1/*
  2 * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
  3 *
  4 * This program is free software; you can redistribute it and/or
  5 * modify it under the terms of the GNU General Public License
  6 * as published by the Free Software Foundation; either version 2
  7 * of the License, or (at your option) any later version.
  8 *
  9 * This program is distributed in the hope that it will be useful,
 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 12 * GNU General Public License for more details.
 13 *
 14 * You should have received a copy of the GNU General Public License
 15 * along with this program; if not, see <http://www.gnu.org/licenses/>.
 16 */
 17
 18#include <unistd.h>
 19#include "orc.h"
 20#include "warn.h"
 21
 22static const char *reg_name(unsigned int reg)
 23{
 24	switch (reg) {
 25	case ORC_REG_PREV_SP:
 26		return "prevsp";
 27	case ORC_REG_DX:
 28		return "dx";
 29	case ORC_REG_DI:
 30		return "di";
 31	case ORC_REG_BP:
 32		return "bp";
 33	case ORC_REG_SP:
 34		return "sp";
 35	case ORC_REG_R10:
 36		return "r10";
 37	case ORC_REG_R13:
 38		return "r13";
 39	case ORC_REG_BP_INDIRECT:
 40		return "bp(ind)";
 41	case ORC_REG_SP_INDIRECT:
 42		return "sp(ind)";
 43	default:
 44		return "?";
 45	}
 46}
 47
 48static const char *orc_type_name(unsigned int type)
 49{
 50	switch (type) {
 51	case ORC_TYPE_CALL:
 52		return "call";
 53	case ORC_TYPE_REGS:
 54		return "regs";
 55	case ORC_TYPE_REGS_IRET:
 56		return "iret";
 57	default:
 58		return "?";
 59	}
 60}
 61
 62static void print_reg(unsigned int reg, int offset)
 63{
 64	if (reg == ORC_REG_BP_INDIRECT)
 65		printf("(bp%+d)", offset);
 66	else if (reg == ORC_REG_SP_INDIRECT)
 67		printf("(sp%+d)", offset);
 68	else if (reg == ORC_REG_UNDEFINED)
 69		printf("(und)");
 70	else
 71		printf("%s%+d", reg_name(reg), offset);
 72}
 73
 74int orc_dump(const char *_objname)
 75{
 76	int fd, nr_entries, i, *orc_ip = NULL, orc_size = 0;
 77	struct orc_entry *orc = NULL;
 78	char *name;
 79	size_t nr_sections;
 80	Elf64_Addr orc_ip_addr = 0;
 81	size_t shstrtab_idx;
 82	Elf *elf;
 83	Elf_Scn *scn;
 84	GElf_Shdr sh;
 85	GElf_Rela rela;
 86	GElf_Sym sym;
 87	Elf_Data *data, *symtab = NULL, *rela_orc_ip = NULL;
 88
 89
 90	objname = _objname;
 91
 92	elf_version(EV_CURRENT);
 93
 94	fd = open(objname, O_RDONLY);
 95	if (fd == -1) {
 96		perror("open");
 97		return -1;
 98	}
 99
100	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
101	if (!elf) {
102		WARN_ELF("elf_begin");
103		return -1;
104	}
105
106	if (elf_getshdrnum(elf, &nr_sections)) {
107		WARN_ELF("elf_getshdrnum");
108		return -1;
109	}
110
111	if (elf_getshdrstrndx(elf, &shstrtab_idx)) {
112		WARN_ELF("elf_getshdrstrndx");
113		return -1;
114	}
115
116	for (i = 0; i < nr_sections; i++) {
117		scn = elf_getscn(elf, i);
118		if (!scn) {
119			WARN_ELF("elf_getscn");
120			return -1;
121		}
122
123		if (!gelf_getshdr(scn, &sh)) {
124			WARN_ELF("gelf_getshdr");
125			return -1;
126		}
127
128		name = elf_strptr(elf, shstrtab_idx, sh.sh_name);
129		if (!name) {
130			WARN_ELF("elf_strptr");
131			return -1;
132		}
133
134		data = elf_getdata(scn, NULL);
135		if (!data) {
136			WARN_ELF("elf_getdata");
137			return -1;
138		}
139
140		if (!strcmp(name, ".symtab")) {
141			symtab = data;
142		} else if (!strcmp(name, ".orc_unwind")) {
143			orc = data->d_buf;
144			orc_size = sh.sh_size;
145		} else if (!strcmp(name, ".orc_unwind_ip")) {
146			orc_ip = data->d_buf;
147			orc_ip_addr = sh.sh_addr;
148		} else if (!strcmp(name, ".rela.orc_unwind_ip")) {
149			rela_orc_ip = data;
150		}
151	}
152
153	if (!symtab || !orc || !orc_ip)
154		return 0;
155
156	if (orc_size % sizeof(*orc) != 0) {
157		WARN("bad .orc_unwind section size");
158		return -1;
159	}
160
161	nr_entries = orc_size / sizeof(*orc);
162	for (i = 0; i < nr_entries; i++) {
163		if (rela_orc_ip) {
164			if (!gelf_getrela(rela_orc_ip, i, &rela)) {
165				WARN_ELF("gelf_getrela");
166				return -1;
167			}
168
169			if (!gelf_getsym(symtab, GELF_R_SYM(rela.r_info), &sym)) {
170				WARN_ELF("gelf_getsym");
171				return -1;
172			}
173
174			scn = elf_getscn(elf, sym.st_shndx);
175			if (!scn) {
176				WARN_ELF("elf_getscn");
177				return -1;
178			}
179
180			if (!gelf_getshdr(scn, &sh)) {
181				WARN_ELF("gelf_getshdr");
182				return -1;
183			}
184
185			name = elf_strptr(elf, shstrtab_idx, sh.sh_name);
186			if (!name || !*name) {
187				WARN_ELF("elf_strptr");
188				return -1;
189			}
190
191			printf("%s+%llx:", name, (unsigned long long)rela.r_addend);
192
193		} else {
194			printf("%llx:", (unsigned long long)(orc_ip_addr + (i * sizeof(int)) + orc_ip[i]));
195		}
196
197
198		printf(" sp:");
199
200		print_reg(orc[i].sp_reg, orc[i].sp_offset);
201
202		printf(" bp:");
203
204		print_reg(orc[i].bp_reg, orc[i].bp_offset);
205
206		printf(" type:%s\n", orc_type_name(orc[i].type));
207	}
208
209	elf_end(elf);
210	close(fd);
211
212	return 0;
213}