[PATCH 0/2] libxl: FreeBSD related fixes

[PATCH 0/2] libxl: FreeBSD related fixes

[Roger Pau Monne]

Hello,

This series contains a couple of small fixes for FreeBSD. The first one is 
regarding the newly introduced libxl__dm_runas_helper function and it's 
usage of sysconf, while the second one fixes a long-stading bug that impacts 
UUID usage on FreeBSD [0] (and NetBSD AFAICT).

Thanks, Roger.

[0] https://lists.freebsd.org/pipermail/freebsd-xen/2015-December/002608.html

[PATCH v2 1/2] libxl: fix _SC_GETPW_R_SIZE_MAX usage

[Roger Pau Monne]

If sysconf(_SC_GETPW_R_SIZE_MAX) fails for any reason just use an initial
buffer size of 2048. This is not a critical failure, and the code that
makes use of this buffer is able to expand it later if required.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
---
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
---
Changes since v1:
 - Use a default buffer size if sysconf(_SC_GETPW_R_SIZE_MAX) fails for any
   reason, this should not be a critical failure.
---
 tools/libxl/libxl_dm.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c
index 0aaefd9..a088d71 100644
--- a/tools/libxl/libxl_dm.c
+++ b/tools/libxl/libxl_dm.c
@@ -730,9 +730,10 @@ static int libxl__dm_runas_helper(libxl__gc *gc, const char *username)
 
     buf_size = sysconf(_SC_GETPW_R_SIZE_MAX);
     if (buf_size < 0) {
-        LOGE(ERROR, "sysconf(_SC_GETPW_R_SIZE_MAX) returned error %ld",
-                buf_size);
-        return ERROR_FAIL;
+        buf_size = 2048;
+        LOG(DEBUG,
+"sysconf(_SC_GETPW_R_SIZE_MAX) failed, setting the initial buffer size to %ld",
+            buf_size);
     }
 
     while (1) {
-- 
1.9.5 (Apple Git-50.3)


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[PATCH v2 2/2] libxl: fix UUID usage on FreeBSD

[Roger Pau Monne]

libxl makes the assumtion that libxl_uuid == uuid_t, and that uuid_t can be
freely used as a byte array. This is not true on FreeBSD (and NetBSD
too, not sure about other BSD UUID implementations), where the internals of
uuid don't match what libxl expects as a byte array because of endianness
issues.

Fix this by converting the libxl_uuid type to a struct with an internal
uuid_t field and a byte-array. Also introduce a new function that should be
used in order to load a byte array into a uuid_t struct.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
---
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
---
 tools/libxl/libxl.c      |  2 +-
 tools/libxl/libxl.h      |  9 +++++++++
 tools/libxl/libxl_uuid.c | 22 +++++++++++++++++++---
 tools/libxl/libxl_uuid.h |  3 ++-
 4 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index 9207621..ae08b2f 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -616,7 +616,7 @@ static void xcinfo2xlinfo(libxl_ctx *ctx,
 {
     size_t size;
 
-    memcpy(&(xlinfo->uuid), xcinfo->handle, sizeof(xen_domain_handle_t));
+    libxl_uuid_from_bytearray(&xlinfo->uuid, xcinfo->handle);
     xlinfo->domid = xcinfo->domain;
     xlinfo->ssidref = xcinfo->ssidref;
     if (libxl_flask_sid_to_context(ctx, xlinfo->ssidref,
diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h
index 05606a7..876fca8 100644
--- a/tools/libxl/libxl.h
+++ b/tools/libxl/libxl.h
@@ -867,6 +867,15 @@ void libxl_mac_copy(libxl_ctx *ctx, libxl_mac *dst, libxl_mac *src);
  */
 #define LIBXL_HAVE_DEVICE_MODEL_VERSION_NONE 1
 
