/* $OpenBSD: bt_parser.h,v 1.27 2025/01/23 11:17:32 mpi Exp $ */ /* * Copyright (c) 2019-2021 Martin Pieuchot <mpi@openbsd.org> * * Permission to use, copy, modify, and distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ #ifndef BT_PARSER_H #define BT_PARSER_H #ifndef nitems #define nitems(_a) (sizeof((_a)) / sizeof((_a)[0])) #endif /* * Probes represent entry points where events can be recorded. * * Those specified in a given bt(5) script are enabled at runtime. They * are represented as: * * "provider:function:name" * or * "provider:time_unit:number" * * Multiple probes can be associated to the same action. */ struct bt_probe { SLIST_ENTRY(bt_probe) bp_next; /* next probe for this rule */ const char *bp_prov; /* provider */ const char *bp_func; /* function or time unit */ const char *bp_name; uint64_t bp_nsecs; #define bp_unit bp_func enum bt_ptype { B_PT_BEGIN = 1, B_PT_END, B_PT_PROBE, } bp_type; /* BEGIN, END or 'probe' */ void *bp_cookie; /* ioctl request */ uint32_t bp_pbn; /* ID assigned by the kernel */ }; /* * Event filters correspond to checks performed in-kernel. */ struct bt_evtfilter { int bf_op; enum bt_filtervar { B_FV_NONE = 1, B_FV_PID, B_FV_TID } bf_var; uint32_t bf_val; }; /* * Filters, also known as predicates, describe under which set of * conditions a rule is executed. * * They are performed when a rule is evaluated and events might be * discarded at runtime. */ struct bt_filter { struct bt_stmt *bf_condition; /* per event condition */ }; TAILQ_HEAD(bt_ruleq, bt_rule); /* * A rule is the language representation of which 'action' to attach to * which 'probe' under which conditions ('filter'). In other words it * represents the following: * * probe / filter / { action } */ struct bt_rule { TAILQ_ENTRY(bt_rule) br_next; /* linkage in global list */ SLIST_HEAD(, bt_probe) br_probes; /* list of probes */ struct bt_filter *br_filter; SLIST_HEAD(, bt_stmt) br_action; SLIST_HEAD(, bt_var) br_variables; /* local variables */ }; /* * Global and local variable representation. * * Variables are untyped and also include maps and histograms. */ struct bt_var { SLIST_ENTRY(bt_var) bv_next; /* linkage in global list */ const char *bv_name; /* name of the variable */ struct bt_arg *bv_value; /* corresponding value */ enum bt_vartype { B_VT_STR = 1, B_VT_LONG, B_VT_TUPLE, B_VT_MAP, B_VT_HIST, } bv_type; }; /* * Representation of an argument. * * A so called "argument" can be any symbol representing a value or * a combination of those through an operation. */ struct bt_arg { SLIST_ENTRY(bt_arg) ba_next; void *ba_value; struct bt_arg *ba_key; /* key for maps/histograms */ enum bt_argtype { B_AT_STR = 1, /* C-style string */ B_AT_LONG, /* Number (integer) */ B_AT_VAR, /* global/local variable */ B_AT_MAP, /* global map (@map[]) */ B_AT_HIST, /* histogram */ B_AT_TUPLE, /* tuple (1, 42, "str") */ B_AT_TMEMBER, /* tuple member $t.2 */ B_AT_NIL, /* empty value */ B_AT_BI_PID, B_AT_BI_TID, B_AT_BI_COMM, B_AT_BI_CPU, B_AT_BI_NSECS, B_AT_BI_KSTACK, B_AT_BI_USTACK, B_AT_BI_ARG0, B_AT_BI_ARG1, B_AT_BI_ARG2, B_AT_BI_ARG3, B_AT_BI_ARG4, B_AT_BI_ARG5, B_AT_BI_ARG6, B_AT_BI_ARG7, B_AT_BI_ARG8, B_AT_BI_ARG9, B_AT_BI_ARGS, B_AT_BI_RETVAL, B_AT_BI_PROBE, B_AT_FN_STR, /* str($1); str($1, 3); */ B_AT_MF_COUNT, /* @map[key] = count() */ B_AT_MF_MAX, /* @map[key] = max(nsecs) */ B_AT_MF_MIN, /* @map[key] = min(pid) */ B_AT_MF_SUM, /* @map[key] = sum(@elapsed) */ B_AT_OP_PLUS, B_AT_OP_MINUS, B_AT_OP_MULT, B_AT_OP_DIVIDE, B_AT_OP_MODULO, B_AT_OP_BAND, B_AT_OP_XOR, B_AT_OP_BOR, B_AT_OP_EQ, B_AT_OP_NE, B_AT_OP_LE, B_AT_OP_LT, B_AT_OP_GE, B_AT_OP_GT, B_AT_OP_LAND, B_AT_OP_LOR, } ba_type; }; #define BA_INITIALIZER(v, t) { { NULL }, (void *)(v), NULL, (t) } /* * Represents branches of an if-else statement. */ struct bt_cond { struct bt_stmt *bc_condbs; struct bt_stmt *bc_elsebs; }; /* * Each action associated with a given probe is made of at least one * statement. * * Statements are interpreted linearly in userland to format data * recorded in the form of events. */ struct bt_stmt { SLIST_ENTRY(bt_stmt) bs_next; struct bt_var *bs_var; /* for STOREs */ SLIST_HEAD(, bt_arg) bs_args; enum bt_action { B_AC_BUCKETIZE, /* @h = hist(42) */ B_AC_CLEAR, /* clear(@map) */ B_AC_DELETE, /* delete(@map[key]) */ B_AC_EXIT, /* exit() */ B_AC_INSERT, /* @map[key] = 42 */ B_AC_PRINT, /* print(@map, 10) */ B_AC_PRINTF, /* printf("hello!\n") */ B_AC_STORE, /* @a = 3 */ B_AC_TEST, /* if (@a) */ B_AC_TIME, /* time("%H:%M:%S ") */ B_AC_ZERO, /* zero(@map) */ } bs_act; }; extern struct bt_ruleq g_rules; /* Successfully parsed rules. */ extern int g_nprobes; /* # of probes to attach */ extern struct bt_arg g_nullba; extern struct bt_arg g_maxba; int btparse(const char *, size_t, const char *, int); #define ba_new(v, t) ba_new0((void *)(v), (t)) struct bt_arg *ba_new0(void *, enum bt_argtype); const char *bv_name(struct bt_var *); #endif /* BT_PARSER_H */
