Release 4.10 tools/perf/util/bpf-loader.c

/*
 * bpf-loader.c
 *
 * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
 * Copyright (C) 2015 Huawei Inc.
 */

#include <linux/bpf.h>
#include <bpf/libbpf.h>
#include <bpf/bpf.h>
#include <linux/err.h>
#include <linux/string.h>
#include "perf.h"
#include "debug.h"
#include "bpf-loader.h"
#include "bpf-prologue.h"
#include "probe-event.h"
#include "probe-finder.h" // for MAX_PROBES
#include "parse-events.h"
#include "llvm-utils.h"
#include "c++/clang-c.h"


#define DEFINE_PRINT_FN(name, level) \
static int libbpf_##name(const char *fmt, ...)  \
{                                               \
        va_list args;                           \
        int ret;                                \
                                                \
        va_start(args, fmt);                    \
        ret = veprintf(level, verbose, pr_fmt(fmt), args);\
        va_end(args);                           \
        return ret;                             \
}

DEFINE_PRINT_FN(warning, 1)
DEFINE_PRINT_FN(info, 1)
DEFINE_PRINT_FN(debug, 1)


struct bpf_prog_priv {
	
bool is_tp;
	
char *sys_name;
	
char *evt_name;
	
struct perf_probe_event pev;
	
bool need_prologue;
	
struct bpf_insn *insns_buf;
	
int nr_types;
	
int *type_mapping;
};


static bool libbpf_initialized;


struct bpf_object *

bpf__prepare_load_buffer(void *obj_buf, size_t obj_buf_sz, const char *name)
{
	struct bpf_object *obj;

	if (!libbpf_initialized) {
		libbpf_set_print(libbpf_warning,
				 libbpf_info,
				 libbpf_debug);
		libbpf_initialized = true;
	}

	obj = bpf_object__open_buffer(obj_buf, obj_buf_sz, name);
	if (IS_ERR(obj)) {
		pr_debug("bpf: failed to load buffer\n");
		return ERR_PTR(-EINVAL);
	}

	return obj;
}

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struct bpf_object *bpf__prepare_load(const char *filename, bool source)
{
	struct bpf_object *obj;

	if (!libbpf_initialized) {
		libbpf_set_print(libbpf_warning,
				 libbpf_info,
				 libbpf_debug);
		libbpf_initialized = true;
	}

	if (source) {
		int err;
		void *obj_buf;
		size_t obj_buf_sz;

		perf_clang__init();
		err = perf_clang__compile_bpf(filename, &obj_buf, &obj_buf_sz);
		perf_clang__cleanup();
		if (err) {
			pr_warning("bpf: builtin compilation failed: %d, try external compiler\n", err);
			err = llvm__compile_bpf(filename, &obj_buf, &obj_buf_sz);
			if (err)
				return ERR_PTR(-BPF_LOADER_ERRNO__COMPILE);
		} else
			pr_debug("bpf: successfull builtin compilation\n");
		obj = bpf_object__open_buffer(obj_buf, obj_buf_sz, filename);

		if (!IS_ERR(obj) && llvm_param.dump_obj)
			llvm__dump_obj(filename, obj_buf, obj_buf_sz);

		free(obj_buf);
	} else
		obj = bpf_object__open(filename);

	if (IS_ERR(obj)) {
		pr_debug("bpf: failed to load %s\n", filename);
		return obj;
	}

	return obj;
}

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void bpf__clear(void)
{
	struct bpf_object *obj, *tmp;

	bpf_object__for_each_safe(obj, tmp) {
		bpf__unprobe(obj);
		bpf_object__close(obj);
	}
}

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static void

clear_prog_priv(struct bpf_program *prog __maybe_unused,
		void *_priv)
{
	struct bpf_prog_priv *priv = _priv;

	cleanup_perf_probe_events(&priv->pev, 1);
	zfree(&priv->insns_buf);
	zfree(&priv->type_mapping);
	zfree(&priv->sys_name);
	zfree(&priv->evt_name);
	free(priv);
}

