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qemu/dump.c
Luiz Capitulino 2f61652d66 qmp: dump-guest-memory: don't spin if non-blocking fd would block 
fd_write_vmcore() will indefinitely spin for a non-blocking
file-descriptor that would block. However, if the fd is non-blocking,
how does it make sense to spin?

Change this behavior to return an error instead.

Note that this can only happen with an fd provided by a management
application. The fd opened internally by dump-guest-memory is blocking.

While there, also fix 'writen_size' variable name.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
2012-09-27 09:46:17 -03:00

866 lines
22 KiB
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/*
* QEMU dump
*
* Copyright Fujitsu, Corp. 2011, 2012
*
* Authors:
* Wen Congyang <wency@cn.fujitsu.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*
*/
#include "qemu-common.h"
#include "elf.h"
#include "cpu.h"
#include "cpu-all.h"
#include "targphys.h"
#include "monitor.h"
#include "kvm.h"
#include "dump.h"
#include "sysemu.h"
#include "memory_mapping.h"
#include "error.h"
#include "qmp-commands.h"
#include "gdbstub.h"
static uint16_t cpu_convert_to_target16(uint16_t val, int endian)
{
if (endian == ELFDATA2LSB) {
val = cpu_to_le16(val);
} else {
val = cpu_to_be16(val);
}
return val;
}
static uint32_t cpu_convert_to_target32(uint32_t val, int endian)
{
if (endian == ELFDATA2LSB) {
val = cpu_to_le32(val);
} else {
val = cpu_to_be32(val);
}
return val;
}
static uint64_t cpu_convert_to_target64(uint64_t val, int endian)
{
if (endian == ELFDATA2LSB) {
val = cpu_to_le64(val);
} else {
val = cpu_to_be64(val);
}
return val;
}
typedef struct DumpState {
ArchDumpInfo dump_info;
MemoryMappingList list;
uint16_t phdr_num;
uint32_t sh_info;
bool have_section;
bool resume;
size_t note_size;
target_phys_addr_t memory_offset;
int fd;
RAMBlock *block;
ram_addr_t start;
bool has_filter;
int64_t begin;
int64_t length;
Error **errp;
} DumpState;
static int dump_cleanup(DumpState *s)
{
int ret = 0;
memory_mapping_list_free(&s->list);
if (s->fd != -1) {
close(s->fd);
}
if (s->resume) {
vm_start();
}
return ret;
}
static void dump_error(DumpState *s, const char *reason)
{
dump_cleanup(s);
}
static int fd_write_vmcore(void *buf, size_t size, void *opaque)
{
DumpState *s = opaque;
size_t written_size;
written_size = qemu_write_full(s->fd, buf, size);
if (written_size != size) {
return -1;
}
return 0;
}
static int write_elf64_header(DumpState *s)
{
Elf64_Ehdr elf_header;
int ret;
int endian = s->dump_info.d_endian;
memset(&elf_header, 0, sizeof(Elf64_Ehdr));
memcpy(&elf_header, ELFMAG, SELFMAG);
elf_header.e_ident[EI_CLASS] = ELFCLASS64;
elf_header.e_ident[EI_DATA] = s->dump_info.d_endian;
elf_header.e_ident[EI_VERSION] = EV_CURRENT;
elf_header.e_type = cpu_convert_to_target16(ET_CORE, endian);
elf_header.e_machine = cpu_convert_to_target16(s->dump_info.d_machine,
endian);
elf_header.e_version = cpu_convert_to_target32(EV_CURRENT, endian);
elf_header.e_ehsize = cpu_convert_to_target16(sizeof(elf_header), endian);
elf_header.e_phoff = cpu_convert_to_target64(sizeof(Elf64_Ehdr), endian);
