[linux-2.6-block.git] / Documentation / perf_counter / util / symbol.c

#include "util.h"
#include "../perf.h"
#include "string.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, unsigned int priv_size)
{
	size_t namelen = strlen(name) + 1;
	struct symbol *self = malloc(priv_size + sizeof(*self) + namelen);

	if (self != NULL) {
		if (priv_size) {
			memset(self, 0, priv_size);
			self = ((void *)self) + priv_size;
		}
		self->start = start;
		self->end   = start + len - 1;
		memcpy(self->name, name, namelen);
	}

	return self;
}

static void symbol__delete(struct symbol *self, unsigned int priv_size)
{
	free(((void *)self) - priv_size);
}

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, unsigned int sym_priv_size)
{
	struct dso *self = malloc(sizeof(*self) + strlen(name) + 1);

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

	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);
		rb_erase(&pos->rb_node, &self->syms);
		symbol__delete(pos, self->sym_priv_size);
	}
}

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 dso__load_kallsyms(struct dso *self, symbol_filter_t filter, int verbose)
{
	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)) {
		__u64 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 = hex2u64(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,
				  self->sym_priv_size);

		if (sym == NULL)
			goto out_delete_line;

		if (filter && filter(self, sym))
			symbol__delete(sym, self->sym_priv_size);
		else
			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;
}

#define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
	for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
	     idx < nr_entries; \
	     ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))

#define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
	for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
	     idx < nr_entries; \
	     ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))

static int dso__synthesize_plt_symbols(struct  dso *self, Elf *elf,
				       GElf_Ehdr *ehdr, Elf_Scn *scn_dynsym,
				       GElf_Shdr *shdr_dynsym,
				       size_t dynsym_idx)
{
	uint32_t nr_rel_entries, idx;
	GElf_Sym sym;
	__u64 plt_offset;
	GElf_Shdr shdr_plt;
	struct symbol *f;
	GElf_Shdr shdr_rel_plt;
	Elf_Data *reldata, *syms, *symstrs;
	Elf_Scn *scn_plt_rel, *scn_symstrs;
	char sympltname[1024];
	int nr = 0, symidx;

	scn_plt_rel = elf_section_by_name(elf, ehdr, &shdr_rel_plt,
					  ".rela.plt", NULL);
	if (scn_plt_rel == NULL) {
		scn_plt_rel = elf_section_by_name(elf, ehdr, &shdr_rel_plt,
						  ".rel.plt", NULL);
		if (scn_plt_rel == NULL)
			return 0;
	}

	if (shdr_rel_plt.sh_link != dynsym_idx)
		return 0;

	if (elf_section_by_name(elf, ehdr, &shdr_plt, ".plt", NULL) == NULL)
		return 0;

	/*
	 * Fetch the relocation section to find the indexes to the GOT
	 * and the symbols in the .dynsym they refer to.
	 */
	reldata = elf_getdata(scn_plt_rel, NULL);
	if (reldata == NULL)
		return -1;

	syms = elf_getdata(scn_dynsym, NULL);
	if (syms == NULL)
		return -1;

	scn_symstrs = elf_getscn(elf, shdr_dynsym->sh_link);
	if (scn_symstrs == NULL)
		return -1;

	symstrs = elf_getdata(scn_symstrs, NULL);
	if (symstrs == NULL)
		return -1;

	nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
	plt_offset = shdr_plt.sh_offset;

	if (shdr_rel_plt.sh_type == SHT_RELA) {
		GElf_Rela pos_mem, *pos;

		elf_section__for_each_rela(reldata, pos, pos_mem, idx,
					   nr_rel_entries) {
			symidx = GELF_R_SYM(pos->r_info);
			plt_offset += shdr_plt.sh_entsize;
			gelf_getsym(syms, symidx, &sym);
			snprintf(sympltname, sizeof(sympltname),
				 "%s@plt", elf_sym__name(&sym, symstrs));

			f = symbol__new(plt_offset, shdr_plt.sh_entsize,
					sympltname, self->sym_priv_size);
			if (!f)
				return -1;

			dso__insert_symbol(self, f);
			++nr;
		}
	} else if (shdr_rel_plt.sh_type == SHT_REL) {
		GElf_Rel pos_mem, *pos;
		elf_section__for_each_rel(reldata, pos, pos_mem, idx,
					  nr_rel_entries) {
			symidx = GELF_R_SYM(pos->r_info);
			plt_offset += shdr_plt.sh_entsize;
			gelf_getsym(syms, symidx, &sym);
			snprintf(sympltname, sizeof(sympltname),
				 "%s@plt", elf_sym__name(&sym, symstrs));

