Documentation/perf_counter/util/symbol.c - maze/linux - Git at Google

 #include "util.h"
 #include "../perf.h"
 #include "symbol.h"

 #include <libelf.h>
 #include <gelf.h>
 #include <elf.h>

 static struct symbol *symbol__new(uint64_t start, uint64_t len,
 				  const char *name)
 {
 	struct symbol *self = malloc(sizeof(*self) + strlen(name) + 1);

 	if (self != NULL) {
 		self->start = start;
 		self->end   = start + len;
 		strcpy(self->name, name);
 	}

 	return self;
 }

 static void symbol__delete(struct symbol *self)
 {
 	free(self);
 }

 static size_t symbol__fprintf(struct symbol *self, FILE *fp)
 {
 	return fprintf(fp, " %llx-%llx %s\n",
 		       self->start, self->end, self->name);
 }

 struct dso *dso__new(const char *name)
 {
 	struct dso *self = malloc(sizeof(*self) + strlen(name) + 1);

 	if (self != NULL) {
 		strcpy(self->name, name);
 		self->syms = RB_ROOT;
 	}

 	return self;
 }

 static void dso__delete_symbols(struct dso *self)
 {
 	struct symbol *pos;
 	struct rb_node *next = rb_first(&self->syms);

 	while (next) {
 		pos = rb_entry(next, struct symbol, rb_node);
 		next = rb_next(&pos->rb_node);
 		symbol__delete(pos);
 	}
 }

 void dso__delete(struct dso *self)
 {
 	dso__delete_symbols(self);
 	free(self);
 }

 static void dso__insert_symbol(struct dso *self, struct symbol *sym)
 {
 	struct rb_node **p = &self->syms.rb_node;
 	struct rb_node *parent = NULL;
 	const uint64_t ip = sym->start;
 	struct symbol *s;

 	while (*p != NULL) {
 		parent = *p;
 		s = rb_entry(parent, struct symbol, rb_node);
 		if (ip < s->start)
 			p = &(*p)->rb_left;
 		else
 			p = &(*p)->rb_right;
 	}
 	rb_link_node(&sym->rb_node, parent, p);
 	rb_insert_color(&sym->rb_node, &self->syms);
 }

 struct symbol *dso__find_symbol(struct dso *self, uint64_t ip)
 {
 	struct rb_node *n;

 	if (self == NULL)
 		return NULL;

 	n = self->syms.rb_node;

 	while (n) {
 		struct symbol *s = rb_entry(n, struct symbol, rb_node);

 		if (ip < s->start)
 			n = n->rb_left;
 		else if (ip > s->end)
 			n = n->rb_right;
 		else
 			return s;
 	}

 	return NULL;
 }

 size_t dso__fprintf(struct dso *self, FILE *fp)
 {
 	size_t ret = fprintf(fp, "dso: %s\n", self->name);

 	struct rb_node *nd;
 	for (nd = rb_first(&self->syms); nd; nd = rb_next(nd)) {
 		struct symbol *pos = rb_entry(nd, struct symbol, rb_node);
 		ret += symbol__fprintf(pos, fp);
 	}

 	return ret;
 }

 static int hex(char ch)
 {
 	if ((ch >= '0') && (ch <= '9'))
 		return ch - '0';
 	if ((ch >= 'a') && (ch <= 'f'))
 		return ch - 'a' + 10;
 	if ((ch >= 'A') && (ch <= 'F'))
 		return ch - 'A' + 10;
 	return -1;
 }

 /*
  * While we find nice hex chars, build a long_val.
  * Return number of chars processed.
  */
 static int hex2long(char *ptr, unsigned long *long_val)
 {
 	const char *p = ptr;
 	*long_val = 0;

 	while (*p) {
 		const int hex_val = hex(*p);

 		if (hex_val < 0)
 			break;

