cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

libjvmti.c (11233B)


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