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| author | Alan Davis <adavis@ti.com> | 2011-05-26 18:15:06 +0200 |
|---|---|---|
| committer | Bernd Schmidt <bernds@codesourcery.com> | 2011-05-27 12:46:03 +0200 |
| commit | 8514218c136c9a21a5ed4f123d2c49f21ef86947 (patch) | |
| tree | 63f7c5443dc40be862a7c3d4592a143169203b0e | |
| parent | 71d63ed75648da9b0b71afabb9c60aaad792c55c (diff) | |
| download | uClibc-alpine-8514218c136c9a21a5ed4f123d2c49f21ef86947.tar.bz2 uClibc-alpine-8514218c136c9a21a5ed4f123d2c49f21ef86947.tar.xz | |
Correct a bug when remapping textrel segments on nommu
From: Alan Davis <adavis@ti.com>
On C6X, when trying to execute a program that has a textrel DSO, it
fails to load. The telltale line in the LD_DEBUG output is:
_dl_get_ready_to_run:779: file=''; needed by './a.out'
The corresponding DT_NEEDED entry has 'libc.so.0', but here the
filename is empty. This is what is happening in
_dl_elf_shared_library():
First, map all segments according to their permissions. Text gets
initially mapped read-only.
Then, parse the dynamic information. The dynamic table is in RW but
some of the tags may point to RO. For example, DT_NEEDED points to a
string in .dynstr which is in RO. These pointers get computed
according to the loadmap from the original mapping.
Then, in response to a DT_TEXTREL tag, the RO segment gets remapped,
thereby invaliding anything that points to it, in particular certain
dynamic tags such as DT_NEEDED.
The following patch re-parses the dynamic info after the remapping so
as to re-compute any invalid pointers.
Signed-off-by: Alan Davis <adavis@ti.com>
Signed-off-by: Bernd Schmidt <bernds@codesourcery.com>
| -rw-r--r-- | ldso/ldso/dl-elf.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/ldso/ldso/dl-elf.c b/ldso/ldso/dl-elf.c index 7b5d75146..09b3aaf01 100644 --- a/ldso/ldso/dl-elf.c +++ b/ldso/ldso/dl-elf.c @@ -714,6 +714,9 @@ struct elf_resolve *_dl_load_elf_shared_library(int secure, DL_UPDATE_LOADADDR_HDR(lib_loadaddr, new_addr + (ppnt->p_vaddr & ADDR_ALIGN), ppnt); + /* This has invalidated all pointers into the previously readonly segment. + Update any them to point into the remapped segment. */ + _dl_parse_dynamic_info(dpnt, dynamic_info, NULL, lib_loadaddr); #endif } } |