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2522fe45 | 1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
828c365c RM |
2 | /* |
3 | * Access to user system call parameters and results | |
4 | * | |
268e4671 | 5 | * Copyright (C) 2008-2009 Red Hat, Inc. All rights reserved. |
828c365c | 6 | * |
828c365c RM |
7 | * This file is a stub providing documentation for what functions |
8 | * asm-ARCH/syscall.h files need to define. Most arch definitions | |
9 | * will be simple inlines. | |
10 | * | |
11 | * All of these functions expect to be called with no locks, | |
12 | * and only when the caller is sure that the task of interest | |
13 | * cannot return to user mode while we are looking at it. | |
14 | */ | |
15 | ||
16 | #ifndef _ASM_SYSCALL_H | |
17 | #define _ASM_SYSCALL_H 1 | |
18 | ||
19 | struct task_struct; | |
20 | struct pt_regs; | |
21 | ||
22 | /** | |
23 | * syscall_get_nr - find what system call a task is executing | |
24 | * @task: task of interest, must be blocked | |
25 | * @regs: task_pt_regs() of @task | |
26 | * | |
27 | * If @task is executing a system call or is at system call | |
28 | * tracing about to attempt one, returns the system call number. | |
29 | * If @task is not executing a system call, i.e. it's blocked | |
30 | * inside the kernel for a fault or signal, returns -1. | |
31 | * | |
268e4671 RM |
32 | * Note this returns int even on 64-bit machines. Only 32 bits of |
33 | * system call number can be meaningful. If the actual arch value | |
34 | * is 64 bits, this truncates to 32 bits so 0xffffffff means -1. | |
35 | * | |
828c365c RM |
36 | * It's only valid to call this when @task is known to be blocked. |
37 | */ | |
268e4671 | 38 | int syscall_get_nr(struct task_struct *task, struct pt_regs *regs); |
828c365c RM |
39 | |
40 | /** | |
41 | * syscall_rollback - roll back registers after an aborted system call | |
42 | * @task: task of interest, must be in system call exit tracing | |
43 | * @regs: task_pt_regs() of @task | |
44 | * | |
45 | * It's only valid to call this when @task is stopped for system | |
64c19ba2 | 46 | * call exit tracing (due to %SYSCALL_WORK_SYSCALL_TRACE or TIF_SYSCALL_AUDIT), |
828c365c RM |
47 | * after tracehook_report_syscall_entry() returned nonzero to prevent |
48 | * the system call from taking place. | |
49 | * | |
50 | * This rolls back the register state in @regs so it's as if the | |
51 | * system call instruction was a no-op. The registers containing | |
52 | * the system call number and arguments are as they were before the | |
53 | * system call instruction. This may not be the same as what the | |
54 | * register state looked like at system call entry tracing. | |
55 | */ | |
56 | void syscall_rollback(struct task_struct *task, struct pt_regs *regs); | |
57 | ||
58 | /** | |
59 | * syscall_get_error - check result of traced system call | |
60 | * @task: task of interest, must be blocked | |
61 | * @regs: task_pt_regs() of @task | |
62 | * | |
63 | * Returns 0 if the system call succeeded, or -ERRORCODE if it failed. | |
64 | * | |
65 | * It's only valid to call this when @task is stopped for tracing on exit | |
64c19ba2 | 66 | * from a system call, due to %SYSCALL_WORK_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT. |
828c365c RM |
67 | */ |
68 | long syscall_get_error(struct task_struct *task, struct pt_regs *regs); | |
69 | ||
70 | /** | |
71 | * syscall_get_return_value - get the return value of a traced system call | |
72 | * @task: task of interest, must be blocked | |
73 | * @regs: task_pt_regs() of @task | |
74 | * | |
75 | * Returns the return value of the successful system call. | |
76 | * This value is meaningless if syscall_get_error() returned nonzero. | |
