Re: [Qemu-devel] [PATCH RFC v3 for-2.9 03/11] rbd: Don't limit length of parameter values

[Jeff Cody <jcody@redhat.com>]

On Mon, Mar 27, 2017 at 03:26:27PM +0200, Markus Armbruster wrote:
> We laboriously enforce parameter values are between one and some

s/are/that are/

or maybe just s/are//

> arbitrary limit in length.  Only RBD_MAX_IMAGE_NAME_SIZE comes from
> librbd.h, and I'm not sure it applies.  Where the other limits come
> from is unclear.
> 
> Drop the length checking.  The limits librbd actually imposes must be
> checked by librbd anyway.
> 
> There's one minor complication: BDRVRBDState member name is a
> fixed-size array.  Depends on the length limit.  Make it a pointer to
> a dynamically allocated string.
> 
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> Reviewed-by: Eric Blake <eblake@redhat.com>

Reviewed-by: Jeff Cody <jcody@redhat.com>


> ---
>  block/rbd.c | 91 ++++++++++---------------------------------------------------
>  1 file changed, 14 insertions(+), 77 deletions(-)
> 
> diff --git a/block/rbd.c b/block/rbd.c
> index 5ba2a87..0fea348 100644
> --- a/block/rbd.c
> +++ b/block/rbd.c
> @@ -56,11 +56,6 @@
>  
>  #define OBJ_MAX_SIZE (1UL << OBJ_DEFAULT_OBJ_ORDER)
>  
> -#define RBD_MAX_CONF_NAME_SIZE 128
> -#define RBD_MAX_CONF_VAL_SIZE 512
> -#define RBD_MAX_CONF_SIZE 1024
> -#define RBD_MAX_POOL_NAME_SIZE 128
> -#define RBD_MAX_SNAP_NAME_SIZE 128
>  #define RBD_MAX_SNAPS 100
>  
>  /* The LIBRBD_SUPPORTS_IOVEC is defined in librbd.h */
> @@ -99,16 +94,12 @@ typedef struct BDRVRBDState {
>      rados_t cluster;
>      rados_ioctx_t io_ctx;
>      rbd_image_t image;
> -    char name[RBD_MAX_IMAGE_NAME_SIZE];
> +    char *name;
>      char *snap;
>  } BDRVRBDState;
>  
> -static char *qemu_rbd_next_tok(int max_len,
> -                               char *src, char delim,
> -                               const char *name,
> -                               char **p, Error **errp)
> +static char *qemu_rbd_next_tok(char *src, char delim, char **p)
>  {
> -    int l;
>      char *end;
>  
>      *p = NULL;
> @@ -127,15 +118,6 @@ static char *qemu_rbd_next_tok(int max_len,
>              *end = '\0';
>          }
>      }
> -    l = strlen(src);
> -    if (l >= max_len) {
> -        error_setg(errp, "%s too long", name);
> -        return NULL;
> -    } else if (l == 0) {
> -        error_setg(errp, "%s too short", name);
> -        return NULL;
> -    }
> -
>      return src;
>  }
>  
> @@ -159,7 +141,6 @@ static void qemu_rbd_parse_filename(const char *filename, QDict *options,
>      char *p, *buf, *keypairs;
>      char *found_str;
>      size_t max_keypair_size;
> -    Error *local_err = NULL;
>  
>      if (!strstart(filename, "rbd:", &start)) {
>          error_setg(errp, "File name must start with 'rbd:'");
> @@ -171,11 +152,7 @@ static void qemu_rbd_parse_filename(const char *filename, QDict *options,
>      keypairs = g_malloc0(max_keypair_size);
>      p = buf;
>  
> -    found_str = qemu_rbd_next_tok(RBD_MAX_POOL_NAME_SIZE, p,
> -                                  '/', "pool name", &p, &local_err);
> -    if (local_err) {
> -        goto done;
> -    }
> +    found_str = qemu_rbd_next_tok(p, '/', &p);
>      if (!p) {
>          error_setg(errp, "Pool name is required");
>          goto done;
> @@ -184,27 +161,15 @@ static void qemu_rbd_parse_filename(const char *filename, QDict *options,
>      qdict_put(options, "pool", qstring_from_str(found_str));
>  
>      if (strchr(p, '@')) {
> -        found_str = qemu_rbd_next_tok(RBD_MAX_IMAGE_NAME_SIZE, p,
> -                                      '@', "object name", &p, &local_err);
> -        if (local_err) {
> -            goto done;
> -        }
> +        found_str = qemu_rbd_next_tok(p, '@', &p);
>          qemu_rbd_unescape(found_str);
>          qdict_put(options, "image", qstring_from_str(found_str));
>  
> -        found_str = qemu_rbd_next_tok(RBD_MAX_SNAP_NAME_SIZE, p,
> -                                      ':', "snap name", &p, &local_err);
> -        if (local_err) {
> -            goto done;
> -        }
> +        found_str = qemu_rbd_next_tok(p, ':', &p);
>          qemu_rbd_unescape(found_str);
>          qdict_put(options, "snapshot", qstring_from_str(found_str));
