diff options
author | Roland McGrath <roland@redhat.com> | 2008-07-25 22:45:57 -0400 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-07-26 15:00:09 -0400 |
commit | 828c365cc8b8d38c346fccb19fa80d28f2240831 (patch) | |
tree | cedb0f1ce389f4b12d7b0975ce52c8af7939cfcd /include | |
parent | 64b1208d5b0ef8859fd52ea7ae286a3eb994669b (diff) |
tracehook: asm/syscall.h
This adds asm-generic/syscall.h, which documents what a real
asm-ARCH/syscall.h file should define. This is not used yet, but will
provide all the machine-dependent details of examining a user system call
about to begin, in progress, or just ended.
Each arch should add an asm-ARCH/syscall.h that defines all the entry
points documented in asm-generic/syscall.h, as short inlines if possible.
This lets us write new tracing code that understands user system call
registers, without any new arch-specific work.
Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r-- | include/asm-generic/syscall.h | 141 | ||||
-rw-r--r-- | include/linux/tracehook.h | 3 |
2 files changed, 143 insertions, 1 deletions
diff --git a/include/asm-generic/syscall.h b/include/asm-generic/syscall.h new file mode 100644 index 000000000000..abcf34c2fdc7 --- /dev/null +++ b/include/asm-generic/syscall.h | |||
@@ -0,0 +1,141 @@ | |||
1 | /* | ||
2 | * Access to user system call parameters and results | ||
3 | * | ||
4 | * Copyright (C) 2008 Red Hat, Inc. All rights reserved. | ||
5 | * | ||
6 | * This copyrighted material is made available to anyone wishing to use, | ||
7 | * modify, copy, or redistribute it subject to the terms and conditions | ||
8 | * of the GNU General Public License v.2. | ||
9 | * | ||
10 | * This file is a stub providing documentation for what functions | ||
11 | * asm-ARCH/syscall.h files need to define. Most arch definitions | ||
12 | * will be simple inlines. | ||
13 | * | ||
14 | * All of these functions expect to be called with no locks, | ||
15 | * and only when the caller is sure that the task of interest | ||
16 | * cannot return to user mode while we are looking at it. | ||
17 | */ | ||
18 | |||
19 | #ifndef _ASM_SYSCALL_H | ||
20 | #define _ASM_SYSCALL_H 1 | ||
21 | |||
22 | struct task_struct; | ||
23 | struct pt_regs; | ||
24 | |||
25 | /** | ||
26 | * syscall_get_nr - find what system call a task is executing | ||
27 | * @task: task of interest, must be blocked | ||
28 | * @regs: task_pt_regs() of @task | ||
29 | * | ||
30 | * If @task is executing a system call or is at system call | ||
31 | * tracing about to attempt one, returns the system call number. | ||
32 | * If @task is not executing a system call, i.e. it's blocked | ||
33 | * inside the kernel for a fault or signal, returns -1. | ||
34 | * | ||
35 | * It's only valid to call this when @task is known to be blocked. | ||
36 | */ | ||
37 | long syscall_get_nr(struct task_struct *task, struct pt_regs *regs); | ||
38 | |||
39 | /** | ||
40 | * syscall_rollback - roll back registers after an aborted system call | ||
41 | * @task: task of interest, must be in system call exit tracing | ||
42 | * @regs: task_pt_regs() of @task | ||
43 | * | ||
44 | * It's only valid to call this when @task is stopped for system | ||
45 | * call exit tracing (due to TIF_SYSCALL_TRACE or TIF_SYSCALL_AUDIT), | ||
46 | * after tracehook_report_syscall_entry() returned nonzero to prevent | ||
47 | * the system call from taking place. | ||
48 | * | ||
49 | * This rolls back the register state in @regs so it's as if the | ||
50 | * system call instruction was a no-op. The registers containing | ||
51 | * the system call number and arguments are as they were before the | ||
52 | * system call instruction. This may not be the same as what the | ||
53 | * register state looked like at system call entry tracing. | ||
54 | */ | ||
55 | void syscall_rollback(struct task_struct *task, struct pt_regs *regs); | ||
56 | |||
57 | /** | ||
58 | * syscall_get_error - check result of traced system call | ||
59 | * @task: task of interest, must be blocked | ||
60 | * @regs: task_pt_regs() of @task | ||
61 | * | ||
62 | * Returns 0 if the system call succeeded, or -ERRORCODE if it failed. | ||
63 | * | ||
64 | * It's only valid to call this when @task is stopped for tracing on exit | ||
65 | * from a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT. | ||
66 | */ | ||
67 | long syscall_get_error(struct task_struct *task, struct pt_regs *regs); | ||
68 | |||
69 | /** | ||
70 | * syscall_get_return_value - get the return value of a traced system call | ||
71 | * @task: task of interest, must be blocked | ||
72 | * @regs: task_pt_regs() of @task | ||
73 | * | ||