elf_header.e_phentsize = cpu_convert_to_target16(sizeof(Elf64_Phdr),
endian);
elf_header.e_phnum = cpu_convert_to_target16(s->phdr_num, endian);
if (s->have_section) {
uint64_t shoff = sizeof(Elf64_Ehdr) + sizeof(Elf64_Phdr) * s->sh_info;
elf_header.e_shoff = cpu_convert_to_target64(shoff, endian);
elf_header.e_shentsize = cpu_convert_to_target16(sizeof(Elf64_Shdr),
endian);
elf_header.e_shnum = cpu_convert_to_target16(1, endian);
}
ret = fd_write_vmcore(&elf_header, sizeof(elf_header), s);
if (ret < 0) {
dump_error(s, "dump: failed to write elf header.\n");
return -1;
}
return 0;
}
static int write_elf32_header(DumpState *s)
{
Elf32_Ehdr elf_header;
int ret;
int endian = s->dump_info.d_endian;
memset(&elf_header, 0, sizeof(Elf32_Ehdr));
memcpy(&elf_header, ELFMAG, SELFMAG);
elf_header.e_ident[EI_CLASS] = ELFCLASS32;
elf_header.e_ident[EI_DATA] = endian;
elf_header.e_ident[EI_VERSION] = EV_CURRENT;
elf_header.e_type = cpu_convert_to_target16(ET_CORE, endian);
elf_header.e_machine = cpu_convert_to_target16(s->dump_info.d_machine,
endian);
elf_header.e_version = cpu_convert_to_target32(EV_CURRENT, endian);
elf_header.e_ehsize = cpu_convert_to_target16(sizeof(elf_header), endian);
elf_header.e_phoff = cpu_convert_to_target32(sizeof(Elf32_Ehdr), endian);
elf_header.e_phentsize = cpu_convert_to_target16(sizeof(Elf32_Phdr),
endian);
elf_header.e_phnum = cpu_convert_to_target16(s->phdr_num, endian);
if (s->have_section) {
uint32_t shoff = sizeof(Elf32_Ehdr) + sizeof(Elf32_Phdr) * s->sh_info;
elf_header.e_shoff = cpu_convert_to_target32(shoff, endian);
elf_header.e_shentsize = cpu_convert_to_target16(sizeof(Elf32_Shdr),
endian);
elf_header.e_shnum = cpu_convert_to_target16(1, endian);
}
ret = fd_write_vmcore(&elf_header, sizeof(elf_header), s);
if (ret < 0) {
dump_error(s, "dump: failed to write elf header.\n");
return -1;
}
return 0;
}
static int write_elf64_load(DumpState *s, MemoryMapping *memory_mapping,
int phdr_index, target_phys_addr_t offset)
{
Elf64_Phdr phdr;
int ret;
int endian = s->dump_info.d_endian;
memset(&phdr, 0, sizeof(Elf64_Phdr));
phdr.p_type = cpu_convert_to_target32(PT_LOAD, endian);
phdr.p_offset = cpu_convert_to_target64(offset, endian);
phdr.p_paddr = cpu_convert_to_target64(memory_mapping->phys_addr, endian);
if (offset == -1) {
/* When the memory is not stored into vmcore, offset will be -1 */
phdr.p_filesz = 0;
} else {
phdr.p_filesz = cpu_convert_to_target64(memory_mapping->length, endian);
}
phdr.p_memsz = cpu_convert_to_target64(memory_mapping->length, endian);
phdr.p_vaddr = cpu_convert_to_target64(memory_mapping->virt_addr, endian);
ret = fd_write_vmcore(&phdr, sizeof(Elf64_Phdr), s);
if (ret < 0) {
dump_error(s, "dump: failed to write program header table.\n");
return -1;
}
return 0;
}
static int write_elf32_load(DumpState *s, MemoryMapping *memory_mapping,
int phdr_index, target_phys_addr_t offset)
{
Elf32_Phdr phdr;
int ret;
int endian = s->dump_info.d_endian;
memset(&phdr, 0, sizeof(Elf32_Phdr));
phdr.p_type = cpu_convert_to_target32(PT_LOAD, endian);
phdr.p_offset = cpu_convert_to_target32(offset, endian);
