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6fc6931231
qemu/bsd-user/main.c
Ilya Leoshkevich 6604b05763 gdbstub: Call gdbserver_fork() both in parent and in child 
The upcoming follow-fork-mode child support requires post-fork message
exchange between the parent and the child. Prepare gdbserver_fork() for
this purpose. Rename it to gdbserver_fork_end() to better reflect its
purpose.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Message-Id: <20240219141628.246823-8-iii@linux.ibm.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20240305121005.3528075-9-alex.bennee@linaro.org>
2024-03-06 12:35:19 +00:00

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/*
* qemu bsd user main
*
* Copyright (c) 2003-2008 Fabrice Bellard
* Copyright (c) 2013-14 Stacey Son
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include <sys/resource.h>
#include <sys/sysctl.h>
#include "qemu/help-texts.h"
#include "qemu/units.h"
#include "qemu/accel.h"
#include "qemu-version.h"
#include <machine/trap.h>
#include "qapi/error.h"
#include "qemu.h"
#include "qemu/config-file.h"
#include "qemu/error-report.h"
#include "qemu/path.h"
#include "qemu/help_option.h"
#include "qemu/module.h"
#include "exec/exec-all.h"
#include "tcg/startup.h"
#include "qemu/timer.h"
#include "qemu/envlist.h"
#include "qemu/cutils.h"
#include "exec/log.h"
#include "trace/control.h"
#include "crypto/init.h"
#include "qemu/guest-random.h"
#include "gdbstub/user.h"
#include "host-os.h"
#include "target_arch_cpu.h"
/*
* TODO: Remove these and rely only on qemu_real_host_page_size().
*/
uintptr_t qemu_host_page_size;
intptr_t qemu_host_page_mask;
static bool opt_one_insn_per_tb;
uintptr_t guest_base;
bool have_guest_base;
/*
* When running 32-on-64 we should make sure we can fit all of the possible
* guest address space into a contiguous chunk of virtual host memory.
*
* This way we will never overlap with our own libraries or binaries or stack
* or anything else that QEMU maps.
*
* Many cpus reserve the high bit (or more than one for some 64-bit cpus)
* of the address for the kernel. Some cpus rely on this and user space
* uses the high bit(s) for pointer tagging and the like. For them, we
* must preserve the expected address space.
*/
#ifndef MAX_RESERVED_VA
# if HOST_LONG_BITS > TARGET_VIRT_ADDR_SPACE_BITS
# if TARGET_VIRT_ADDR_SPACE_BITS == 32 && \
(TARGET_LONG_BITS == 32 || defined(TARGET_ABI32))
# define MAX_RESERVED_VA 0xfffffffful
# else
# define MAX_RESERVED_VA ((1ul << TARGET_VIRT_ADDR_SPACE_BITS) - 1)
# endif
# else
# define MAX_RESERVED_VA 0
# endif
#endif
/*
* That said, reserving *too* much vm space via mmap can run into problems
* with rlimits, oom due to page table creation, etc. We will still try it,
* if directed by the command-line option, but not by default.
*/
#if HOST_LONG_BITS == 64 && TARGET_VIRT_ADDR_SPACE_BITS <= 32
unsigned long reserved_va = MAX_RESERVED_VA;
#else
unsigned long reserved_va;
#endif
const char *interp_prefix = CONFIG_QEMU_INTERP_PREFIX;
const char *qemu_uname_release;
char qemu_proc_pathname[PATH_MAX]; /* full path to exeutable */
unsigned long target_maxtsiz = TARGET_MAXTSIZ; /* max text size */
unsigned long target_dfldsiz = TARGET_DFLDSIZ; /* initial data size limit */
unsigned long target_maxdsiz = TARGET_MAXDSIZ; /* max data size */
unsigned long target_dflssiz = TARGET_DFLSSIZ; /* initial data size limit */
unsigned long target_maxssiz = TARGET_MAXSSIZ; /* max stack size */
unsigned long target_sgrowsiz = TARGET_SGROWSIZ; /* amount to grow stack */
/* Helper routines for implementing atomic operations. */
void fork_start(void)
{
start_exclusive();
cpu_list_lock();
mmap_fork_start();
gdbserver_fork_start();
}
void fork_end(pid_t pid)
{
bool child = pid == 0;
if (child) {
CPUState *cpu, *next_cpu;
/*
* Child processes created by fork() only have a single thread. Discard
* information about the parent threads.