74 | * Returns the return value of the successful system call. | ||
75 | * This value is meaningless if syscall_get_error() returned nonzero. | ||
76 | * | ||
77 | * It's only valid to call this when @task is stopped for tracing on exit | ||
78 | * from a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT. | ||
79 | */ | ||
80 | long syscall_get_return_value(struct task_struct *task, struct pt_regs *regs); | ||
81 | |||
82 | /** | ||
83 | * syscall_set_return_value - change the return value of a traced system call | ||
84 | * @task: task of interest, must be blocked | ||
85 | * @regs: task_pt_regs() of @task | ||
86 | * @error: negative error code, or zero to indicate success | ||
87 | * @val: user return value if @error is zero | ||
88 | * | ||
89 | * This changes the results of the system call that user mode will see. | ||
90 | * If @error is zero, the user sees a successful system call with a | ||
91 | * return value of @val. If @error is nonzero, it's a negated errno | ||
92 | * code; the user sees a failed system call with this errno code. | ||
93 | * | ||
94 | * It's only valid to call this when @task is stopped for tracing on exit | ||
95 | * from a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT. | ||
96 | */ | ||
97 | void syscall_set_return_value(struct task_struct *task, struct pt_regs *regs, | ||
98 | int error, long val); | ||
99 | |||
100 | /** | ||
101 | * syscall_get_arguments - extract system call parameter values | ||
102 | * @task: task of interest, must be blocked | ||
103 | * @regs: task_pt_regs() of @task | ||
104 | * @i: argument index [0,5] | ||
105 | * @n: number of arguments; n+i must be [1,6]. | ||
106 | * @args: array filled with argument values | ||
107 | * | ||
108 | * Fetches @n arguments to the system call starting with the @i'th argument | ||
109 | * (from 0 through 5). Argument @i is stored in @args[0], and so on. | ||
110 | * An arch inline version is probably optimal when @i and @n are constants. | ||
111 | * | ||
112 | * It's only valid to call this when @task is stopped for tracing on | ||
113 | * entry to a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT. | ||
114 | * It's invalid to call this with @i + @n > 6; we only support system calls | ||
115 | * taking up to 6 arguments. | ||
116 | */ | ||
117 | void syscall_get_arguments(struct task_struct *task, struct pt_regs *regs, | ||
118 | unsigned int i, unsigned int n, unsigned long *args); | ||
119 | |||
120 | /** | ||
121 | * syscall_set_arguments - change system call parameter value | ||
122 | * @task: task of interest, must be in system call entry tracing | ||
123 | * @regs: task_pt_regs() of @task | ||
124 | * @i: argument index [0,5] | ||
125 | * @n: number of arguments; n+i must be [1,6]. | ||
126 | * @args: array of argument values to store | ||
127 | * | ||
128 | * Changes @n arguments to the system call starting with the @i'th argument. | ||
129 | * @n'th argument to @val. Argument @i gets value @args[0], and so on. | ||
130 | * An arch inline version is probably optimal when @i and @n are constants. | ||
131 | * | ||
132 | * It's only valid to call this when @task is stopped for tracing on | ||
133 | * entry to a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT. | ||
134 | * It's invalid to call this with @i + @n > 6; we only support system calls | ||
135 | * taking up to 6 arguments. | ||
136 | */ | ||
137 | void syscall_set_arguments(struct task_struct *task, struct pt_regs *regs, | ||
138 | unsigned int i, unsigned int n, | ||
139 | const unsigned long *args); | ||
140 | |||
141 | #endif /* _ASM_SYSCALL_H */ | ||
diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h index 32867ab86c70..589f429619c9 100644 --- a/include/linux/tracehook.h +++ b/include/linux/tracehook.h | |||
@@ -103,7 +103,8 @@ static inline void ptrace_report_syscall(struct pt_regs *regs) | |||
103 | * the system call. That must prevent normal entry so no system call is | 103 | * the system call. That must prevent normal entry so no system call is |
104 | * made. If @task ever returns to user mode after this, its register state | 104 | * made. If @task ever returns to user mode after this, its register state |
105 | * is unspecified, but should be something harmless like an %ENOSYS error | 105 | * is unspecified, but should be something harmless like an %ENOSYS error |
106 | * return. | 106 | * return. It should preserve enough information so that syscall_rollback() |
107 | * can work (see asm-generic/syscall.h). | ||
107 | * | 108 | * |
108 | * Called without locks, just after entering kernel mode. | 109 | * Called without locks, just after entering kernel mode. |
109 | */ | 110 | */ |