Re: [PATCH v6 for-4.5 5/5] xl: add support for 'channels'

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Wed, Sep 24, 2014 at 09:48:05PM +0100, David Scott wrote:
> This adds support for channel declarations of the form:
> 
>  channel = [ "name=...,connection=...[,path=...][,backend=...]" ]
> 
> where 'name' is a label to identify the channel to the frontend.
> 
> If 'connection = pty' then the channel is connected to a pty in the
>  backend domain
> If 'connection = socket' then the channel is connected to a Unix domain
>  socket given by 'path = ...' in the backend domain.
> 
> This patch also adds the command:
> 
>  xl channel-list <domain>
> 
> which allows the state of channels to be queried. In particular if
> 'connection=pty' this will show the path of the pty slave device.
> 
> Signed-off-by: David Scott <dave.scott@citrix.com>
> ---
>  docs/man/xl.cfg.pod.5     |   53 +++++++++++++++++++
>  docs/man/xl.pod.1         |   10 ++++
>  tools/libxl/xl.h          |    1 +
>  tools/libxl/xl_cmdimpl.c  |  129 ++++++++++++++++++++++++++++++++++++++++++---
>  tools/libxl/xl_cmdtable.c |    5 ++
>  5 files changed, 190 insertions(+), 8 deletions(-)
> 
> diff --git a/docs/man/xl.cfg.pod.5 b/docs/man/xl.cfg.pod.5
> index 517ae2f..6626323 100644
> --- a/docs/man/xl.cfg.pod.5
> +++ b/docs/man/xl.cfg.pod.5
> @@ -530,6 +530,59 @@ L<qemu(1)> manpage. The default is B<en-us>.
>  
>  =back
>  
> +=item B<channel=[ "CHANNEL_SPEC_STRING", "CHANNEL_SPEC_STRING", ...]>
> +
> +Specifies the virtual channels to be provided to the guest. A
> +channel is a low-bandwidth, bidirectional byte stream, which resembles
> +a serial link. Typical uses for channels include transmitting VM
> +configuration after boot and signalling to in-guest agents. Please see
> +F<docs/misc/channels.txt> for more details.
> +
> +Each B<CHANNEL_SPEC_STRING> is a comma-separated list of C<KEY=VALUE>
> +seettings. Leading and trailing whitespace is ignored in both KEY and
> +VALUE. Neither KEY nor VALUE may contain ',', '=' or '"'. Defined values
> +are:
> +
> +=over 4
> +
> +=item C<backend=DOMAIN>
> +
> +Specify the backend domain name or id. This parameter is optional. If
> +this parameter is omitted then the toolstack domain will be assumed.
> +
> +=item C<name=NAME>
> +
> +Specify the string name for this device. This parameter is mandatory.
> +This should be a well-known name for the specific application (e.g.
> +guest agent) and should be used by the frontend to connect the
> +application to the right channel device. There is no formal registry
> +of channel names, so application authors are encouraged to make their
> +names unique by including domain name and version number in the string
> +(e.g. org.mydomain.guestagent.1).
> +
> +=item C<connection=CONNECTION>
> +
> +Specify how the backend will be implemented. This following options are
> +available:
> +
> +=over 4
> +
> +=item B<connection=SOCKET>:
> +
> +The backend will bind a Unix domain socket (at the path given by
> +B<path=PATH>), call listen and accept connections. The backend will proxy
> +data between the channel and the connected socket.
> +
> +=item B<connection=PTY>:
> +
> +The backend will create a pty and proxy data between the channel and the
> +master device. The command B<xl channel-list> can be used to discover the
> +assigned slave device.
> +
> +=back
> +
> +=back
> +
>  =item B<pci=[ "PCI_SPEC_STRING", "PCI_SPEC_STRING", ... ]>
>  
>  Specifies the host PCI devices to passthrough to this guest. Each B<PCI_SPEC_STRING>
> diff --git a/docs/man/xl.pod.1 b/docs/man/xl.pod.1
> index f1e95db..35aa3a4 100644
> --- a/docs/man/xl.pod.1
> +++ b/docs/man/xl.pod.1
> @@ -1215,6 +1215,16 @@ List virtual network interfaces for a domain.
>  
>  =back
>  
> +=head2 CHANNEL DEVICES
> +
> +=over 4
> +
> +=item B<channel-list> I<domain-id>
> +
> +List virtual channel interfaces for a domain.
> +
> +=back
> +
>  =head2 VTPM DEVICES
>  
>  =over 4
> diff --git a/tools/libxl/xl.h b/tools/libxl/xl.h
> index 10a2e66..afc5f8b 100644
> --- a/tools/libxl/xl.h
> +++ b/tools/libxl/xl.h
> @@ -78,6 +78,7 @@ int main_top(int argc, char **argv);
>  int main_networkattach(int argc, char **argv);
>  int main_networklist(int argc, char **argv);
>  int main_networkdetach(int argc, char **argv);
> +int main_channellist(int argc, char **argv);
>  int main_blockattach(int argc, char **argv);
>  int main_blocklist(int argc, char **argv);
>  int main_blockdetach(int argc, char **argv);
> diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
> index d6f311f..89a8697 100644
> --- a/tools/libxl/xl_cmdimpl.c
> +++ b/tools/libxl/xl_cmdimpl.c
> @@ -530,7 +530,7 @@ static void split_string_into_string_list(const char *str,
>  