 		*long_val = (*long_val << 4) | hex_val;
 		p++;
 	}

 	return p - ptr;
 }

 int dso__load_kallsyms(struct dso *self)
 {
 	struct rb_node *nd, *prevnd;
 	char *line = NULL;
 	size_t n;
 	FILE *file = fopen("/proc/kallsyms", "r");

 	if (file == NULL)
 		goto out_failure;

 	while (!feof(file)) {
 		unsigned long start;
 		struct symbol *sym;
 		int line_len, len;
 		char symbol_type;

 		line_len = getline(&line, &n, file);
 		if (line_len < 0)
 			break;

 		if (!line)
 			goto out_failure;

 		line[--line_len] = '\0'; /* \n */

 		len = hex2long(line, &start);

 		len++;
 		if (len + 2 >= line_len)
 			continue;

 		symbol_type = toupper(line[len]);
 		/*
 		 * We're interested only in code ('T'ext)
 		 */
 		if (symbol_type != 'T' && symbol_type != 'W')
 			continue;
 		/*
 		 * Well fix up the end later, when we have all sorted.
 		 */
 		sym = symbol__new(start, 0xdead, line + len + 2);

 		if (sym == NULL)
 			goto out_delete_line;

 		dso__insert_symbol(self, sym);
 	}

 	/*
 	 * Now that we have all sorted out, just set the ->end of all
 	 * symbols
 	 */
 	prevnd = rb_first(&self->syms);

 	if (prevnd == NULL)
 		goto out_delete_line;

 	for (nd = rb_next(prevnd); nd; nd = rb_next(nd)) {
 		struct symbol *prev = rb_entry(prevnd, struct symbol, rb_node),
 			      *curr = rb_entry(nd, struct symbol, rb_node);

 		prev->end = curr->start - 1;
 		prevnd = nd;
 	}

 	free(line);
 	fclose(file);

 	return 0;

 out_delete_line:
 	free(line);
 out_failure:
 	return -1;
 }

 /**
  * elf_symtab__for_each_symbol - iterate thru all the symbols
  *
  * @self: struct elf_symtab instance to iterate
  * @index: uint32_t index
  * @sym: GElf_Sym iterator
  */
 #define elf_symtab__for_each_symbol(syms, nr_syms, index, sym) \
 	for (index = 0, gelf_getsym(syms, index, &sym);\
 	     index < nr_syms; \
 	     index++, gelf_getsym(syms, index, &sym))

 static inline uint8_t elf_sym__type(const GElf_Sym *sym)
 {
 	return GELF_ST_TYPE(sym->st_info);
 }

 static inline int elf_sym__is_function(const GElf_Sym *sym)
 {
 	return elf_sym__type(sym) == STT_FUNC &&
 	       sym->st_name != 0 &&
 	       sym->st_shndx != SHN_UNDEF &&
 	       sym->st_size != 0;
 }

 static inline const char *elf_sym__name(const GElf_Sym *sym,
 					const Elf_Data *symstrs)
 {
 	return symstrs->d_buf + sym->st_name;
 }

 static Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
 				    GElf_Shdr *shp, const char *name,
 				    size_t *index)
 {
 	Elf_Scn *sec = NULL;
 	size_t cnt = 1;

 	while ((sec = elf_nextscn(elf, sec)) != NULL) {
 		char *str;

 		gelf_getshdr(sec, shp);
 		str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
 		if (!strcmp(name, str)) {
 			if (index)
 				*index = cnt;
 			break;
 		}
 		++cnt;
 	}

 	return sec;
 }

 static int dso__load_sym(struct dso *self, int fd, const char *name)
 {
 	Elf_Data *symstrs;
 	uint32_t nr_syms;
 	int err = -1;
 	uint32_t index;
 	GElf_Ehdr ehdr;
 	GElf_Shdr shdr;
 	Elf_Data *syms;
 	GElf_Sym sym;
 	Elf_Scn *sec;
 	Elf *elf;
 	int nr = 0;

 	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
 	if (elf == NULL) {
 		fprintf(stderr, "%s: cannot read %s ELF file.\n",
 			__func__, name);
 		goto out_close;
 	}

 	if (gelf_getehdr(elf, &ehdr) == NULL) {
 		fprintf(stderr, "%s: cannot get elf header.\n", __func__);
 		goto out_elf_end;
 	}

 	sec = elf_section_by_name(elf, &ehdr, &shdr, ".symtab", NULL);
 	if (sec == NULL)
 		sec = elf_section_by_name(elf, &ehdr, &shdr, ".dynsym", NULL);

 	if (sec == NULL)
 		goto out_elf_end;

 	syms = elf_getdata(sec, NULL);
 	if (syms == NULL)
 		goto out_elf_end;