			f = symbol__new(plt_offset, shdr_plt.sh_entsize,
					sympltname, self->sym_priv_size);
			if (!f)
				return -1;

			dso__insert_symbol(self, f);
			++nr;
		}
	} else {
		/*
		 * TODO: There are still one more shdr_rel_plt.sh_type
		 * I have to investigate, but probably should be ignored.
		 */
	}

	return nr;
}

static int dso__load_sym(struct dso *self, int fd, const char *name,
			 symbol_filter_t filter, int verbose)
{
	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, *sec_dynsym;
	Elf *elf;
	size_t dynsym_idx;
	int nr = 0;

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

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

	/*
	 * We need to check if we have a .dynsym, so that we can handle the
	 * .plt, synthesizing its symbols, that aren't on the symtabs (be it
	 * .dynsym or .symtab)
	 */
	sec_dynsym = elf_section_by_name(elf, &ehdr, &shdr,
					 ".dynsym", &dynsym_idx);
	if (sec_dynsym != NULL) {
		nr = dso__synthesize_plt_symbols(self, elf, &ehdr,
						 sec_dynsym, &shdr,
						 dynsym_idx);
		if (nr < 0)
			goto out_elf_end;
	}

	/*
	 * But if we have a full .symtab (that is a superset of .dynsym) we
	 * should add the symbols not in the .dynsyn
	 */
	sec = elf_section_by_name(elf, &ehdr, &shdr, ".symtab", NULL);
	if (sec == NULL) {
		if (sec_dynsym == NULL)
			goto out_elf_end;

		sec = sec_dynsym;
		gelf_getshdr(sec, &shdr);
	}

	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),
				self->sym_priv_size);
		if (!f)
			goto out_elf_end;

		if (filter && filter(self, f))
			symbol__delete(f, self->sym_priv_size);
		else {
			dso__insert_symbol(self, f);
			nr++;
		}
	}

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

int dso__load(struct dso *self, symbol_filter_t filter, int verbose)
{
	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, filter, verbose);
	close(fd);

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

out:
	free(name);
	return ret;
}

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

	if (fd < 0)
		return -1;

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

	return err;
}

int dso__load_kernel(struct dso *self, const char *vmlinux,
		     symbol_filter_t filter, int verbose)
{
	int err = -1;

	if (vmlinux)
		err = dso__load_vmlinux(self, vmlinux, filter, verbose);

	if (err)
		err = dso__load_kallsyms(self, filter, verbose);

