xref: /openbmc/linux/tools/perf/jvmti/libjvmti.c (revision 98ddec80)
1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/compiler.h>
3 #include <sys/types.h>
4 #include <stdio.h>
5 #include <string.h>
6 #include <stdlib.h>
7 #include <err.h>
8 #include <jvmti.h>
9 #include <jvmticmlr.h>
10 #include <limits.h>
11 
12 #include "jvmti_agent.h"
13 
14 static int has_line_numbers;
15 void *jvmti_agent;
16 
17 static void print_error(jvmtiEnv *jvmti, const char *msg, jvmtiError ret)
18 {
19 	char *err_msg = NULL;
20 	jvmtiError err;
21 	err = (*jvmti)->GetErrorName(jvmti, ret, &err_msg);
22 	if (err == JVMTI_ERROR_NONE) {
23 		warnx("%s failed with %s", msg, err_msg);
24 		(*jvmti)->Deallocate(jvmti, (unsigned char *)err_msg);
25 	} else {
26 		warnx("%s failed with an unknown error %d", msg, ret);
27 	}
28 }
29 
30 static jvmtiError
31 do_get_line_numbers(jvmtiEnv *jvmti, void *pc, jmethodID m, jint bci,
32 		    jvmti_line_info_t *tab, jint *nr)
33 {
34 	jint i, lines = 0;
35 	jint nr_lines = 0;
36 	jvmtiLineNumberEntry *loc_tab = NULL;
37 	jvmtiError ret;
38 
39 	ret = (*jvmti)->GetLineNumberTable(jvmti, m, &nr_lines, &loc_tab);
40 	if (ret != JVMTI_ERROR_NONE) {
41 		print_error(jvmti, "GetLineNumberTable", ret);
42 		return ret;
43 	}
44 
45 	for (i = 0; i < nr_lines; i++) {
46 		if (loc_tab[i].start_location < bci) {
47 			tab[lines].pc = (unsigned long)pc;
48 			tab[lines].line_number = loc_tab[i].line_number;
49 			tab[lines].discrim = 0; /* not yet used */
50 			tab[lines].methodID = m;
51 			lines++;
52 		} else {
53 			break;
54 		}
55 	}
56 	(*jvmti)->Deallocate(jvmti, (unsigned char *)loc_tab);
57 	*nr = lines;
58 	return JVMTI_ERROR_NONE;
59 }
60 
61 static jvmtiError
62 get_line_numbers(jvmtiEnv *jvmti, const void *compile_info, jvmti_line_info_t **tab, int *nr_lines)
63 {
64 	const jvmtiCompiledMethodLoadRecordHeader *hdr;
65 	jvmtiCompiledMethodLoadInlineRecord *rec;
66 	jvmtiLineNumberEntry *lne = NULL;
67 	PCStackInfo *c;
68 	jint nr, ret;
69 	int nr_total = 0;
70 	int i, lines_total = 0;
71 
72 	if (!(tab && nr_lines))
73 		return JVMTI_ERROR_NULL_POINTER;
74 
75 	/*
76 	 * Phase 1 -- get the number of lines necessary
77 	 */
78 	for (hdr = compile_info; hdr != NULL; hdr = hdr->next) {
79 		if (hdr->kind == JVMTI_CMLR_INLINE_INFO) {
80 			rec = (jvmtiCompiledMethodLoadInlineRecord *)hdr;
81 			for (i = 0; i < rec->numpcs; i++) {
82 				c = rec->pcinfo + i;
83 				nr = 0;
84 				/*
85 				 * unfortunately, need a tab to get the number of lines!