 	sec = elf_getscn(elf, shdr.sh_link);
 	if (sec == NULL)
 		goto out_elf_end;

 	symstrs = elf_getdata(sec, NULL);
 	if (symstrs == NULL)
 		goto out_elf_end;

 	nr_syms = shdr.sh_size / shdr.sh_entsize;

 	elf_symtab__for_each_symbol(syms, nr_syms, index, sym) {
 		struct symbol *f;

 		if (!elf_sym__is_function(&sym))
 			continue;

 		sec = elf_getscn(elf, sym.st_shndx);
 		if (!sec)
 			goto out_elf_end;

 		gelf_getshdr(sec, &shdr);
 		sym.st_value -= shdr.sh_addr - shdr.sh_offset;

 		f = symbol__new(sym.st_value, sym.st_size,
 				elf_sym__name(&sym, symstrs));
 		if (!f)
 			goto out_elf_end;

 		dso__insert_symbol(self, f);

 		nr++;
 	}

 	err = nr;
 out_elf_end:
 	elf_end(elf);
 out_close:
 	return err;
 }

 int dso__load(struct dso *self)
 {
 	int size = strlen(self->name) + sizeof("/usr/lib/debug%s.debug");
 	char *name = malloc(size);
 	int variant = 0;
 	int ret = -1;
 	int fd;

 	if (!name)
 		return -1;

 more:
 	do {
 		switch (variant) {
 		case 0: /* Fedora */
 			snprintf(name, size, "/usr/lib/debug%s.debug", self->name);
 			break;
 		case 1: /* Ubuntu */
 			snprintf(name, size, "/usr/lib/debug%s", self->name);
 			break;
 		case 2: /* Sane people */
 			snprintf(name, size, "%s", self->name);
 			break;

 		default:
 			goto out;
 		}
 		variant++;

 		fd = open(name, O_RDONLY);
 	} while (fd < 0);

 	ret = dso__load_sym(self, fd, name);
 	close(fd);

 	/*
 	 * Some people seem to have debuginfo files _WITHOUT_ debug info!?!?
 	 */
 	if (!ret)
 		goto more;

 out:
 	free(name);
 	return ret;
 }

 int dso__load_vmlinux(struct dso *self, const char *vmlinux)
 {
 	int err, fd = open(vmlinux, O_RDONLY);

 	if (fd < 0)
 		return -1;

 	err = dso__load_sym(self, fd, vmlinux);
 	close(fd);

 	return err;
 }

 void symbol__init(void)
 {
 	elf_version(EV_CURRENT);
 }
	#include "util.h"
	#include "../perf.h"
	#include "symbol.h"

	#include <libelf.h>
	#include <gelf.h>
	#include <elf.h>

	static struct symbol *symbol__new(uint64_t start, uint64_t len,
	const char *name)
	{
	struct symbol self = malloc(sizeof(self) + strlen(name) + 1);

	if (self != NULL) {
	self->start = start;
	self->end = start + len;
	strcpy(self->name, name);
	}

	return self;
	}

	static void symbol__delete(struct symbol *self)
	{
	free(self);
	}

	static size_t symbol__fprintf(struct symbol self, FILE fp)
	{
	return fprintf(fp, " %llx-%llx %s\n",
	self->start, self->end, self->name);
	}

	struct dso dso__new(const char name)
	{
	struct dso self = malloc(sizeof(self) + strlen(name) + 1);

	if (self != NULL) {
	strcpy(self->name, name);
	self->syms = RB_ROOT;
	}

	return self;
	}

	static void dso__delete_symbols(struct dso *self)
	{
	struct symbol *pos;
	struct rb_node *next = rb_first(&self->syms);

	while (next) {
	pos = rb_entry(next, struct symbol, rb_node);
	next = rb_next(&pos->rb_node);
	symbol__delete(pos);
	}
	}

	void dso__delete(struct dso *self)
	{
	dso__delete_symbols(self);
	free(self);
	}

	static void dso__insert_symbol(struct dso self, struct symbol sym)
	{
	struct rb_node **p = &self->syms.rb_node;
	struct rb_node *parent = NULL;
	const uint64_t ip = sym->start;
	struct symbol *s;