	return err;
}

void symbol__init(void)
{
	elf_version(EV_CURRENT);
}
Commit	Line	Data
a2928c42 ACM	1	#include "util.h"
a2928c42 ACM	2	#include "../perf.h"
a0055ae2	3	#include "string.h"
a2928c42 ACM	4	#include "symbol.h"
	5
	6	#include <libelf.h>
	7	#include <gelf.h>
	8	#include <elf.h>
	9
	10	static struct symbol *symbol__new(uint64_t start, uint64_t len,
0085c954	11	const char *name, unsigned int priv_size)
a2928c42	12	{
0085c954 ACM	13	size_t namelen = strlen(name) + 1;
0085c954 ACM	14	struct symbol self = malloc(priv_size + sizeof(self) + namelen);
a2928c42 ACM	15
a2928c42 ACM	16	if (self != NULL) {
0085c954 ACM	17	if (priv_size) {
	18	memset(self, 0, priv_size);
	19	self = ((void *)self) + priv_size;
	20	}
a2928c42	21	self->start = start;
18374ab7	22	self->end = start + len - 1;
0085c954	23	memcpy(self->name, name, namelen);
a2928c42 ACM	24	}
	25
	26	return self;
	27	}
	28
0085c954	29	static void symbol__delete(struct symbol *self, unsigned int priv_size)
a2928c42	30	{
0085c954	31	free(((void *)self) - priv_size);
a2928c42 ACM	32	}
	33
	34	static size_t symbol__fprintf(struct symbol self, FILE fp)
	35	{
	36	return fprintf(fp, " %llx-%llx %s\n",
	37	self->start, self->end, self->name);
	38	}
	39
0085c954	40	struct dso dso__new(const char name, unsigned int sym_priv_size)
a2928c42 ACM	41	{
	42	struct dso self = malloc(sizeof(self) + strlen(name) + 1);
	43
	44	if (self != NULL) {
	45	strcpy(self->name, name);
	46	self->syms = RB_ROOT;
0085c954	47	self->sym_priv_size = sym_priv_size;
a2928c42 ACM	48	}
	49
	50	return self;
	51	}
	52
	53	static void dso__delete_symbols(struct dso *self)
	54	{
	55	struct symbol *pos;
	56	struct rb_node *next = rb_first(&self->syms);
	57
	58	while (next) {
	59	pos = rb_entry(next, struct symbol, rb_node);
	60	next = rb_next(&pos->rb_node);
c8c96525	61	rb_erase(&pos->rb_node, &self->syms);
0085c954	62	symbol__delete(pos, self->sym_priv_size);
a2928c42 ACM	63	}
	64	}
	65
	66	void dso__delete(struct dso *self)
	67	{
	68	dso__delete_symbols(self);
	69	free(self);
	70	}
	71
	72	static void dso__insert_symbol(struct dso self, struct symbol sym)
	73	{
	74	struct rb_node **p = &self->syms.rb_node;
	75	struct rb_node *parent = NULL;
	76	const uint64_t ip = sym->start;
	77	struct symbol *s;
	78
	79	while (*p != NULL) {
	80	parent = *p;
	81	s = rb_entry(parent, struct symbol, rb_node);
	82	if (ip < s->start)
	83	p = &(*p)->rb_left;
	84	else
	85	p = &(*p)->rb_right;
	86	}
	87	rb_link_node(&sym->rb_node, parent, p);
	88	rb_insert_color(&sym->rb_node, &self->syms);
	89	}
	90
	91	struct symbol dso__find_symbol(struct dso self, uint64_t ip)
	92	{
	93	struct rb_node *n;
	94
	95	if (self == NULL)
	96	return NULL;
	97
	98	n = self->syms.rb_node;
	99
	100	while (n) {
	101	struct symbol *s = rb_entry(n, struct symbol, rb_node);
	102
	103	if (ip < s->start)
	104	n = n->rb_left;
	105	else if (ip > s->end)
	106	n = n->rb_right;
	107	else
	108	return s;
	109	}
	110
	111	return NULL;
	112	}
	113
	114	size_t dso__fprintf(struct dso self, FILE fp)
	115	{
	116	size_t ret = fprintf(fp, "dso: %s\n", self->name);
	117
	118	struct rb_node *nd;
	119	for (nd = rb_first(&self->syms); nd; nd = rb_next(nd)) {
	120	struct symbol *pos = rb_entry(nd, struct symbol, rb_node);
	121	ret += symbol__fprintf(pos, fp);
	122	}
	123
	124	return ret;
	125	}
	126
bd74137e	127	static int dso__load_kallsyms(struct dso *self, symbol_filter_t filter, int verbose)
a2928c42 ACM	128	{
	129	struct rb_node nd, prevnd;
	130	char *line = NULL;
	131	size_t n;
	132	FILE *file = fopen("/proc/kallsyms", "r");
	133
	134	if (file == NULL)
	135	goto out_failure;
	136
	137	while (!feof(file)) {