+/*
+ * LIBXL_HAVE_UUID_FROM_BYTEARRAY
+ *
+ * In the case that LIBXL_HAVE_UUID_FROM_BYTEARRAY is set libxl
+ * provides a function (libxl_uuid_from_bytearray) to convert an
+ * octet stream into a UUID.
+ */
+#define LIBXL_HAVE_UUID_FROM_BYTEARRAY 1
+
 typedef char **libxl_string_list;
 void libxl_string_list_dispose(libxl_string_list *sl);
 int libxl_string_list_length(const libxl_string_list *sl);
diff --git a/tools/libxl/libxl_uuid.c b/tools/libxl/libxl_uuid.c
index 7d4a032..f566f50 100644
--- a/tools/libxl/libxl_uuid.c
+++ b/tools/libxl/libxl_uuid.c
@@ -33,6 +33,12 @@ int libxl_uuid_from_string(libxl_uuid *uuid, const char *in)
      return uuid_parse(in, uuid->uuid);
 }
 
+int libxl_uuid_from_bytearray(libxl_uuid *uuid, const uint8_t *raw)
+{
+    memcpy(uuid, raw, sizeof(*uuid));
+    return 0;
+}
+
 void libxl_uuid_copy(libxl_ctx *ctx_opt, libxl_uuid *dst,
                      const libxl_uuid *src)
 {
@@ -72,9 +78,9 @@ void libxl_uuid_generate(libxl_uuid *uuid)
 {
     uint32_t status;
 
-    BUILD_BUG_ON(sizeof(libxl_uuid) != sizeof(uuid_t));
     uuid_create(&uuid->uuid, &status);
     assert(status == uuid_s_ok);
+    uuid_enc_be(uuid->uuid_raw, &uuid->uuid);
 }
 
 #ifdef __FreeBSD__
@@ -85,6 +91,8 @@ int libxl_uuid_from_string(libxl_uuid *uuid, const char *in)
     uuid_from_string(in, &uuid->uuid, &status);
     if (status != uuid_s_ok)
         return -1;
+    uuid_enc_be(uuid->uuid_raw, &uuid->uuid);
+
     return 0;
 }
 #else
@@ -101,15 +109,23 @@ int libxl_uuid_from_string(libxl_uuid *uuid, const char *in)
 #undef LIBXL__UUID_PTRS
 #endif
 
+int libxl_uuid_from_bytearray(libxl_uuid *uuid, const uint8_t *raw)
+{
+    uuid_dec_le(raw, &uuid->uuid);
+    uuid_enc_be(uuid->uuid_raw, &uuid->uuid);
+
+    return 0;
+}
+
 void libxl_uuid_copy(libxl_ctx *ctx_opt, libxl_uuid *dst,
                      const libxl_uuid *src)
 {
-    memcpy(&dst->uuid, &src->uuid, sizeof(dst->uuid));
+    memcpy(dst, src, sizeof(*dst));
 }
 
 void libxl_uuid_clear(libxl_uuid *uuid)
 {
-    memset(&uuid->uuid, 0, sizeof(uuid->uuid));
+    memset(uuid, 0, sizeof(*uuid));
 }
 
 #ifdef __FreeBSD__
diff --git a/tools/libxl/libxl_uuid.h b/tools/libxl/libxl_uuid.h
index c5041c7..d84e3d1 100644
--- a/tools/libxl/libxl_uuid.h
+++ b/tools/libxl/libxl_uuid.h
@@ -42,7 +42,7 @@ typedef struct {
 #include <stdio.h>
 #include <assert.h>
 
-typedef union {
+typedef struct {
     uuid_t uuid;
     uint8_t uuid_raw[16];
 } libxl_uuid;
@@ -73,6 +73,7 @@ void libxl_uuid_clear(libxl_uuid *uuid);
 int libxl_uuid_compare(const libxl_uuid *uuid1, const libxl_uuid *uuid2);
 const uint8_t *libxl_uuid_bytearray_const(const libxl_uuid *uuid);
 uint8_t *libxl_uuid_bytearray(libxl_uuid *uuid);
+int libxl_uuid_from_bytearray(libxl_uuid *uuid, const uint8_t *raw);
 
