1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/compiler.h>
12 #include "jvmti_agent.h"
14 static int has_line_numbers;
17 static void print_error(jvmtiEnv *jvmti, const char *msg, jvmtiError ret)
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);
26 warnx("%s failed with an unknown error %d", msg, ret);
31 do_get_line_numbers(jvmtiEnv *jvmti, void *pc, jmethodID m, jint bci,
32 jvmti_line_info_t *tab, jint *nr)
36 jvmtiLineNumberEntry *loc_tab = NULL;
39 ret = (*jvmti)->GetLineNumberTable(jvmti, m, &nr_lines, &loc_tab);
40 if (ret != JVMTI_ERROR_NONE) {
41 print_error(jvmti, "GetLineNumberTable", ret);
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 */
55 (*jvmti)->Deallocate(jvmti, (unsigned char *)loc_tab);
57 return JVMTI_ERROR_NONE;
61 get_line_numbers(jvmtiEnv *jvmti, const void *compile_info, jvmti_line_info_t **tab, int *nr_lines)
63 const jvmtiCompiledMethodLoadRecordHeader *hdr;
64 jvmtiCompiledMethodLoadInlineRecord *rec;
65 jvmtiLineNumberEntry *lne = NULL;
69 int i, lines_total = 0;
71 if (!(tab && nr_lines))
72 return JVMTI_ERROR_NULL_POINTER;
75 * Phase 1 -- get the number of lines necessary
77 for (hdr = compile_info; hdr != NULL; hdr = hdr->next) {
78 if (hdr->kind == JVMTI_CMLR_INLINE_INFO) {
79 rec = (jvmtiCompiledMethodLoadInlineRecord *)hdr;
80 for (i = 0; i < rec->numpcs; i++) {
84 * unfortunately, need a tab to get the number of lines!
86 ret = (*jvmti)->GetLineNumberTable(jvmti, c->methods[0], &nr, &lne);
87 if (ret == JVMTI_ERROR_NONE) {
88 /* free what was allocated for nothing */
89 (*jvmti)->Deallocate(jvmti, (unsigned char *)lne);
92 print_error(jvmti, "GetLineNumberTable", ret);
99 return JVMTI_ERROR_NOT_FOUND;
102 * Phase 2 -- allocate big enough line table
104 *tab = malloc(nr_total * sizeof(**tab));
106 return JVMTI_ERROR_OUT_OF_MEMORY;
108 for (hdr = compile_info; hdr != NULL; hdr = hdr->next) {
109 if (hdr->kind == JVMTI_CMLR_INLINE_INFO) {
110 rec = (jvmtiCompiledMethodLoadInlineRecord *)hdr;
111 for (i = 0; i < rec->numpcs; i++) {
114 ret = do_get_line_numbers(jvmti, c->pc,
119 if (ret == JVMTI_ERROR_NONE)
124 *nr_lines = lines_total;
125 return JVMTI_ERROR_NONE;
129 compiled_method_load_cb(jvmtiEnv *jvmti,
132 void const *code_addr,
134 jvmtiAddrLocationMap const *map,
135 const void *compile_info)
137 jvmti_line_info_t *line_tab = NULL;
139 char *class_sign = NULL;
140 char *func_name = NULL;
141 char *func_sign = NULL;
142 char *file_name= NULL;
144 uint64_t addr = (uint64_t)(uintptr_t)code_addr;
146 int nr_lines = 0; /* in line_tab[] */
149 ret = (*jvmti)->GetMethodDeclaringClass(jvmti, method,
151 if (ret != JVMTI_ERROR_NONE) {
152 print_error(jvmti, "GetMethodDeclaringClass", ret);
156 if (has_line_numbers && map && map_length) {
157 ret = get_line_numbers(jvmti, compile_info, &line_tab, &nr_lines);
158 if (ret != JVMTI_ERROR_NONE) {
159 warnx("jvmti: cannot get line table for method");
164 ret = (*jvmti)->GetSourceFileName(jvmti, decl_class, &file_name);
165 if (ret != JVMTI_ERROR_NONE) {
166 print_error(jvmti, "GetSourceFileName", ret);
170 ret = (*jvmti)->GetClassSignature(jvmti, decl_class,
172 if (ret != JVMTI_ERROR_NONE) {
173 print_error(jvmti, "GetClassSignature", ret);
177 ret = (*jvmti)->GetMethodName(jvmti, method, &func_name,
179 if (ret != JVMTI_ERROR_NONE) {
180 print_error(jvmti, "GetMethodName", ret);
185 * Assume path name is class hierarchy, this is a common practice with Java programs
187 if (*class_sign == 'L') {