a0055ae2	138	__u64 start;
a2928c42 ACM	139	struct symbol *sym;
	140	int line_len, len;
	141	char symbol_type;
	142
	143	line_len = getline(&line, &n, file);
	144	if (line_len < 0)
	145	break;
	146
	147	if (!line)
	148	goto out_failure;
	149
	150	line[--line_len] = '\0'; /* \n */
	151
a0055ae2	152	len = hex2u64(line, &start);
a2928c42 ACM	153
	154	len++;
	155	if (len + 2 >= line_len)
	156	continue;
	157
	158	symbol_type = toupper(line[len]);
	159	/*
	160	* We're interested only in code ('T'ext)
	161	*/
	162	if (symbol_type != 'T' && symbol_type != 'W')
	163	continue;
	164	/*
	165	* Well fix up the end later, when we have all sorted.
	166	*/
0085c954 ACM	167	sym = symbol__new(start, 0xdead, line + len + 2,
0085c954 ACM	168	self->sym_priv_size);
a2928c42 ACM	169
	170	if (sym == NULL)
	171	goto out_delete_line;
	172
69ee69f6 ACM	173	if (filter && filter(self, sym))
	174	symbol__delete(sym, self->sym_priv_size);
	175	else
	176	dso__insert_symbol(self, sym);
a2928c42 ACM	177	}
	178
	179	/*
	180	* Now that we have all sorted out, just set the ->end of all
	181	* symbols
	182	*/
	183	prevnd = rb_first(&self->syms);
	184
	185	if (prevnd == NULL)
	186	goto out_delete_line;
	187
	188	for (nd = rb_next(prevnd); nd; nd = rb_next(nd)) {
	189	struct symbol *prev = rb_entry(prevnd, struct symbol, rb_node),
	190	*curr = rb_entry(nd, struct symbol, rb_node);
	191
	192	prev->end = curr->start - 1;
	193	prevnd = nd;
	194	}
	195
	196	free(line);
	197	fclose(file);
	198
	199	return 0;
	200
	201	out_delete_line:
	202	free(line);
	203	out_failure:
	204	return -1;
	205	}
	206
	207	/**
	208	* elf_symtab__for_each_symbol - iterate thru all the symbols
	209	*
	210	* @self: struct elf_symtab instance to iterate
	211	* @index: uint32_t index
	212	* @sym: GElf_Sym iterator
	213	*/
	214	#define elf_symtab__for_each_symbol(syms, nr_syms, index, sym) \
	215	for (index = 0, gelf_getsym(syms, index, &sym);\
	216	index < nr_syms; \
	217	index++, gelf_getsym(syms, index, &sym))
	218
	219	static inline uint8_t elf_sym__type(const GElf_Sym *sym)
	220	{
	221	return GELF_ST_TYPE(sym->st_info);
	222	}
	223
	224	static inline int elf_sym__is_function(const GElf_Sym *sym)
	225	{
	226	return elf_sym__type(sym) == STT_FUNC &&
	227	sym->st_name != 0 &&
	228	sym->st_shndx != SHN_UNDEF &&
	229	sym->st_size != 0;
	230	}
	231
	232	static inline const char elf_sym__name(const GElf_Sym sym,
	233	const Elf_Data *symstrs)
	234	{
	235	return symstrs->d_buf + sym->st_name;
	236	}
	237
	238	static Elf_Scn elf_section_by_name(Elf elf, GElf_Ehdr *ep,
	239	GElf_Shdr shp, const char name,
	240	size_t *index)
241	{
242	Elf_Scn *sec = NULL;
243	size_t cnt = 1;
244
245	while ((sec = elf_nextscn(elf, sec)) != NULL) {
246	char *str;
247
248	gelf_getshdr(sec, shp);
249	str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
250	if (!strcmp(name, str)) {
251	if (index)
252	*index = cnt;
253	break;
254	}
255	++cnt;
256	}
257
258	return sec;
259	}
260
8ce998d6 ACM	261	#define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
	262	for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
	263	idx < nr_entries; \
	264	++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
	265
	266	#define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
	267	for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
	268	idx < nr_entries; \
	269	++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
	270
	271	static int dso__synthesize_plt_symbols(struct dso self, Elf elf,
	272	GElf_Ehdr ehdr, Elf_Scn scn_dynsym,
	273	GElf_Shdr *shdr_dynsym,
	274	size_t dynsym_idx)
	275	{
	276	uint32_t nr_rel_entries, idx;
	277	GElf_Sym sym;
	278	__u64 plt_offset;