77 | * | |
78 | * It's only valid to call this when @task is stopped for tracing on exit | |
64c19ba2 | 79 | * from a system call, due to %SYSCALL_WORK_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT. |
828c365c RM |
80 | */ |
81 | long syscall_get_return_value(struct task_struct *task, struct pt_regs *regs); | |
82 | ||
83 | /** | |
84 | * syscall_set_return_value - change the return value of a traced system call | |
85 | * @task: task of interest, must be blocked | |
86 | * @regs: task_pt_regs() of @task | |
87 | * @error: negative error code, or zero to indicate success | |
88 | * @val: user return value if @error is zero | |
89 | * | |
90 | * This changes the results of the system call that user mode will see. | |
91 | * If @error is zero, the user sees a successful system call with a | |
92 | * return value of @val. If @error is nonzero, it's a negated errno | |
93 | * code; the user sees a failed system call with this errno code. | |
94 | * | |
95 | * It's only valid to call this when @task is stopped for tracing on exit | |
64c19ba2 | 96 | * from a system call, due to %SYSCALL_WORK_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT. |
828c365c RM |
97 | */ |
98 | void syscall_set_return_value(struct task_struct *task, struct pt_regs *regs, | |
99 | int error, long val); | |
100 | ||
101 | /** | |
102 | * syscall_get_arguments - extract system call parameter values | |
103 | * @task: task of interest, must be blocked | |
104 | * @regs: task_pt_regs() of @task | |
828c365c RM |
105 | * @args: array filled with argument values |
106 | * | |
b35f549d SRRH |
107 | * Fetches 6 arguments to the system call. First argument is stored in |
108 | * @args[0], and so on. | |
828c365c RM |
109 | * |
110 | * It's only valid to call this when @task is stopped for tracing on | |
64c19ba2 | 111 | * entry to a system call, due to %SYSCALL_WORK_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT. |
828c365c RM |
112 | */ |
113 | void syscall_get_arguments(struct task_struct *task, struct pt_regs *regs, | |
b35f549d | 114 | unsigned long *args); |
828c365c RM |
115 | |
116 | /** | |
117 | * syscall_set_arguments - change system call parameter value | |
118 | * @task: task of interest, must be in system call entry tracing | |
119 | * @regs: task_pt_regs() of @task | |
828c365c RM |
120 | * @args: array of argument values to store |
121 | * | |
32d92586 SRV |
122 | * Changes 6 arguments to the system call. |
123 | * The first argument gets value @args[0], and so on. | |
828c365c RM |
124 | * |
125 | * It's only valid to call this when @task is stopped for tracing on | |
64c19ba2 | 126 | * entry to a system call, due to %SYSCALL_WORK_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT. |
828c365c RM |
127 | */ |
128 | void syscall_set_arguments(struct task_struct *task, struct pt_regs *regs, | |
828c365c RM |
129 | const unsigned long *args); |
130 | ||
07bd18d0 WD |
131 | /** |
132 | * syscall_get_arch - return the AUDIT_ARCH for the current system call | |
16add411 | 133 | * @task: task of interest, must be blocked |
07bd18d0 WD |
134 | * |
135 | * Returns the AUDIT_ARCH_* based on the system call convention in use. | |
136 | * | |
16add411 | 137 | * It's only valid to call this when @task is stopped on entry to a system |
64c19ba2 GKB |
138 | * call, due to %SYSCALL_WORK_SYSCALL_TRACE, %TIF_SYSCALL_AUDIT, or |
139 | * %SYSCALL_WORK_SECCOMP. | |
07bd18d0 WD |
140 | * |
141 | * Architectures which permit CONFIG_HAVE_ARCH_SECCOMP_FILTER must | |
142 | * provide an implementation of this. | |
143 | */ | |
16add411 | 144 | int syscall_get_arch(struct task_struct *task); |
828c365c | 145 | #endif /* _ASM_SYSCALL_H */ |