*/
CPU_FOREACH_SAFE(cpu, next_cpu) {
if (cpu != thread_cpu) {
QTAILQ_REMOVE_RCU(&cpus_queue, cpu, node);
}
}
mmap_fork_end(child);
/*
* qemu_init_cpu_list() takes care of reinitializing the exclusive
* state, so we don't need to end_exclusive() here.
*/
qemu_init_cpu_list();
get_task_state(thread_cpu)->ts_tid = qemu_get_thread_id();
gdbserver_fork_end(thread_cpu, pid);
} else {
mmap_fork_end(child);
cpu_list_unlock();
gdbserver_fork_end(thread_cpu, pid);
end_exclusive();
}
}
void cpu_loop(CPUArchState *env)
{
target_cpu_loop(env);
}
static void usage(void)
{
printf("qemu-" TARGET_NAME " version " QEMU_FULL_VERSION
"\n" QEMU_COPYRIGHT "\n"
"usage: qemu-" TARGET_NAME " [options] program [arguments...]\n"
"BSD CPU emulator (compiled for %s emulation)\n"
"\n"
"Standard options:\n"
"-h print this help\n"
"-g port wait gdb connection to port\n"
"-L path set the elf interpreter prefix (default=%s)\n"
"-s size set the stack size in bytes (default=%ld)\n"
"-cpu model select CPU (-cpu help for list)\n"
"-drop-ld-preload drop LD_PRELOAD for target process\n"
"-E var=value sets/modifies targets environment variable(s)\n"
"-U var unsets targets environment variable(s)\n"
"-B address set guest_base address to address\n"
"\n"
"Debug options:\n"
"-d item1[,...] enable logging of specified items\n"
" (use '-d help' for a list of log items)\n"
"-D logfile write logs to 'logfile' (default stderr)\n"
"-one-insn-per-tb run with one guest instruction per emulated TB\n"
"-strace log system calls\n"
"-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
" specify tracing options\n"
"\n"
"Environment variables:\n"
"QEMU_STRACE Print system calls and arguments similar to the\n"
" 'strace' program. Enable by setting to any value.\n"
"You can use -E and -U options to set/unset environment variables\n"
"for target process. It is possible to provide several variables\n"
"by repeating the option. For example:\n"
" -E var1=val2 -E var2=val2 -U LD_PRELOAD -U LD_DEBUG\n"
"Note that if you provide several changes to single variable\n"
"last change will stay in effect.\n"
"\n"
QEMU_HELP_BOTTOM "\n"
,
TARGET_NAME,
interp_prefix,
target_dflssiz);
exit(1);
}
__thread CPUState *thread_cpu;
void stop_all_tasks(void)
{
/*
* We trust when using NPTL (pthreads) start_exclusive() handles thread
* stopping correctly.
*/
start_exclusive();
}
bool qemu_cpu_is_self(CPUState *cpu)
{
return thread_cpu == cpu;
}
void qemu_cpu_kick(CPUState *cpu)
{
cpu_exit(cpu);
}
/* Assumes contents are already zeroed. */
static void init_task_state(TaskState *ts)
{
ts->sigaltstack_used = (struct target_sigaltstack) {
.ss_sp = 0,
.ss_size = 0,
.ss_flags = TARGET_SS_DISABLE,
};
}
void gemu_log(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
va_end(ap);
}
static void
adjust_ssize(void)
{
struct rlimit rl;
if (getrlimit(RLIMIT_STACK, &rl) != 0) {
return;
}
target_maxssiz = MIN(target_maxssiz, rl.rlim_max);
target_dflssiz = MIN(MAX(target_dflssiz, rl.rlim_cur), target_maxssiz);
rl.rlim_max = target_maxssiz;
rl.rlim_cur = target_dflssiz;
setrlimit(RLIMIT_STACK, &rl);
}
static void save_proc_pathname(char *argv0)
{
int mib[4];
size_t len;
mib[0] = CTL_KERN;
mib[1] = KERN_PROC;
mib[2] = KERN_PROC_PATHNAME;
mib[3] = -1;
len = sizeof(qemu_proc_pathname);
if (sysctl(mib, 4, qemu_proc_pathname, &len, NULL, 0)) {
perror("sysctl");
}
}
int main(int argc, char **argv)
{
const char *filename;
const char *cpu_model;
const char *cpu_type;
const char *log_file = NULL;
const char *log_mask = NULL;
const char *seed_optarg = NULL;
struct target_pt_regs regs1, *regs = &regs1;
struct image_info info1, *info = &info1;
struct bsd_binprm bprm;
TaskState *ts;
CPUArchState *env;
CPUState *cpu;
int optind, rv;
const char *r;
const char *gdbstub = NULL;
char **target_environ, **wrk;
envlist_t *envlist = NULL;
char *argv0 = NULL;
adjust_ssize();
if (argc <= 1) {
usage();
}
save_proc_pathname(argv[0]);
error_init(argv[0]);
module_call_init(MODULE_INIT_TRACE);
qemu_init_cpu_list();
module_call_init(MODULE_INIT_QOM);
envlist = envlist_create();
