Patchwork [3/3] QAPI: Introduce memchar-read QMP command

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Submitter Lei Li
Date Jan. 24, 2013, 4:03 p.m.
Message ID <1359043401-19810-4-git-send-email-lilei@linux.vnet.ibm.com>
Download mbox | patch
Permalink /patch/215406/
State New
Headers show

Comments

Lei Li - Jan. 24, 2013, 4:03 p.m.
Signed-off-by: Lei Li <lilei@linux.vnet.ibm.com>
---
 hmp-commands.hx  |   21 +++++++++++++++++++++
 hmp.c            |   21 +++++++++++++++++++++
 hmp.h            |    1 +
 qapi-schema.json |   36 ++++++++++++++++++++++++++++++++++++
 qemu-char.c      |   48 ++++++++++++++++++++++++++++++++++++++++++++++++
 qmp-commands.hx  |   33 +++++++++++++++++++++++++++++++++
 6 files changed, 160 insertions(+), 0 deletions(-)
Luiz Capitulino - Jan. 25, 2013, 1:47 p.m.
On Fri, 25 Jan 2013 00:03:21 +0800
Lei Li <lilei@linux.vnet.ibm.com> wrote:

> +MemCharRead *qmp_memchar_read(const char *device, int64_t size,
> +                              bool has_format, enum DataFormat format,
> +                              Error **errp)
> +{
> +    CharDriverState *chr;
> +    guchar *read_data;
> +    MemCharRead *meminfo;
> +    size_t count;
> +
> +    chr = qemu_chr_find(device);
> +    if (!chr) {
> +        error_set(errp, QERR_DEVICE_NOT_FOUND, device);
> +        return NULL;
> +    }
> +
> +    if (qemu_is_chr(chr, "memory")) {
> +        error_setg(errp,"%s is not memory char device", device);
> +        return NULL;
> +    }
> +
> +    if (size <= 0) {
> +        error_setg(errp, "size must be greater than zero");
> +        return NULL;
> +    }
> +
> +    meminfo = g_malloc0(sizeof(MemCharRead));
> +
> +    count = qemu_chr_cirmem_count(chr);
> +    if (count == 0) {
> +        return meminfo;

Although things work out, you can't return meminfo->data=NULL because
'data' isn't (and shouldn't be) optional. The right thing to do is to
return an empty string.

As I believe you'll agree with that change, and to avoid you a respin,
I'll make that change for you. Also:

> +    }
> +
> +    size = size > count ? count : size;
> +    read_data = g_malloc0(size + 1);
> +
> +    meminfo->count = cirmem_chr_read(chr, read_data, size);
> +
> +    if (has_format && (format == DATA_FORMAT_BASE64)) {
> +       if (read_data) {

This check is not needed (and you actually do the wrong thing is read_data=NULL.
But I'll just drop it for you.

> +           meminfo->data = g_base64_encode(read_data, (size_t)meminfo->count);
> +       }
> +    } else {
> +        meminfo->data = (char *)read_data;
> +    }
> +
> +    return meminfo;
> +}
> +
>  QemuOpts *qemu_chr_parse_compat(const char *label, const char *filename)
>  {
>      char host[65], port[33], width[8], height[8];
> diff --git a/qmp-commands.hx b/qmp-commands.hx
> index 8d10a67..17f83b3 100644
> --- a/qmp-commands.hx
> +++ b/qmp-commands.hx
> @@ -499,6 +499,39 @@ Example:
>  EQMP
>  
>      {
> +        .name       = "memchar-read",
> +        .args_type  = "device:s,size:i,format:s?",
> +        .mhandler.cmd_new = qmp_marshal_input_memchar_read,
> +    },
> +
> +SQMP
> +memchar-read
> +-------------
> +
> +Provide read interface for CirMemCharDriver. Read from the char
> +device memory and return the data with size.
> +
> +Arguments:
> +
> +- "device": the name of the char device, must be unique (json-string)
> +- "size": the memory size wanted to read in bytes (refer to unencoded
> +          size of the raw data), would adjust to the init size of the
> +          memchar if the requested size is larger than it. (json-int)
> +- "format": the data format write to memchardev, default is
> +            utf8. (json-string, optional)
> +          - Possible values: "utf8", "base64"
> +
> +Example:
> +
> +-> { "execute": "memchar-read",
> +                "arguments": { "device": foo,
> +                               "size": 1000,
> +                               "format": "utf8" } }
> +<- { "return": { "data": "data string...", "count": 1000 } }
> +
> +EQMP
> +
> +    {
>          .name       = "xen-save-devices-state",
>          .args_type  = "filename:F",
>      .mhandler.cmd_new = qmp_marshal_input_xen_save_devices_state,