phdr.p_paddr = cpu_convert_to_target32(memory_mapping->phys_addr, endian);
if (offset == -1) {
/* When the memory is not stored into vmcore, offset will be -1 */
phdr.p_filesz = 0;
} else {
phdr.p_filesz = cpu_convert_to_target32(memory_mapping->length, endian);
}
phdr.p_memsz = cpu_convert_to_target32(memory_mapping->length, endian);
phdr.p_vaddr = cpu_convert_to_target32(memory_mapping->virt_addr, endian);
ret = fd_write_vmcore(&phdr, sizeof(Elf32_Phdr), s);
if (ret < 0) {
dump_error(s, "dump: failed to write program header table.\n");
return -1;
}
return 0;
}
static int write_elf64_note(DumpState *s)
{
Elf64_Phdr phdr;
int endian = s->dump_info.d_endian;
target_phys_addr_t begin = s->memory_offset - s->note_size;
int ret;
memset(&phdr, 0, sizeof(Elf64_Phdr));
phdr.p_type = cpu_convert_to_target32(PT_NOTE, endian);
phdr.p_offset = cpu_convert_to_target64(begin, endian);
phdr.p_paddr = 0;
phdr.p_filesz = cpu_convert_to_target64(s->note_size, endian);
phdr.p_memsz = cpu_convert_to_target64(s->note_size, endian);
phdr.p_vaddr = 0;
ret = fd_write_vmcore(&phdr, sizeof(Elf64_Phdr), s);
if (ret < 0) {
dump_error(s, "dump: failed to write program header table.\n");
return -1;
}
return 0;
}
static int write_elf64_notes(DumpState *s)
{
CPUArchState *env;
int ret;
int id;
for (env = first_cpu; env != NULL; env = env->next_cpu) {
id = cpu_index(env);
ret = cpu_write_elf64_note(fd_write_vmcore, env, id, s);
if (ret < 0) {
dump_error(s, "dump: failed to write elf notes.\n");
return -1;
}
}
for (env = first_cpu; env != NULL; env = env->next_cpu) {
ret = cpu_write_elf64_qemunote(fd_write_vmcore, env, s);
if (ret < 0) {
dump_error(s, "dump: failed to write CPU status.\n");
return -1;
}
}
return 0;
}
static int write_elf32_note(DumpState *s)
{
target_phys_addr_t begin = s->memory_offset - s->note_size;
Elf32_Phdr phdr;
int endian = s->dump_info.d_endian;
int ret;
memset(&phdr, 0, sizeof(Elf32_Phdr));
phdr.p_type = cpu_convert_to_target32(PT_NOTE, endian);
phdr.p_offset = cpu_convert_to_target32(begin, endian);
phdr.p_paddr = 0;
phdr.p_filesz = cpu_convert_to_target32(s->note_size, endian);
phdr.p_memsz = cpu_convert_to_target32(s->note_size, endian);
phdr.p_vaddr = 0;
ret = fd_write_vmcore(&phdr, sizeof(Elf32_Phdr), s);
if (ret < 0) {
dump_error(s, "dump: failed to write program header table.\n");
return -1;
}
return 0;
}
static int write_elf32_notes(DumpState *s)
{
CPUArchState *env;
int ret;
int id;
for (env = first_cpu; env != NULL; env = env->next_cpu) {
id = cpu_index(env);
ret = cpu_write_elf32_note(fd_write_vmcore, env, id, s);
if (ret < 0) {
dump_error(s, "dump: failed to write elf notes.\n");
return -1;
}
}
for (env = first_cpu; env != NULL; env = env->next_cpu) {
ret = cpu_write_elf32_qemunote(fd_write_vmcore, env, s);
if (ret < 0) {
dump_error(s, "dump: failed to write CPU status.\n");
return -1;
}
}
return 0;
}
static int write_elf_section(DumpState *s, int type)
{
Elf32_Shdr shdr32;
Elf64_Shdr shdr64;
int endian = s->dump_info.d_endian;
int shdr_size;
void *shdr;
int ret;
if (type == 0) {
shdr_size = sizeof(Elf32_Shdr);
memset(&shdr32, 0, shdr_size);
shdr32.sh_info = cpu_convert_to_target32(s->sh_info, endian);
