123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488 |
- /*
- * gdbstub user-mode helper routines.
- *
- * We know for user-mode we are using TCG so we can call stuff directly.
- *
- * Copyright (c) 2003-2005 Fabrice Bellard
- * Copyright (c) 2022 Linaro Ltd
- *
- * SPDX-License-Identifier: LGPL-2.0+
- */
- #include "qemu/osdep.h"
- #include "qemu/cutils.h"
- #include "qemu/sockets.h"
- #include "exec/hwaddr.h"
- #include "exec/tb-flush.h"
- #include "exec/gdbstub.h"
- #include "gdbstub/syscalls.h"
- #include "gdbstub/user.h"
- #include "hw/core/cpu.h"
- #include "trace.h"
- #include "internals.h"
- /* User-mode specific state */
- typedef struct {
- int fd;
- char *socket_path;
- int running_state;
- } GDBUserState;
- static GDBUserState gdbserver_user_state;
- int gdb_get_char(void)
- {
- uint8_t ch;
- int ret;
- for (;;) {
- ret = recv(gdbserver_user_state.fd, &ch, 1, 0);
- if (ret < 0) {
- if (errno == ECONNRESET) {
- gdbserver_user_state.fd = -1;
- }
- if (errno != EINTR) {
- return -1;
- }
- } else if (ret == 0) {
- close(gdbserver_user_state.fd);
- gdbserver_user_state.fd = -1;
- return -1;
- } else {
- break;
- }
- }
- return ch;
- }
- bool gdb_got_immediate_ack(void)
- {
- int i;
- i = gdb_get_char();
- if (i < 0) {
- /* no response, continue anyway */
- return true;
- }
- if (i == '+') {
- /* received correctly, continue */
- return true;
- }
- /* anything else, including '-' then try again */
- return false;
- }
- void gdb_put_buffer(const uint8_t *buf, int len)
- {
- int ret;
- while (len > 0) {
- ret = send(gdbserver_user_state.fd, buf, len, 0);
- if (ret < 0) {
- if (errno != EINTR) {
- return;
- }
- } else {
- buf += ret;
- len -= ret;
- }
- }
- }
- /* Tell the remote gdb that the process has exited. */
- void gdb_exit(int code)
- {
- char buf[4];
- if (!gdbserver_state.init) {
- return;
- }
- if (gdbserver_user_state.socket_path) {
- unlink(gdbserver_user_state.socket_path);
- }
- if (gdbserver_user_state.fd < 0) {
- return;
- }
- trace_gdbstub_op_exiting((uint8_t)code);
- snprintf(buf, sizeof(buf), "W%02x", (uint8_t)code);
- gdb_put_packet(buf);
- }
- int gdb_handlesig(CPUState *cpu, int sig)
- {
- char buf[256];
- int n;
- if (!gdbserver_state.init || gdbserver_user_state.fd < 0) {
- return sig;
- }
- /* disable single step if it was enabled */
- cpu_single_step(cpu, 0);
- tb_flush(cpu);
- if (sig != 0) {
- gdb_set_stop_cpu(cpu);
- g_string_printf(gdbserver_state.str_buf,
- "T%02xthread:", gdb_target_signal_to_gdb(sig));
- gdb_append_thread_id(cpu, gdbserver_state.str_buf);
- g_string_append_c(gdbserver_state.str_buf, ';');
- gdb_put_strbuf();
- }
- /*
- * gdb_put_packet() might have detected that the peer terminated the
- * connection.
- */
- if (gdbserver_user_state.fd < 0) {
- return sig;
- }
- sig = 0;
- gdbserver_state.state = RS_IDLE;
- gdbserver_user_state.running_state = 0;
- while (gdbserver_user_state.running_state == 0) {
- n = read(gdbserver_user_state.fd, buf, 256);
- if (n > 0) {
- int i;
- for (i = 0; i < n; i++) {
- gdb_read_byte(buf[i]);
- }
- } else {
- /*
- * XXX: Connection closed. Should probably wait for another
- * connection before continuing.
