Re: [PATCH] lib/m2: SYS_gettimeofday expects pointers

[Janneke Nieuwenhuizen]

Meghan Denny writes:

Hello Meghan,

> As this is my first email to the list I wanted to start off by saying
> thanks for all this great work.

It's a pleasure, well most of the time :-)  Glad you like it.

> While working on a project of my own I came across the wip-x86_64
> branch and discovered the attached patch and wanted to send it along
> in case it helped out.

Thanks for the patch, it does not work for me however.

Mes uses M2-Planet 1.10.0:

    $ guix shell
    guix shell: loading environment from 
'/home/janneke/src/mes/wip-x86_64/guix.scm'...
    07:28:13 janneke@drakenpad:~/src/mes/wip-x86_64 [env]
    $ M2-Planet --version
    M2-Planet v1.10.0
    $ git am 0001-lib-m2-SYS_gettimeofday-expects-pointers.patch
    Applying: lib/m2: SYS_gettimeofday expects pointers
    07:28:41 janneke@drakenpad:~/src/mes/wip-x86_64 [env]
    $ kaem
    >>WARNING<<
    >>WARNING<<
    include/time.h:25:feature: #include_next unsupported in M2-Planet
    [..]
    lib/m2/time.c:35:ERROR in statement
    MISSING ;
    Subprocess error 1
    ABORTING HARD
    [1]07:28:45 janneke@drakenpad:~/src/mes/wip-x86_64 [env]

Is it for a newer version of M2-Planet?  AFAIK, M2-Planet cannot not
allocate data for structs without using `malloc', so the current code
leads to a segfault.  So, thanks for pointing this out.  I'm now using
the attached patch.

Thanks!
Janneke

>From ee352a7b5c8ce40e3661bddf50e8d5c72d98017d Mon Sep 17 00:00:00 2001
From: "Jan (janneke) Nieuwenhuizen" <janneke@gnu.org>
Date: Tue, 24 Jan 2023 07:59:49 +0100
Subject: [PATCH] DRAFT lib/m2: time: Fix segfault by allocating timeval
 struct.

Suggested by Meghan Denny <hello@nektro.net>.

* lib/m2/time.c (__tv): New global variable.
(time): Use it to allocate timeval struct.
---
 lib/m2/time.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/lib/m2/time.c b/lib/m2/time.c
index c589de85..45ae1afb 100644
--- a/lib/m2/time.c
+++ b/lib/m2/time.c
@@ -1,6 +1,6 @@
 /* -*-comment-start: "//";comment-end:""-*-
  * GNU Mes --- Maxwell Equations of Software
- * Copyright © 2018,2019,2022 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+ * Copyright © 2018,2019,2022,2023 Jan (janneke) Nieuwenhuizen 
<janneke@gnu.org>
  *
  * This file is part of GNU Mes.
  *
@@ -22,13 +22,16 @@
 #include <syscall.h>
 #include <time.h>
 
+char *__tv;
+
 long
 time (long* result)
 {
   int r;
-  struct timeval tv;
-  struct timezone tz;
-  r = _sys_call2 (SYS_gettimeofday, tv, tz);
+  if (__tv == 0)
+    __tv = malloc (sizeof (struct timeval));
+  struct timeval *tv = __tv;
+  r = _sys_call2 (SYS_gettimeofday, tv, 0);
   if (r != 0)
     return -1;
   if (result != 0)
-- 
2.38.1

-- 
Janneke Nieuwenhuizen <janneke@gnu.org>  | GNU LilyPond https://LilyPond.org
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