/*
* add current environment into the list
* envlist_setenv adds to the front of the list; to preserve environ
* order add from back to front
*/
for (wrk = environ; *wrk != NULL; wrk++) {
continue;
}
while (wrk != environ) {
wrk--;
(void) envlist_setenv(envlist, *wrk);
}
qemu_host_page_size = getpagesize();
qemu_host_page_size = MAX(qemu_host_page_size, TARGET_PAGE_SIZE);
cpu_model = NULL;
qemu_add_opts(&qemu_trace_opts);
optind = 1;
for (;;) {
if (optind >= argc) {
break;
}
r = argv[optind];
if (r[0] != '-') {
break;
}
optind++;
r++;
if (!strcmp(r, "-")) {
break;
} else if (!strcmp(r, "d")) {
if (optind >= argc) {
break;
}
log_mask = argv[optind++];
} else if (!strcmp(r, "D")) {
if (optind >= argc) {
break;
}
log_file = argv[optind++];
} else if (!strcmp(r, "E")) {
r = argv[optind++];
if (envlist_setenv(envlist, r) != 0) {
usage();
}
} else if (!strcmp(r, "ignore-environment")) {
envlist_free(envlist);
envlist = envlist_create();
} else if (!strcmp(r, "U")) {
r = argv[optind++];
if (envlist_unsetenv(envlist, r) != 0) {
usage();
}
} else if (!strcmp(r, "s")) {
r = argv[optind++];
rv = qemu_strtoul(r, &r, 0, &target_dflssiz);
if (rv < 0 || target_dflssiz <= 0) {
usage();
}
if (*r == 'M') {
target_dflssiz *= 1024 * 1024;
} else if (*r == 'k' || *r == 'K') {
target_dflssiz *= 1024;
}
if (target_dflssiz > target_maxssiz) {
usage();
}
} else if (!strcmp(r, "L")) {
interp_prefix = argv[optind++];
} else if (!strcmp(r, "p")) {
unsigned size, want = qemu_real_host_page_size();
r = argv[optind++];
if (qemu_strtoui(r, NULL, 10, &size) || size != want) {
warn_report("Deprecated page size option cannot "
"change host page size (%u)", want);
}
} else if (!strcmp(r, "g")) {
gdbstub = g_strdup(argv[optind++]);
} else if (!strcmp(r, "r")) {
qemu_uname_release = argv[optind++];
} else if (!strcmp(r, "cpu")) {
cpu_model = argv[optind++];
if (is_help_option(cpu_model)) {
list_cpus();
exit(1);
}
} else if (!strcmp(r, "B")) {
rv = qemu_strtoul(argv[optind++], NULL, 0, &guest_base);
if (rv < 0) {
usage();
}
have_guest_base = true;
} else if (!strcmp(r, "drop-ld-preload")) {
(void) envlist_unsetenv(envlist, "LD_PRELOAD");
} else if (!strcmp(r, "seed")) {
seed_optarg = optarg;
} else if (!strcmp(r, "one-insn-per-tb")) {
opt_one_insn_per_tb = true;
} else if (!strcmp(r, "strace")) {
do_strace = 1;
} else if (!strcmp(r, "trace")) {
trace_opt_parse(optarg);
} else if (!strcmp(r, "0")) {
argv0 = argv[optind++];
} else {
usage();
}
}
qemu_host_page_mask = -qemu_host_page_size;
/* init debug */
{
int mask = 0;
if (log_mask) {
mask = qemu_str_to_log_mask(log_mask);
if (!mask) {
qemu_print_log_usage(stdout);
exit(1);
}
}
qemu_set_log_filename_flags(log_file, mask, &error_fatal);
}
if (optind >= argc) {
usage();
}
filename = argv[optind];
if (argv0) {
argv[optind] = argv0;
}
if (!trace_init_backends()) {
exit(1);
}
trace_init_file();
/* Zero out regs */
memset(regs, 0, sizeof(struct target_pt_regs));
/* Zero bsd params */
memset(&bprm, 0, sizeof(bprm));
/* Zero out image_info */
memset(info, 0, sizeof(struct image_info));
/* Scan interp_prefix dir for replacement files. */
init_paths(interp_prefix);
if (cpu_model == NULL) {
cpu_model = TARGET_DEFAULT_CPU_MODEL;
}
cpu_type = parse_cpu_option(cpu_model);
/* init tcg before creating CPUs and to get qemu_host_page_size */
{
AccelState *accel = current_accel();
AccelClass *ac = ACCEL_GET_CLASS(accel);
accel_init_interfaces(ac);
object_property_set_bool(OBJECT(accel), "one-insn-per-tb",
opt_one_insn_per_tb, &error_abort);
ac->init_machine(NULL);
}
cpu = cpu_create(cpu_type);
env = cpu_env(cpu);
cpu_reset(cpu);
thread_cpu = cpu;
if (getenv("QEMU_STRACE")) {
do_strace = 1;
}
target_environ = envlist_to_environ(envlist, NULL);
envlist_free(envlist);
{
Error *err = NULL;
if (seed_optarg != NULL) {
qemu_guest_random_seed_main(seed_optarg, &err);
} else {
qcrypto_init(&err);
}
if (err) {
error_reportf_err(err, "cannot initialize crypto: ");
exit(1);
}
}
/*
* Now that page sizes are configured we can do
* proper page alignment for guest_base.