shdr = &shdr32;
} else {
shdr_size = sizeof(Elf64_Shdr);
memset(&shdr64, 0, shdr_size);
shdr64.sh_info = cpu_convert_to_target32(s->sh_info, endian);
shdr = &shdr64;
}
ret = fd_write_vmcore(&shdr, shdr_size, s);
if (ret < 0) {
dump_error(s, "dump: failed to write section header table.\n");
return -1;
}
return 0;
}
static int write_data(DumpState *s, void *buf, int length)
{
int ret;
ret = fd_write_vmcore(buf, length, s);
if (ret < 0) {
dump_error(s, "dump: failed to save memory.\n");
return -1;
}
return 0;
}
/* write the memroy to vmcore. 1 page per I/O. */
static int write_memory(DumpState *s, RAMBlock *block, ram_addr_t start,
int64_t size)
{
int64_t i;
int ret;
for (i = 0; i < size / TARGET_PAGE_SIZE; i++) {
ret = write_data(s, block->host + start + i * TARGET_PAGE_SIZE,
TARGET_PAGE_SIZE);
if (ret < 0) {
return ret;
}
}
if ((size % TARGET_PAGE_SIZE) != 0) {
ret = write_data(s, block->host + start + i * TARGET_PAGE_SIZE,
size % TARGET_PAGE_SIZE);
if (ret < 0) {
return ret;
}
}
return 0;
}
/* get the memory's offset in the vmcore */
static target_phys_addr_t get_offset(target_phys_addr_t phys_addr,
DumpState *s)
{
RAMBlock *block;
target_phys_addr_t offset = s->memory_offset;
int64_t size_in_block, start;
if (s->has_filter) {
if (phys_addr < s->begin || phys_addr >= s->begin + s->length) {
return -1;
}
}
QLIST_FOREACH(block, &ram_list.blocks, next) {
if (s->has_filter) {
if (block->offset >= s->begin + s->length ||
block->offset + block->length <= s->begin) {
/* This block is out of the range */
continue;
}
if (s->begin <= block->offset) {
start = block->offset;
} else {
start = s->begin;
}
size_in_block = block->length - (start - block->offset);
if (s->begin + s->length < block->offset + block->length) {
size_in_block -= block->offset + block->length -
(s->begin + s->length);
}
} else {
start = block->offset;
size_in_block = block->length;
}
if (phys_addr >= start && phys_addr < start + size_in_block) {
return phys_addr - start + offset;
}
offset += size_in_block;
}
return -1;
}
static int write_elf_loads(DumpState *s)
{
target_phys_addr_t offset;
MemoryMapping *memory_mapping;
uint32_t phdr_index = 1;
int ret;
uint32_t max_index;
if (s->have_section) {
max_index = s->sh_info;
} else {
max_index = s->phdr_num;
}
QTAILQ_FOREACH(memory_mapping, &s->list.head, next) {
offset = get_offset(memory_mapping->phys_addr, s);
if (s->dump_info.d_class == ELFCLASS64) {
ret = write_elf64_load(s, memory_mapping, phdr_index++, offset);
} else {
ret = write_elf32_load(s, memory_mapping, phdr_index++, offset);
}
if (ret < 0) {
return -1;
}
if (phdr_index >= max_index) {
break;
}
}
return 0;
}
/* write elf header, PT_NOTE and elf note to vmcore. */
static int dump_begin(DumpState *s)
{
int ret;
/*
* the vmcore's format is:
* --------------
* | elf header |
* --------------
* | PT_NOTE |
* --------------
* | PT_LOAD |
* --------------
* | ...... |
* --------------
* | PT_LOAD |
* --------------
* | sec_hdr |
* --------------
* | elf note |
* --------------
* | memory |
* --------------
*
* we only know where the memory is saved after we write elf note into
* vmcore.
