text: #include <linux/types.h>
  #include <stdlib.h>
  #include <unistd.h>
  #include <stdio.h>
  #include <ctype.h>
  #include <string.h>
  
  #include "parse-events.h"
  #include "evlist.h"
  #include "evsel.h"
  #include "thread_map.h"
  #include "cpumap.h"
  #include "machine.h"
  #include "event.h"
  #include "thread.h"
  
  #include "tests.h"
  
  #define BUFSZ	1024
  #define READLEN	128
  
  struct state {
  	u64 done[1024];
  	size_t done_cnt;
  };
  
  static unsigned int hex(char c)
  {
  	if (c >= '0' && c <= '9')
  		return c - '0';
  	if (c >= 'a' && c <= 'f')
  		return c - 'a' + 10;
  	return c - 'A' + 10;
  }
  
  static size_t read_objdump_chunk(const char **line, unsigned char **buf,
  				 size_t *buf_len)
  {
  	size_t bytes_read = 0;
  	unsigned char *chunk_start = *buf;
  
  	/* Read bytes */
  	while (*buf_len > 0) {
  		char c1, c2;
  
  		/* Get 2 hex digits */
  		c1 = *(*line)++;
  		if (!isxdigit(c1))
  			break;
  		c2 = *(*line)++;
  		if (!isxdigit(c2))
  			break;
  
  		/* Store byte and advance buf */
  		**buf = (hex(c1) << 4) | hex(c2);
  		(*buf)++;
  		(*buf_len)--;
  		bytes_read++;
  
  		/* End of chunk? */
  		if (isspace(**line))
  			break;
  	}
  
  	/*
  	 * objdump will display raw insn as LE if code endian
  	 * is LE and bytes_per_chunk > 1. In that case reverse
  	 * the chunk we just read.
  	 *
  	 * see disassemble_bytes() at binutils/objdump.c for details
  	 * how objdump chooses display endian)
  	 */
  	if (bytes_read > 1 && !bigendian()) {
  		unsigned char *chunk_end = chunk_start + bytes_read - 1;
  		unsigned char tmp;
  
  		while (chunk_start < chunk_end) {
  			tmp = *chunk_start;
  			*chunk_start = *chunk_end;
  			*chunk_end = tmp;
  			chunk_start++;
  			chunk_end--;
  		}
  	}
  
  	return bytes_read;
  }
  
  static size_t read_objdump_line(const char *line, unsigned char *buf,
  				size_t buf_len)
  {
  	const char *p;
  	size_t ret, bytes_read = 0;
  
  	/* Skip to a colon */
  	p = strchr(line, ':');
  	if (!p)
  		return 0;
  	p++;
  
  	/* Skip initial spaces */
  	while (*p) {
  		if (!isspace(*p))
  			break;
  		p++;
  	}
  
  	do {
  		ret = read_objdump_chunk(&p, &buf, &buf_len);
  		bytes_read += ret;
  		p++;
  	} while (ret > 0);
  
  	/* return number of successfully read bytes */
  	return bytes_read;
  }
  
  static int read_objdump_output(FILE *f, void *buf, size_t *len, u64 start_addr)
  {
  	char *line = NULL;
  	size_t line_len, off_last = 0;
  	ssize_t ret;
  	int err = 0;
  	u64 addr, last_addr = start_addr;
  
  	while (off_last < *len) {
  		size_t off, read_bytes, written_bytes;
  		unsigned char tmp[BUFSZ];
  
  		ret = getline(&line, &line_len, f);
  		if (feof(f))
  			break;
  		if (ret < 0) {
  			pr_debug("getline failed\n");
  			err = -1;
  			break;
  		}
  
  		/* read objdump data into temporary buffer */
  		read_bytes = read_objdump_line(line, tmp, sizeof(tmp));
  		if (!read_bytes)
  			continue;
  
  		if (sscanf(line, "%"PRIx64, &addr) != 1)
  			continue;
  		if (addr < last_addr) {
  			pr_debug("addr going backwards, read beyond section?\n");
  			break;
  		}
  		last_addr = addr;
  
