[dpdk-dev] [PATCH] eal: do not try to load library with a local pathname

[dpdk-dev] [PATCH] eal: do not try to load library with a local pathname

[David Marchand]

From: Pascal Mazon <pascal.mazon@6wind.com>

When loading a library "libfoo.so" (depending on "libbar.so", located in an
entirely different folder), with a LD_LIBRARY_PATH=/path/to/libfoo.so", it
returns an error:

 EAL: ./libfoo.so: cannot open shared object file: No such file or directory

If the first dlopen() fails (here, because it can't find all dependencies),
the code requires for a second dlopen() that looks for "./libfoo.so". It
turns on pathname matching, which does not use LD_LIBRARY_PATH. As a result,
it fails because it cannot find "./libfoo.so".

The error message matches the error of the second dlopen(), not the first's.

Do not try to look for a different library ("./"-prefixed) than the one
provided in argument. Let the dynamic library management handle it, just
provide an appropriate LD_LIBRARY_PATH.

Signed-off-by: Pascal Mazon <pascal.mazon@6wind.com>
---
 lib/librte_eal/linuxapp/eal/eal.c |    6 ------
 1 file changed, 6 deletions(-)

diff --git a/lib/librte_eal/linuxapp/eal/eal.c b/lib/librte_eal/linuxapp/eal/eal.c
index 3ded563..d2753ec 100644
--- a/lib/librte_eal/linuxapp/eal/eal.c
+++ b/lib/librte_eal/linuxapp/eal/eal.c
@@ -1049,12 +1049,6 @@ rte_eal_init(int argc, char **argv)
 	TAILQ_FOREACH(solib, &solib_list, next) {
 		RTE_LOG(INFO, EAL, "open shared lib %s\n", solib->name);
 		solib->lib_handle = dlopen(solib->name, RTLD_NOW);
-		if ((solib->lib_handle == NULL) && (solib->name[0] != '/')) {
-			/* relative path: try again with "./" prefix */
-			char sopath[PATH_MAX];
-			snprintf(sopath, sizeof(sopath), "./%s", solib->name);
-			solib->lib_handle = dlopen(sopath, RTLD_NOW);
-		}
 		if (solib->lib_handle == NULL)
 			RTE_LOG(WARNING, EAL, "%s\n", dlerror());
 	}
-- 
1.7.10.4

Re: [dpdk-dev] [PATCH] eal: do not try to load library with a local pathname

[Neil Horman]

On Tue, Apr 15, 2014 at 03:50:22PM +0200, David Marchand wrote:
> From: Pascal Mazon <pascal.mazon@6wind.com>
> 
> When loading a library "libfoo.so" (depending on "libbar.so", located in an
> entirely different folder), with a LD_LIBRARY_PATH=/path/to/libfoo.so", it
> returns an error:
> 
>  EAL: ./libfoo.so: cannot open shared object file: No such file or directory
> 
> If the first dlopen() fails (here, because it can't find all dependencies),
> the code requires for a second dlopen() that looks for "./libfoo.so". It
> turns on pathname matching, which does not use LD_LIBRARY_PATH. As a result,
> it fails because it cannot find "./libfoo.so".
> 
> The error message matches the error of the second dlopen(), not the first's.
> 
> Do not try to look for a different library ("./"-prefixed) than the one
> provided in argument. Let the dynamic library management handle it, just
> provide an appropriate LD_LIBRARY_PATH.
> 
> Signed-off-by: Pascal Mazon <pascal.mazon@6wind.com>

Acked-by: Neil Horman <nhorman@tuxdriver.com>

> ---
>  lib/librte_eal/linuxapp/eal/eal.c |    6 ------
>  1 file changed, 6 deletions(-)
> 
> diff --git a/lib/librte_eal/linuxapp/eal/eal.c b/lib/librte_eal/linuxapp/eal/eal.c
> index 3ded563..d2753ec 100644
> --- a/lib/librte_eal/linuxapp/eal/eal.c
> +++ b/lib/librte_eal/linuxapp/eal/eal.c
> @@ -1049,12 +1049,6 @@ rte_eal_init(int argc, char **argv)
>  	TAILQ_FOREACH(solib, &solib_list, next) {
>  		RTE_LOG(INFO, EAL, "open shared lib %s\n", solib->name);
>  		solib->lib_handle = dlopen(solib->name, RTLD_NOW);
> -		if ((solib->lib_handle == NULL) && (solib->name[0] != '/')) {
> -			/* relative path: try again with "./" prefix */
> -			char sopath[PATH_MAX];
> -			snprintf(sopath, sizeof(sopath), "./%s", solib->name);
> -			solib->lib_handle = dlopen(sopath, RTLD_NOW);
> -		}
>  		if (solib->lib_handle == NULL)
>  			RTE_LOG(WARNING, EAL, "%s\n", dlerror());
>  	}
> -- 
> 1.7.10.4
> 
> 

Re: [dpdk-dev] [PATCH] eal: do not try to load library with a local pathname

[Thomas Monjalon]

> > When loading a library "libfoo.so" (depending on "libbar.so", located in
> > an
> > entirely different folder), with a LD_LIBRARY_PATH=/path/to/libfoo.so", it
> > 
> > returns an error:
> >  EAL: ./libfoo.so: cannot open shared object file: No such file or
> >  directory
> > 
> > If the first dlopen() fails (here, because it can't find all
> > dependencies),
> > the code requires for a second dlopen() that looks for "./libfoo.so". It
> > turns on pathname matching, which does not use LD_LIBRARY_PATH. As a
> > result, it fails because it cannot find "./libfoo.so".
> > 
> > The error message matches the error of the second dlopen(), not the
> > first's.
> > 
> > Do not try to look for a different library ("./"-prefixed) than the one
> > provided in argument. Let the dynamic library management handle it, just
> > provide an appropriate LD_LIBRARY_PATH.
> > 
> > Signed-off-by: Pascal Mazon <pascal.mazon@6wind.com>
> 
> Acked-by: Neil Horman <nhorman@tuxdriver.com>

Applied for version 1.6.0r2.

Thanks, it's a good usability improvement (simpler is better :)
-- 
Thomas