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tools/jprof/elf.cpp@97036ab72558 (annotated)

tools/jprof/elf.cpp

Tue, 06 Jan 2015 21:39:09 +0100

author

Michael Schloh von Bennewitz <michael@schloh.com>

date

Tue, 06 Jan 2015 21:39:09 +0100

branch

TOR_BUG_9701

changeset 8

97036ab72558

permissions

-rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

michael@0	1	/* This Source Code Form is subject to the terms of the Mozilla Public
michael@0	2	* License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0	3	* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0	4
michael@0	5	#include "leaky.h"
michael@0	6
michael@0	7	#ifdef USE_ELF
michael@0	8
michael@0	9	#include "leaky.h"
michael@0	10	#include <stdio.h>
michael@0	11	#include <malloc.h>
michael@0	12	#include <libelf/libelf.h>
michael@0	13	#include <unistd.h>
michael@0	14	#include <fcntl.h>
michael@0	15	#include <string.h>
michael@0	16
michael@0	17	void leaky::readSymbols(const char *fileName)
michael@0	18	{
michael@0	19	int fd = ::open(fileName, O_RDONLY);
michael@0	20	if (fd < 0) {
michael@0	21	fprintf(stderr, "%s: unable to open \"%s\"\n", applicationName,
michael@0	22	fileName);
michael@0	23	exit(-1);
michael@0	24	}
michael@0	25
michael@0	26	elf_version(EV_CURRENT);
michael@0	27	Elf *elf = elf_begin(fd, ELF_C_READ, 0);
michael@0	28	if (!elf) {
michael@0	29	fprintf(stderr, "%s: \"%s\": has no symbol table\n", applicationName,
michael@0	30	fileName);
michael@0	31	exit(-1);
michael@0	32	}
michael@0	33
michael@0	34	long alloced = 10000;
michael@0	35	Symbol* syms = (Symbol*) malloc(sizeof(Symbol) * 10000);
michael@0	36	Symbol* sp = syms;
michael@0	37	Symbol* last = syms + alloced;
michael@0	38
michael@0	39	// Get each of the relevant sections and add them to the list of
michael@0	40	// symbols.
michael@0	41	Elf32_Ehdr *ehdr = elf32_getehdr(elf);
michael@0	42	if (!ehdr) {
michael@0	43	fprintf(stderr, "%s: elf library lossage\n", applicationName);
michael@0	44	exit(-1);
michael@0	45	}
michael@0	46	#if 0
michael@0	47	Elf32_Half ndx = ehdr->e_shstrndx;
michael@0	48	#endif
michael@0	49
michael@0	50	Elf_Scn *scn = 0;
michael@0	51	int strtabndx = -1;
michael@0	52	for (int i = 1; (scn = elf_nextscn(elf, scn)) != 0; i++) {
michael@0	53	Elf32_Shdr *shdr = elf32_getshdr(scn);
michael@0	54	#if 0
michael@0	55	char *name = elf_strptr(elf, ndx, (size_t) shdr->sh_name);
michael@0	56	printf("Section %s (%d 0x%x)\n", name ? name : "(null)",
michael@0	57	shdr->sh_type, shdr->sh_type);
michael@0	58	#endif
michael@0	59	if (shdr->sh_type == SHT_STRTAB) {
michael@0	60	/* We assume here that string tables preceed symbol tables... */
michael@0	61	strtabndx = i;
michael@0	62	continue;
michael@0	63	}
michael@0	64	#if 0
michael@0	65	if (shdr->sh_type == SHT_DYNAMIC) {
michael@0	66	/* Dynamic */
michael@0	67	Elf_Data *data = elf_getdata(scn, 0);
michael@0	68	if (!data || !data->d_size) {
michael@0	69	printf("No data...");
michael@0	70	continue;
michael@0	71	}
michael@0	72
michael@0	73	Elf32_Dyn *dyn = (Elf32_Dyn*) data->d_buf;
michael@0	74	Elf32_Dyn *lastdyn =
michael@0	75	(Elf32_Dyn*) ((char*) data->d_buf + data->d_size);
michael@0	76	for (; dyn < lastdyn; dyn++) {
michael@0	77	printf("tag=%d value=0x%x\n", dyn->d_tag, dyn->d_un.d_val);
michael@0	78	}
michael@0	79	} else
michael@0	80	#endif
michael@0	81	if ((shdr->sh_type == SHT_SYMTAB) ||
michael@0	82	(shdr->sh_type == SHT_DYNSYM)) {
michael@0	83	/* Symbol table */
michael@0	84	Elf_Data *data = elf_getdata(scn, 0);
michael@0	85	if (!data || !data->d_size) {
michael@0	86	printf("No data...");
michael@0	87	continue;
michael@0	88	}
michael@0	89
michael@0	90	/* In theory we now have the symbols... */
michael@0	91	Elf32_Sym *esym = (Elf32_Sym*) data->d_buf;
michael@0	92	Elf32_Sym *lastsym =
michael@0	93	(Elf32_Sym*) ((char*) data->d_buf + data->d_size);
michael@0	94	for (; esym < lastsym; esym++) {
michael@0	95	#if 0
michael@0	96	char *nm = elf_strptr(elf, strtabndx, (size_t)esym->st_name);
michael@0	97	printf("%20s 0x%08x %02x %02x\n",
michael@0	98	nm, esym->st_value, ELF32_ST_BIND(esym->st_info),
michael@0	99	ELF32_ST_TYPE(esym->st_info));
michael@0	100	#endif
michael@0	101	if ((esym->st_value == 0) ||
michael@0	102	(ELF32_ST_BIND(esym->st_info) == STB_WEAK) ||
michael@0	103	(ELF32_ST_BIND(esym->st_info) == STB_NUM) ||
michael@0	104	(ELF32_ST_TYPE(esym->st_info) != STT_FUNC)) {
michael@0	105	continue;
michael@0	106	}
michael@0	107	#if 1
michael@0	108	char *nm = elf_strptr(elf, strtabndx, (size_t)esym->st_name);
michael@0	109	#endif
michael@0	110	sp->name = nm ? strdup(nm) : "(no name)";
michael@0	111	sp->address = esym->st_value;
michael@0	112	sp++;
michael@0	113	if (sp >= last) {
michael@0	114	long n = alloced + 10000;
michael@0	115	syms = (Symbol*)
michael@0	116	realloc(syms, (size_t) (sizeof(Symbol) * n));
michael@0	117	last = syms + n;
michael@0	118	sp = syms + alloced;
michael@0	119	alloced = n;
michael@0	120	}
michael@0	121	}
michael@0	122	}
michael@0	123	}
michael@0	124
michael@0	125	int interesting = sp - syms;
michael@0	126	if (!quiet) {
michael@0	127	printf("Total of %d symbols\n", interesting);
michael@0	128	}
michael@0	129	usefulSymbols = interesting;
michael@0	130	externalSymbols = syms;
michael@0	131	}
michael@0	132
michael@0	133	#endif /* USE_ELF */