  		/* copy it from temporary buffer to 'buf' according
  		 * to address on current objdump line */
  		off = addr - start_addr;
  		if (off >= *len)
  			break;
  		written_bytes = MIN(read_bytes, *len - off);
  		memcpy(buf + off, tmp, written_bytes);
  		off_last = off + written_bytes;
  	}
  
  	/* len returns number of bytes that could not be read */
  	*len -= off_last;
  
  	free(line);
  
  	return err;
  }
  
  static int read_via_objdump(const char *filename, u64 addr, void *buf,
  			    size_t len)
  {
  	char cmd[PATH_MAX * 2];
  	const char *fmt;
  	FILE *f;
  	int ret;
  
  	fmt = "%s -z -d --start-address=0x%"PRIx64" --stop-address=0x%"PRIx64" %s";
  	ret = snprintf(cmd, sizeof(cmd), fmt, "objdump", addr, addr + len,
  		       filename);
  	if (ret <= 0 || (size_t)ret >= sizeof(cmd))
  		return -1;
  
  	pr_debug("Objdump command is: %s\n", cmd);
  
  	/* Ignore objdump errors */
  	strcat(cmd, " 2>/dev/null");
  
  	f = popen(cmd, "r");
  	if (!f) {
  		pr_debug("popen failed\n");
  		return -1;
  	}
  
  	ret = read_objdump_output(f, buf, &len, addr);
  	if (len) {
  		pr_debug("objdump read too few bytes: %zd\n", len);
  		if (!ret)
  			ret = len;
  	}
  
  	pclose(f);
  
  	return ret;
  }
  
  static void dump_buf(unsigned char *buf, size_t len)
  {
  	size_t i;
  
  	for (i = 0; i < len; i++) {
  		pr_debug("0x%02x ", buf[i]);
  		if (i % 16 == 15)
  			pr_debug("\n");
  	}
  	pr_debug("\n");
  }
  
  static int read_object_code(u64 addr, size_t len, u8 cpumode,
  			    struct thread *thread, struct state *state)
  {
  	struct addr_location al;
  	unsigned char buf1[BUFSZ];
  	unsigned char buf2[BUFSZ];
  	size_t ret_len;
  	u64 objdump_addr;
  	int ret;
  
  	pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr);
  
  	thread__find_addr_map(thread, cpumode, MAP__FUNCTION, addr, &al);
  	if (!al.map || !al.map->dso) {
  		pr_debug("thread__find_addr_map failed\n");
  		return -1;
  	}
  
  	pr_debug("File is: %s\n", al.map->dso->long_name);
  
  	if (al.map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS &&
  	    !dso__is_kcore(al.map->dso)) {
  		pr_debug("Unexpected kernel address - skipping\n");
  		return 0;
  	}
  
  	pr_debug("On file address is: %#"PRIx64"\n", al.addr);
  
  	if (len > BUFSZ)
  		len = BUFSZ;
  
  	/* Do not go off the map */
  	if (addr + len > al.map->end)
  		len = al.map->end - addr;
  
  	/* Read the object code using perf */
  	ret_len = dso__data_read_offset(al.map->dso, thread->mg->machine,
  					al.addr, buf1, len);
  	if (ret_len != len) {
  		pr_debug("dso__data_read_offset failed\n");
  		return -1;
  	}
  
  	/*
  	 * Converting addresses for use by objdump requires more information.
  	 * map__load() does that.  See map__rip_2objdump() for details.
  	 */
  	if (map__load(al.map))
  		return -1;
  
  	/* objdump struggles with kcore - try each map only once */
  	if (dso__is_kcore(al.map->dso)) {
  		size_t d;
  
  		for (d = 0; d < state->done_cnt; d++) {
  			if (state->done[d] == al.map->start) {
  				pr_debug("kcore map tested already");
  				pr_debug(" - skipping\n");
  				return 0;
  			}
  		}
  		if (state->done_cnt >= ARRAY_SIZE(state->done)) {
  			pr_debug("Too many kcore maps - skipping\n");
  			return 0;
  		}
  		state->done[state->done_cnt++] = al.map->start;
  	}
  
