Re: [PATCH v2 11/13] tools: split up xen-init-dom0.c

[Ian Campbell <ian.campbell@citrix.com>]

On Fri, 2015-12-18 at 14:14 +0100, Juergen Gross wrote:
> Split up tools/helpers/xen-init-dom0.c in order to prepare reusing
> generation of the json configuration by init-xenstore-domain.c.
> 
> Signed-off-by: Juergen Gross <jgross@suse.com>

Wei, was there a reason for using atexit() to free the handles which I'm
not seeing? IOW I think there is a single exit path which could have done
all that today, so Juergen is OK to change it in this way.

Ian.


> ---
>  tools/helpers/Makefile        |  2 +-
>  tools/helpers/init-dom-json.c | 59 ++++++++++++++++++++++++++++++++++
>  tools/helpers/init-dom-json.h | 18 +++++++++++
>  tools/helpers/xen-init-dom0.c | 73 ++++++-------------------------------
> ------
>  4 files changed, 88 insertions(+), 64 deletions(-)
>  create mode 100644 tools/helpers/init-dom-json.c
>  create mode 100644 tools/helpers/init-dom-json.h
> 
> diff --git a/tools/helpers/Makefile b/tools/helpers/Makefile
> index 92aead4..cfb86f5 100644
> --- a/tools/helpers/Makefile
> +++ b/tools/helpers/Makefile
> @@ -10,7 +10,7 @@ ifeq ($(CONFIG_Linux),y)
>  PROGS += init-xenstore-domain
>  endif
>  
> -XEN_INIT_DOM0_OBJS = xen-init-dom0.o
> +XEN_INIT_DOM0_OBJS = xen-init-dom0.o init-dom-json.o
>  $(XEN_INIT_DOM0_OBJS): CFLAGS += $(CFLAGS_libxenctrl)
>  $(XEN_INIT_DOM0_OBJS): CFLAGS += $(CFLAGS_libxenstore)
>  $(XEN_INIT_DOM0_OBJS): CFLAGS += $(CFLAGS_libxenlight)
> diff --git a/tools/helpers/init-dom-json.c b/tools/helpers/init-dom-
> json.c
> new file mode 100644
> index 0000000..91b1fdf
> --- /dev/null
> +++ b/tools/helpers/init-dom-json.c
> @@ -0,0 +1,59 @@
> +#include <err.h>
> +#include <stdlib.h>
> +#include <stdint.h>
> +#include <string.h>
> +#include <stdio.h>
> +
> +#include <xenctrl.h>
> +#include <libxl.h>
> +
> +int gen_stub_json_config(uint32_t domid)
> +{
> +    int rc = 1;
> +    xentoollog_logger_stdiostream *logger;
> +    libxl_ctx *ctx;
> +    libxl_domain_config dom_config;
> +    char *json = NULL;
> +
> +    logger = xtl_createlogger_stdiostream(stderr, XTL_ERROR, 0);
> +    if (!logger)
> +        return 1;
> +
> +    if (libxl_ctx_alloc(&ctx, LIBXL_VERSION, 0,
> +                        (xentoollog_logger *)logger)) {
> +        fprintf(stderr, "cannot init libxl context\n");
> +        goto outlog;
> +    }
> +
> +    libxl_domain_config_init(&dom_config);
> +
> +    /* Generate stub JSON config. */
> +    dom_config.c_info.type = LIBXL_DOMAIN_TYPE_PV;
> +    libxl_domain_build_info_init_type(&dom_config.b_info,
> +                                      LIBXL_DOMAIN_TYPE_PV);
> +
> +    json = libxl_domain_config_to_json(ctx, &dom_config);
> +    /* libxl-json format requires the string ends with '\0'. Code
> +     * snippet taken from libxl.
> +     */
> +    rc = libxl_userdata_store(ctx, domid, "libxl-json",
> +                              (const uint8_t *)json,
> +                              strlen(json) + 1 /* include '\0' */);
> +    if (rc)
> +        fprintf(stderr, "cannot store stub json config for domain %u\n",
> domid);
> +
> +    libxl_domain_config_dispose(&dom_config);
> +    free(json);
> +    libxl_ctx_free(ctx);
> +outlog:
> +    xtl_logger_destroy((xentoollog_logger *)logger);
> +    return rc;
> +}
> +
> +/*
> + * Local variables:
> + * mode: C
> + * c-basic-offset: 4
> + * indent-tabs-mode: nil
> + * End:
> + */
> diff --git a/tools/helpers/init-dom-json.h b/tools/helpers/init-dom-
> json.h
> new file mode 100644
> index 0000000..58c85df
> --- /dev/null
> +++ b/tools/helpers/init-dom-json.h
> @@ -0,0 +1,18 @@
