diff mbox

ldso: fix standalone execution on x86_64 architecture

Message ID 20140407080440.GB16008@reddwarf.lablan
State Accepted
Commit 278a06d7abcc8774ba9bb9c15779749c7e2d68cd
Headers show

Commit Message

vincent April 7, 2014, 8:04 a.m. UTC
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@st.com>

v2: use "ElfW(Addr)", as suggested by Bernhard Reutner-Fischer
---
 ldso/ldso/ldso.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Bernhard Reutner-Fischer April 8, 2014, 1:23 p.m. UTC | #1
On 7 April 2014 10:04, =?UTF-8?q?C=C3=A9dric=20VINCENT?=
<cedric.vincent@st.com> wrote:
> 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@st.com>
>
> v2: use "ElfW(Addr)", as suggested by Bernhard Reutner-Fischer

Applied, thanks!
diff mbox

Patch

diff --git a/ldso/ldso/ldso.c b/ldso/ldso/ldso.c
index becabd3..a3745c3 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];
+		ElfW(Addr) *aux_dat = (ElfW(Addr) *) argv;
+		int argc = (int) aux_dat[-1];
 
 		tpnt->libname = argv[0];
 		while (argc > 1)