- */
- if (n == 0) {
- close(gdbserver_user_state.fd);
- }
- gdbserver_user_state.fd = -1;
- return sig;
- }
- }
- sig = gdbserver_state.signal;
- gdbserver_state.signal = 0;
- return sig;
- }
- /* Tell the remote gdb that the process has exited due to SIG. */
- void gdb_signalled(CPUArchState *env, int sig)
- {
- char buf[4];
- if (!gdbserver_state.init || gdbserver_user_state.fd < 0) {
- return;
- }
- snprintf(buf, sizeof(buf), "X%02x", gdb_target_signal_to_gdb(sig));
- gdb_put_packet(buf);
- }
- static void gdb_accept_init(int fd)
- {
- gdb_init_gdbserver_state();
- gdb_create_default_process(&gdbserver_state);
- gdbserver_state.processes[0].attached = true;
- gdbserver_state.c_cpu = gdb_first_attached_cpu();
- gdbserver_state.g_cpu = gdbserver_state.c_cpu;
- gdbserver_user_state.fd = fd;
- gdb_has_xml = false;
- }
- static bool gdb_accept_socket(int gdb_fd)
- {
- int fd;
- for (;;) {
- fd = accept(gdb_fd, NULL, NULL);
- if (fd < 0 && errno != EINTR) {
- perror("accept socket");
- return false;
- } else if (fd >= 0) {
- qemu_set_cloexec(fd);
- break;
- }
- }
- gdb_accept_init(fd);
- return true;
- }
- static int gdbserver_open_socket(const char *path)
- {
- struct sockaddr_un sockaddr = {};
- int fd, ret;
- fd = socket(AF_UNIX, SOCK_STREAM, 0);
- if (fd < 0) {
- perror("create socket");
- return -1;
- }
- sockaddr.sun_family = AF_UNIX;
- pstrcpy(sockaddr.sun_path, sizeof(sockaddr.sun_path) - 1, path);
- ret = bind(fd, (struct sockaddr *)&sockaddr, sizeof(sockaddr));
- if (ret < 0) {
- perror("bind socket");
- close(fd);
- return -1;
- }
- ret = listen(fd, 1);
- if (ret < 0) {
- perror("listen socket");
- close(fd);
- return -1;
- }
- return fd;
- }
- static bool gdb_accept_tcp(int gdb_fd)
- {
- struct sockaddr_in sockaddr = {};
- socklen_t len;
- int fd;
- for (;;) {
- len = sizeof(sockaddr);
- fd = accept(gdb_fd, (struct sockaddr *)&sockaddr, &len);
- if (fd < 0 && errno != EINTR) {
- perror("accept");
- return false;
- } else if (fd >= 0) {
- qemu_set_cloexec(fd);
- break;
- }
- }
- /* set short latency */
- if (socket_set_nodelay(fd)) {
- perror("setsockopt");
- close(fd);
- return false;
- }
- gdb_accept_init(fd);
- return true;
- }
- static int gdbserver_open_port(int port)
- {
- struct sockaddr_in sockaddr;
- int fd, ret;
- fd = socket(PF_INET, SOCK_STREAM, 0);
- if (fd < 0) {
- perror("socket");
- return -1;
- }
- qemu_set_cloexec(fd);
- socket_set_fast_reuse(fd);
- sockaddr.sin_family = AF_INET;
- sockaddr.sin_port = htons(port);
- sockaddr.sin_addr.s_addr = 0;
- ret = bind(fd, (struct sockaddr *)&sockaddr, sizeof(sockaddr));
- if (ret < 0) {
- perror("bind");
- close(fd);
- return -1;
- }
- ret = listen(fd, 1);
- if (ret < 0) {
- perror("listen");
- close(fd);
- return -1;
- }
- return fd;
- }
- int gdbserver_start(const char *port_or_path)
- {
- int port = g_ascii_strtoull(port_or_path, NULL, 10);
