1 /* $OpenBSD: bt_parser.h,v 1.13 2021/02/08 09:46:45 mpi Exp $ */ 2 3 /* 4 * Copyright (c) 2019-2021 Martin Pieuchot <mpi@openbsd.org> 5 * 6 * Permission to use, copy, modify, and distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 * 10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 */ 18 19 #ifndef BT_PARSER_H 20 #define BT_PARSER_H 21 22 #ifndef nitems 23 #define nitems(_a) (sizeof((_a)) / sizeof((_a)[0])) 24 #endif 25 26 /* 27 * Probes represent entry points where events can be recorded. 28 * 29 * Those specified in a given bt(5) script are enabled at runtime. They 30 * are represented as: 31 * 32 * "provider:function:name" 33 * or 34 * "provider:time_unit:rate" 35 */ 36 struct bt_probe { 37 const char *bp_prov; /* provider */ 38 const char *bp_func; /* function or time unit */ 39 const char *bp_name; 40 uint32_t bp_rate; 41 #define bp_unit bp_func 42 }; 43 44 45 /* 46 * Event filters correspond to checks performed in-kernel. 47 */ 48 struct bt_evtfilter { 49 int bf_op; 50 enum bt_filtervar { 51 B_FV_NONE = 1, 52 B_FV_PID, 53 B_FV_TID 54 } bf_var; 55 uint32_t bf_val; 56 }; 57 58 /* 59 * Filters, also known as predicates, describe under which set of 60 * conditions a rule is executed. 61 * 62 * Depending on their type they are performed in-kernel or when a rule 63 * is evaluated. In the first case they might prevent the recording of 64 * events, in the second case events might be discarded at runtime. 65 */ 66 struct bt_filter { 67 struct bt_evtfilter bf_evtfilter; /* in-kernel event filter */ 68 struct bt_stmt *bf_condition; /* per event condition */ 69 }; 70 71 TAILQ_HEAD(bt_ruleq, bt_rule); 72 73 /* 74 * A rule is the language representation of which 'action' to attach to 75 * which 'probe' under which conditions ('filter'). In other words it 76 * represents the following: 77 * 78 * probe / filter / { action } 79 */ 80 struct bt_rule { 81 TAILQ_ENTRY(bt_rule) br_next; /* linkage in global list */ 82 struct bt_probe *br_probe; 83 struct bt_filter *br_filter; 84 SLIST_HEAD(, bt_stmt) br_action; 85 86 enum bt_rtype { 87 B_RT_BEGIN = 1, 88 B_RT_END, 89 B_RT_PROBE, 90 } br_type; /* BEGIN, END or 'probe' */ 91 92 uint32_t br_pbn; /* ID assigned by the kernel */ 93 void *br_cookie; 94 }; 95 96 /* 97 * Global variable representation. 98 * 99 * Variables are untyped and also include maps and histograms. 100 */ 101 struct bt_var { 102 SLIST_ENTRY(bt_var) bv_next; /* linkage in global list */ 103 const char *bv_name; /* name of the variable */ 104 struct bt_arg *bv_value; /* corresponding value */ 105 }; 106 107 /* 108 * Respresentation of an argument. 109 * 110 * A so called "argument" can be any symbol representing a value or 111 * a combination of those through an operation. 112 */ 113 struct bt_arg { 114 SLIST_ENTRY(bt_arg) ba_next; 115 void *ba_value; 116 struct bt_arg *ba_key; /* key for maps/histograms */ 117 enum bt_argtype { 118 B_AT_STR = 1, /* C-style string */ 119 B_AT_LONG, /* Number (integer) */ 120 B_AT_VAR, /* global variable (@var) */ 121 B_AT_MAP, /* global map (@map[]) */ 122 B_AT_HIST, /* histogram */ 123 124 B_AT_BI_PID, 125 B_AT_BI_TID, 126 B_AT_BI_COMM, 127 B_AT_BI_CPU, 128 B_AT_BI_NSECS, 129 B_AT_BI_KSTACK, 130 B_AT_BI_USTACK, 131 B_AT_BI_ARG0, 132 B_AT_BI_ARG1, 133 B_AT_BI_ARG2, 134 B_AT_BI_ARG3, 135 B_AT_BI_ARG4, 136 B_AT_BI_ARG5, 137 B_AT_BI_ARG6, 138 B_AT_BI_ARG7, 139 B_AT_BI_ARG8, 140 B_AT_BI_ARG9, 141 B_AT_BI_ARGS, 142 B_AT_BI_RETVAL, 143 144 B_AT_MF_COUNT, /* @map[key] = count() */ 145 B_AT_MF_MAX, /* @map[key] = max(nsecs) */ 146 B_AT_MF_MIN, /* @map[key] = min(pid) */ 147 B_AT_MF_SUM, /* @map[key] = sum(@elapsed) */ 148 149 B_AT_OP_PLUS, 150 B_AT_OP_MINUS, 151 B_AT_OP_MULT, 152 B_AT_OP_DIVIDE, 153 B_AT_OP_BAND, 154 B_AT_OP_BOR, 155 B_AT_OP_EQ, 156 B_AT_OP_NE, 157 B_AT_OP_LE, 158 B_AT_OP_GE, 159 B_AT_OP_LAND, 160 B_AT_OP_LOR, 161 } ba_type; 162 }; 163 164 #define BA_INITIALIZER(v, t) { { NULL }, (void *)(v), NULL, (t) } 165 166 /* 167 * Each action associated with a given probe is made of at least one 168 * statement. 169 * 170 * Statements are interpreted linearly in userland to format data 171 * recorded in the form of events. 172 */ 173 struct bt_stmt { 174 SLIST_ENTRY(bt_stmt) bs_next; 175 struct bt_var *bs_var; /* for STOREs */ 176 SLIST_HEAD(, bt_arg) bs_args; 177 enum bt_action { 178 B_AC_BUCKETIZE, /* @h = hist(42) */ 179 B_AC_CLEAR, /* clear(@map) */ 180 B_AC_DELETE, /* delete(@map[key]) */ 181 B_AC_EXIT, /* exit() */ 182 B_AC_INSERT, /* @map[key] = 42 */ 183 B_AC_PRINT, /* print(@map, 10) */ 184 B_AC_PRINTF, /* printf("hello!\n") */ 185 B_AC_STORE, /* @a = 3 */ 186 B_AC_TEST, /* if (@a) */ 187 B_AC_TIME, /* time("%H:%M:%S ") */ 188 B_AC_ZERO, /* zero(@map) */ 189 } bs_act; 190 }; 191 192 extern struct bt_ruleq g_rules; /* Successfully parsed rules. */ 193 extern int g_nprobes; /* # of probes to attach */ 194 195 int btparse(const char *, size_t, const char *, int); 196 197 #define ba_new(v, t) ba_new0((void *)(v), (t)) 198 struct bt_arg *ba_new0(void *, enum bt_argtype); 199 200 const char *bv_name(struct bt_var *); 201 202 void bm_insert(struct bt_var *, struct bt_arg *, 203 struct bt_arg *); 204 205 #endif /* BT_PARSER_H */ 206