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static int

prog_config__exec(const char *value, struct perf_probe_event *pev)
{
	pev->uprobes = true;
	pev->target = strdup(value);
	if (!pev->target)
		return -ENOMEM;
	return 0;
}

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static int

prog_config__module(const char *value, struct perf_probe_event *pev)
{
	pev->uprobes = false;
	pev->target = strdup(value);
	if (!pev->target)
		return -ENOMEM;
	return 0;
}

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static int

prog_config__bool(const char *value, bool *pbool, bool invert)
{
	int err;
	bool bool_value;

	if (!pbool)
		return -EINVAL;

	err = strtobool(value, &bool_value);
	if (err)
		return err;

	*pbool = invert ? !bool_value : bool_value;
	return 0;
}

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static int

prog_config__inlines(const char *value,
		     struct perf_probe_event *pev __maybe_unused)
{
	return prog_config__bool(value, &probe_conf.no_inlines, true);
}

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static int

prog_config__force(const char *value,
		   struct perf_probe_event *pev __maybe_unused)
{
	return prog_config__bool(value, &probe_conf.force_add, false);
}

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static struct {
	
const char *key;
	
const char *usage;
	
const char *desc;
	
int (*func)(const char *, struct perf_probe_event *);
} 
bpf_prog_config_terms[] = {
	{
		.key	= "exec",
		.usage	= "exec=<full path of file>",
		.desc	= "Set uprobe target",
		.func	= prog_config__exec,
        },
	{
		.key	= "module",
		.usage	= "module=<module name>    ",
		.desc	= "Set kprobe module",
		.func	= prog_config__module,
        },
	{
		.key	= "inlines",
		.usage	= "inlines=[yes|no]        ",
		.desc	= "Probe at inline symbol",
		.func	= prog_config__inlines,
        },
	{
		.key	= "force",
		.usage	= "force=[yes|no]          ",
		.desc	= "Forcibly add events with existing name",
		.func	= prog_config__force,
        },
};


static int

do_prog_config(const char *key, const char *value,
	       struct perf_probe_event *pev)
{
	unsigned int i;

	pr_debug("config bpf program: %s=%s\n", key, value);
	for (i = 0; i < ARRAY_SIZE(bpf_prog_config_terms); i++)
		if (strcmp(key, bpf_prog_config_terms[i].key) == 0)
			return bpf_prog_config_terms[i].func(value, pev);

	pr_debug("BPF: ERROR: invalid program config option: %s=%s\n",
		 key, value);

	pr_debug("\nHint: Valid options are:\n");
	for (i = 0; i < ARRAY_SIZE(bpf_prog_config_terms); i++)
		pr_debug("\t%s:\t%s\n", bpf_prog_config_terms[i].usage,
			 bpf_prog_config_terms[i].desc);
	pr_debug("\n");

	return -BPF_LOADER_ERRNO__PROGCONF_TERM;
}

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static const char *

parse_prog_config_kvpair(const char *config_str, struct perf_probe_event *pev)
{
	char *text = strdup(config_str);
	char *sep, *line;
	const char *main_str = NULL;
	int err = 0;

	if (!text) {
		pr_debug("Not enough memory: dup config_str failed\n");
		return ERR_PTR(-ENOMEM);
	}

	line = text;
	while ((sep = strchr(line, ';'))) {
		char *equ;

		*sep = '\0';
		equ = strchr(line, '=');
		if (!equ) {
			pr_warning("WARNING: invalid config in BPF object: %s\n",
				   line);
			pr_warning("\tShould be 'key=value'.\n");
			goto nextline;
		}
		*equ = '\0';

		err = do_prog_config(line, equ + 1, pev);
		if (err)
			break;
nextline:
		line = sep + 1;
	}

	if (!err)
		main_str = config_str + (line - text);
	free(text);

	return err ? ERR_PTR(err) : main_str;
}

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static int

parse_prog_config(const char *config_str, const char **p_main_str,
		  bool *is_tp, struct perf_probe_event *pev)
{
	int err;
	const char *main_str = parse_prog_config_kvpair(config_str, pev);

	if (IS_ERR(main_str))
		return PTR_ERR(main_str);