  	/* Read the object code using objdump */
  	objdump_addr = map__rip_2objdump(al.map, al.addr);
  	ret = read_via_objdump(al.map->dso->long_name, objdump_addr, buf2, len);
  	if (ret > 0) {
  		/*
  		 * The kernel maps are inaccurate - assume objdump is right in
  		 * that case.
  		 */
  		if (cpumode == PERF_RECORD_MISC_KERNEL ||
  		    cpumode == PERF_RECORD_MISC_GUEST_KERNEL) {
  			len -= ret;
  			if (len) {
  				pr_debug("Reducing len to %zu\n", len);
  			} else if (dso__is_kcore(al.map->dso)) {
  				/*
  				 * objdump cannot handle very large segments
  				 * that may be found in kcore.
  				 */
  				pr_debug("objdump failed for kcore");
  				pr_debug(" - skipping\n");
  				return 0;
  			} else {
  				return -1;
  			}
  		}
  	}
  	if (ret < 0) {
  		pr_debug("read_via_objdump failed\n");
  		return -1;
  	}
  
  	/* The results should be identical */
  	if (memcmp(buf1, buf2, len)) {
  		pr_debug("Bytes read differ from those read by objdump\n");
  		pr_debug("buf1 (dso):\n");
  		dump_buf(buf1, len);
  		pr_debug("buf2 (objdump):\n");
  		dump_buf(buf2, len);
  		return -1;
  	}
  	pr_debug("Bytes read match those read by objdump\n");
  
  	return 0;
  }
  
  static int process_sample_event(struct machine *machine,
  				struct perf_evlist *evlist,
  				union perf_event *event, struct state *state)
  {
  	struct perf_sample sample;
  	struct thread *thread;
  	int ret;
  
  	if (perf_evlist__parse_sample(evlist, event, &sample)) {
  		pr_debug("perf_evlist__parse_sample failed\n");
  		return -1;
  	}
  
  	thread = machine__findnew_thread(machine, sample.pid, sample.tid);
  	if (!thread) {
  		pr_debug("machine__findnew_thread failed\n");
  		return -1;
  	}
  
  	ret = read_object_code(sample.ip, READLEN, sample.cpumode, thread, state);
  	thread__put(thread);
  	return ret;
  }
  
  static int process_event(struct machine *machine, struct perf_evlist *evlist,
  			 union perf_event *event, struct state *state)
  {
  	if (event->header.type == PERF_RECORD_SAMPLE)
  		return process_sample_event(machine, evlist, event, state);
  
  	if (event->header.type == PERF_RECORD_THROTTLE ||
  	    event->header.type == PERF_RECORD_UNTHROTTLE)
  		return 0;
  
  	if (event->header.type < PERF_RECORD_MAX) {
  		int ret;
  
  		ret = machine__process_event(machine, event, NULL);
  		if (ret < 0)
  			pr_debug("machine__process_event failed, event type %u\n",
  				 event->header.type);
  		return ret;
  	}
  
  	return 0;
  }
  
  static int process_events(struct machine *machine, struct perf_evlist *evlist,
  			  struct state *state)
  {
  	union perf_event *event;
  	int i, ret;
  
  	for (i = 0; i < evlist->nr_mmaps; i++) {
  		while ((event = perf_evlist__mmap_read(evlist, i)) != NULL) {
  			ret = process_event(machine, evlist, event, state);
  			perf_evlist__mmap_consume(evlist, i);
  			if (ret < 0)
  				return ret;
  		}
  	}
  	return 0;
  }
  
  static int comp(const void *a, const void *b)
  {
  	return *(int *)a - *(int *)b;
  }
  
  static void do_sort_something(void)
  {
  	int buf[40960], i;
  
  	for (i = 0; i < (int)ARRAY_SIZE(buf); i++)
  		buf[i] = ARRAY_SIZE(buf) - i - 1;
  