86 				 */
87 				ret = (*jvmti)->GetLineNumberTable(jvmti, c->methods[0], &nr, &lne);
88 				if (ret == JVMTI_ERROR_NONE) {
89 					/* free what was allocated for nothing */
90 					(*jvmti)->Deallocate(jvmti, (unsigned char *)lne);
91 					nr_total += (int)nr;
92 				} else {
93 					print_error(jvmti, "GetLineNumberTable", ret);
94 				}
95 			}
96 		}
97 	}
98 
99 	if (nr_total == 0)
100 		return JVMTI_ERROR_NOT_FOUND;
101 
102 	/*
103 	 * Phase 2 -- allocate big enough line table
104 	 */
105 	*tab = malloc(nr_total * sizeof(**tab));
106 	if (!*tab)
107 		return JVMTI_ERROR_OUT_OF_MEMORY;
108 
109 	for (hdr = compile_info; hdr != NULL; hdr = hdr->next) {
110 		if (hdr->kind == JVMTI_CMLR_INLINE_INFO) {
111 			rec = (jvmtiCompiledMethodLoadInlineRecord *)hdr;
112 			for (i = 0; i < rec->numpcs; i++) {
113 				c = rec->pcinfo + i;
114 				nr = 0;
115 				ret = do_get_line_numbers(jvmti, c->pc,
116 							  c->methods[0],
117 							  c->bcis[0],
118 							  *tab + lines_total,
119 							  &nr);
120 				if (ret == JVMTI_ERROR_NONE)
121 					lines_total += nr;
122 			}
123 		}
124 	}
125 	*nr_lines = lines_total;
126 	return JVMTI_ERROR_NONE;
127 }
128 
129 static void
130 copy_class_filename(const char * class_sign, const char * file_name, char * result, size_t max_length)
131 {
132 	/*
133 	* Assume path name is class hierarchy, this is a common practice with Java programs
134 	*/
135 	if (*class_sign == 'L') {
136 		int j, i = 0;
137 		char *p = strrchr(class_sign, '/');
138 		if (p) {
139 			/* drop the 'L' prefix and copy up to the final '/' */
140 			for (i = 0; i < (p - class_sign); i++)
141 				result[i] = class_sign[i+1];
142 		}
143 		/*
144 		* append file name, we use loops and not string ops to avoid modifying
145 		* class_sign which is used later for the symbol name
146 		*/
147 		for (j = 0; i < (max_length - 1) && file_name && j < strlen(file_name); j++, i++)
148 			result[i] = file_name[j];
149 
150 		result[i] = '\0';
151 	} else {
152 		/* fallback case */
153 		size_t file_name_len = strlen(file_name);
154 		strncpy(result, file_name, file_name_len < max_length ? file_name_len : max_length);
155 	}
156 }
157 
158 static jvmtiError
159 get_source_filename(jvmtiEnv *jvmti, jmethodID methodID, char ** buffer)
160 {
161 	jvmtiError ret;
162 	jclass decl_class;
163 	char *file_name = NULL;
164 	char *class_sign = NULL;
165 	char fn[PATH_MAX];
166 	size_t len;
167 
168 	ret = (*jvmti)->GetMethodDeclaringClass(jvmti, methodID, &decl_class);
169 	if (ret != JVMTI_ERROR_NONE) {
170 		print_error(jvmti, "GetMethodDeclaringClass", ret);
171 		return ret;
172 	}
173 
174 	ret = (*jvmti)->GetSourceFileName(jvmti, decl_class, &file_name);
175 	if (ret != JVMTI_ERROR_NONE) {
176 		print_error(jvmti, "GetSourceFileName", ret);
177 		return ret;
178 	}
179 
180 	ret = (*jvmti)->GetClassSignature(jvmti, decl_class, &class_sign, NULL);
181 	if (ret != JVMTI_ERROR_NONE) {
182 		print_error(jvmti, "GetClassSignature", ret);
183 		goto free_file_name_error;
184 	}
185 
186 	copy_class_filename(class_sign, file_name, fn, PATH_MAX);
187 	len = strlen(fn);
188 	*buffer = malloc((len + 1) * sizeof(char));
189 	if (!*buffer) {
190 		print_error(jvmti, "GetClassSignature", ret);
191 		ret = JVMTI_ERROR_OUT_OF_MEMORY;
192 		goto free_class_sign_error;
193 	}
194 	strcpy(*buffer, fn);
195 	ret = JVMTI_ERROR_NONE;
196 
197 free_class_sign_error:
198 	(*jvmti)->Deallocate(jvmti, (unsigned char *)class_sign);
199 free_file_name_error:
