[PATCH] plugins: add plugin API to get args passed to binary

demin.han posted 1 patch 3 weeks, 1 day ago
include/qemu/qemu-plugin.h   | 11 +++++++++++
plugins/api.c                | 16 ++++++++++++++++
plugins/qemu-plugins.symbols |  1 +
3 files changed, 28 insertions(+)
[PATCH] plugins: add plugin API to get args passed to binary
Posted by demin.han 3 weeks, 1 day ago
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
Re: [PATCH] plugins: add plugin API to get args passed to binary
Posted by Pierrick Bouvier 3 weeks ago
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