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150 lines
5.6 KiB
150 lines
5.6 KiB
/* SPDX-License-Identifier: GPL-2.0-only */ |
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/* |
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* Access to user system call parameters and results |
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* |
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* Copyright (C) 2008-2009 Red Hat, Inc. All rights reserved. |
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* |
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* This file is a stub providing documentation for what functions |
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* asm-ARCH/syscall.h files need to define. Most arch definitions |
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* will be simple inlines. |
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* |
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* All of these functions expect to be called with no locks, |
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* and only when the caller is sure that the task of interest |
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* cannot return to user mode while we are looking at it. |
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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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struct task_struct; |
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struct pt_regs; |
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/** |
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* syscall_get_nr - find what system call a task is executing |
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* @task: task of interest, must be blocked |
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* @regs: task_pt_regs() of @task |
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* |
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* If @task is executing a system call or is at system call |
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* tracing about to attempt one, returns the system call number. |
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* If @task is not executing a system call, i.e. it's blocked |
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* inside the kernel for a fault or signal, returns -1. |
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* |
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* Note this returns int even on 64-bit machines. Only 32 bits of |
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* system call number can be meaningful. If the actual arch value |
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* is 64 bits, this truncates to 32 bits so 0xffffffff means -1. |
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* |
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* It's only valid to call this when @task is known to be blocked. |
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*/ |
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int syscall_get_nr(struct task_struct *task, struct pt_regs *regs); |
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/** |
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* syscall_rollback - roll back registers after an aborted system call |
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* @task: task of interest, must be in system call exit tracing |
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* @regs: task_pt_regs() of @task |
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* |
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* It's only valid to call this when @task is stopped for system |
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* call exit tracing (due to %SYSCALL_WORK_SYSCALL_TRACE or |
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* %SYSCALL_WORK_SYSCALL_AUDIT), after tracehook_report_syscall_entry() |
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* returned nonzero to prevent the system call from taking place. |
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* |
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* This rolls back the register state in @regs so it's as if the |
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* system call instruction was a no-op. The registers containing |
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* the system call number and arguments are as they were before the |
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* system call instruction. This may not be the same as what the |
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* register state looked like at system call entry tracing. |
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*/ |
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void syscall_rollback(struct task_struct *task, struct pt_regs *regs); |
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/** |
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* syscall_get_error - check result of traced system call |
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* @task: task of interest, must be blocked |
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* @regs: task_pt_regs() of @task |
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* |
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* Returns 0 if the system call succeeded, or -ERRORCODE if it failed. |
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* |
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* It's only valid to call this when @task is stopped for tracing on exit |
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* from a system call, due to %SYSCALL_WORK_SYSCALL_TRACE or |
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* %SYSCALL_WORK_SYSCALL_AUDIT. |
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*/ |
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long syscall_get_error(struct task_struct *task, struct pt_regs *regs); |
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/** |
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* syscall_get_return_value - get the return value of a traced system call |
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* @task: task of interest, must be blocked |
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* @regs: task_pt_regs() of @task |
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* |
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* Returns the return value of the successful system call. |
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* This value is meaningless if syscall_get_error() returned nonzero. |
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* |
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* It's only valid to call this when @task is stopped for tracing on exit |
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* from a system call, due to %SYSCALL_WORK_SYSCALL_TRACE or |
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* %SYSCALL_WORK_SYSCALL_AUDIT. |
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*/ |
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long syscall_get_return_value(struct task_struct *task, struct pt_regs *regs); |
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/** |
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* syscall_set_return_value - change the return value of a traced system call |
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* @task: task of interest, must be blocked |
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* @regs: task_pt_regs() of @task |
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* @error: negative error code, or zero to indicate success |
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* @val: user return value if @error is zero |
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* |
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* This changes the results of the system call that user mode will see. |
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* If @error is zero, the user sees a successful system call with a |
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* return value of @val. If @error is nonzero, it's a negated errno |
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* code; the user sees a failed system call with this errno code. |
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* |
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* It's only valid to call this when @task is stopped for tracing on exit |
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* from a system call, due to %SYSCALL_WORK_SYSCALL_TRACE or |
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* %SYSCALL_WORK_SYSCALL_AUDIT. |
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*/ |
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void syscall_set_return_value(struct task_struct *task, struct pt_regs *regs, |
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int error, long val); |
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/** |
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* syscall_get_arguments - extract system call parameter values |
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* @task: task of interest, must be blocked |
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* @regs: task_pt_regs() of @task |
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* @args: array filled with argument values |
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* |
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* Fetches 6 arguments to the system call. First argument is stored in |
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* @args[0], and so on. |
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* |
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* It's only valid to call this when @task is stopped for tracing on |
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* entry to a system call, due to %SYSCALL_WORK_SYSCALL_TRACE or |
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* %SYSCALL_WORK_SYSCALL_AUDIT. |
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*/ |
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void syscall_get_arguments(struct task_struct *task, struct pt_regs *regs, |
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unsigned long *args); |
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/** |
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* syscall_set_arguments - change system call parameter value |
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* @task: task of interest, must be in system call entry tracing |
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* @regs: task_pt_regs() of @task |
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* @args: array of argument values to store |
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* |
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* Changes 6 arguments to the system call. |
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* The first argument gets value @args[0], and so on. |
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* |
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* It's only valid to call this when @task is stopped for tracing on |
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* entry to a system call, due to %SYSCALL_WORK_SYSCALL_TRACE or |
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* %SYSCALL_WORK_SYSCALL_AUDIT. |
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*/ |
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void syscall_set_arguments(struct task_struct *task, struct pt_regs *regs, |
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const unsigned long *args); |
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/** |
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* syscall_get_arch - return the AUDIT_ARCH for the current system call |
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* @task: task of interest, must be blocked |
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* |
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* Returns the AUDIT_ARCH_* based on the system call convention in use. |
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* |
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* It's only valid to call this when @task is stopped on entry to a system |
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* call, due to %SYSCALL_WORK_SYSCALL_TRACE, %SYSCALL_WORK_SYSCALL_AUDIT, or |
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* %SYSCALL_WORK_SECCOMP. |
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* |
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* Architectures which permit CONFIG_HAVE_ARCH_SECCOMP_FILTER must |
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* provide an implementation of this. |
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*/ |
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int syscall_get_arch(struct task_struct *task); |
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#endif /* _ASM_SYSCALL_H */
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