xref: /linux/tools/perf/util/srcline.c (revision cc04a46f11ea046ed53e2c832ae29e4790f7e35f)
1 #include <stdio.h>
2 #include <stdlib.h>
3 #include <string.h>
4 
5 #include <linux/kernel.h>
6 
7 #include "util/dso.h"
8 #include "util/util.h"
9 #include "util/debug.h"
10 
11 #include "symbol.h"
12 
13 bool srcline_full_filename;
14 
15 #ifdef HAVE_LIBBFD_SUPPORT
16 
17 /*
18  * Implement addr2line using libbfd.
19  */
20 #define PACKAGE "perf"
21 #include <bfd.h>
22 
23 struct a2l_data {
24 	const char 	*input;
25 	u64	 	addr;
26 
27 	bool 		found;
28 	const char 	*filename;
29 	const char 	*funcname;
30 	unsigned 	line;
31 
32 	bfd 		*abfd;
33 	asymbol 	**syms;
34 };
35 
36 static int bfd_error(const char *string)
37 {
38 	const char *errmsg;
39 
40 	errmsg = bfd_errmsg(bfd_get_error());
41 	fflush(stdout);
42 
43 	if (string)
44 		pr_debug("%s: %s\n", string, errmsg);
45 	else
46 		pr_debug("%s\n", errmsg);
47 
48 	return -1;
49 }
50 
51 static int slurp_symtab(bfd *abfd, struct a2l_data *a2l)
52 {
53 	long storage;
54 	long symcount;
55 	asymbol **syms;
56 	bfd_boolean dynamic = FALSE;
57 
58 	if ((bfd_get_file_flags(abfd) & HAS_SYMS) == 0)
59 		return bfd_error(bfd_get_filename(abfd));
60 
61 	storage = bfd_get_symtab_upper_bound(abfd);
62 	if (storage == 0L) {
63 		storage = bfd_get_dynamic_symtab_upper_bound(abfd);
64 		dynamic = TRUE;
65 	}
66 	if (storage < 0L)
67 		return bfd_error(bfd_get_filename(abfd));
68 
69 	syms = malloc(storage);
70 	if (dynamic)
71 		symcount = bfd_canonicalize_dynamic_symtab(abfd, syms);
72 	else
73 		symcount = bfd_canonicalize_symtab(abfd, syms);
74 
75 	if (symcount < 0) {
76 		free(syms);
77 		return bfd_error(bfd_get_filename(abfd));
78 	}
79 
80 	a2l->syms = syms;
81 	return 0;
82 }
83 
84 static void find_address_in_section(bfd *abfd, asection *section, void *data)
85 {
86 	bfd_vma pc, vma;
87 	bfd_size_type size;
88 	struct a2l_data *a2l = data;
89 
90 	if (a2l->found)
91 		return;
92 
93 	if ((bfd_get_section_flags(abfd, section) & SEC_ALLOC) == 0)
94 		return;
95 
96 	pc = a2l->addr;
97 	vma = bfd_get_section_vma(abfd, section);
98 	size = bfd_get_section_size(section);
99 
100 	if (pc < vma || pc >= vma + size)
101 		return;
102 
103 	a2l->found = bfd_find_nearest_line(abfd, section, a2l->syms, pc - vma,
104 					   &a2l->filename, &a2l->funcname,
105 					   &a2l->line);
106 }
107 
108 static struct a2l_data *addr2line_init(const char *path)
109 {
110 	bfd *abfd;
111 	struct a2l_data *a2l = NULL;
112 
113 	abfd = bfd_openr(path, NULL);
114 	if (abfd == NULL)
115 		return NULL;
116 
117 	if (!bfd_check_format(abfd, bfd_object))
118 		goto out;
119 
120 	a2l = zalloc(sizeof(*a2l));
121 	if (a2l == NULL)
122 		goto out;
123 
124 	a2l->abfd = abfd;
125 	a2l->input = strdup(path);
126 	if (a2l->input == NULL)
127 		goto out;
128 
129 	if (slurp_symtab(abfd, a2l))
130 		goto out;
131 
132 	return a2l;
133 
134 out:
135 	if (a2l) {
136 		zfree((char **)&a2l->input);
137 		free(a2l);
138 	}
139 	bfd_close(abfd);
140 	return NULL;
141 }
142 
143 static void addr2line_cleanup(struct a2l_data *a2l)
144 {
145 	if (a2l->abfd)
146 		bfd_close(a2l->abfd);
147 	zfree((char **)&a2l->input);
148 	zfree(&a2l->syms);
149 	free(a2l);
150 }
151 
152 static int addr2line(const char *dso_name, u64 addr,
153 		     char **file, unsigned int *line, struct dso *dso)
154 {
155 	int ret = 0;
156 	struct a2l_data *a2l = dso->a2l;
157 
158 	if (!a2l) {
