From: Bodo Stroesser <[EMAIL PROTECTED]>
To use ptrace-option PTRACE_O_TRACESYSGOOD, it must be enabled
by a PTRACE_SETOPTIONS call.
This call the first time was implemented in linux 2.4, where
PTRACE_SETOPTIONS was set to 21.
In linux 2.6, PTRACE_SETOPTIONS is redefined to 0x4200, while
the old value 21 still is available as PTRACE_OLDSETOPTIONS.
So, if UML uses PTRACE_SETOPTIONS, an UML-kernel built on a 2.4
won't run on a 2.6 host and vice versa.
UML always should use PTRACE_OLDSETOPTIONS with its value
of 21. Since PTRACE_OLDSETOPTIONS isn't defined on a 2.4
generally and on those 2.6 subarchs, that hadn't supported
TRACESYSGOOD on 2.4, we additionaly include:
#ifndef PTRACE_OLDSETOPTIONS
#define PTRACE_OLDSETOPTIONS PTRACE_SETOTIONS
#endif
Some architectures only have PTRACE_SETOPTIONS with a value
of 0x4200, since they didn't support it on 2.4
On those architectures, the redefinition lets UML use 0x4200
as PTRACE_OLDSETOPTIONS.
Signed-off-by: Bodo Stroesser <[EMAIL PROTECTED]>
---
diff -puN arch/um/kernel/tt/tracer.c~use-OLSSETOPTIONS
arch/um/kernel/tt/tracer.c
--- linux-2.6.10-rc2-mm4/arch/um/kernel/tt/tracer.c~use-OLSSETOPTIONS
2004-12-10 15:53:52.344598828 +0100
+++ linux-2.6.10-rc2-mm4-root/arch/um/kernel/tt/tracer.c 2004-12-10
15:53:52.356594650 +0100
@@ -72,7 +72,7 @@ void attach_process(int pid)
(ptrace(PTRACE_CONT, pid, 0, 0) < 0))
tracer_panic("OP_FORK failed to attach pid");
wait_for_stop(pid, SIGSTOP, PTRACE_CONT, NULL);
- if (ptrace(PTRACE_SETOPTIONS, pid, 0, (void *)PTRACE_O_TRACESYSGOOD) <
0)
+ if (ptrace(PTRACE_OLDSETOPTIONS, pid, 0, (void *)PTRACE_O_TRACESYSGOOD)
< 0)
tracer_panic("OP_FORK: PTRACE_SETOPTIONS failed, errno = %d",
errno);
if(ptrace(PTRACE_CONT, pid, 0, 0) < 0)
tracer_panic("OP_FORK failed to continue process");
@@ -200,7 +200,7 @@ int tracer(int (*init_proc)(void *), voi
printf("waitpid on idle thread failed, errno = %d\n", errno);
exit(1);
}
- if (ptrace(PTRACE_SETOPTIONS, pid, 0, (void *)PTRACE_O_TRACESYSGOOD) <
0) {
+ if (ptrace(PTRACE_OLDSETOPTIONS, pid, 0, (void *)PTRACE_O_TRACESYSGOOD)
< 0) {
printf("Failed to PTRACE_SETOPTIONS for idle thread, errno =
%d\n", errno);
exit(1);
}
diff -puN arch/um/kernel/tt/exec_user.c~use-OLSSETOPTIONS
arch/um/kernel/tt/exec_user.c
--- linux-2.6.10-rc2-mm4/arch/um/kernel/tt/exec_user.c~use-OLSSETOPTIONS
2004-12-10 15:53:52.346598132 +0100
+++ linux-2.6.10-rc2-mm4-root/arch/um/kernel/tt/exec_user.c 2004-12-10
15:53:52.356594650 +0100
@@ -39,7 +39,7 @@ void do_exec(int old_pid, int new_pid)
os_kill_ptraced_process(old_pid, 0);
- if (ptrace(PTRACE_SETOPTIONS, new_pid, 0, (void
*)PTRACE_O_TRACESYSGOOD) < 0)
+ if (ptrace(PTRACE_OLDSETOPTIONS, new_pid, 0, (void
*)PTRACE_O_TRACESYSGOOD) < 0)
tracer_panic("do_exec: PTRACE_SETOPTIONS failed, errno = %d",
errno);
if(ptrace_setregs(new_pid, regs) < 0)