>      s = strdup(str);
>      if (s == NULL) {
> -        fprintf(stderr, "unable to allocate memory to parse bootloader args\n");
> +        fprintf(stderr, "unable to allocate memory to split string\n");
>          exit(-1);
>      }
>  
> @@ -546,7 +546,7 @@ static void split_string_into_string_list(const char *str,
>  
>      sl = malloc((nr+1) * sizeof (char *));
>      if (sl == NULL) {
> -        fprintf(stderr, "unable to allocate memory for bootloader args\n");
> +        fprintf(stderr, "unable to allocate memory to split string\n");
>          exit(-1);
>      }
>  
> @@ -567,7 +567,6 @@ static void split_string_into_string_list(const char *str,
>     and look for CTYPE in libxl_internal.h */
>  typedef int (*char_predicate_t)(const int c);
>  
> -static void trim(char_predicate_t predicate, const char *input, char **output) __attribute__ ((unused));
>  static void trim(char_predicate_t predicate, const char *input, char **output)
>  {
>      char *p, *q, *tmp;
> @@ -593,10 +592,6 @@ static void trim(char_predicate_t predicate, const char *input, char **output)
>  static int split_string_into_pair(const char *str,
>                                    const char *delim,
>                                    char **a,
> -                                  char **b) __attribute__ ((unused));
> -static int split_string_into_pair(const char *str,
> -                                  const char *delim,
> -                                  char **a,
>                                    char **b)
>  {
>      char *s, *p, *saveptr, *aa = NULL, *bb = NULL;
> @@ -891,7 +886,7 @@ static void parse_config_data(const char *config_source,
>      long l;
>      XLU_Config *config;
>      XLU_ConfigList *cpus, *vbds, *nics, *pcis, *cvfbs, *cpuids, *vtpms;
> -    XLU_ConfigList *ioports, *irqs, *iomem;
> +    XLU_ConfigList *channels, *ioports, *irqs, *iomem;
>      int num_ioports, num_irqs, num_iomem, num_cpus;
>      int pci_power_mgmt = 0;
>      int pci_msitranslate = 0;
> @@ -1376,6 +1371,79 @@ static void parse_config_data(const char *config_source,
>          }
>      }
>  
> +    if (!xlu_cfg_get_list (config, "channel", &channels, 0, 0)) {
> +        d_config->num_channels = 0;
> +        d_config->channels = NULL;
> +        while ((buf = xlu_cfg_get_listitem (channels,
> +                d_config->num_channels)) != NULL) {
> +            libxl_device_channel *chn;
> +            libxl_string_list pairs;
> +            char *path = NULL;
> +            int len;
> +
> +            chn = ARRAY_EXTEND_INIT(d_config->channels, d_config->num_channels,
> +                                   libxl_device_channel_init);
> +
> +            split_string_into_string_list(buf, ",", &pairs);
> +            len = libxl_string_list_length(&pairs);
> +            for (i = 0; i < len; i++) {
> +                char *key, *key_untrimmed, *value, *value_untrimmed;
> +                int rc;
> +                rc = split_string_into_pair(pairs[i], "=",
> +                                            &key_untrimmed,
> +                                            &value_untrimmed);
> +                if (rc != 0) {
> +                    fprintf(stderr, "failed to parse channel configuration: %s",
> +                            pairs[i]);
> +                    exit(1);
> +                }
> +                trim(isspace, key_untrimmed, &key);
> +                trim(isspace, value_untrimmed, &value);
> +
> +                if (!strcmp(key, "backend")) {
> +                    replace_string(&chn->backend_domname, value);
> +                } else if (!strcmp(key, "name")) {
> +                    replace_string(&chn->name, value);
> +                } else if (!strcmp(key, "path")) {
> +                    replace_string(&path, value);
> +                } else if (!strcmp(key, "connection")) {
> +                    if (!strcmp(value, "pty")) {
> +                        chn->connection = LIBXL_CHANNEL_CONNECTION_PTY;
> +                    } else if (!strcmp(value, "socket")) {
> +                        chn->connection = LIBXL_CHANNEL_CONNECTION_SOCKET;
> +                    } else {
> +                        fprintf(stderr, "unknown channel connection '%s'\n",
> +                                value);
> +                        exit(1);
> +                    }
> +                } else {
> +                    fprintf(stderr, "unknown channel parameter '%s',"
> +                                  " ignoring\n", key);
> +                }
> +                free(key);
> +                free(key_untrimmed);
> +                free(value);
> +                free(value_untrimmed);
> +            }
> +            switch (chn->connection){