	while (*p != NULL) {
	parent = *p;
	s = rb_entry(parent, struct symbol, rb_node);
	if (ip < s->start)
	p = &(*p)->rb_left;
	else
	p = &(*p)->rb_right;
	}
	rb_link_node(&sym->rb_node, parent, p);
	rb_insert_color(&sym->rb_node, &self->syms);
	}

	struct symbol dso__find_symbol(struct dso self, uint64_t ip)
	{
	struct rb_node *n;

	if (self == NULL)
	return NULL;

	n = self->syms.rb_node;

	while (n) {
	struct symbol *s = rb_entry(n, struct symbol, rb_node);

	if (ip < s->start)
	n = n->rb_left;
	else if (ip > s->end)
	n = n->rb_right;
	else
	return s;
	}

	return NULL;
	}

	size_t dso__fprintf(struct dso self, FILE fp)
	{
	size_t ret = fprintf(fp, "dso: %s\n", self->name);

	struct rb_node *nd;
	for (nd = rb_first(&self->syms); nd; nd = rb_next(nd)) {
	struct symbol *pos = rb_entry(nd, struct symbol, rb_node);
	ret += symbol__fprintf(pos, fp);
	}

	return ret;
	}

	static int hex(char ch)
	{
	if ((ch >= '0') && (ch <= '9'))
	return ch - '0';
	if ((ch >= 'a') && (ch <= 'f'))
	return ch - 'a' + 10;
	if ((ch >= 'A') && (ch <= 'F'))
	return ch - 'A' + 10;
	return -1;
	}

	/*
	* While we find nice hex chars, build a long_val.
	* Return number of chars processed.
	*/
	static int hex2long(char ptr, unsigned long long_val)
	{
	const char *p = ptr;
	*long_val = 0;

	while (*p) {
	const int hex_val = hex(*p);

	if (hex_val < 0)
	break;

	long_val = (long_val << 4) \| hex_val;
	p++;
	}

	return p - ptr;
	}

	int dso__load_kallsyms(struct dso *self)
	{
	struct rb_node nd, prevnd;
	char *line = NULL;
	size_t n;
	FILE *file = fopen("/proc/kallsyms", "r");

	if (file == NULL)
	goto out_failure;

	while (!feof(file)) {
	unsigned long start;
	struct symbol *sym;
	int line_len, len;
	char symbol_type;

	line_len = getline(&line, &n, file);
	if (line_len < 0)
	break;

	if (!line)
	goto out_failure;

	line[--line_len] = '\0'; /* \n */

	len = hex2long(line, &start);

	len++;
	if (len + 2 >= line_len)
	continue;

	symbol_type = toupper(line[len]);
	/*
	* We're interested only in code ('T'ext)
	*/
	if (symbol_type != 'T' && symbol_type != 'W')
	continue;
	/*
	* Well fix up the end later, when we have all sorted.
	*/
	sym = symbol__new(start, 0xdead, line + len + 2);

	if (sym == NULL)
	goto out_delete_line;

	dso__insert_symbol(self, sym);
	}

	/*
	* Now that we have all sorted out, just set the ->end of all
	* symbols
	*/
	prevnd = rb_first(&self->syms);

	if (prevnd == NULL)
	goto out_delete_line;

	for (nd = rb_next(prevnd); nd; nd = rb_next(nd)) {
	struct symbol *prev = rb_entry(prevnd, struct symbol, rb_node),
	*curr = rb_entry(nd, struct symbol, rb_node);

	prev->end = curr->start - 1;
	prevnd = nd;
	}

	free(line);
	fclose(file);

	return 0;

	out_delete_line:
	free(line);
	out_failure:
	return -1;
	}

	/**
	* elf_symtab__for_each_symbol - iterate thru all the symbols
	*
	* @self: struct elf_symtab instance to iterate
	* @index: uint32_t index
	* @sym: GElf_Sym iterator
	*/
	#define elf_symtab__for_each_symbol(syms, nr_syms, index, sym) \
	for (index = 0, gelf_getsym(syms, index, &sym);\
	index < nr_syms; \
	index++, gelf_getsym(syms, index, &sym))

	static inline uint8_t elf_sym__type(const GElf_Sym *sym)
	{
	return GELF_ST_TYPE(sym->st_info);
	}

	static inline int elf_sym__is_function(const GElf_Sym *sym)
	{
	return elf_sym__type(sym) == STT_FUNC &&
	sym->st_name != 0 &&
	sym->st_shndx != SHN_UNDEF &&
	sym->st_size != 0;
	}

