From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jim Meyering <jim@meyering.net>
Subject: Re: [PATCH] use xstrdup, not strdup in ll-merge.c
Date: Mon, 15 Jun 2009 10:02:00 +0200
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To: Alex Riesen <raa.lkml@gmail.com>
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In-Reply-To: <81b0412b0906141503v14484d9fyea56198910305bfc@mail.gmail.com>
	(Alex Riesen's message of "Mon, 15 Jun 2009 00:03:27 +0200")
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Alex Riesen wrote:
> 2009/6/14 Jim Meyering <jim@meyering.net>:
>> @@ -231,7 +231,7 @@ static int read_merge_config(const char *var, co=
nst char *value, void *cb)
>>
>> =C2=A0 =C2=A0 =C2=A0 =C2=A0if (!strcmp(var, "merge.default")) {
>> =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0if (value)
>> - =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 default_ll_merge =3D strdup(value);
>> + =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 default_ll_merge =3D xstrdup(value);
>
> read_merge_config has a failure mode (where it returns -1), why not u=
se it?

I didn't even consider it, because it would be inconsistent with
the other heap-allocation functions used there (xcalloc, xmemdupz).

However, now that I do, it looks like that would mean adding four times
the same code (including conditionals and code to generate a diagnostic=
 via
a call to error -- or a goto). Why bother, when all of that is already
encapsulated in xmalloc?
Maybe because you want to be able to continue after an allocation failu=
re?
If a small strdup allocation fails, odds are good that the code won't
be able to do anything useful, so when not in library code, cleanest is
simply to exit.

In addition, if you insist on using strdup, you'll probably want to
be consistent and use calloc and memdupz, too.  Adding all of the code
required to recover from those failures and to avoid leaks would be mes=
sy.