| /* |
| * Access to user system call parameters and results |
| * |
| * Copyright (C) 2008-2009 Red Hat, Inc. All rights reserved. |
| * |
| * This copyrighted material is made available to anyone wishing to use, |
| * modify, copy, or redistribute it subject to the terms and conditions |
| * of the GNU General Public License v.2. |
| * |
| * This file is a stub providing documentation for what functions |
| * asm-ARCH/syscall.h files need to define. Most arch definitions |
| * will be simple inlines. |
| * |
| * All of these functions expect to be called with no locks, |
| * and only when the caller is sure that the task of interest |
| * cannot return to user mode while we are looking at it. |
| */ |
| |
| #ifndef _ASM_SYSCALL_H |
| #define _ASM_SYSCALL_H 1 |
| |
| struct task_struct; |
| struct pt_regs; |
| |
| /** |
| * syscall_get_nr - find what system call a task is executing |
| * @task: task of interest, must be blocked |
| * @regs: task_pt_regs() of @task |
| * |
| * If @task is executing a system call or is at system call |
| * tracing about to attempt one, returns the system call number. |
| * If @task is not executing a system call, i.e. it's blocked |
| * inside the kernel for a fault or signal, returns -1. |
| * |
| * Note this returns int even on 64-bit machines. Only 32 bits of |
| * system call number can be meaningful. If the actual arch value |
| * is 64 bits, this truncates to 32 bits so 0xffffffff means -1. |
| * |
| * It's only valid to call this when @task is known to be blocked. |
| */ |
| int syscall_get_nr(struct task_struct *task, struct pt_regs *regs); |
| |
| /** |
| * syscall_rollback - roll back registers after an aborted system call |
| * @task: task of interest, must be in system call exit tracing |
| * @regs: task_pt_regs() of @task |
| * |
| * It's only valid to call this when @task is stopped for system |
| * call exit tracing (due to TIF_SYSCALL_TRACE or TIF_SYSCALL_AUDIT), |
| * after tracehook_report_syscall_entry() returned nonzero to prevent |
| * the system call from taking place. |
| * |
| * This rolls back the register state in @regs so it's as if the |
| * system call instruction was a no-op. The registers containing |
| * the system call number and arguments are as they were before the |
| * system call instruction. This may not be the same as what the |
| * register state looked like at system call entry tracing. |
| */ |
| void syscall_rollback(struct task_struct *task, struct pt_regs *regs); |
| |
| /** |
| * syscall_get_error - check result of traced system call |
| * @task: task of interest, must be blocked |
| * @regs: task_pt_regs() of @task |
| * |
| * Returns 0 if the system call succeeded, or -ERRORCODE if it failed. |
| * |
| * It's only valid to call this when @task is stopped for tracing on exit |
| * from a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT. |
| */ |
| long syscall_get_error(struct task_struct *task, struct pt_regs *regs); |
| |
| /** |
| * syscall_get_return_value - get the return value of a traced system call |
| * @task: task of interest, must be blocked |
| * @regs: task_pt_regs() of @task |
| * |
| * Returns the return value of the successful system call. |
| * This value is meaningless if syscall_get_error() returned nonzero. |
| * |
| * It's only valid to call this when @task is stopped for tracing on exit |
| * from a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT. |
| */ |
| long syscall_get_return_value(struct task_struct *task, struct pt_regs *regs); |
| |
| /** |
| * syscall_set_return_value - change the return value of a traced system call |
| * @task: task of interest, must be blocked |
| * @regs: task_pt_regs() of @task |
| * @error: negative error code, or zero to indicate success |
| * @val: user return value if @error is zero |
| * |
| * This changes the results of the system call that user mode will see. |
| * If @error is zero, the user sees a successful system call with a |
| * return value of @val. If @error is nonzero, it's a negated errno |
| * code; the user sees a failed system call with this errno code. |
| * |
| * It's only valid to call this when @task is stopped for tracing on exit |
| * from a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT. |
| */ |
| void syscall_set_return_value(struct task_struct *task, struct pt_regs *regs, |
| int error, long val); |
| |
| /** |
| * syscall_get_arguments - extract system call parameter values |
| * @task: task of interest, must be blocked |
| * @regs: task_pt_regs() of @task |
| * @i: argument index [0,5] |
| * @n: number of arguments; n+i must be [1,6]. |
| * @args: array filled with argument values |
| * |
| * Fetches @n arguments to the system call starting with the @i'th argument |
| * (from 0 through 5). Argument @i is stored in @args[0], and so on. |
| * An arch inline version is probably optimal when @i and @n are constants. |
| * |
| * It's only valid to call this when @task is stopped for tracing on |
| * entry to a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT. |
| * It's invalid to call this with @i + @n > 6; we only support system calls |
| * taking up to 6 arguments. |
| */ |
| void syscall_get_arguments(struct task_struct *task, struct pt_regs *regs, |
| unsigned int i, unsigned int n, unsigned long *args); |
| |
| /** |
| * syscall_set_arguments - change system call parameter value |
| * @task: task of interest, must be in system call entry tracing |
| * @regs: task_pt_regs() of @task |
| * @i: argument index [0,5] |
| * @n: number of arguments; n+i must be [1,6]. |
| * @args: array of argument values to store |
| * |
| * Changes @n arguments to the system call starting with the @i'th argument. |
| * Argument @i gets value @args[0], and so on. |
| * An arch inline version is probably optimal when @i and @n are constants. |
| * |
| * It's only valid to call this when @task is stopped for tracing on |
| * entry to a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT. |
| * It's invalid to call this with @i + @n > 6; we only support system calls |
| * taking up to 6 arguments. |
| */ |
| void syscall_set_arguments(struct task_struct *task, struct pt_regs *regs, |
| unsigned int i, unsigned int n, |
| const unsigned long *args); |
| |
| /** |
| * syscall_get_arch - return the AUDIT_ARCH for the current system call |
| * |
| * Returns the AUDIT_ARCH_* based on the system call convention in use. |
| * |
| * It's only valid to call this when current is stopped on entry to a system |
| * call, due to %TIF_SYSCALL_TRACE, %TIF_SYSCALL_AUDIT, or %TIF_SECCOMP. |
| * |
| * Architectures which permit CONFIG_HAVE_ARCH_SECCOMP_FILTER must |
| * provide an implementation of this. |
| */ |
| int syscall_get_arch(void); |
| #endif /* _ASM_SYSCALL_H */ |