*/
if (have_guest_base) {
if (guest_base & ~qemu_host_page_mask) {
error_report("Selected guest base not host page aligned");
exit(1);
}
}
/*
* If reserving host virtual address space, do so now.
* Combined with '-B', ensure that the chosen range is free.
*/
if (reserved_va) {
void *p;
if (have_guest_base) {
p = mmap((void *)guest_base, reserved_va + 1, PROT_NONE,
MAP_ANON | MAP_PRIVATE | MAP_FIXED | MAP_EXCL, -1, 0);
} else {
p = mmap(NULL, reserved_va + 1, PROT_NONE,
MAP_ANON | MAP_PRIVATE, -1, 0);
}
if (p == MAP_FAILED) {
const char *err = strerror(errno);
char *sz = size_to_str(reserved_va + 1);
if (have_guest_base) {
error_report("Cannot allocate %s bytes at -B %p for guest "
"address space: %s", sz, (void *)guest_base, err);
} else {
error_report("Cannot allocate %s bytes for guest "
"address space: %s", sz, err);
}
exit(1);
}
guest_base = (uintptr_t)p;
have_guest_base = true;
/* Ensure that mmap_next_start is within range. */
if (reserved_va <= mmap_next_start) {
mmap_next_start = (reserved_va / 4 * 3)
& TARGET_PAGE_MASK & qemu_host_page_mask;
}
}
if (loader_exec(filename, argv + optind, target_environ, regs, info,
&bprm) != 0) {
printf("Error loading %s\n", filename);
_exit(1);
}
for (wrk = target_environ; *wrk; wrk++) {
g_free(*wrk);
}
g_free(target_environ);
if (qemu_loglevel_mask(CPU_LOG_PAGE)) {
FILE *f = qemu_log_trylock();
if (f) {
fprintf(f, "guest_base %p\n", (void *)guest_base);
fprintf(f, "page layout changed following binary load\n");
page_dump(f);
fprintf(f, "end_code 0x" TARGET_ABI_FMT_lx "\n",
info->end_code);
fprintf(f, "start_code 0x" TARGET_ABI_FMT_lx "\n",
info->start_code);
fprintf(f, "start_data 0x" TARGET_ABI_FMT_lx "\n",
info->start_data);
fprintf(f, "end_data 0x" TARGET_ABI_FMT_lx "\n",
info->end_data);
fprintf(f, "start_stack 0x" TARGET_ABI_FMT_lx "\n",
info->start_stack);
fprintf(f, "brk 0x" TARGET_ABI_FMT_lx "\n", info->brk);
fprintf(f, "entry 0x" TARGET_ABI_FMT_lx "\n", info->entry);
qemu_log_unlock(f);
}
}
/* build Task State */
ts = g_new0(TaskState, 1);
init_task_state(ts);
ts->info = info;
ts->bprm = &bprm;
cpu->opaque = ts;
target_set_brk(info->brk);
syscall_init();
signal_init();
/*
* Now that we've loaded the binary, GUEST_BASE is fixed. Delay
* generating the prologue until now so that the prologue can take
* the real value of GUEST_BASE into account.
*/
tcg_prologue_init();
target_cpu_init(env, regs);
if (gdbstub) {
gdbserver_start(gdbstub);
gdb_handlesig(cpu, 0);
}
cpu_loop(env);
/* never exits */
return 0;
}
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