	*p_main_str = main_str;
	if (!strchr(main_str, '=')) {
		/* Is a tracepoint event? */
		const char *s = strchr(main_str, ':');

		if (!s) {
			pr_debug("bpf: '%s' is not a valid tracepoint\n",
				 config_str);
			return -BPF_LOADER_ERRNO__CONFIG;
		}

		*is_tp = true;
		return 0;
	}

	*is_tp = false;
	err = parse_perf_probe_command(main_str, pev);
	if (err < 0) {
		pr_debug("bpf: '%s' is not a valid config string\n",
			 config_str);
		/* parse failed, don't need clear pev. */
		return -BPF_LOADER_ERRNO__CONFIG;
	}
	return 0;
}

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static int

config_bpf_program(struct bpf_program *prog)
{
	struct perf_probe_event *pev = NULL;
	struct bpf_prog_priv *priv = NULL;
	const char *config_str, *main_str;
	bool is_tp = false;
	int err;

	/* Initialize per-program probing setting */
	probe_conf.no_inlines = false;
	probe_conf.force_add = false;

	config_str = bpf_program__title(prog, false);
	if (IS_ERR(config_str)) {
		pr_debug("bpf: unable to get title for program\n");
		return PTR_ERR(config_str);
	}

	priv = calloc(sizeof(*priv), 1);
	if (!priv) {
		pr_debug("bpf: failed to alloc priv\n");
		return -ENOMEM;
	}
	pev = &priv->pev;

	pr_debug("bpf: config program '%s'\n", config_str);
	err = parse_prog_config(config_str, &main_str, &is_tp, pev);
	if (err)
		goto errout;

	if (is_tp) {
		char *s = strchr(main_str, ':');

		priv->is_tp = true;
		priv->sys_name = strndup(main_str, s - main_str);
		priv->evt_name = strdup(s + 1);
		goto set_priv;
	}

	if (pev->group && strcmp(pev->group, PERF_BPF_PROBE_GROUP)) {
		pr_debug("bpf: '%s': group for event is set and not '%s'.\n",
			 config_str, PERF_BPF_PROBE_GROUP);
		err = -BPF_LOADER_ERRNO__GROUP;
		goto errout;
	} else if (!pev->group)
		pev->group = strdup(PERF_BPF_PROBE_GROUP);

	if (!pev->group) {
		pr_debug("bpf: strdup failed\n");
		err = -ENOMEM;
		goto errout;
	}

	if (!pev->event) {
		pr_debug("bpf: '%s': event name is missing. Section name should be 'key=value'\n",
			 config_str);
		err = -BPF_LOADER_ERRNO__EVENTNAME;
		goto errout;
	}
	pr_debug("bpf: config '%s' is ok\n", config_str);

set_priv:
	err = bpf_program__set_priv(prog, priv, clear_prog_priv);
	if (err) {
		pr_debug("Failed to set priv for program '%s'\n", config_str);
		goto errout;
	}

	return 0;

errout:
	if (pev)
		clear_perf_probe_event(pev);
	free(priv);
	return err;
}

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static int bpf__prepare_probe(void)
{
	static int err = 0;
	static bool initialized = false;

	/*
         * Make err static, so if init failed the first, bpf__prepare_probe()
         * fails each time without calling init_probe_symbol_maps multiple
         * times.
         */
	if (initialized)
		return err;

	initialized = true;
	err = init_probe_symbol_maps(false);
	if (err < 0)
		pr_debug("Failed to init_probe_symbol_maps\n");
	probe_conf.max_probes = MAX_PROBES;
	return err;
}