159 		dso->a2l = addr2line_init(dso_name);
160 		a2l = dso->a2l;
161 	}
162 
163 	if (a2l == NULL) {
164 		pr_warning("addr2line_init failed for %s\n", dso_name);
165 		return 0;
166 	}
167 
168 	a2l->addr = addr;
169 	a2l->found = false;
170 
171 	bfd_map_over_sections(a2l->abfd, find_address_in_section, a2l);
172 
173 	if (a2l->found && a2l->filename) {
174 		*file = strdup(a2l->filename);
175 		*line = a2l->line;
176 
177 		if (*file)
178 			ret = 1;
179 	}
180 
181 	return ret;
182 }
183 
184 void dso__free_a2l(struct dso *dso)
185 {
186 	struct a2l_data *a2l = dso->a2l;
187 
188 	if (!a2l)
189 		return;
190 
191 	addr2line_cleanup(a2l);
192 
193 	dso->a2l = NULL;
194 }
195 
196 #else /* HAVE_LIBBFD_SUPPORT */
197 
198 static int addr2line(const char *dso_name, u64 addr,
199 		     char **file, unsigned int *line_nr,
200 		     struct dso *dso __maybe_unused)
201 {
202 	FILE *fp;
203 	char cmd[PATH_MAX];
204 	char *filename = NULL;
205 	size_t len;
206 	char *sep;
207 	int ret = 0;
208 
209 	scnprintf(cmd, sizeof(cmd), "addr2line -e %s %016"PRIx64,
210 		  dso_name, addr);
211 
212 	fp = popen(cmd, "r");
213 	if (fp == NULL) {
214 		pr_warning("popen failed for %s\n", dso_name);
215 		return 0;
216 	}
217 
218 	if (getline(&filename, &len, fp) < 0 || !len) {
219 		pr_warning("addr2line has no output for %s\n", dso_name);
220 		goto out;
221 	}
222 
223 	sep = strchr(filename, '\n');
224 	if (sep)
225 		*sep = '\0';
226 
227 	if (!strcmp(filename, "??:0")) {
228 		pr_debug("no debugging info in %s\n", dso_name);
229 		free(filename);
230 		goto out;
231 	}
232 
233 	sep = strchr(filename, ':');
234 	if (sep) {
235 		*sep++ = '\0';
236 		*file = filename;
237 		*line_nr = strtoul(sep, NULL, 0);
238 		ret = 1;
239 	}
240 out:
241 	pclose(fp);
242 	return ret;
243 }
244 
245 void dso__free_a2l(struct dso *dso __maybe_unused)
246 {
247 }
248 
249 #endif /* HAVE_LIBBFD_SUPPORT */
250 
251 /*
252  * Number of addr2line failures (without success) before disabling it for that
253  * dso.
254  */
255 #define A2L_FAIL_LIMIT 123
256 
257 char *get_srcline(struct dso *dso, u64 addr, struct symbol *sym,
258 		  bool show_sym)
259 {
260 	char *file = NULL;
261 	unsigned line = 0;
262 	char *srcline;
263 	const char *dso_name;
264 
265 	if (!dso->has_srcline)
266 		goto out;
267 
268 	if (dso->symsrc_filename)
269 		dso_name = dso->symsrc_filename;
270 	else
271 		dso_name = dso->long_name;
272 
273 	if (dso_name[0] == '[')
274 		goto out;
275 
276 	if (!strncmp(dso_name, "/tmp/perf-", 10))
277 		goto out;
278 
279 	if (!addr2line(dso_name, addr, &file, &line, dso))
280 		goto out;
281 
282 	if (asprintf(&srcline, "%s:%u",
283 				srcline_full_filename ? file : basename(file),
284 				line) < 0) {
285 		free(file);
286 		goto out;
287 	}
288 
289 	dso->a2l_fails = 0;
290 
291 	free(file);
292 	return srcline;
293 
294 out:
295 	if (dso->a2l_fails && ++dso->a2l_fails > A2L_FAIL_LIMIT) {
296 		dso->has_srcline = 0;
297 		dso__free_a2l(dso);
298 	}
299 	if (sym) {
300 		if (asprintf(&srcline, "%s+%" PRIu64, show_sym ? sym->name : "",
301 					addr - sym->start) < 0)
302 			return SRCLINE_UNKNOWN;
303 	} else if (asprintf(&srcline, "%s[%" PRIx64 "]", dso->short_name, addr) < 0)
304 		return SRCLINE_UNKNOWN;
305 	return srcline;
306 }
307 
308 void free_srcline(char *srcline)
309 {
310 	if (srcline && strcmp(srcline, SRCLINE_UNKNOWN) != 0)
311 		free(srcline);
312 }
313