> +#ifndef __INIT_DOM_JSON_H
> +#define __INIT_DOM_JSON_H
> +
> +/*
> + * Generate a stub JSON config for a domain with the given domid.
> + */
> +int gen_stub_json_config(uint32_t domid);
> +
> +#endif
> +/*
> + * Local variables:
> + * mode: C
> + * c-file-style: "BSD"
> + * c-basic-offset: 4
> + * tab-width: 4
> + * indent-tabs-mode: nil
> + * End:
> + */
> diff --git a/tools/helpers/xen-init-dom0.c b/tools/helpers/xen-init-
> dom0.c
> index 7925d64..9ab8468 100644
> --- a/tools/helpers/xen-init-dom0.c
> +++ b/tools/helpers/xen-init-dom0.c
> @@ -1,65 +1,26 @@
> -#include <err.h>
>  #include <stdlib.h>
>  #include <stdint.h>
>  #include <string.h>
>  #include <stdio.h>
>  
> -#include <xenctrl.h>
>  #include <xenstore.h>
> -#include <libxl.h>
> +
> +#include "init-dom-json.h"
>  
>  #define DOMNAME_PATH   "/local/domain/0/name"
>  #define DOMID_PATH     "/local/domain/0/domid"
>  
> -static libxl_ctx *ctx;
> -static xentoollog_logger_stdiostream *logger;
> -static struct xs_handle *xsh;
> -
> -static void ctx_alloc(void)
> +int main(int argc, char **argv)
>  {
> -    if (libxl_ctx_alloc(&ctx, LIBXL_VERSION, 0,
> -                        (xentoollog_logger *)logger)) {
> -        fprintf(stderr, "cannot init libxl context\n");
> -        exit(1);
> -    }
> +    int rc;
> +    struct xs_handle *xsh;
> +    char *domname_string = NULL, *domid_string = NULL;
> +
>      xsh = xs_open(0);
>      if (!xsh) {
>          fprintf(stderr, "cannot open xenstore connection\n");
>          exit(1);
>      }
> -}
> -
> -static void ctx_free(void)
> -{
> -    if (ctx) {
> -        libxl_ctx_free(ctx);
> -        ctx = NULL;
> -    }
> -    if (logger) {
> -        xtl_logger_destroy((xentoollog_logger *)logger);
> -        logger = NULL;
> -    }
> -    if (xsh) {
> -        xs_close(xsh);
> -        xsh = NULL;
> -    }
> -}
> -
> -int main(int argc, char **argv)
> -{
> -    int rc;
> -    libxl_domain_config dom0_config;
> -    char *domname_string = NULL, *domid_string = NULL;
> -    char *json = NULL;;
> -
> -    logger = xtl_createlogger_stdiostream(stderr, XTL_ERROR, 0);
> -    if (!logger) exit(1);
> -
> -    atexit(ctx_free);
> -
> -    ctx_alloc();
> -
> -    libxl_domain_config_init(&dom0_config);
>  
>      /* Sanity check: this program can only be run once. */
>      domid_string = xs_read(xsh, XBT_NULL, DOMID_PATH, NULL);
> @@ -70,22 +31,9 @@ int main(int argc, char **argv)
>          goto out;
>      }
>  
> -    /* Generate stub JSON config. */
> -    dom0_config.c_info.type = LIBXL_DOMAIN_TYPE_PV;
> -    libxl_domain_build_info_init_type(&dom0_config.b_info,
> -                                      LIBXL_DOMAIN_TYPE_PV);
> -
> -    json = libxl_domain_config_to_json(ctx, &dom0_config);
> -    /* libxl-json format requires the string ends with '\0'. Code
> -     * snippet taken from libxl.
> -     */
> -    rc = libxl_userdata_store(ctx, 0, "libxl-json",
> -                              (const uint8_t *)json,
> -                              strlen(json) + 1 /* include '\0' */);
> -    if (rc) {
> -        fprintf(stderr, "cannot store stub json config for Dom0\n");
> +    rc = gen_stub_json_config(0);
> +    if (rc)
>          goto out;
> -    }
>  
>      /* Write xenstore entries. */
>      if (!xs_write(xsh, XBT_NULL, DOMID_PATH, "0", strlen("0"))) {
> @@ -104,10 +52,9 @@ int main(int argc, char **argv)
>      printf("Done setting up Dom0\n");
>  
>  out:
> -    libxl_domain_config_dispose(&dom0_config);
>      free(domid_string);
>      free(domname_string);
> -    free(json);
> +    xs_close(xsh);
>      return rc;
>  }
>  
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