200 	(*jvmti)->Deallocate(jvmti, (unsigned char *)file_name);
201 
202 	return ret;
203 }
204 
205 static jvmtiError
206 fill_source_filenames(jvmtiEnv *jvmti, int nr_lines,
207 		      const jvmti_line_info_t * line_tab,
208 		      char ** file_names)
209 {
210 	int index;
211 	jvmtiError ret;
212 
213 	for (index = 0; index < nr_lines; ++index) {
214 		ret = get_source_filename(jvmti, line_tab[index].methodID, &(file_names[index]));
215 		if (ret != JVMTI_ERROR_NONE)
216 			return ret;
217 	}
218 
219 	return JVMTI_ERROR_NONE;
220 }
221 
222 static void JNICALL
223 compiled_method_load_cb(jvmtiEnv *jvmti,
224 			jmethodID method,
225 			jint code_size,
226 			void const *code_addr,
227 			jint map_length,
228 			jvmtiAddrLocationMap const *map,
229 			const void *compile_info)
230 {
231 	jvmti_line_info_t *line_tab = NULL;
232 	char ** line_file_names = NULL;
233 	jclass decl_class;
234 	char *class_sign = NULL;
235 	char *func_name = NULL;
236 	char *func_sign = NULL;
237 	char *file_name = NULL;
238 	char fn[PATH_MAX];
239 	uint64_t addr = (uint64_t)(uintptr_t)code_addr;
240 	jvmtiError ret;
241 	int nr_lines = 0; /* in line_tab[] */
242 	size_t len;
243 	int output_debug_info = 0;
244 
245 	ret = (*jvmti)->GetMethodDeclaringClass(jvmti, method,
246 						&decl_class);
247 	if (ret != JVMTI_ERROR_NONE) {
248 		print_error(jvmti, "GetMethodDeclaringClass", ret);
249 		return;
250 	}
251 
252 	if (has_line_numbers && map && map_length) {
253 		ret = get_line_numbers(jvmti, compile_info, &line_tab, &nr_lines);
254 		if (ret != JVMTI_ERROR_NONE) {
255 			warnx("jvmti: cannot get line table for method");
256 			nr_lines = 0;
257 		} else if (nr_lines > 0) {
258 			line_file_names = malloc(sizeof(char*) * nr_lines);
259 			if (!line_file_names) {
260 				warnx("jvmti: cannot allocate space for line table method names");
261 			} else {
262 				memset(line_file_names, 0, sizeof(char*) * nr_lines);
263 				ret = fill_source_filenames(jvmti, nr_lines, line_tab, line_file_names);
264 				if (ret != JVMTI_ERROR_NONE) {
265 					warnx("jvmti: fill_source_filenames failed");
266 				} else {
267 					output_debug_info = 1;
268 				}
269 			}
270 		}
271 	}
272 
273 	ret = (*jvmti)->GetSourceFileName(jvmti, decl_class, &file_name);
274 	if (ret != JVMTI_ERROR_NONE) {
275 		print_error(jvmti, "GetSourceFileName", ret);
276 		goto error;
277 	}
278 
279 	ret = (*jvmti)->GetClassSignature(jvmti, decl_class,
280 					  &class_sign, NULL);
281 	if (ret != JVMTI_ERROR_NONE) {
282 		print_error(jvmti, "GetClassSignature", ret);
283 		goto error;
284 	}
285 
286 	ret = (*jvmti)->GetMethodName(jvmti, method, &func_name,
287 				      &func_sign, NULL);
288 	if (ret != JVMTI_ERROR_NONE) {
289 		print_error(jvmti, "GetMethodName", ret);
290 		goto error;
291 	}
292 
293 	copy_class_filename(class_sign, file_name, fn, PATH_MAX);
294 
295 	/*
296 	 * write source line info record if we have it
297 	 */
298 	if (output_debug_info)
299 		if (jvmti_write_debug_info(jvmti_agent, addr, nr_lines, line_tab, (const char * const *) line_file_names))
300 			warnx("jvmti: write_debug_info() failed");
301 
302 	len = strlen(func_name) + strlen(class_sign) + strlen(func_sign) + 2;
303 	{
304 		char str[len];
305 		snprintf(str, len, "%s%s%s", class_sign, func_name, func_sign);
306 
307 		if (jvmti_write_code(jvmti_agent, str, addr, code_addr, code_size))
308 			warnx("jvmti: write_code() failed");
309 	}
310 error:
