[git commit] ldso: fix standalone execution on x86_64 architecture

Bernhard Reutner-Fischer rep.dot.nop at gmail.com
Tue Apr 8 13:19:48 UTC 2014


commit: http://git.uclibc.org/uClibc/commit/?id=278a06d7abcc8774ba9bb9c15779749c7e2d68cd
branch: http://git.uclibc.org/uClibc/commit/?id=refs/heads/master

If the dynamic linker is built with LDSO_STANDALONE_SUPPORT=y, it can
load then run a dynamically linked program when explicitly invoked
from the command line.  This is used for test and prelink purposes,
and also by other tools like PRoot to force the kernel to load the
right ELF interpreter.

This feature is currently broken on x86_64 since the number of command
line arguments (ie. argc) passed from the kernel is an "elf_addr_t"
(64 bit on x86_64), whereas it is read as an "unsigned int" (32 bit on
x86_64).

Ref: https://github.com/cedric-vincent/PRoot/issues/45
Signed-off-by: Cédric VINCENT <cedric.vincent at st.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop at gmail.com>
---
 ldso/ldso/ldso.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/ldso/ldso/ldso.c b/ldso/ldso/ldso.c
index 0c2ed07..3b00e05 100644
--- a/ldso/ldso/ldso.c
+++ b/ldso/ldso/ldso.c
@@ -526,8 +526,8 @@ void *_dl_get_ready_to_run(struct elf_resolve *tpnt, DL_LOADADDR_TYPE load_addr,
 
 #ifdef __LDSO_STANDALONE_SUPPORT__
 	if (_start == (void *) auxvt[AT_ENTRY].a_un.a_val) {
-		unsigned int *aux_dat = (unsigned int *) argv;
-		int argc = aux_dat[-1];
+		int argc = (int) aux_dat[-1];
+		ElfW(Addr) *aux_dat = (ElfW(Addr) *) argv;
 
 		tpnt->libname = argv[0];
 		while (argc > 1)


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