*/
/* write elf header to vmcore */
if (s->dump_info.d_class == ELFCLASS64) {
ret = write_elf64_header(s);
} else {
ret = write_elf32_header(s);
}
if (ret < 0) {
return -1;
}
if (s->dump_info.d_class == ELFCLASS64) {
/* write PT_NOTE to vmcore */
if (write_elf64_note(s) < 0) {
return -1;
}
/* write all PT_LOAD to vmcore */
if (write_elf_loads(s) < 0) {
return -1;
}
/* write section to vmcore */
if (s->have_section) {
if (write_elf_section(s, 1) < 0) {
return -1;
}
}
/* write notes to vmcore */
if (write_elf64_notes(s) < 0) {
return -1;
}
} else {
/* write PT_NOTE to vmcore */
if (write_elf32_note(s) < 0) {
return -1;
}
/* write all PT_LOAD to vmcore */
if (write_elf_loads(s) < 0) {
return -1;
}
/* write section to vmcore */
if (s->have_section) {
if (write_elf_section(s, 0) < 0) {
return -1;
}
}
/* write notes to vmcore */
if (write_elf32_notes(s) < 0) {
return -1;
}
}
return 0;
}
/* write PT_LOAD to vmcore */
static int dump_completed(DumpState *s)
{
dump_cleanup(s);
return 0;
}
static int get_next_block(DumpState *s, RAMBlock *block)
{
while (1) {
block = QLIST_NEXT(block, next);
if (!block) {
/* no more block */
return 1;
}
s->start = 0;
s->block = block;
if (s->has_filter) {
if (block->offset >= s->begin + s->length ||
block->offset + block->length <= s->begin) {
/* This block is out of the range */
continue;
}
if (s->begin > block->offset) {
s->start = s->begin - block->offset;
}
}
return 0;
}
}
/* write all memory to vmcore */
static int dump_iterate(DumpState *s)
{
RAMBlock *block;
int64_t size;
int ret;
while (1) {
block = s->block;
size = block->length;
if (s->has_filter) {
size -= s->start;
if (s->begin + s->length < block->offset + block->length) {
size -= block->offset + block->length - (s->begin + s->length);
}
}
ret = write_memory(s, block, s->start, size);
if (ret == -1) {
return ret;
}
ret = get_next_block(s, block);
if (ret == 1) {
dump_completed(s);
return 0;
}
}
}
static int create_vmcore(DumpState *s)
{
int ret;
ret = dump_begin(s);
if (ret < 0) {
return -1;
}
ret = dump_iterate(s);
if (ret < 0) {
return -1;
}
return 0;
}
static ram_addr_t get_start_block(DumpState *s)
{
RAMBlock *block;
if (!s->has_filter) {
s->block = QLIST_FIRST(&ram_list.blocks);
return 0;
}
QLIST_FOREACH(block, &ram_list.blocks, next) {
if (block->offset >= s->begin + s->length ||
block->offset + block->length <= s->begin) {
/* This block is out of the range */
continue;
}
s->block = block;
if (s->begin > block->offset) {
s->start = s->begin - block->offset;
} else {
s->start = 0;
}
return s->start;
}
return -1;
}
static int dump_init(DumpState *s, int fd, bool paging, bool has_filter,
int64_t begin, int64_t length, Error **errp)
{
CPUArchState *env;
int nr_cpus;
int ret;
if (runstate_is_running()) {
vm_stop(RUN_STATE_SAVE_VM);
s->resume = true;
} else {
s->resume = false;
}
s->errp = errp;
s->fd = fd;
s->has_filter = has_filter;
s->begin = begin;
s->length = length;
s->start = get_start_block(s);
if (s->start == -1) {
error_set(errp, QERR_INVALID_PARAMETER, "begin");
goto cleanup;
}
/*
* get dump info: endian, class and architecture.