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static int

preproc_gen_prologue(struct bpf_program *prog, int n,
		     struct bpf_insn *orig_insns, int orig_insns_cnt,
		     struct bpf_prog_prep_result *res)
{
	struct bpf_prog_priv *priv = bpf_program__priv(prog);
	struct probe_trace_event *tev;
	struct perf_probe_event *pev;
	struct bpf_insn *buf;
	size_t prologue_cnt = 0;
	int i, err;

	if (IS_ERR(priv) || !priv || priv->is_tp)
		goto errout;

	pev = &priv->pev;

	if (n < 0 || n >= priv->nr_types)
		goto errout;

	/* Find a tev belongs to that type */
	for (i = 0; i < pev->ntevs; i++) {
		if (priv->type_mapping[i] == n)
			break;
	}

	if (i >= pev->ntevs) {
		pr_debug("Internal error: prologue type %d not found\n", n);
		return -BPF_LOADER_ERRNO__PROLOGUE;
	}

	tev = &pev->tevs[i];

	buf = priv->insns_buf;
	err = bpf__gen_prologue(tev->args, tev->nargs,
				buf, &prologue_cnt,
				BPF_MAXINSNS - orig_insns_cnt);
	if (err) {
		const char *title;

		title = bpf_program__title(prog, false);
		if (!title)
			title = "[unknown]";

		pr_debug("Failed to generate prologue for program %s\n",
			 title);
		return err;
	}

	memcpy(&buf[prologue_cnt], orig_insns,
	       sizeof(struct bpf_insn) * orig_insns_cnt);

	res->new_insn_ptr = buf;
	res->new_insn_cnt = prologue_cnt + orig_insns_cnt;
	res->pfd = NULL;
	return 0;

errout:
	pr_debug("Internal error in preproc_gen_prologue\n");
	return -BPF_LOADER_ERRNO__PROLOGUE;
}

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/*
 * compare_tev_args is reflexive, transitive and antisymmetric.
 * I can proof it but this margin is too narrow to contain.
 */


static int compare_tev_args(const void *ptev1, const void *ptev2)
{
	int i, ret;
	const struct probe_trace_event *tev1 =
		*(const struct probe_trace_event **)ptev1;
	const struct probe_trace_event *tev2 =
		*(const struct probe_trace_event **)ptev2;

	ret = tev2->nargs - tev1->nargs;
	if (ret)
		return ret;

	for (i = 0; i < tev1->nargs; i++) {
		struct probe_trace_arg *arg1, *arg2;
		struct probe_trace_arg_ref *ref1, *ref2;

		arg1 = &tev1->args[i];
		arg2 = &tev2->args[i];

		ret = strcmp(arg1->value, arg2->value);
		if (ret)
			return ret;

		ref1 = arg1->ref;
		ref2 = arg2->ref;

		while (ref1 && ref2) {
			ret = ref2->offset - ref1->offset;
			if (ret)
				return ret;

			ref1 = ref1->next;
			ref2 = ref2->next;
		}

		if (ref1 || ref2)
			return ref2 ? 1 : -1;
	}

	return 0;
}

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/*
 * Assign a type number to each tevs in a pev.
 * mapping is an array with same slots as tevs in that pev.
 * nr_types will be set to number of types.
 */


static int map_prologue(struct perf_probe_event *pev, int *mapping,
			int *nr_types)
{
	int i, type = 0;
	struct probe_trace_event **ptevs;

	size_t array_sz = sizeof(*ptevs) * pev->ntevs;

	ptevs = malloc(array_sz);
	if (!ptevs) {
		pr_debug("Not enough memory: alloc ptevs failed\n");
		return -ENOMEM;
	}

	pr_debug("In map_prologue, ntevs=%d\n", pev->ntevs);
	for (i = 0; i < pev->ntevs; i++)
		ptevs[i] = &pev->tevs[i];

	qsort(ptevs, pev->ntevs, sizeof(*ptevs),
	      compare_tev_args);

	for (i = 0; i < pev->ntevs; i++) {
		int n;

		n = ptevs[i] - pev->tevs;
		if (i == 0) {
			mapping[n] = type;
			pr_debug("mapping[%d]=%d\n", n, type);
			continue;
		}