Your editor ate a space.

> +            case LIBXL_CHANNEL_CONNECTION_UNKNOWN:
> +                fprintf(stderr, "channel has unknown 'connection'\n");
> +                exit(1);
> +            case LIBXL_CHANNEL_CONNECTION_SOCKET:
> +                if (!path) {
> +                    fprintf(stderr, "channel connection 'socket' requires path=..\n");
> +                    exit(1);
> +                }
> +                chn->u.socket.path = xstrdup(path);
> +                break;
> +            default:
> +                break;
> +            }
> +            libxl_string_list_dispose(&pairs);
> +            free(path);
> +        }
> +    }
> +
>      if (!xlu_cfg_get_list (config, "vif", &nics, 0, 0)) {
>          d_config->num_nics = 0;
>          d_config->nics = NULL;
> @@ -6045,6 +6113,51 @@ int main_networkdetach(int argc, char **argv)
>      return 0;
>  }
>  
> +int main_channellist(int argc, char **argv)
> +{
> +    int opt;
> +    libxl_device_channel *channels;
> +    libxl_channelinfo channelinfo;
> +    int nb, i;
> +
> +    SWITCH_FOREACH_OPT(opt, "", NULL, "channel-list", 1) {
> +        /* No options */
> +    }
> +
> +    /*      Idx BE state evt-ch ring-ref connection params*/
> +    printf("%-3s %-2s %-5s %-6s %8s %-10s %-30s\n",
> +           "Idx", "BE", "state", "evt-ch", "ring-ref", "connection", "");
> +    for (argv += optind, argc -= optind; argc > 0; --argc, ++argv) {
> +        uint32_t domid = find_domain(*argv);
> +        channels = libxl_device_channel_list(ctx, domid, &nb);
> +        if (!channels) {
> +            continue;
> +        }

I think you can drop the '{}'.

> +        for (i = 0; i < nb; ++i) {
> +            if (!libxl_device_channel_getinfo(ctx, domid, &channels[i],
> +                &channelinfo)) {
> +                printf("%-3d %-2d ", channels[i].devid, channelinfo.backend_id);
> +                printf("%-5d ", channelinfo.state);
> +                printf("%-6d %-8d ", channelinfo.evtch, channelinfo.rref);
> +                printf("%-10s ", libxl_channel_connection_to_string(
> +                       channels[i].connection));
> +                switch (channels[i].connection) {
> +                    case LIBXL_CHANNEL_CONNECTION_PTY:
> +                        printf("%-30s ", channelinfo.u.pty.path);
> +                        break;
> +                    default:
> +                        break;
> +                }
> +                printf("\n");
> +                libxl_channelinfo_dispose(&channelinfo);
> +            }
> +            libxl_device_channel_dispose(&channels[i]);
> +        }
> +        free(channels);
> +    }
> +    return 0;
> +}
> +
>  int main_blockattach(int argc, char **argv)
>  {
>      int opt;
> diff --git a/tools/libxl/xl_cmdtable.c b/tools/libxl/xl_cmdtable.c
> index 35f02c4..a6df234 100644
> --- a/tools/libxl/xl_cmdtable.c
> +++ b/tools/libxl/xl_cmdtable.c
> @@ -337,6 +337,11 @@ struct cmd_spec cmd_table[] = {
>        "Destroy a domain's virtual network device",
>        "<Domain> <DevId|mac>",
>      },
> +    { "channel-list",
> +      &main_channellist, 0, 0,
> +      "List virtual channel devices for a domain",
> +      "<Domain(s)>",
> +    },
>      { "block-attach",
>        &main_blockattach, 1, 1,
>        "Create a new virtual block device",
> -- 
> 1.7.10.4
> 
> 
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