Patch

diff --git a/hmp-commands.hx b/hmp-commands.hx
index bcfea11..bdd48f3 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -858,6 +858,27 @@  to char device 'memory'.
 ETEXI
 
     {
+        .name       = "memchar_read",
+        .args_type  = "device:s,size:i",
+        .params     = "device size",
+        .help       = "Provide read interface for CirMemCharDriver. Read from"
+                      "it and return the data with size.",
+        .mhandler.cmd = hmp_memchar_read,
+    },
+
+STEXI
+@item memchar_read @var{device}
+@findex memchar_read
+Provide read interface for CirMemCharDriver. Read from char device
+'memory' and return the data.
+
+@var{size} is the size of data want to read from. Refer to unencoded
+size of the raw data, would adjust to the init size of the memchar
+if the requested size is larger than it.
+
+ETEXI
+
+    {
         .name       = "migrate",
         .args_type  = "detach:-d,blk:-b,inc:-i,uri:s",
         .params     = "[-d] [-b] [-i] uri",
diff --git a/hmp.c b/hmp.c
index 647316a..6092359 100644
--- a/hmp.c
+++ b/hmp.c
@@ -697,6 +697,27 @@  void hmp_memchar_write(Monitor *mon, const QDict *qdict)
     hmp_handle_error(mon, &errp);
 }
 
+void hmp_memchar_read(Monitor *mon, const QDict *qdict)
+{
+    uint32_t size = qdict_get_int(qdict, "size");
+    const char *chardev = qdict_get_str(qdict, "device");
+    MemCharRead *meminfo;
+    Error *errp = NULL;
+
+    meminfo = qmp_memchar_read(chardev, size, false, 0, &errp);
+    if (errp) {
+        monitor_printf(mon, "%s\n", error_get_pretty(errp));
+        error_free(errp);
+        return;
+    }
+
+    if (meminfo->data) {
+        monitor_printf(mon, "%s\n", meminfo->data);
+    }
+
+    qapi_free_MemCharRead(meminfo);
+}
+
 static void hmp_cont_cb(void *opaque, int err)
 {
     if (!err) {
diff --git a/hmp.h b/hmp.h
index 06d6ea2..076d8cf 100644
--- a/hmp.h
+++ b/hmp.h
@@ -44,6 +44,7 @@  void hmp_cpu(Monitor *mon, const QDict *qdict);
 void hmp_memsave(Monitor *mon, const QDict *qdict);
 void hmp_pmemsave(Monitor *mon, const QDict *qdict);
 void hmp_memchar_write(Monitor *mon, const QDict *qdict);
+void hmp_memchar_read(Monitor *mon, const QDict *qdict);
 void hmp_cont(Monitor *mon, const QDict *qdict);
 void hmp_system_wakeup(Monitor *mon, const QDict *qdict);
 void hmp_inject_nmi(Monitor *mon, const QDict *qdict);
diff --git a/qapi-schema.json b/qapi-schema.json
index 8202311..ad4e276 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -363,6 +363,42 @@ 
            '*format': 'DataFormat'} }
 
