Date: Tue, 11 Sep 2018 22:47:58 +0200 From: Andreas Longwitz <longwitz@incore.de> To: Konstantin Belousov <kostikbel@gmail.com> Cc: freebsd-stable@freebsd.org Subject: Re: Constraints in libmap(32).conf do not work as expected, possible bug in rtld-elf Message-ID: <5B9829FE.10700@incore.de> In-Reply-To: <20180902120603.GI2340@kib.kiev.ua> References: <5B89C1E7.4090002@incore.de> <20180902120603.GI2340@kib.kiev.ua>
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Thanks very much for answer !
Now I use the following libmap32.conf:
## php52
[/usr/local/php52/lib/php/20060613/mysql.so]
/usr/local/lib/mysql /usr/local/lib32/mysql
[/usr/local/php52/]
/usr/local/lib /usr/local/lib32
> I am having problem understanding what do you mean by step1/step2. The
> refobj reference that you cache in the patch, comes into load_object()
> as the pointer to the object which initiate the load_object() call. It
> is NULL for preloaded objects, otherwise it is not.
> So, could you, please, explain where does it get passed as NULL in your
> case ?
Ok, I try to explain better:
step1 means: call of lm_find() in rtld.c (line 1500) and first argument
is refobj->path, which is used in libmap.c to find the correct entry in
the lmp_list.
step2 means: call of lm_findn() in rtld.c (line 2834) when called from
search_library_path(). In this case the first argument is NULL and in
libmap.c this means "$DEFAULT" entry in the lmp_list. Please notice that
after reading libmap32.conf in lm_init() the entry $DEFAULT in the
lmp_list does not exist, when all mappings are defined with constraints.
> Also, your patch makes the ref_object stuck for all future invocations
> of the load_object(), so it cannot be correct for this reason alone.
I do not think so. The patch only caches refobj->path from step1 to use
the same path in step2. I have updated my patch a little bit to clarify,
that the patch only wants to change the call of lm_findn() in the case
of search_library_path():
--- rtld.c.orig 2018-03-20 16:56:48.000000000 +0100
+++ rtld.c 2018-09-11 21:44:03.333739000 +0200
@@ -186,6 +186,7 @@
static Obj_Entry obj_rtld; /* The dynamic linker shared object */
static unsigned int obj_count; /* Number of objects in obj_list */
static unsigned int obj_loads; /* Number of loads of objects (gen count) */
+static char *lm_refobj_path = NULL;
static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
STAILQ_HEAD_INITIALIZER(list_global);
@@ -1496,6 +1497,8 @@
__DECONST(char *, xname)));
}
+ if (objgiven)
+ lm_refobj_path = refobj->path;
if (libmap_disable || !objgiven ||
(name = lm_find(refobj->path, xname)) == NULL)
name = (char *)xname;
@@ -1513,8 +1516,10 @@
(refobj != NULL &&
(pathname = search_library_path(name, refobj->rpath)) != NULL) ||
(pathname = search_library_path(name, gethints(false))) !=
NULL ||
- (pathname = search_library_path(name, STANDARD_LIBRARY_PATH))
!= NULL)
+ (pathname = search_library_path(name, STANDARD_LIBRARY_PATH))
!= NULL) {
+ lm_refobj_path = NULL;
return (pathname);
+ }
} else {
nodeflib = objgiven ? refobj->z_nodeflib : false;
if ((objgiven &&
@@ -1526,10 +1531,13 @@
(pathname = search_library_path(name, refobj->runpath)) !=
NULL) ||
(pathname = search_library_path(name, gethints(nodeflib))) !=
NULL ||
(objgiven && !nodeflib &&
- (pathname = search_library_path(name, STANDARD_LIBRARY_PATH))
!= NULL))
+ (pathname = search_library_path(name, STANDARD_LIBRARY_PATH))
!= NULL)) {
+ lm_refobj_path = NULL;
return (pathname);
+ }
}
+ lm_refobj_path = NULL;
if (objgiven && refobj->path != NULL) {
_rtld_error("Shared object \"%s\" not found, required by \"%s\"",
name, basename(refobj->path));
@@ -2831,7 +2839,7 @@
char *res;
len = strcspn(path, ":;");
- trans = lm_findn(NULL, path, len);
+ trans = lm_findn(lm_refobj_path, path, len);
if (trans)
res = callback(trans, strlen(trans), arg);
else
> Another note is that libmap.conf use that you put it for, is quite the
> strengthen of the original purpose. You should just add the pathes
> with your libraries to LD_32_LIBRARY_PATH or configure them into
> /var/run/ld-elf32.so.hints using 'ldconfig -32'.
I have tried this without success. With the original ld-elf32.so.1 and
my constraints in libmap32.conf I got the following:
-> /usr/local/php52/bin/php -v
Shared object "libxml2.so.5" not found, required by "php"
The error changed after setting LD_32_LIBRARY_PATH or (with same result)
the file /var/run/ld-elf32.so.hints using 'ldconfig -32.
-> export LD_32_LIBRARY_PATH="/usr/local/lib32:/usr/local/lib32/mysql"
-> /usr/local/php52/bin/php -v
/usr/local/lib/libiconv.so.3: unsupported file layout
This error disappears when I move this 64-bit library libiconv.so away,
but thats not a solution.
For your information I append the beginning of the dynamic section from
readelf output of /usr/local/php52/bin/php:
Tag Type Name/Value
0x00000001 (NEEDED) Shared library: [libcrypt.so.5]
0x00000001 (NEEDED) Shared library: [librt.so.1]
0x00000001 (NEEDED) Shared library: [libm.so.5]
0x00000001 (NEEDED) Shared library: [libxml2.so.5]
0x00000001 (NEEDED) Shared library: [libz.so.5]
0x00000001 (NEEDED) Shared library: [libiconv.so.3]
0x00000001 (NEEDED) Shared library: [libc.so.7]
0x0000000f (RPATH) Library rpath: [/usr/local/lib]
Andreas Longwitz
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