diff -puN arch/um/kernel/skas/process.c~use-OLSSETOPTIONS
arch/um/kernel/skas/process.c
--- linux-2.6.10-rc2-mm4/arch/um/kernel/skas/process.c~use-OLSSETOPTIONS
2004-12-10 15:53:52.349597087 +0100
+++ linux-2.6.10-rc2-mm4-root/arch/um/kernel/skas/process.c 2004-12-10
15:53:52.356594650 +0100
@@ -122,7 +122,7 @@ void start_userspace(int cpu)
panic("start_userspace : expected SIGSTOP, got status = %d",
status);
- if (ptrace(PTRACE_SETOPTIONS, pid, NULL, (void *)PTRACE_O_TRACESYSGOOD)
< 0)
+ if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL, (void
*)PTRACE_O_TRACESYSGOOD) < 0)
panic("start_userspace : PTRACE_SETOPTIONS failed, errno=%d\n",
errno);
diff -puN arch/um/kernel/process.c~use-OLSSETOPTIONS arch/um/kernel/process.c
--- linux-2.6.10-rc2-mm4/arch/um/kernel/process.c~use-OLSSETOPTIONS
2004-12-10 15:53:52.351596391 +0100
+++ linux-2.6.10-rc2-mm4-root/arch/um/kernel/process.c 2004-12-10
15:53:52.357594302 +0100
@@ -321,7 +321,7 @@ void __init check_ptrace(void)
printk("Checking that ptrace can change system call numbers...");
pid = start_ptraced_child(&stack);
- if(ptrace(PTRACE_SETOPTIONS, pid, 0, (void *)PTRACE_O_TRACESYSGOOD) < 0)
+ if (ptrace(PTRACE_OLDSETOPTIONS, pid, 0, (void *)PTRACE_O_TRACESYSGOOD)
< 0)
panic("check_ptrace: PTRACE_SETOPTIONS failed, errno = %d",
errno);
while(1){
diff -puN arch/um/include/ptrace_user.h~use-OLSSETOPTIONS
arch/um/include/ptrace_user.h
--- linux-2.6.10-rc2-mm4/arch/um/include/ptrace_user.h~use-OLSSETOPTIONS
2004-12-10 15:56:44.711572089 +0100
+++ linux-2.6.10-rc2-mm4-root/arch/um/include/ptrace_user.h 2004-12-10
16:16:41.218676798 +0100
@@ -26,6 +26,26 @@ extern void ptrace_pokeuser(unsigned lon
#define PTRACE_SYSEMU_SINGLESTEP 32
#endif
+/* On architectures, that started to support PTRACE_O_TRACESYSGOOD
+ * in linux 2.4, there are two different definitions of
+ * PTRACE_SETOPTIONS: linux 2.4 uses 21 while linux 2.6 uses 0x4200.
+ * For binary compatibility, 2.6 also supports the old "21", named
+ * PTRACE_OLDSETOPTION. On these architectures, UML always must use
+ * "21", to ensure the kernel runs on 2.4 and 2.6 host without
+ * recompilation. So, we use PTRACE_OLDSETOPTIONS in UML.
+ * We also want to be able to build the kernel on 2.4, which doesn't
+ * have PTRACE_OLDSETOPTIONS. So, if it is missing, we declare
+ * PTRACE_OLDSETOPTIONS to to be the same as PTRACE_SETOPTIONS.
+ *
+ * On architectures, that start to support PTRACE_O_TRACESYSGOOD on
+ * linux 2.6, PTRACE_OLDSETOPTIONS never is defined, and also isn't
+ * supported by the host kernel. In that case, our trick lets us use
+ * the new 0x4200 with the name PTRACE_OLDSETOPTIONS.
+ */
+#ifndef PTRACE_OLDSETOPTIONS
+#define PTRACE_OLDSETOPTIONS PTRACE_SETOPTIONS
+#endif
+
void set_using_sysemu(int value);
int get_using_sysemu(void);
extern int sysemu_supported;
_
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