311 	(*jvmti)->Deallocate(jvmti, (unsigned char *)func_name);
312 	(*jvmti)->Deallocate(jvmti, (unsigned char *)func_sign);
313 	(*jvmti)->Deallocate(jvmti, (unsigned char *)class_sign);
314 	(*jvmti)->Deallocate(jvmti, (unsigned char *)file_name);
315 	free(line_tab);
316 	while (line_file_names && (nr_lines > 0)) {
317 	    if (line_file_names[nr_lines - 1]) {
318 	        free(line_file_names[nr_lines - 1]);
319 	    }
320 	    nr_lines -= 1;
321 	}
322 	free(line_file_names);
323 }
324 
325 static void JNICALL
326 code_generated_cb(jvmtiEnv *jvmti,
327 		  char const *name,
328 		  void const *code_addr,
329 		  jint code_size)
330 {
331 	uint64_t addr = (uint64_t)(unsigned long)code_addr;
332 	int ret;
333 
334 	ret = jvmti_write_code(jvmti_agent, name, addr, code_addr, code_size);
335 	if (ret)
336 		warnx("jvmti: write_code() failed for code_generated");
337 }
338 
339 JNIEXPORT jint JNICALL
340 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved __maybe_unused)
341 {
342 	jvmtiEventCallbacks cb;
343 	jvmtiCapabilities caps1;
344 	jvmtiJlocationFormat format;
345 	jvmtiEnv *jvmti = NULL;
346 	jint ret;
347 
348 	jvmti_agent = jvmti_open();
349 	if (!jvmti_agent) {
350 		warnx("jvmti: open_agent failed");
351 		return -1;
352 	}
353 
354 	/*
355 	 * Request a JVMTI interface version 1 environment
356 	 */
357 	ret = (*jvm)->GetEnv(jvm, (void *)&jvmti, JVMTI_VERSION_1);
358 	if (ret != JNI_OK) {
359 		warnx("jvmti: jvmti version 1 not supported");
360 		return -1;
361 	}
362 
363 	/*
364 	 * acquire method_load capability, we require it
365 	 * request line numbers (optional)
366 	 */
367 	memset(&caps1, 0, sizeof(caps1));
368 	caps1.can_generate_compiled_method_load_events = 1;
369 
370 	ret = (*jvmti)->AddCapabilities(jvmti, &caps1);
371 	if (ret != JVMTI_ERROR_NONE) {
372 		print_error(jvmti, "AddCapabilities", ret);
373 		return -1;
374 	}
375 	ret = (*jvmti)->GetJLocationFormat(jvmti, &format);
376         if (ret == JVMTI_ERROR_NONE && format == JVMTI_JLOCATION_JVMBCI) {
377                 memset(&caps1, 0, sizeof(caps1));
378                 caps1.can_get_line_numbers = 1;
379                 caps1.can_get_source_file_name = 1;
380 		ret = (*jvmti)->AddCapabilities(jvmti, &caps1);
381                 if (ret == JVMTI_ERROR_NONE)
382                         has_line_numbers = 1;
383         } else if (ret != JVMTI_ERROR_NONE)
384 		print_error(jvmti, "GetJLocationFormat", ret);
385 
386 
387 	memset(&cb, 0, sizeof(cb));
388 
389 	cb.CompiledMethodLoad   = compiled_method_load_cb;
390 	cb.DynamicCodeGenerated = code_generated_cb;
391 
392 	ret = (*jvmti)->SetEventCallbacks(jvmti, &cb, sizeof(cb));
393 	if (ret != JVMTI_ERROR_NONE) {
394 		print_error(jvmti, "SetEventCallbacks", ret);
395 		return -1;
396 	}
397 
398 	ret = (*jvmti)->SetEventNotificationMode(jvmti, JVMTI_ENABLE,
399 			JVMTI_EVENT_COMPILED_METHOD_LOAD, NULL);
400 	if (ret != JVMTI_ERROR_NONE) {
401 		print_error(jvmti, "SetEventNotificationMode(METHOD_LOAD)", ret);
402 		return -1;
403 	}
404 
405 	ret = (*jvmti)->SetEventNotificationMode(jvmti, JVMTI_ENABLE,
406 			JVMTI_EVENT_DYNAMIC_CODE_GENERATED, NULL);
407 	if (ret != JVMTI_ERROR_NONE) {
408 		print_error(jvmti, "SetEventNotificationMode(CODE_GENERATED)", ret);
409 		return -1;
410 	}
411 	return 0;
412 }
413 
414 JNIEXPORT void JNICALL
415 Agent_OnUnload(JavaVM *jvm __maybe_unused)
416 {
417 	int ret;
418 
419 	ret = jvmti_close(jvmti_agent);
420 	if (ret)
421 		errx(1, "Error: op_close_agent()");
422 }
423