[patch] ld.so.8: Expand DT_RUNPATH details.

[patch] ld.so.8: Expand DT_RUNPATH details.

[Carlos O'Donell]

ld.so.8: Expand DT_RUNPATH details.

Every 3 years we get asked why DT_RUNPATH doesn't work like DT_RPATH.
The most recent question was here:
https://www.sourceware.org/ml/libc-help/2017-06/msg00013.html

We need to expand the description of DT_RUNPATH to cover this situation
and explain that the DT_RUNPATH entries apply only to the immediate
DT_NEEDED, not that of another, say dlopen'd child object.

Applies to master.

Signed-off-by: Carlos O'Donell <carlos-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
---
diff --git a/man8/ld.so.8 b/man8/ld.so.8
index 89965a1..e9e320d 100644
--- a/man8/ld.so.8
+++ b/man8/ld.so.8
@@ -68,7 +68,11 @@ in which case it is ignored.
 .IP o
 Using the directories specified in the
 DT_RUNPATH dynamic section attribute
-of the binary if present.
+of the binary if present. Such directories are only searched to
+find those objects required by DT_NEEDED (direct dependencies) entries
+and do not apply to those object's children who must themselves have
+their own DT_RUNPATH entries. This is unlike DT_RPATH which is applied
+to searches for all children in the dependency tree.
 .IP o
 From the cache file
 .IR /etc/ld.so.cache ,
-- 
Cheers,
Carlos.
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Re: [patch] ld.so.8: Expand DT_RUNPATH details.

[Michael Kerrisk (man-pages)]

On 06/29/2017 06:21 PM, Carlos O'Donell wrote:
> ld.so.8: Expand DT_RUNPATH details.
> 
> Every 3 years we get asked why DT_RUNPATH doesn't work like DT_RPATH.
> The most recent question was here:
> https://www.sourceware.org/ml/libc-help/2017-06/msg00013.html
> 
> We need to expand the description of DT_RUNPATH to cover this situation
> and explain that the DT_RUNPATH entries apply only to the immediate
> DT_NEEDED, not that of another, say dlopen'd child object.
> 
> Applies to master.

Thanks, Carlos. Applied.

Cheers,

Michael


> Signed-off-by: Carlos O'Donell <carlos-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> ---
> diff --git a/man8/ld.so.8 b/man8/ld.so.8
> index 89965a1..e9e320d 100644
> --- a/man8/ld.so.8
> +++ b/man8/ld.so.8
> @@ -68,7 +68,11 @@ in which case it is ignored.
>  .IP o
>  Using the directories specified in the
>  DT_RUNPATH dynamic section attribute
> -of the binary if present.
> +of the binary if present. Such directories are only searched to
> +find those objects required by DT_NEEDED (direct dependencies) entries
> +and do not apply to those object's children who must themselves have
> +their own DT_RUNPATH entries. This is unlike DT_RPATH which is applied
> +to searches for all children in the dependency tree.
>  .IP o
>  From the cache file
>  .IR /etc/ld.so.cache ,
> 


-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
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