Ability to manipulate fork() return values

From: Pavel Machek (pavel@suse.cz)
Date: Sun Feb 20 2000 - 05:41:59 EST

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Hi!

Fork behaves other than normal syscalls -- debugger is not called at
syscall exit. This patch fixes that. It does touch only return path
from fork(), which is "cold enough". Ability to change registers after
fork() is essential if strace wants to work correctly with clone().

[patch is against 42, but I checked it applies to 46]
Pavel

--- linux-2.3.42/arch/i386/kernel/entry.S.orig Sat Feb 5 02:07:42 2000
+++ linux-2.3.42/arch/i386/kernel/entry.S Sat Feb 5 02:09:32 2000
@@ -180,6 +180,8 @@
         call SYMBOL_NAME(schedule_tail)
         addl $4, %esp
         GET_CURRENT(%ebx)
+ testb $0x20,flags(%ebx) # PF_TRACESYS
+ jne tracesys_exit
         jmp ret_from_sys_call

/*

-- I'm pavel@ucw.cz. "In my country we have almost anarchy and I don't care." Panos Katsaloulis describing me w.r.t. patents me at discuss@linmodems.org

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Next message: Glenn McGrath: "Re: Userland encrypted filesystem that root cannot access."
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