>      } else {
> -        found_str = qemu_rbd_next_tok(RBD_MAX_IMAGE_NAME_SIZE, p,
> -                                      ':', "object name", &p, &local_err);
> -        if (local_err) {
> -            goto done;
> -        }
> +        found_str = qemu_rbd_next_tok(p, ':', &p);
>          qemu_rbd_unescape(found_str);
>          qdict_put(options, "image", qstring_from_str(found_str));
>      }
> @@ -212,11 +177,7 @@ static void qemu_rbd_parse_filename(const char *filename, QDict *options,
>          goto done;
>      }
>  
> -    found_str = qemu_rbd_next_tok(RBD_MAX_CONF_NAME_SIZE, p,
> -                                  '\0', "configuration", &p, &local_err);
> -    if (local_err) {
> -        goto done;
> -    }
> +    found_str = qemu_rbd_next_tok(p, '\0', &p);
>  
>      p = found_str;
>  
> @@ -224,12 +185,7 @@ static void qemu_rbd_parse_filename(const char *filename, QDict *options,
>       * 'id' and 'conf' a bit special.  Key/value pairs may be in any order. */
>      while (p) {
>          char *name, *value;
> -        name = qemu_rbd_next_tok(RBD_MAX_CONF_NAME_SIZE, p,
> -                                 '=', "conf option name", &p, &local_err);
> -        if (local_err) {
> -            break;
> -        }
> -
> +        name = qemu_rbd_next_tok(p, '=', &p);
>          if (!p) {
>              error_setg(errp, "conf option %s has no value", name);
>              break;
> @@ -237,11 +193,7 @@ static void qemu_rbd_parse_filename(const char *filename, QDict *options,
>  
>          qemu_rbd_unescape(name);
>  
> -        value = qemu_rbd_next_tok(RBD_MAX_CONF_VAL_SIZE, p,
> -                                  ':', "conf option value", &p, &local_err);
> -        if (local_err) {
> -            break;
> -        }
> +        value = qemu_rbd_next_tok(p, ':', &p);
>          qemu_rbd_unescape(value);
>  
>          if (!strcmp(name, "conf")) {
> @@ -274,9 +226,6 @@ static void qemu_rbd_parse_filename(const char *filename, QDict *options,
>  
>  
>  done:
> -    if (local_err) {
> -        error_propagate(errp, local_err);
> -    }
>      g_free(buf);
>      g_free(keypairs);
>      return;
> @@ -308,30 +257,20 @@ static int qemu_rbd_set_keypairs(rados_t cluster, const char *keypairs,
>      char *p, *buf;
>      char *name;
>      char *value;
> -    Error *local_err = NULL;
>      int ret = 0;
>  
>      buf = g_strdup(keypairs);
>      p = buf;
>  
>      while (p) {
> -        name = qemu_rbd_next_tok(RBD_MAX_CONF_NAME_SIZE, p,
> -                                 '=', "conf option name", &p, &local_err);
> -        if (local_err) {
> -            break;
> -        }
> -
> +        name = qemu_rbd_next_tok(p, '=', &p);
>          if (!p) {
>              error_setg(errp, "conf option %s has no value", name);
>              ret = -EINVAL;
>              break;
>          }
>  
> -        value = qemu_rbd_next_tok(RBD_MAX_CONF_VAL_SIZE, p,
> -                                  ':', "conf option value", &p, &local_err);
> -        if (local_err) {
> -            break;
> -        }
> +        value = qemu_rbd_next_tok(p, ':', &p);
>  
>          ret = rados_conf_set(cluster, name, value);
>          if (ret < 0) {
> @@ -341,10 +280,6 @@ static int qemu_rbd_set_keypairs(rados_t cluster, const char *keypairs,
>          }
>      }
>  
> -    if (local_err) {
> -        error_propagate(errp, local_err);
> -        ret = -EINVAL;
> -    }
>      g_free(buf);
>      return ret;
>  }
> @@ -724,7 +659,7 @@ static int qemu_rbd_open(BlockDriverState *bs, QDict *options, int flags,
>      }
>  
>      s->snap = g_strdup(snap);
> -    pstrcpy(s->name, RBD_MAX_IMAGE_NAME_SIZE, name);
> +    s->name = g_strdup(name);
>  
>      /* try default location when conf=NULL, but ignore failure */
>      r = rados_conf_read_file(s->cluster, conf);
> @@ -798,6 +733,7 @@ failed_open:
>  failed_shutdown:
>      rados_shutdown(s->cluster);
>      g_free(s->snap);
> +    g_free(s->name);
>  failed_opts:
>      qemu_opts_del(opts);
>      g_free(mon_host);
> @@ -812,6 +748,7 @@ static void qemu_rbd_close(BlockDriverState *bs)
>      rbd_close(s->image);
>      rados_ioctx_destroy(s->io_ctx);
>      g_free(s->snap);
> +    g_free(s->name);
>      rados_shutdown(s->cluster);
>  }
>  
> -- 
> 2.7.4
>