	static inline const char elf_sym__name(const GElf_Sym sym,
	const Elf_Data *symstrs)
	{
	return symstrs->d_buf + sym->st_name;
	}

	static Elf_Scn elf_section_by_name(Elf elf, GElf_Ehdr *ep,
	GElf_Shdr shp, const char name,
	size_t *index)
	{
	Elf_Scn *sec = NULL;
	size_t cnt = 1;

	while ((sec = elf_nextscn(elf, sec)) != NULL) {
	char *str;

	gelf_getshdr(sec, shp);
	str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
	if (!strcmp(name, str)) {
	if (index)
	*index = cnt;
	break;
	}
	++cnt;
	}

	return sec;
	}

	static int dso__load_sym(struct dso self, int fd, const char name)
	{
	Elf_Data *symstrs;
	uint32_t nr_syms;
	int err = -1;
	uint32_t index;
	GElf_Ehdr ehdr;
	GElf_Shdr shdr;
	Elf_Data *syms;
	GElf_Sym sym;
	Elf_Scn *sec;
	Elf *elf;
	int nr = 0;

	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
	if (elf == NULL) {
	fprintf(stderr, "%s: cannot read %s ELF file.\n",
	__func__, name);
	goto out_close;
	}

	if (gelf_getehdr(elf, &ehdr) == NULL) {
	fprintf(stderr, "%s: cannot get elf header.\n", __func__);
	goto out_elf_end;
	}

	sec = elf_section_by_name(elf, &ehdr, &shdr, ".symtab", NULL);
	if (sec == NULL)
	sec = elf_section_by_name(elf, &ehdr, &shdr, ".dynsym", NULL);

	if (sec == NULL)
	goto out_elf_end;

	syms = elf_getdata(sec, NULL);
	if (syms == NULL)
	goto out_elf_end;

	sec = elf_getscn(elf, shdr.sh_link);
	if (sec == NULL)
	goto out_elf_end;

	symstrs = elf_getdata(sec, NULL);
	if (symstrs == NULL)
	goto out_elf_end;

	nr_syms = shdr.sh_size / shdr.sh_entsize;

	elf_symtab__for_each_symbol(syms, nr_syms, index, sym) {
	struct symbol *f;

	if (!elf_sym__is_function(&sym))
	continue;

	sec = elf_getscn(elf, sym.st_shndx);
	if (!sec)
	goto out_elf_end;

	gelf_getshdr(sec, &shdr);
	sym.st_value -= shdr.sh_addr - shdr.sh_offset;

	f = symbol__new(sym.st_value, sym.st_size,
	elf_sym__name(&sym, symstrs));
	if (!f)
	goto out_elf_end;

	dso__insert_symbol(self, f);

	nr++;
	}

	err = nr;
	out_elf_end:
	elf_end(elf);
	out_close:
	return err;
	}

	int dso__load(struct dso *self)
	{
	int size = strlen(self->name) + sizeof("/usr/lib/debug%s.debug");
	char *name = malloc(size);
	int variant = 0;
	int ret = -1;
	int fd;

	if (!name)
	return -1;

	more:
	do {
	switch (variant) {
	case 0: /* Fedora */
	snprintf(name, size, "/usr/lib/debug%s.debug", self->name);
	break;
	case 1: /* Ubuntu */
	snprintf(name, size, "/usr/lib/debug%s", self->name);
	break;
	case 2: /* Sane people */
	snprintf(name, size, "%s", self->name);
	break;

	default:
	goto out;
	}
	variant++;

	fd = open(name, O_RDONLY);
	} while (fd < 0);

	ret = dso__load_sym(self, fd, name);
	close(fd);

	/*
	* Some people seem to have debuginfo files _WITHOUT_ debug info!?!?
	*/
	if (!ret)
	goto more;

	out:
	free(name);
	return ret;
	}

	int dso__load_vmlinux(struct dso self, const char vmlinux)
	{
	int err, fd = open(vmlinux, O_RDONLY);

	if (fd < 0)
	return -1;

	err = dso__load_sym(self, fd, vmlinux);
	close(fd);

	return err;
	}

	void symbol__init(void)
	{
	elf_version(EV_CURRENT);
	}