	279	GElf_Shdr shdr_plt;
	280	struct symbol *f;
	281	GElf_Shdr shdr_rel_plt;
	282	Elf_Data reldata, syms, *symstrs;
	283	Elf_Scn scn_plt_rel, scn_symstrs;
	284	char sympltname[1024];
	285	int nr = 0, symidx;
	286
	287	scn_plt_rel = elf_section_by_name(elf, ehdr, &shdr_rel_plt,
	288	".rela.plt", NULL);
	289	if (scn_plt_rel == NULL) {
	290	scn_plt_rel = elf_section_by_name(elf, ehdr, &shdr_rel_plt,
	291	".rel.plt", NULL);
	292	if (scn_plt_rel == NULL)
	293	return 0;
	294	}
	295
	296	if (shdr_rel_plt.sh_link != dynsym_idx)
	297	return 0;
	298
	299	if (elf_section_by_name(elf, ehdr, &shdr_plt, ".plt", NULL) == NULL)
	300	return 0;
	301
	302	/*
	303	* Fetch the relocation section to find the indexes to the GOT
	304	* and the symbols in the .dynsym they refer to.
	305	*/
	306	reldata = elf_getdata(scn_plt_rel, NULL);
	307	if (reldata == NULL)
	308	return -1;
	309
	310	syms = elf_getdata(scn_dynsym, NULL);
	311	if (syms == NULL)
	312	return -1;
	313
	314	scn_symstrs = elf_getscn(elf, shdr_dynsym->sh_link);
	315	if (scn_symstrs == NULL)
	316	return -1;
	317
	318	symstrs = elf_getdata(scn_symstrs, NULL);
	319	if (symstrs == NULL)
	320	return -1;
	321
	322	nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
	323	plt_offset = shdr_plt.sh_offset;
	324
325	if (shdr_rel_plt.sh_type == SHT_RELA) {
326	GElf_Rela pos_mem, *pos;
327
328	elf_section__for_each_rela(reldata, pos, pos_mem, idx,
329	nr_rel_entries) {
330	symidx = GELF_R_SYM(pos->r_info);
331	plt_offset += shdr_plt.sh_entsize;
332	gelf_getsym(syms, symidx, &sym);
333	snprintf(sympltname, sizeof(sympltname),
334	"%s@plt", elf_sym__name(&sym, symstrs));
335
336	f = symbol__new(plt_offset, shdr_plt.sh_entsize,
337	sympltname, self->sym_priv_size);
338	if (!f)
339	return -1;
340
341	dso__insert_symbol(self, f);
342	++nr;
343	}
344	} else if (shdr_rel_plt.sh_type == SHT_REL) {
345	GElf_Rel pos_mem, *pos;
346	elf_section__for_each_rel(reldata, pos, pos_mem, idx,
347	nr_rel_entries) {
348	symidx = GELF_R_SYM(pos->r_info);
349	plt_offset += shdr_plt.sh_entsize;
350	gelf_getsym(syms, symidx, &sym);
351	snprintf(sympltname, sizeof(sympltname),
352	"%s@plt", elf_sym__name(&sym, symstrs));
353
354	f = symbol__new(plt_offset, shdr_plt.sh_entsize,
355	sympltname, self->sym_priv_size);
356	if (!f)
357	return -1;
358
359	dso__insert_symbol(self, f);
360	++nr;
361	}
362	} else {
363	/*
364	* TODO: There are still one more shdr_rel_plt.sh_type
365	* I have to investigate, but probably should be ignored.
366	*/
367	}
368
369	return nr;
370	}
371
69ee69f6	372	static int dso__load_sym(struct dso self, int fd, const char name,
bd74137e	373	symbol_filter_t filter, int verbose)
a2928c42 ACM	374	{
	375	Elf_Data *symstrs;
	376	uint32_t nr_syms;
	377	int err = -1;
	378	uint32_t index;
	379	GElf_Ehdr ehdr;
	380	GElf_Shdr shdr;
	381	Elf_Data *syms;
	382	GElf_Sym sym;
8ce998d6	383	Elf_Scn sec, sec_dynsym;
a2928c42	384	Elf *elf;
8ce998d6	385	size_t dynsym_idx;
a2928c42 ACM	386	int nr = 0;
	387
	388	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
	389	if (elf == NULL) {
bd74137e IM	390	if (verbose)
	391	fprintf(stderr, "%s: cannot read %s ELF file.\n",
	392	__func__, name);
a2928c42 ACM	393	goto out_close;
	394	}
	395
	396	if (gelf_getehdr(elf, &ehdr) == NULL) {
bd74137e IM	397	if (verbose)
bd74137e IM	398	fprintf(stderr, "%s: cannot get elf header.\n", __func__);
a2928c42 ACM	399	goto out_elf_end;
	400	}
	401
8ce998d6 ACM	402	/*
	403	* We need to check if we have a .dynsym, so that we can handle the
	404	* .plt, synthesizing its symbols, that aren't on the symtabs (be it
	405	* .dynsym or .symtab)
	406	*/
	407	sec_dynsym = elf_section_by_name(elf, &ehdr, &shdr,
