From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:43093) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TT8z8-0005e5-1e for qemu-devel@nongnu.org; Tue, 30 Oct 2012 06:23:56 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TT8z1-0005ql-9f for qemu-devel@nongnu.org; Tue, 30 Oct 2012 06:23:49 -0400 Received: from e28smtp08.in.ibm.com ([122.248.162.8]:40258) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TT8z0-0005qa-CC for qemu-devel@nongnu.org; Tue, 30 Oct 2012 06:23:43 -0400 Received: from /spool/local by e28smtp08.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 30 Oct 2012 15:53:40 +0530 Received: from d28av04.in.ibm.com (d28av04.in.ibm.com [9.184.220.66]) by d28relay01.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q9UANcRi28639366 for ; Tue, 30 Oct 2012 15:53:38 +0530 Received: from d28av04.in.ibm.com (loopback [127.0.0.1]) by d28av04.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id q9UFrSE7023756 for ; Wed, 31 Oct 2012 02:53:28 +1100 Message-ID: <508FAA76.3010002@linux.vnet.ibm.com> Date: Tue, 30 Oct 2012 18:22:46 +0800 From: Lei Li MIME-Version: 1.0 References: <1351250512-6386-1-git-send-email-lilei@linux.vnet.ibm.com> <1351250512-6386-4-git-send-email-lilei@linux.vnet.ibm.com> <20121026153918.76675272@doriath.home> <508E0182.2070901@linux.vnet.ibm.com> <20121029111718.0e03750e@doriath.home> In-Reply-To: <20121029111718.0e03750e@doriath.home> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 3/4] QAPI: Introduce memchar-read QMP command List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Luiz Capitulino Cc: blauwirbel@gmail.com, aliguori@us.ibm.com, qemu-devel@nongnu.org On 10/29/2012 09:17 PM, Luiz Capitulino wrote: > On Mon, 29 Oct 2012 12:09:38 +0800 > Lei Li wrote: > >> On 10/27/2012 01:39 AM, Luiz Capitulino wrote: >>> On Fri, 26 Oct 2012 19:21:51 +0800 >>> Lei Li wrote: >>> >>>> Signed-off-by: Lei Li >>>> --- >>>> hmp-commands.hx | 19 ++++++++++++++++++ >>>> hmp.c | 19 ++++++++++++++++++ >>>> hmp.h | 1 + >>>> qapi-schema.json | 27 ++++++++++++++++++++++++++ >>>> qemu-char.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ >>>> qmp-commands.hx | 40 +++++++++++++++++++++++++++++++++++++++ >>>> 6 files changed, 161 insertions(+), 0 deletions(-) >>>> >>>> diff --git a/hmp-commands.hx b/hmp-commands.hx >>>> index a37b8e9..df294eb 100644 >>>> --- a/hmp-commands.hx >>>> +++ b/hmp-commands.hx >>>> @@ -842,6 +842,25 @@ is full/empty, for now just assume a drop behaver in these two commands. >>>> ETEXI >>>> >>>> { >>>> + .name = "memchar_read", >>>> + .args_type = "chardev:s,size:i", >>>> + .params = "chardev size", >>>> + .mhandler.cmd = hmp_memchar_read, >>>> + }, >>>> + >>>> +STEXI >>>> +@item memchar_read @var{chardev} >>>> +@findex memchar_read >>>> +Provide read interface for CirMemCharDriver. Read from cirmemchr >>>> +char device and return @var{size} of 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 082985b..ef85736 100644 >>>> --- a/hmp.c >>>> +++ b/hmp.c >>>> @@ -698,6 +698,25 @@ 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, "chardev"); >>>> + char *data; >>>> + enum DataFormat format; >>> You don't need this variable. >> ok. >> >>>> + Error *errp = NULL; >>>> + >>>> + format = DATA_FORMAT_UTF8; >>>> + data = qmp_memchar_read(chardev, size, true, format, &errp); >>>> + if (errp) { >>>> + monitor_printf(mon, "%s\n", error_get_pretty(errp)); >>>> + error_free(errp); >>>> + return; >>>> + } >>>> + >>>> + monitor_printf(mon, "%s\n", data); >>>> +} >>>> + >>>> static void hmp_cont_cb(void *opaque, int err) >>>> { >>>> if (!err) { >>>> diff --git a/hmp.h b/hmp.h >>>> index 406ebb1..a5a0cfe 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 43ef6bc..a8c9430 100644 >>>> --- a/qapi-schema.json >>>> +++ b/qapi-schema.json >>>> @@ -372,6 +372,33 @@ >>>> '*format': 'DataFormat'} } >>>> >>>> ## >>>> +# @memchar-read: >>>> +# >>>> +# Provide read interface for memchardev. Read from memchar >>>> +# char device and return the data. >>>> +# >>>> +# @chardev: the name of the memchar 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: The data read from memchar as string >>>> +# If @chardev is not a valid memchr device, DeviceNotFound >>>> +# >>>> +# Notes: The option 