 ##
+# @MemCharRead
+#
+# Result of QMP command memchar-read.
+#
+# @data: The data read from memchar as string.
+#
+# @count: The numbers of bytes read from.
+#
+# Since: 1.4
+##
+{ 'type': 'MemCharRead',
+  'data': { 'data': 'str', 'count': 'int' } }
+
+##
+# @memchar-read:
+#
+# Provide read interface for memchardev. Read from the char
+# device 'memory' and return the data.
+#
+# @device: the name of the memory char device.
+#
+# @size: the size to read in bytes.
+#
+# @format: #optional the format of the data want to read from
+#          memchardev, by default is 'utf8'.
+#
+# Returns: @MemCharRead
+#          If @device is not a valid memchr device, DeviceNotFound
+#
+# Since: 1.4
+##
+{ 'command': 'memchar-read',
+  'data': {'device': 'str', 'size': 'int', '*format': 'DataFormat'},
+  'returns': 'MemCharRead' }
+
+##
 # @CommandInfo:
 #
 # Information about a QMP command
diff --git a/qemu-char.c b/qemu-char.c
index dbd1a7c..9d63fe7 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -2790,6 +2790,54 @@  void qmp_memchar_write(const char *device, int64_t size,
     }
 }
 
+MemCharRead *qmp_memchar_read(const char *device, int64_t size,
+                              bool has_format, enum DataFormat format,
+                              Error **errp)
+{
+    CharDriverState *chr;
+    guchar *read_data;
+    MemCharRead *meminfo;
+    size_t count;
+
+    chr = qemu_chr_find(device);
+    if (!chr) {
+        error_set(errp, QERR_DEVICE_NOT_FOUND, device);
+        return NULL;
+    }
+
+    if (qemu_is_chr(chr, "memory")) {
+        error_setg(errp,"%s is not memory char device", device);
+        return NULL;
+    }
+
+    if (size <= 0) {
+        error_setg(errp, "size must be greater than zero");
+        return NULL;
+    }
+
+    meminfo = g_malloc0(sizeof(MemCharRead));
+
+    count = qemu_chr_cirmem_count(chr);
+    if (count == 0) {
+        return meminfo;
+    }
+
+    size = size > count ? count : size;
+    read_data = g_malloc0(size + 1);
+
+    meminfo->count = cirmem_chr_read(chr, read_data, size);
+
+    if (has_format && (format == DATA_FORMAT_BASE64)) {
+       if (read_data) {
+           meminfo->data = g_base64_encode(read_data, (size_t)meminfo->count);
+       }
+    } else {
+        meminfo->data = (char *)read_data;
+    }
+
+    return meminfo;
+}
+
 QemuOpts *qemu_chr_parse_compat(const char *label, const char *filename)
 {
     char host[65], port[33], width[8], height[8];
diff --git a/qmp-commands.hx b/qmp-commands.hx
index 8d10a67..17f83b3 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -499,6 +499,39 @@  Example:
 EQMP
 
     {
+        .name       = "memchar-read",
+        .args_type  = "device:s,size:i,format:s?",
+        .mhandler.cmd_new = qmp_marshal_input_memchar_read,
+    },
+
+SQMP
+memchar-read
+-------------
+
+Provide read interface for CirMemCharDriver. Read from the char
+device memory and return the data with size.
+
+Arguments:
+
+- "device": the name of the char device, must be unique (json-string)
+- "size": the memory size wanted to read in bytes (refer to unencoded
+          size of the raw data), would adjust to the init size of the
+          memchar if the requested size is larger than it. (json-int)
+- "format": the data format write to memchardev, default is
+            utf8. (json-string, optional)
+          - Possible values: "utf8", "base64"
+
+Example:
+
+-> { "execute": "memchar-read",
+                "arguments": { "device": foo,
+                               "size": 1000,
+                               "format": "utf8" } }
+<- { "return": { "data": "data string...", "count": 1000 } }
+
+EQMP
+
+    {
         .name       = "xen-save-devices-state",
         .args_type  = "filename:F",
     .mhandler.cmd_new = qmp_marshal_input_xen_save_devices_state,