xref: /freebsd/sys/kern/subr_stack.c (revision 39beb93c3f8bdbf72a61fda42300b5ebed7390c8)
1 /*-
2  * Copyright (c) 2005 Antoine Brodin
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include "opt_ddb.h"
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include <sys/param.h>
33 #include <sys/kernel.h>
34 #ifdef KTR
35 #include <sys/ktr.h>
36 #endif
37 #include <sys/linker.h>
38 #include <sys/malloc.h>
39 #include <sys/sbuf.h>
40 #include <sys/stack.h>
41 #include <sys/systm.h>
42 
43 static MALLOC_DEFINE(M_STACK, "stack", "Stack Traces");
44 
45 static void stack_symbol(vm_offset_t pc, char *namebuf, u_int buflen,
46 	    long *offset);
47 #ifdef DDB
48 static void stack_symbol_ddb(vm_offset_t pc, const char **name, long *offset);
49 #endif
50 
51 struct stack *
52 stack_create(void)
53 {
54 	struct stack *st;
55 
56 	st = malloc(sizeof *st, M_STACK, M_WAITOK | M_ZERO);
57 	return (st);
58 }
59 
60 void
61 stack_destroy(struct stack *st)
62 {
63 
64 	free(st, M_STACK);
65 }
66 
67 int
68 stack_put(struct stack *st, vm_offset_t pc)
69 {
70 
71 	if (st->depth < STACK_MAX) {
72 		st->pcs[st->depth++] = pc;
73 		return (0);
74 	} else
75 		return (-1);
76 }
77 
78 void
79 stack_copy(struct stack *src, struct stack *dst)
80 {
81 
82 	*dst = *src;
83 }
84 
85 void
86 stack_zero(struct stack *st)
87 {
88 
89 	bzero(st, sizeof *st);
90 }
91 
92 void
93 stack_print(struct stack *st)
94 {
95 	char namebuf[64];
96 	long offset;
97 	int i;
98 
99 	KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
100 	for (i = 0; i < st->depth; i++) {
101 		stack_symbol(st->pcs[i], namebuf, sizeof(namebuf), &offset);
102 		printf("#%d %p at %s+%#lx\n", i, (void *)st->pcs[i],
103 		    namebuf, offset);
104 	}
105 }
106 
107 #ifdef DDB
108 void
109 stack_print_ddb(struct stack *st)
110 {
111 	const char *name;
112 	long offset;
113 	int i;
114 
115 	KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
116 	for (i = 0; i < st->depth; i++) {
117 		stack_symbol_ddb(st->pcs[i], &name, &offset);
118 		printf("#%d %p at %s+%#lx\n", i, (void *)st->pcs[i],
119 		    name, offset);
120 	}
121 }
122 #endif
123 
124 /*
125  * Two print routines -- one for use from DDB and DDB-like contexts, the
126  * other for use in the live kernel.
127  */
128 void
129 stack_sbuf_print(struct sbuf *sb, struct stack *st)
130 {
131 	char namebuf[64];
132 	long offset;
133 	int i;
134 
135 	KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
136 	for (i = 0; i < st->depth; i++) {
137 		stack_symbol(st->pcs[i], namebuf, sizeof(namebuf), &offset);
138 		sbuf_printf(sb, "#%d %p at %s+%#lx\n", i, (void *)st->pcs[i],
139 		    namebuf, offset);
140 	}
141 }
142 
143 #ifdef DDB
144 void
145 stack_sbuf_print_ddb(struct sbuf *sb, struct stack *st)
146 {
147 	const char *name;
148 	long offset;
149 	int i;
150 
151 	KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
152 	for (i = 0; i < st->depth; i++) {
153 		stack_symbol_ddb(st->pcs[i], &name, &offset);
154 		sbuf_printf(sb, "#%d %p at %s+%#lx\n", i, (void *)st->pcs[i],
155 		    name, offset);
156 	}
157 }
158 #endif
159 
160 #ifdef KTR
161 void
162 stack_ktr(u_int mask, const char *file, int line, struct stack *st, u_int depth,
163     int cheap)
164 {
165 #ifdef DDB
166 	const char *name;
167 	long offset;
168 	int i;
169 #endif
170 
171 	KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
172 	if (cheap) {
173 		ktr_tracepoint(mask, file, line, "#0 %p %p %p %p %p %p",
174 		    st->pcs[0], st->pcs[1], st->pcs[2], st->pcs[3],
175 		    st->pcs[4], st->pcs[5]);
176 		if (st->depth <= 6)
177 			return;
178 		ktr_tracepoint(mask, file, line, "#1 %p %p %p %p %p %p",
179 		    st->pcs[6], st->pcs[7], st->pcs[8], st->pcs[9],
180 		    st->pcs[10], st->pcs[11]);
181 		if (st->depth <= 12)
182 			return;
183 		ktr_tracepoint(mask, file, line, "#2 %p %p %p %p %p %p",
184 		    st->pcs[12], st->pcs[13], st->pcs[14], st->pcs[15],
185 		    st->pcs[16], st->pcs[17]);
186 #ifdef DDB
187 	} else {
188 		if (depth == 0 || st->depth < depth)
189 			depth = st->depth;
190 		for (i = 0; i < depth; i++) {
191 			stack_symbol_ddb(st->pcs[i], &name, &offset);
192 			ktr_tracepoint(mask, file, line, "#%d %p at %s+%#lx",
193 			    i, st->pcs[i], (u_long)name, offset, 0, 0);
194 		}
195 #endif
196 	}
197 }
198 #endif
199 
200 /*
201  * Two variants of stack symbol lookup -- one that uses the DDB interfaces
202  * and bypasses linker locking, and the other that doesn't.
203  */
204 static void
205 stack_symbol(vm_offset_t pc, char *namebuf, u_int buflen, long *offset)
206 {
207 
208 	if (linker_search_symbol_name((caddr_t)pc, namebuf, buflen,
209 	    offset) != 0) {
210 		*offset = 0;
211 		strlcpy(namebuf, "??", buflen);
212 	}
213 }
214 
215 #ifdef DDB
216 static void
217 stack_symbol_ddb(vm_offset_t pc, const char **name, long *offset)
218 {
219 	linker_symval_t symval;
220 	c_linker_sym_t sym;
221 
222 	if (linker_ddb_search_symbol((caddr_t)pc, &sym, offset) != 0)
223 		goto out;
224 	if (linker_ddb_symbol_values(sym, &symval) != 0)
225 		goto out;
226 	if (symval.name != NULL) {
227 		*name = symval.name;
228 		return;
229 	}
230  out:
231 	*offset = 0;
232 	*name = "??";
233 }
234 #endif
235