59da21398e
syscall_get_nr() currently returns a valid result only if the call chain of the traced process includes do_syscall_trace_enter(). But collect_syscall() can be called for any sleeping task, the result of syscall_get_nr() in general is completely bogus. To make syscall_get_nr() work for any sleeping task the traps field in pt_regs is replace with svcnr - the system call number the process is executing. If svcnr == 0 the process is not on a system call path. The syscall_get_arguments and syscall_set_arguments use regs->gprs[2] for the first system call parameter. This is incorrect since gprs[2] may have been overwritten with the system call number if the call chain includes do_syscall_trace_enter. Use regs->orig_gprs2 instead. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
84 lines
2 KiB
C
84 lines
2 KiB
C
/*
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* Access to user system call parameters and results
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*
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* Copyright IBM Corp. 2008
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* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License (version 2 only)
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* as published by the Free Software Foundation.
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*/
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#ifndef _ASM_SYSCALL_H
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#define _ASM_SYSCALL_H 1
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#include <asm/ptrace.h>
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static inline long syscall_get_nr(struct task_struct *task,
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struct pt_regs *regs)
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{
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return regs->svcnr ? regs->svcnr : -1;
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}
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static inline void syscall_rollback(struct task_struct *task,
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struct pt_regs *regs)
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{
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regs->gprs[2] = regs->orig_gpr2;
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}
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static inline long syscall_get_error(struct task_struct *task,
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struct pt_regs *regs)
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{
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return (regs->gprs[2] >= -4096UL) ? -regs->gprs[2] : 0;
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}
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static inline long syscall_get_return_value(struct task_struct *task,
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struct pt_regs *regs)
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{
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return regs->gprs[2];
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}
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static inline void syscall_set_return_value(struct task_struct *task,
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struct pt_regs *regs,
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int error, long val)
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{
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regs->gprs[2] = error ? -error : val;
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}
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static inline void syscall_get_arguments(struct task_struct *task,
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struct pt_regs *regs,
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unsigned int i, unsigned int n,
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unsigned long *args)
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{
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unsigned long mask = -1UL;
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BUG_ON(i + n > 6);
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#ifdef CONFIG_COMPAT
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if (test_tsk_thread_flag(task, TIF_31BIT))
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mask = 0xffffffff;
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#endif
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if (i + n == 6)
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args[--n] = regs->args[0] & mask;
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while (n-- > 0)
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if (i + n > 0)
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args[n] = regs->gprs[2 + i + n] & mask;
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if (i == 0)
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args[0] = regs->orig_gpr2 & mask;
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}
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static inline void syscall_set_arguments(struct task_struct *task,
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struct pt_regs *regs,
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unsigned int i, unsigned int n,
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const unsigned long *args)
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{
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BUG_ON(i + n > 6);
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if (i + n == 6)
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regs->args[0] = args[--n];
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while (n-- > 0)
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if (i + n > 0)
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regs->gprs[2 + i + n] = args[n];
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if (i == 0)
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regs->orig_gpr2 = args[0];
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}
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#endif /* _ASM_SYSCALL_H */
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