189 char *p = strrchr(class_sign, '/');
191 /* drop the 'L' prefix and copy up to the final '/' */
192 for (i = 0; i < (p - class_sign); i++)
193 fn[i] = class_sign[i+1];
196 * append file name, we use loops and not string ops to avoid modifying
197 * class_sign which is used later for the symbol name
199 for (j = 0; i < (PATH_MAX - 1) && file_name && j < strlen(file_name); j++, i++)
200 fn[i] = file_name[j];
204 strcpy(fn, file_name);
207 * write source line info record if we have it
209 if (jvmti_write_debug_info(jvmti_agent, addr, fn, line_tab, nr_lines))
210 warnx("jvmti: write_debug_info() failed");
212 len = strlen(func_name) + strlen(class_sign) + strlen(func_sign) + 2;
215 snprintf(str, len, "%s%s%s", class_sign, func_name, func_sign);
217 if (jvmti_write_code(jvmti_agent, str, addr, code_addr, code_size))
218 warnx("jvmti: write_code() failed");
221 (*jvmti)->Deallocate(jvmti, (unsigned char *)func_name);
222 (*jvmti)->Deallocate(jvmti, (unsigned char *)func_sign);
223 (*jvmti)->Deallocate(jvmti, (unsigned char *)class_sign);
224 (*jvmti)->Deallocate(jvmti, (unsigned char *)file_name);
229 code_generated_cb(jvmtiEnv *jvmti,
231 void const *code_addr,
234 uint64_t addr = (uint64_t)(unsigned long)code_addr;
237 ret = jvmti_write_code(jvmti_agent, name, addr, code_addr, code_size);
239 warnx("jvmti: write_code() failed for code_generated");
242 JNIEXPORT jint JNICALL
243 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved __maybe_unused)
245 jvmtiEventCallbacks cb;
246 jvmtiCapabilities caps1;
247 jvmtiJlocationFormat format;
248 jvmtiEnv *jvmti = NULL;
251 jvmti_agent = jvmti_open();
253 warnx("jvmti: open_agent failed");
258 * Request a JVMTI interface version 1 environment
260 ret = (*jvm)->GetEnv(jvm, (void *)&jvmti, JVMTI_VERSION_1);
262 warnx("jvmti: jvmti version 1 not supported");
267 * acquire method_load capability, we require it
268 * request line numbers (optional)
270 memset(&caps1, 0, sizeof(caps1));
271 caps1.can_generate_compiled_method_load_events = 1;
273 ret = (*jvmti)->AddCapabilities(jvmti, &caps1);
274 if (ret != JVMTI_ERROR_NONE) {
275 print_error(jvmti, "AddCapabilities", ret);
278 ret = (*jvmti)->GetJLocationFormat(jvmti, &format);
279 if (ret == JVMTI_ERROR_NONE && format == JVMTI_JLOCATION_JVMBCI) {
280 memset(&caps1, 0, sizeof(caps1));
281 caps1.can_get_line_numbers = 1;
282 caps1.can_get_source_file_name = 1;
283 ret = (*jvmti)->AddCapabilities(jvmti, &caps1);
284 if (ret == JVMTI_ERROR_NONE)
285 has_line_numbers = 1;
286 } else if (ret != JVMTI_ERROR_NONE)
287 print_error(jvmti, "GetJLocationFormat", ret);
290 memset(&cb, 0, sizeof(cb));
292 cb.CompiledMethodLoad = compiled_method_load_cb;
293 cb.DynamicCodeGenerated = code_generated_cb;
295 ret = (*jvmti)->SetEventCallbacks(jvmti, &cb, sizeof(cb));
296 if (ret != JVMTI_ERROR_NONE) {
297 print_error(jvmti, "SetEventCallbacks", ret);
301 ret = (*jvmti)->SetEventNotificationMode(jvmti, JVMTI_ENABLE,
302 JVMTI_EVENT_COMPILED_METHOD_LOAD, NULL);
303 if (ret != JVMTI_ERROR_NONE) {
304 print_error(jvmti, "SetEventNotificationMode(METHOD_LOAD)", ret);
308 ret = (*jvmti)->SetEventNotificationMode(jvmti, JVMTI_ENABLE,
309 JVMTI_EVENT_DYNAMIC_CODE_GENERATED, NULL);
310 if (ret != JVMTI_ERROR_NONE) {
311 print_error(jvmti, "SetEventNotificationMode(CODE_GENERATED)", ret);
317 JNIEXPORT void JNICALL
318 Agent_OnUnload(JavaVM *jvm __maybe_unused)
322 ret = jvmti_close(jvmti_agent);
324 errx(1, "Error: op_close_agent()");