* If the target architecture is not supported, cpu_get_dump_info() will
* return -1.
*
* if we use kvm, we should synchronize the register before we get dump
* info.
*/
nr_cpus = 0;
for (env = first_cpu; env != NULL; env = env->next_cpu) {
cpu_synchronize_state(env);
nr_cpus++;
}
ret = cpu_get_dump_info(&s->dump_info);
if (ret < 0) {
error_set(errp, QERR_UNSUPPORTED);
goto cleanup;
}
s->note_size = cpu_get_note_size(s->dump_info.d_class,
s->dump_info.d_machine, nr_cpus);
if (ret < 0) {
error_set(errp, QERR_UNSUPPORTED);
goto cleanup;
}
/* get memory mapping */
memory_mapping_list_init(&s->list);
if (paging) {
qemu_get_guest_memory_mapping(&s->list);
} else {
qemu_get_guest_simple_memory_mapping(&s->list);
}
if (s->has_filter) {
memory_mapping_filter(&s->list, s->begin, s->length);
}
/*
* calculate phdr_num
*
* the type of ehdr->e_phnum is uint16_t, so we should avoid overflow
*/
s->phdr_num = 1; /* PT_NOTE */
if (s->list.num < UINT16_MAX - 2) {
s->phdr_num += s->list.num;
s->have_section = false;
} else {
s->have_section = true;
s->phdr_num = PN_XNUM;
s->sh_info = 1; /* PT_NOTE */
/* the type of shdr->sh_info is uint32_t, so we should avoid overflow */
if (s->list.num <= UINT32_MAX - 1) {
s->sh_info += s->list.num;
} else {
s->sh_info = UINT32_MAX;
}
}
if (s->dump_info.d_class == ELFCLASS64) {
if (s->have_section) {
s->memory_offset = sizeof(Elf64_Ehdr) +
sizeof(Elf64_Phdr) * s->sh_info +
sizeof(Elf64_Shdr) + s->note_size;
} else {
s->memory_offset = sizeof(Elf64_Ehdr) +
sizeof(Elf64_Phdr) * s->phdr_num + s->note_size;
}
} else {
if (s->have_section) {
s->memory_offset = sizeof(Elf32_Ehdr) +
sizeof(Elf32_Phdr) * s->sh_info +
sizeof(Elf32_Shdr) + s->note_size;
} else {
s->memory_offset = sizeof(Elf32_Ehdr) +
sizeof(Elf32_Phdr) * s->phdr_num + s->note_size;
}
}
return 0;
cleanup:
if (s->resume) {
vm_start();
}
return -1;
}
void qmp_dump_guest_memory(bool paging, const char *file, bool has_begin,
int64_t begin, bool has_length, int64_t length,
Error **errp)
{
const char *p;
int fd = -1;
DumpState *s;
int ret;
if (has_begin && !has_length) {
error_set(errp, QERR_MISSING_PARAMETER, "length");
return;
}
if (!has_begin && has_length) {
error_set(errp, QERR_MISSING_PARAMETER, "begin");
return;
}
#if !defined(WIN32)
if (strstart(file, "fd:", &p)) {
fd = monitor_get_fd(cur_mon, p, errp);
if (fd == -1) {
return;
}
}
#endif
if (strstart(file, "file:", &p)) {
fd = qemu_open(p, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, S_IRUSR);
if (fd < 0) {
error_set(errp, QERR_OPEN_FILE_FAILED, p);
return;
}
}
if (fd == -1) {
error_set(errp, QERR_INVALID_PARAMETER, "protocol");
return;
}
s = g_malloc(sizeof(DumpState));
ret = dump_init(s, fd, paging, has_begin, begin, length, errp);
if (ret < 0) {
g_free(s);
return;
}
if (create_vmcore(s) < 0 && !error_is_set(s->errp)) {
error_set(errp, QERR_IO_ERROR);
}
g_free(s);
}
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