  	qsort(buf, ARRAY_SIZE(buf), sizeof(int), comp);
  
  	for (i = 0; i < (int)ARRAY_SIZE(buf); i++) {
  		if (buf[i] != i) {
  			pr_debug("qsort failed\n");
  			break;
  		}
  	}
  }
  
  static void sort_something(void)
  {
  	int i;
  
  	for (i = 0; i < 10; i++)
  		do_sort_something();
  }
  
  static void syscall_something(void)
  {
  	int pipefd[2];
  	int i;
  
  	for (i = 0; i < 1000; i++) {
  		if (pipe(pipefd) < 0) {
  			pr_debug("pipe failed\n");
  			break;
  		}
  		close(pipefd[1]);
  		close(pipefd[0]);
  	}
  }
  
  static void fs_something(void)
  {
  	const char *test_file_name = "temp-perf-code-reading-test-file--";
  	FILE *f;
  	int i;
  
  	for (i = 0; i < 1000; i++) {
  		f = fopen(test_file_name, "w+");
  		if (f) {
  			fclose(f);
  			unlink(test_file_name);
  		}
  	}
  }
  
  static void do_something(void)
  {
  	fs_something();
  
  	sort_something();
  
  	syscall_something();
  }
  
  enum {
  	TEST_CODE_READING_OK,
  	TEST_CODE_READING_NO_VMLINUX,
  	TEST_CODE_READING_NO_KCORE,
  	TEST_CODE_READING_NO_ACCESS,
  	TEST_CODE_READING_NO_KERNEL_OBJ,
  };
  
  static int do_test_code_reading(bool try_kcore)
  {
  	struct machine *machine;
  	struct thread *thread;
  	struct record_opts opts = {
  		.mmap_pages	     = UINT_MAX,
  		.user_freq	     = UINT_MAX,
  		.user_interval	     = ULLONG_MAX,
  		.freq		     = 500,
  		.target		     = {
  			.uses_mmap   = true,
  		},
  	};
  	struct state state = {
  		.done_cnt = 0,
  	};
  	struct thread_map *threads = NULL;
  	struct cpu_map *cpus = NULL;
  	struct perf_evlist *evlist = NULL;
  	struct perf_evsel *evsel = NULL;
  	int err = -1, ret;
  	pid_t pid;
  	struct map *map;
  	bool have_vmlinux, have_kcore, excl_kernel = false;
  
  	pid = getpid();
  
  	machine = machine__new_host();
  
  	ret = machine__create_kernel_maps(machine);
  	if (ret < 0) {
  		pr_debug("machine__create_kernel_maps failed\n");
  		goto out_err;
  	}
  
  	/* Force the use of kallsyms instead of vmlinux to try kcore */
  	if (try_kcore)
  		symbol_conf.kallsyms_name = "/proc/kallsyms";
  
  	/* Load kernel map */
  	map = machine__kernel_map(machine);
  	ret = map__load(map);
  	if (ret < 0) {
  		pr_debug("map__load failed\n");
  		goto out_err;
  	}
  	have_vmlinux = dso__is_vmlinux(map->dso);
  	have_kcore = dso__is_kcore(map->dso);
  
  	/* 2nd time through we just try kcore */
  	if (try_kcore && !have_kcore)
  		return TEST_CODE_READING_NO_KCORE;
  
  	/* No point getting kernel events if there is no kernel object */
  	if (!have_vmlinux && !have_kcore)
  		excl_kernel = true;
  
  	threads = thread_map__new_by_tid(pid);
  	if (!threads) {
  		pr_debug("thread_map__new_by_tid failed\n");
  		goto out_err;
  	}
  
  	ret = perf_event__synthesize_thread_map(NULL, threads,
  						perf_event__process, machine, false, 500);
  	if (ret < 0) {
  		pr_debug("perf_event__synthesize_thread_map failed\n");
  		goto out_err;
  	}
  
  	thread = machine__findnew_thread(machine, pid, pid);
  	if (!thread) {
  		pr_debug("machine__findnew_thread failed\n");
  		goto out_put;
  	}
  
