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1 | #ifndef _LTTNG_FILTER_H |
2 | #define _LTTNG_FILTER_H | |
3 | ||
4 | /* | |
5 | * lttng-filter.h | |
6 | * | |
7 | * LTTng modules filter header. | |
8 | * | |
9 | * Copyright (C) 2010-2014 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
10 | * | |
11 | * This library is free software; you can redistribute it and/or | |
12 | * modify it under the terms of the GNU Lesser General Public | |
13 | * License as published by the Free Software Foundation; only | |
14 | * version 2.1 of the License. | |
15 | * | |
16 | * This library is distributed in the hope that it will be useful, | |
17 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
19 | * Lesser General Public License for more details. | |
20 | * | |
21 | * You should have received a copy of the GNU Lesser General Public | |
22 | * License along with this library; if not, write to the Free Software | |
23 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
24 | */ | |
25 | ||
26 | #include <linux/kernel.h> | |
27 | ||
28 | #include "lttng-events.h" | |
29 | #include "filter-bytecode.h" | |
30 | ||
31 | /* Filter stack length, in number of entries */ | |
32 | #define FILTER_STACK_LEN 10 /* includes 2 dummy */ | |
33 | #define FILTER_STACK_EMPTY 1 | |
34 | ||
35 | #ifdef DEBUG | |
36 | #define dbg_printk(fmt, args...) \ | |
37 | printk(KERN_DEBUG "[debug bytecode in %s:%s@%u] " fmt, \ | |
38 | __FILE__, __func__, __LINE__, ## args) | |
39 | #else | |
40 | #define dbg_printk(fmt, args...) \ | |
41 | do { \ | |
42 | /* do nothing but check printf format */ \ | |
43 | if (0) \ | |
44 | printk(KERN_DEBUG "[debug bytecode in %s:%s@%u] " fmt, \ | |
45 | __FILE__, __func__, __LINE__, ## args); \ | |
46 | } while (0) | |
47 | #endif | |
48 | ||
49 | /* Linked bytecode. Child of struct lttng_bytecode_runtime. */ | |
50 | struct bytecode_runtime { | |
51 | struct lttng_bytecode_runtime p; | |
52 | uint16_t len; | |
53 | char data[0]; | |
54 | }; | |
55 | ||
56 | enum entry_type { | |
57 | REG_S64, | |
58 | REG_DOUBLE, | |
59 | REG_STRING, | |
60 | REG_TYPE_UNKNOWN, | |
61 | }; | |
62 | ||
63 | /* Validation stack */ | |
64 | struct vstack_entry { | |
65 | enum entry_type type; | |
66 | }; | |
67 | ||
68 | struct vstack { | |
69 | int top; /* top of stack */ | |
70 | struct vstack_entry e[FILTER_STACK_LEN]; | |
71 | }; | |
72 | ||
73 | static inline | |
74 | void vstack_init(struct vstack *stack) | |
75 | { | |
76 | stack->top = -1; | |
77 | } | |
78 | ||
79 | static inline | |
80 | struct vstack_entry *vstack_ax(struct vstack *stack) | |
81 | { | |
82 | if (unlikely(stack->top < 0)) | |
83 | return NULL; | |
84 | return &stack->e[stack->top]; | |
85 | } | |
86 | ||
87 | static inline | |
88 | struct vstack_entry *vstack_bx(struct vstack *stack) | |
89 | { | |
90 | if (unlikely(stack->top < 1)) | |
91 | return NULL; | |
92 | return &stack->e[stack->top - 1]; | |
93 | } | |
94 | ||
95 | static inline | |
96 | int vstack_push(struct vstack *stack) | |
97 | { | |
98 | if (stack->top >= FILTER_STACK_LEN - 1) { | |
99 | printk(KERN_WARNING "Stack full\n"); | |
100 | return -EINVAL; | |
101 | } | |
102 | ++stack->top; | |
103 | return 0; | |
104 | } | |
105 | ||
106 | static inline | |
107 | int vstack_pop(struct vstack *stack) | |
108 | { | |
109 | if (unlikely(stack->top < 0)) { | |
110 | printk(KERN_WARNING "Stack empty\n"); | |
111 | return -EINVAL; | |
112 | } | |
113 | stack->top--; | |
114 | return 0; | |
115 | } | |
116 | ||
117 | /* Execution stack */ | |
118 | struct estack_entry { | |
119 | union { | |
120 | int64_t v; | |
121 | ||
122 | struct { | |
123 | const char *str; | |
f127e61e | 124 | const char __user *user_str; |
07dfc1d0 MD |
125 | size_t seq_len; |
126 | int literal; /* is string literal ? */ | |
f127e61e | 127 | int user; /* is string from userspace ? */ |
07dfc1d0 MD |
128 | } s; |
129 | } u; | |
130 | }; | |
131 | ||
132 | struct estack { | |
133 | int top; /* top of stack */ | |
134 | struct estack_entry e[FILTER_STACK_LEN]; | |
135 | }; | |
136 | ||
137 | #define estack_ax_v ax | |
138 | #define estack_bx_v bx | |
139 | ||
140 | #define estack_ax(stack, top) \ | |
141 | ({ \ | |
142 | WARN_ON_ONCE((top) <= FILTER_STACK_EMPTY); \ | |
143 | &(stack)->e[top]; \ | |
144 | }) | |
145 | ||
146 | #define estack_bx(stack, top) \ | |
147 | ({ \ | |
148 | WARN_ON_ONCE((top) <= FILTER_STACK_EMPTY + 1); \ | |
149 | &(stack)->e[(top) - 1]; \ | |
150 | }) | |
151 | ||
152 | #define estack_push(stack, top, ax, bx) \ | |
153 | do { \ | |
154 | WARN_ON_ONCE((top) >= FILTER_STACK_LEN - 1); \ | |
155 | (stack)->e[(top) - 1].u.v = (bx); \ | |
156 | (bx) = (ax); \ | |
157 | ++(top); \ | |
158 | } while (0) | |
159 | ||
160 | #define estack_pop(stack, top, ax, bx) \ | |
161 | do { \ | |
162 | WARN_ON_ONCE((top) <= FILTER_STACK_EMPTY); \ | |
163 | (ax) = (bx); \ | |
164 | (bx) = (stack)->e[(top) - 2].u.v; \ | |
165 | (top)--; \ | |
166 | } while (0) | |
167 | ||
168 | const char *lttng_filter_print_op(enum filter_op op); | |
169 | ||
170 | int lttng_filter_validate_bytecode(struct bytecode_runtime *bytecode); | |
171 | int lttng_filter_specialize_bytecode(struct bytecode_runtime *bytecode); | |
172 | ||
173 | uint64_t lttng_filter_false(void *filter_data, | |
174 | const char *filter_stack_data); | |
175 | uint64_t lttng_filter_interpret_bytecode(void *filter_data, | |
176 | const char *filter_stack_data); | |
177 | ||
178 | #endif /* _LTTNG_FILTER_H */ |