	408	".dynsym", &dynsym_idx);
	409	if (sec_dynsym != NULL) {
	410	nr = dso__synthesize_plt_symbols(self, elf, &ehdr,
	411	sec_dynsym, &shdr,
	412	dynsym_idx);
	413	if (nr < 0)
	414	goto out_elf_end;
	415	}
	416
	417	/*
	418	* But if we have a full .symtab (that is a superset of .dynsym) we
	419	* should add the symbols not in the .dynsyn
	420	*/
a2928c42	421	sec = elf_section_by_name(elf, &ehdr, &shdr, ".symtab", NULL);
8ce998d6 ACM	422	if (sec == NULL) {
	423	if (sec_dynsym == NULL)
	424	goto out_elf_end;
a2928c42	425
8ce998d6 ACM	426	sec = sec_dynsym;
	427	gelf_getshdr(sec, &shdr);
	428	}
a2928c42 ACM	429
	430	syms = elf_getdata(sec, NULL);
	431	if (syms == NULL)
	432	goto out_elf_end;
	433
	434	sec = elf_getscn(elf, shdr.sh_link);
	435	if (sec == NULL)
	436	goto out_elf_end;
	437
	438	symstrs = elf_getdata(sec, NULL);
	439	if (symstrs == NULL)
	440	goto out_elf_end;
	441
	442	nr_syms = shdr.sh_size / shdr.sh_entsize;
	443
	444	elf_symtab__for_each_symbol(syms, nr_syms, index, sym) {
	445	struct symbol *f;
	446
	447	if (!elf_sym__is_function(&sym))
	448	continue;
	449
	450	sec = elf_getscn(elf, sym.st_shndx);
	451	if (!sec)
	452	goto out_elf_end;
	453
	454	gelf_getshdr(sec, &shdr);
	455	sym.st_value -= shdr.sh_addr - shdr.sh_offset;
	456
	457	f = symbol__new(sym.st_value, sym.st_size,
0085c954 ACM	458	elf_sym__name(&sym, symstrs),
0085c954 ACM	459	self->sym_priv_size);
a2928c42 ACM	460	if (!f)
	461	goto out_elf_end;
	462
69ee69f6 ACM	463	if (filter && filter(self, f))
	464	symbol__delete(f, self->sym_priv_size);
	465	else {
	466	dso__insert_symbol(self, f);
	467	nr++;
	468	}
a2928c42 ACM	469	}
	470
	471	err = nr;
	472	out_elf_end:
	473	elf_end(elf);
	474	out_close:
	475	return err;
	476	}
	477
bd74137e	478	int dso__load(struct dso *self, symbol_filter_t filter, int verbose)
a2928c42 ACM	479	{
	480	int size = strlen(self->name) + sizeof("/usr/lib/debug%s.debug");
	481	char *name = malloc(size);
	482	int variant = 0;
	483	int ret = -1;
	484	int fd;
	485
	486	if (!name)
	487	return -1;
	488
	489	more:
	490	do {
	491	switch (variant) {
	492	case 0: /* Fedora */
	493	snprintf(name, size, "/usr/lib/debug%s.debug", self->name);
	494	break;
	495	case 1: /* Ubuntu */
	496	snprintf(name, size, "/usr/lib/debug%s", self->name);
	497	break;
	498	case 2: /* Sane people */
	499	snprintf(name, size, "%s", self->name);
	500	break;
	501
	502	default:
	503	goto out;
	504	}
	505	variant++;
	506
	507	fd = open(name, O_RDONLY);
	508	} while (fd < 0);
	509
bd74137e	510	ret = dso__load_sym(self, fd, name, filter, verbose);
a2928c42 ACM	511	close(fd);
	512
	513	/*
	514	* Some people seem to have debuginfo files _WITHOUT_ debug info!?!?
	515	*/
	516	if (!ret)
	517	goto more;
	518
	519	out:
	520	free(name);
	521	return ret;
	522	}
	523
69ee69f6	524	static int dso__load_vmlinux(struct dso self, const char vmlinux,
bd74137e	525	symbol_filter_t filter, int verbose)
a2928c42 ACM	526	{
	527	int err, fd = open(vmlinux, O_RDONLY);
	528
	529	if (fd < 0)
	530	return -1;
	531
bd74137e	532	err = dso__load_sym(self, fd, vmlinux, filter, verbose);
a2928c42 ACM	533	close(fd);
	534
	535	return err;
	536	}
	537
bd74137e IM	538	int dso__load_kernel(struct dso self, const char vmlinux,
bd74137e IM	539	symbol_filter_t filter, int verbose)
a827c875 ACM	540	{
	541	int err = -1;
	542
	543	if (vmlinux)
bd74137e	544	err = dso__load_vmlinux(self, vmlinux, filter, verbose);
a827c875 ACM	545
a827c875 ACM	546	if (err)
bd74137e	547	err = dso__load_kallsyms(self, filter, verbose);
a827c875 ACM	548
	549	return err;
	550	}
	551
a2928c42 ACM	552	void symbol__init(void)
	553	{
	554	elf_version(EV_CURRENT);
	555	}