		if (compare_tev_args(ptevs + i, ptevs + i - 1) == 0)
			mapping[n] = type;
		else
			mapping[n] = ++type;

		pr_debug("mapping[%d]=%d\n", n, mapping[n]);
	}
	free(ptevs);
	*nr_types = type + 1;

	return 0;
}

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static int hook_load_preprocessor(struct bpf_program *prog)
{
	struct bpf_prog_priv *priv = bpf_program__priv(prog);
	struct perf_probe_event *pev;
	bool need_prologue = false;
	int err, i;

	if (IS_ERR(priv) || !priv) {
		pr_debug("Internal error when hook preprocessor\n");
		return -BPF_LOADER_ERRNO__INTERNAL;
	}

	if (priv->is_tp) {
		priv->need_prologue = false;
		return 0;
	}

	pev = &priv->pev;
	for (i = 0; i < pev->ntevs; i++) {
		struct probe_trace_event *tev = &pev->tevs[i];

		if (tev->nargs > 0) {
			need_prologue = true;
			break;
		}
	}

	/*
         * Since all tevs don't have argument, we don't need generate
         * prologue.
         */
	if (!need_prologue) {
		priv->need_prologue = false;
		return 0;
	}

	priv->need_prologue = true;
	priv->insns_buf = malloc(sizeof(struct bpf_insn) * BPF_MAXINSNS);
	if (!priv->insns_buf) {
		pr_debug("Not enough memory: alloc insns_buf failed\n");
		return -ENOMEM;
	}

	priv->type_mapping = malloc(sizeof(int) * pev->ntevs);
	if (!priv->type_mapping) {
		pr_debug("Not enough memory: alloc type_mapping failed\n");
		return -ENOMEM;
	}
	memset(priv->type_mapping, -1,
	       sizeof(int) * pev->ntevs);

	err = map_prologue(pev, priv->type_mapping, &priv->nr_types);
	if (err)
		return err;

	err = bpf_program__set_prep(prog, priv->nr_types,
				    preproc_gen_prologue);
	return err;
}

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int bpf__probe(struct bpf_object *obj)
{
	int err = 0;
	struct bpf_program *prog;
	struct bpf_prog_priv *priv;
	struct perf_probe_event *pev;

	err = bpf__prepare_probe();
	if (err) {
		pr_debug("bpf__prepare_probe failed\n");
		return err;
	}

	bpf_object__for_each_program(prog, obj) {
		err = config_bpf_program(prog);
		if (err)
			goto out;

		priv = bpf_program__priv(prog);
		if (IS_ERR(priv) || !priv) {
			err = PTR_ERR(priv);
			goto out;
		}

		if (priv->is_tp) {
			bpf_program__set_tracepoint(prog);
			continue;
		}

		bpf_program__set_kprobe(prog);
		pev = &priv->pev;

		err = convert_perf_probe_events(pev, 1);
		if (err < 0) {
			pr_debug("bpf_probe: failed to convert perf probe events");
			goto out;
		}

		err = apply_perf_probe_events(pev, 1);
		if (err < 0) {
			pr_debug("bpf_probe: failed to apply perf probe events");
			goto out;
		}

		/*
                 * After probing, let's consider prologue, which
                 * adds program fetcher to BPF programs.
                 *
                 * hook_load_preprocessorr() hooks pre-processor
                 * to bpf_program, let it generate prologue
                 * dynamically during loading.
                 */
		err = hook_load_preprocessor(prog);
		if (err)
			goto out;
	}
out:
	return err < 0 ? err : 0;
}

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wang nan
wang nan
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arnaldo carvalho de melo
arnaldo carvalho de melo
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#define EVENTS_WRITE_BUFSIZE  4096


int bpf__unprobe(struct bpf_object *obj)
{
	int err, ret = 0;
	struct bpf_program *prog;

	bpf_object__for_each_program(prog, obj) {
		struct bpf_prog_priv *