +    TaskState *ts = get_task_state(current_cpu);
> +    argc = ts->bprm->argc;
> +    argv = g_malloc(sizeof(char *) * (argc + 1));

 argv = g_new0(char *, argc + 1);

> +    for (i = 0; i < argc; ++i) {
> +        argv[i] = g_strdup(ts->bprm->argv[i]);
> +    }
> +    argv[argc] = NULL;

Allows you to drop this as well.

> +#endif
> +    return argv;
> +}
> +
>  uint64_t qemu_plugin_start_code(void)
>  {
>      uint64_t start = 0;
> diff --git a/plugins/qemu-plugins.symbols b/plugins/qemu-plugins.symbols
> index 032661f9ea..532582effe 100644
> --- a/plugins/qemu-plugins.symbols
> +++ b/plugins/qemu-plugins.symbols
> @@ -1,4 +1,5 @@
>  {
> +  qemu_plugin_argv_to_binary;
>    qemu_plugin_bool_parse;
>    qemu_plugin_end_code;
>    qemu_plugin_entry_code;

You can drop the symbols now we autogenerate them.

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro

Hi,

> -----Original Message-----
> From: Alex Bennée <alex.bennee@linaro.org>
> Sent: 2025年1月9日 19:59
> To: Demin Han <demin.han@starfivetech.com>
> Cc: qemu-devel@nongnu.org; erdnaxe@crans.org; ma.mandourr@gmail.com;
> pierrick.bouvier@linaro.org
> Subject: Re: [PATCH] plugins: add plugin API to get args passed to binary
> 
> "demin.han" <demin.han@starfivetech.com> writes:
> 
> > Why we need args?
> > When plugin outputs log files, only binary path can't distinguish
> > multiple runs if the binary passed with different args.
> > This is bad for CI using plugin.
> 
> New APIs should come with an example use case for testing. However for this
> use case why isn't the plugin using getpid() or gettid() a suitable solution?


We want a meaning and unique name for plugin output. For example
./a arg0 arg1 should have a_arg0_arg1.log
./a arg2 arg3 should have a_arg2_arg3.log
I think getpid() and getid() is not unique

This case can be solved by using a shell wrapper, extract args and pass them to plugin suggested by Pierrick Bouvier

Regards,
Demin

Hi Demin,

thanks for your contribution.

On 11/1/24 02:00, demin.han wrote:
> Why we need args?
> When plugin outputs log files, only binary path can't distinguish multiple
> runs if the binary passed with different args.
> This is bad for CI using plugin.
>

Can it be solved simply by encoding this in name of log file from the CI 
run script?
$ cmd="/usr/bin/echo Hello world"
$ out_file="$(echo "$cmd" | sed -e 's/\s/_/').log"
$ qemu -plugin... -d plugin -D "$out_file" $cmd

I can see some good points to add this new API, but for the use case 
presented in commit message, I'm not sure to see what it solves.

> Signed-off-by: demin.han <demin.han@starfivetech.com>
> ---
>   include/qemu/qemu-plugin.h   | 11 +++++++++++
>   plugins/api.c                | 16 ++++++++++++++++
>   plugins/qemu-plugins.symbols |  1 +
>   3 files changed, 28 insertions(+)
> 
> diff --git a/include/qemu/qemu-plugin.h b/include/qemu/qemu-plugin.h
> index 622c9a0232..daf75c9f5a 100644
> --- a/include/qemu/qemu-plugin.h
> +++ b/include/qemu/qemu-plugin.h
> @@ -837,6 +837,17 @@ bool qemu_plugin_bool_parse(const char *name, const char *val, bool *ret);
>   QEMU_PLUGIN_API
>   const char *qemu_plugin_path_to_binary(void);
>   
> +/**
> + * qemu_plugin_argv_to_binary() - argv to binary file being executed
> + *
> + * Return a string array representing the argv to the binary. For user-mode
> + * this is the main executable's argv. For system emulation we currently
> + * return NULL. The user should g_free() the string array once no longer
> + * needed.
> + */
> +QEMU_PLUGIN_API
> +const char **qemu_plugin_argv_to_binary(void);
> +
>   /**
>    * qemu_plugin_start_code() - returns start of text segment
>    *
> diff --git a/plugins/api.c b/plugins/api.c
> index 24ea64e2de..fa2735db03 100644
> --- a/plugins/api.c
> +++ b/plugins/api.c
> @@ -485,6 +485,22 @@ const char *qemu_plugin_path_to_binary(void)
>       return path;
>   }
>   
> +const char **qemu_plugin_argv_to_binary(void)
> +{
> +    const char **argv = NULL;
> +#ifdef CONFIG_USER_ONLY
> +    int i, argc;
> +    TaskState *ts = get_task_state(current_cpu);
> +    argc = ts->bprm->argc;
> +    argv = g_malloc(sizeof(char *) * (argc + 1));
> +    for (i = 0; i < argc; ++i) {
> +        argv[i] = g_strdup(ts->bprm->argv[i]);
> +    }
> +    argv[argc] = NULL;
> +#endif
> +    return argv;
> +}
> +
>   uint64_t qemu_plugin_start_code(void)
>   {
>       uint64_t start = 0;
> diff --git a/plugins/qemu-plugins.symbols b/plugins/qemu-plugins.symbols
> index 032661f9ea..532582effe 100644
> --- a/plugins/qemu-plugins.symbols
> +++ b/plugins/qemu-plugins.symbols
> @@ -1,4 +1,5 @@
>   {
> +  qemu_plugin_argv_to_binary;
>     qemu_plugin_bool_parse;
>     qemu_plugin_end_code;
>     qemu_plugin_entry_code;

Regards,
Pierrick