 #endif /* __LIBXL_UUID_H__ */
 
-- 
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Re: [PATCH v2 1/2] libxl: fix _SC_GETPW_R_SIZE_MAX usage

[Doug Goldstein]

[-- Attachment #1.1: Type: text/plain, Size: 1561 bytes --]

On 1/14/16 9:06 AM, Roger Pau Monne wrote:
> If sysconf(_SC_GETPW_R_SIZE_MAX) fails for any reason just use an initial
> buffer size of 2048. This is not a critical failure, and the code that
> makes use of this buffer is able to expand it later if required.
> 
> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
> ---
> Cc: Ian Jackson <ian.jackson@eu.citrix.com>
> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> Cc: Ian Campbell <ian.campbell@citrix.com>
> Cc: Wei Liu <wei.liu2@citrix.com>
> ---
> Changes since v1:
>  - Use a default buffer size if sysconf(_SC_GETPW_R_SIZE_MAX) fails for any
>    reason, this should not be a critical failure.
> ---
>  tools/libxl/libxl_dm.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c
> index 0aaefd9..a088d71 100644
> --- a/tools/libxl/libxl_dm.c
> +++ b/tools/libxl/libxl_dm.c
> @@ -730,9 +730,10 @@ static int libxl__dm_runas_helper(libxl__gc *gc, const char *username)
>  
>      buf_size = sysconf(_SC_GETPW_R_SIZE_MAX);
>      if (buf_size < 0) {
> -        LOGE(ERROR, "sysconf(_SC_GETPW_R_SIZE_MAX) returned error %ld",
> -                buf_size);
> -        return ERROR_FAIL;
> +        buf_size = 2048;
> +        LOG(DEBUG,
> +"sysconf(_SC_GETPW_R_SIZE_MAX) failed, setting the initial buffer size to %ld",
> +            buf_size);
>      }
>  
>      while (1) {
> 

Looks sane to me.

Reviewed-by: Doug Goldstein <cardoe@cardoe.com>

-- 
Doug Goldstein


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Re: [PATCH v2 1/2] libxl: fix _SC_GETPW_R_SIZE_MAX usage

[Ian Campbell]

On Thu, 2016-01-14 at 16:06 +0100, Roger Pau Monne wrote:
> If sysconf(_SC_GETPW_R_SIZE_MAX) fails for any reason just use an initial
> buffer size of 2048. This is not a critical failure, and the code that
> makes use of this buffer is able to expand it later if required.
> 
> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
> ---
> Cc: Ian Jackson <ian.jackson@eu.citrix.com>
> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> Cc: Ian Campbell <ian.campbell@citrix.com>
> Cc: Wei Liu <wei.liu2@citrix.com>

Acked-by: Ian Campbell <ian.campbell@citrix.com>

Well done on your prescience on fixing all my comments on v1 before you'd
even seen them!

Applied.

> ---
> Changes since v1:
>  - Use a default buffer size if sysconf(_SC_GETPW_R_SIZE_MAX) fails for
> any
>    reason, this should not be a critical failure.
> ---
>  tools/libxl/libxl_dm.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c
> index 0aaefd9..a088d71 100644
> --- a/tools/libxl/libxl_dm.c
> +++ b/tools/libxl/libxl_dm.c
> @@ -730,9 +730,10 @@ static int libxl__dm_runas_helper(libxl__gc *gc,
> const char *username)
>  
>      buf_size = sysconf(_SC_GETPW_R_SIZE_MAX);
>      if (buf_size < 0) {
> -        LOGE(ERROR, "sysconf(_SC_GETPW_R_SIZE_MAX) returned error %ld",
> -                buf_size);
> -        return ERROR_FAIL;
> +        buf_size = 2048;
> +        LOG(DEBUG,
> +"sysconf(_SC_GETPW_R_SIZE_MAX) failed, setting the initial buffer size
> to %ld",
> +            buf_size);
>      }
>  
>      while (1) {

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