  	cpus = cpu_map__new(NULL);
  	if (!cpus) {
  		pr_debug("cpu_map__new failed\n");
  		goto out_put;
  	}
  
  	while (1) {
  		const char *str;
  
  		evlist = perf_evlist__new();
  		if (!evlist) {
  			pr_debug("perf_evlist__new failed\n");
  			goto out_put;
  		}
  
  		perf_evlist__set_maps(evlist, cpus, threads);
  
  		if (excl_kernel)
  			str = "cycles:u";
  		else
  			str = "cycles";
  		pr_debug("Parsing event '%s'\n", str);
  		ret = parse_events(evlist, str, NULL);
  		if (ret < 0) {
  			pr_debug("parse_events failed\n");
  			goto out_put;
  		}
  
  		perf_evlist__config(evlist, &opts, NULL);
  
  		evsel = perf_evlist__first(evlist);
  
  		evsel->attr.comm = 1;
  		evsel->attr.disabled = 1;
  		evsel->attr.enable_on_exec = 0;
  
  		ret = perf_evlist__open(evlist);
  		if (ret < 0) {
  			if (!excl_kernel) {
  				excl_kernel = true;
  				/*
  				 * Both cpus and threads are now owned by evlist
  				 * and will be freed by following perf_evlist__set_maps
  				 * call. Getting refference to keep them alive.
  				 */
  				cpu_map__get(cpus);
  				thread_map__get(threads);
  				perf_evlist__set_maps(evlist, NULL, NULL);
  				perf_evlist__delete(evlist);
  				evlist = NULL;
  				continue;
  			}
  
  			if (verbose > 0) {
  				char errbuf[512];
  				perf_evlist__strerror_open(evlist, errno, errbuf, sizeof(errbuf));
  				pr_debug("perf_evlist__open() failed!\n%s\n", errbuf);
  			}
  
  			goto out_put;
  		}
  		break;
  	}
  
  	ret = perf_evlist__mmap(evlist, UINT_MAX, false);
  	if (ret < 0) {
  		pr_debug("perf_evlist__mmap failed\n");
  		goto out_put;
  	}
  
  	perf_evlist__enable(evlist);
  
  	do_something();
  
  	perf_evlist__disable(evlist);
  
  	ret = process_events(machine, evlist, &state);
  	if (ret < 0)
  		goto out_put;
  
  	if (!have_vmlinux && !have_kcore && !try_kcore)
  		err = TEST_CODE_READING_NO_KERNEL_OBJ;
  	else if (!have_vmlinux && !try_kcore)
  		err = TEST_CODE_READING_NO_VMLINUX;
  	else if (excl_kernel)
  		err = TEST_CODE_READING_NO_ACCESS;
  	else
  		err = TEST_CODE_READING_OK;
  out_put:
  	thread__put(thread);
  out_err:
  
  	if (evlist) {
  		perf_evlist__delete(evlist);
  	} else {
  		cpu_map__put(cpus);
  		thread_map__put(threads);
  	}
  	machine__delete_threads(machine);
  	machine__delete(machine);
  
  	return err;
  }
  
  int test__code_reading(int subtest __maybe_unused)
  {
  	int ret;
  
  	ret = do_test_code_reading(false);
  	if (!ret)
  		ret = do_test_code_reading(true);
  
  	switch (ret) {
  	case TEST_CODE_READING_OK:
  		return 0;
  	case TEST_CODE_READING_NO_VMLINUX:
  		pr_debug("no vmlinux\n");
  		return 0;
  	case TEST_CODE_READING_NO_KCORE:
  		pr_debug("no kcore\n");
  		return 0;
  	case TEST_CODE_READING_NO_ACCESS:
  		pr_debug("no access\n");
  		return 0;
  	case TEST_CODE_READING_NO_KERNEL_OBJ:
  		pr_debug("no kernel obj\n");
  		return 0;
  	default:
  		return -1;
  	};
  }
  