_uuidmodule.c cannot build on AIX - different typedefs of uuid_t, etc..

[aixtools]

BPO	32399
Nosy	@pitrou, @aixtools
PRs	bpo-32399: Starting with AIX6.1 there is support in libc.a for uuid (RFC4122) #4974

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2017-12-30.21:40:46.835>
created_at = <Date 2017-12-21.18:49:07.780>
labels = ['extension-modules', 'type-bug', '3.7']
title = '_uuidmodule.c cannot build on AIX - different typedefs of uuid_t, etc..'
updated_at = <Date 2017-12-30.21:40:46.834>
user = 'https://github.com/aixtools'

bugs.python.org fields:

activity = <Date 2017-12-30.21:40:46.834>
actor = 'pitrou'
assignee = 'none'
closed = True
closed_date = <Date 2017-12-30.21:40:46.835>
closer = 'pitrou'
components = ['Extension Modules']
creation = <Date 2017-12-21.18:49:07.780>
creator = 'Michael.Felt'
dependencies = []
files = []
hgrepos = []
issue_num = 32399
keywords = ['patch']
message_count = 7.0
messages = ['308894', '308896', '308911', '308929', '308952', '308953', '309262']
nosy_count = 2.0
nosy_names = ['pitrou', 'Michael.Felt']
pr_nums = ['4974']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue32399'
versions = ['Python 3.7']

[aixtools]

I was hoping for something simple - as in:

+1  #define PY_SSIZE_T_CLEAN
+2
+3  #include "Python.h"
+4  #ifndef _AIX
+5  #include <uuid/uuid.h>
+6  #else
+7  #include <uuid.h>
+8  #endif

However, it dies - instantly.

   11 | static PyObject *
   12 | py_uuid_generate_time_safe(void)
   13 | {
   14 | #ifdef HAVE_UUID_GENERATE_TIME_SAFE
   15 |     uuid_t out;
   16 |     int res;
   17 |
   18 |     res = uuid_generate_time_safe(out);
   19 |     return Py_BuildValue("y#i", (const char \*) out, sizeof(out), res);
   20 | #else
   21 |     uuid_t out;
   22 |     uuid_generate_time(out);
   23 |     return Py_BuildValue("y#O", (const char \*) out, sizeof(out), Py_None);
   23 +     return \_Py_BuildValue_SizeT("y#O", (const char \*) out, sizeof(out), (&_Py_NoneStruct));

"/data/prj/python/git/python3-3.7.0.a3/Modules/_uuidmodule.c", line 23.48: 1506-117 (S) Operand must be a scalar type.
24 | #endif
25 | }
26 |

On a linux system I see:

typedef unsigned char uuid_t[16];

while on AIX the typedef is:

/*
 * Universal Unique Identifier (UUID) types.
 */
typedef struct _uuid_t
{
    unsigned32          time_low;
    unsigned16          time_mid;
    unsigned16          time_hi_and_version;
    unsigned8           clock_seq_hi_and_reserved;
    unsigned8           clock_seq_low;
    byte               node[6];
} uuid_t, *uuid_p_t;

So, mentioning this for now - as I do not yet know the module. If someone with intimate knowledge of the current implementation is willing to help me - I'll dabble and learn - and see if we can make it work on AIX as well.

p.s. - guessing on the "Extension Modules" label. If not the right choice, please update.

[aixtools]

So - KISS principle:

This diff shows what can compile:

diff --git a/Modules/_uuidmodule.c b/Modules/_uuidmodule.c
index d4bc3c7..5550705 100644
--- a/Modules/_uuidmodule.c
+++ b/Modules/_uuidmodule.c
@@ -1,7 +1,11 @@
 #define PY_SSIZE_T_CLEAN

 #include "Python.h"
+#ifndef _AIX
 #include <uuid/uuid.h>
+#else
+#include <uuid.h>
+#endif

 static PyObject *
@@ -16,7 +20,11 @@ py_uuid_generate_time_safe(void)
 #else
     uuid_t out;
     uuid_generate_time(out);
+#ifndef _AIX
     return Py_BuildValue("y#O", (const char *) out, sizeof(out), Py_None);
+#else
+    return Py_BuildValue("y#O", (const char *) &out, sizeof(out), Py_None);
+#endif
 #endif
 }

However, no uuid_generate_time(). So, ends with:
ld: 0711-317 ERROR: Undefined symbol: .uuid_generate_time

[pitrou]

Keep in mind _uuid is an optional C extension that is used to accelerate the uuid module when available. It doesn't bring any additional functionality by itself.

[aixtools]

Understood.

What I have learned.

Although the types are quite different, they are both 16 bytes.

Starting with AIX 6.1, libc includes uuid_create(&uuid, &status)
which fills "uuid" with a uuid.uuid1() like result.
After calling uuid_to_string( &uuid, &uuid_string, &status); the result:
"13d866fa-e6f1-11e7-8017-fad18cf76204"

Further reading of the documentation within """ and """ in Lib/uuid.py helps me realize that the AIX approach aligns with the UUID fields description:

    fields      a tuple of the six integer fields of the UUID,
                which are also available as six individual attributes
                and two derived attributes:

        time_low                the first 32 bits of the UUID
        time_mid                the next 16 bits of the UUID
        time_hi_version         the next 16 bits of the UUID
        clock_seq_hi_variant    the next 8 bits of the UUID
        clock_seq_low           the next 8 bits of the UUID
        node                    the last 48 bits of the UUID

So - with this: there is also more than can be done for AIX re: https://bugs.python.org/issue28009

More to come...

[aixtools]

As the 'basics' seem to be 'accepted', going to work on the PR so that configure.ac can prepare the right choices, rather than rely on a hard-coded _AIX determined macro.

[pitrou]

Does this approach allow test_uuid to pass for you?

[pitrou]

New changeset 0d3ccb4 by Antoine Pitrou (Michael Felt) in branch 'master':
bpo-32399: Starting with AIX6.1 there is support in libc.a for uuid (RFC4122) (bpo-4974)
0d3ccb4