'block' is not supported now due to the miss >>>> +# feature in qmp. Will add it later when we gain the necessary >>>> +# infrastructure enhancement. For now just assume 'drop' behaver >>>> +# for this command. >>> Please, replace this note with an explanation of the current behavior. No >>> need to talk about the future. >> ok. >> >>>> +# >>>> +# Since: 1.3 >>>> +## >>>> +{ 'command': 'memchar-read', >>>> + 'data': {'chardev': 'str', 'size': 'int', '*format': 'DataFormat'}, >>>> + 'returns': 'str' } >>>> + >>>> +## >>>> # @CommandInfo: >>>> # >>>> # Information about a QMP command >>>> diff --git a/qemu-char.c b/qemu-char.c >>>> index 6114e29..cf88f71 100644 >>>> --- a/qemu-char.c >>>> +++ b/qemu-char.c >>>> @@ -2761,6 +2761,61 @@ void qmp_memchar_write(const char *chardev, int64_t size, >>>> } >>>> } >>>> >>>> +char *qmp_memchar_read(const char *chardev, int64_t size, >>>> + bool has_format, enum DataFormat format, >>>> + Error **errp) >>>> +{ >>>> + CharDriverState *chr; >>>> + guchar *read_data; >>>> + char *data = NULL; >>>> + int ret; >>>> + >>>> + read_data = g_malloc0(size); >>> This is unsafe, as qmp clients could pass any value here. You should check >>> the number of available bytes and allocate only that. >> This size is not the init size of ring buffer, it's the size user want to read >> from the cirmem backend. > Yes, it's a temporary buffer and you allocate the exact value passed > by the user. What if s/he passes 2G? > > My suggestion is to limit it to the amount of bytes available in the > circular buffer. Done. >> And it'll be checked within cirmem_chr_write. > Not sure I get what you mean. > >>>> + >>>> + chr = qemu_chr_find(chardev); >>>> + if (!chr) { >>>> + error_set(errp, QERR_DEVICE_NOT_FOUND, chardev); >>>> + goto fail; >>>> + } >>>> + >>>> + if (strcmp(chr->filename, "memchr") != 0) { >>>> + error_setg(errp,"The %s is not memory char device\n", chardev); >>>> + goto fail; >>>> + } >>> The same comment I made for the write operation applies here. >>> >>>> + >>>> + /* XXX: For the sync command as 'block', waiting for the qmp >>>> + * to support necessary feature. Now just act as 'drop'. */ >>> Here too. >>> >>>> + if (cirmem_chr_is_empty(chr)) { >>>> + error_setg(errp, "Failed to read from memchr %s", chardev); >>>> + goto fail; >>>> + } >>>> + >>>> + if (size == 0) { >>>> + size = CBUFF_SIZE; >>>> + } >>> IMO, you should refuse size=0. >> Do you think it's better to refuse it than giving a default size? > Down QMP yes. OK, done. >>>> + >>>> + ret = cirmem_chr_read(chr, read_data, size); >>>> + >>>> + if (ret < 0) { >>>> + error_setg(errp, "Failed to read from memchr %s", chardev); >>>> + goto fail; >>>> + } >>>> + >>>> + if (has_format && (format == DATA_FORMAT_BASE64)) { >>>> + if (read_data) { >>>> + data = g_base64_encode(read_data, (size_t)size); >>>> + } >>>> + } else { >>>> + data = (char *)read_data; >>>> + } >>>> + >>>> + return data; >>>> + >>>> +fail: >>>> + g_free(read_data); >>>> + return NULL; >>>> +} >>>> + >>>> 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 7548b9b..7729fb0 100644 >>>> --- a/qmp-commands.hx >>>> +++ b/qmp-commands.hx >>>> @@ -500,6 +500,46 @@ Example: >>>> EQMP >>>> >>>> { >>>> + .name = "memchar-read", >>>> + .args_type = "chardev:s,size:i,format:s?", >>>> + .help = "return the size of data from memchar chardev", >>>> + .mhandler.cmd_new = qmp_marshal_input_memchar_read, >>>> + }, >>>> + >>>> +SQMP >>>> +memchar-read >>>> +------------- >>>> + >>>> +Provide read interface for memchardev. Read from memchar >>>> +char device and return the data. >>>> + >>>> +Arguments: >>>> + >>>> +- "chardev": 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": { "chardev": foo, >>>> + "size": 1000, >>>> + "format": "utf8" } } >>>> +<- { "return": "data string..." } >>>> + >>>> +Notes: >>>> + >>>> +We will add 'control' options for read and write command that specifies >>>> +behavior when the queue is full/empty, for now just assume a drop >>>> +behaver in these two commands. >>> Please drop this. >> Sure. >> >>>> + >>>> +EQMP >>>> + >>>> + { >>>> .name = "xen-save-devices-state", >>>> .args_type = "filename:F", >>>> .mhandler.cmd_new = qmp_marshal_input_xen_save_devices_state, >> -- Lei