- int gdb_fd;
- if (port > 0) {
- gdb_fd = gdbserver_open_port(port);
- } else {
- gdb_fd = gdbserver_open_socket(port_or_path);
- }
- if (gdb_fd < 0) {
- return -1;
- }
- if (port > 0 && gdb_accept_tcp(gdb_fd)) {
- return 0;
- } else if (gdb_accept_socket(gdb_fd)) {
- gdbserver_user_state.socket_path = g_strdup(port_or_path);
- return 0;
- }
- /* gone wrong */
- close(gdb_fd);
- return -1;
- }
- /* Disable gdb stub for child processes. */
- void gdbserver_fork(CPUState *cpu)
- {
- if (!gdbserver_state.init || gdbserver_user_state.fd < 0) {
- return;
- }
- close(gdbserver_user_state.fd);
- gdbserver_user_state.fd = -1;
- cpu_breakpoint_remove_all(cpu, BP_GDB);
- /* no cpu_watchpoint_remove_all for user-mode */
- }
- /*
- * Execution state helpers
- */
- void gdb_handle_query_attached(GArray *params, void *user_ctx)
- {
- gdb_put_packet("0");
- }
- void gdb_continue(void)
- {
- gdbserver_user_state.running_state = 1;
- trace_gdbstub_op_continue();
- }
- /*
- * Resume execution, for user-mode emulation it's equivalent to
- * gdb_continue.
- */
- int gdb_continue_partial(char *newstates)
- {
- CPUState *cpu;
- int res = 0;
- /*
- * This is not exactly accurate, but it's an improvement compared to the
- * previous situation, where only one CPU would be single-stepped.
- */
- CPU_FOREACH(cpu) {
- if (newstates[cpu->cpu_index] == 's') {
- trace_gdbstub_op_stepping(cpu->cpu_index);
- cpu_single_step(cpu, gdbserver_state.sstep_flags);
- }
- }
- gdbserver_user_state.running_state = 1;
- return res;
- }
- /*
- * Memory access helpers
- */
- int gdb_target_memory_rw_debug(CPUState *cpu, hwaddr addr,
- uint8_t *buf, int len, bool is_write)
- {
- CPUClass *cc;
- cc = CPU_GET_CLASS(cpu);
- if (cc->memory_rw_debug) {
- return cc->memory_rw_debug(cpu, addr, buf, len, is_write);
- }
- return cpu_memory_rw_debug(cpu, addr, buf, len, is_write);
- }
- /*
- * cpu helpers
- */
- unsigned int gdb_get_max_cpus(void)
- {
- CPUState *cpu;
- unsigned int max_cpus = 1;
- CPU_FOREACH(cpu) {
- max_cpus = max_cpus <= cpu->cpu_index ? cpu->cpu_index + 1 : max_cpus;
- }
- return max_cpus;
- }
- /* replay not supported for user-mode */
- bool gdb_can_reverse(void)
- {
- return false;
- }
- /*
- * Break/Watch point helpers
- */
- bool gdb_supports_guest_debug(void)
- {
- /* user-mode == TCG == supported */
- return true;
- }
- int gdb_breakpoint_insert(CPUState *cs, int type, vaddr addr, vaddr len)
- {
- CPUState *cpu;
- int err = 0;
- switch (type) {
- case GDB_BREAKPOINT_SW:
- case GDB_BREAKPOINT_HW:
- CPU_FOREACH(cpu) {
- err = cpu_breakpoint_insert(cpu, addr, BP_GDB, NULL);
- if (err) {
- break;
- }
- }
- return err;
- default:
- /* user-mode doesn't support watchpoints */
- return -ENOSYS;
- }
- }
- int gdb_breakpoint_remove(CPUState *cs, int type, vaddr addr, vaddr len)
- {
- CPUState *cpu;
- int err = 0;
- switch (type) {
- case GDB_BREAKPOINT_SW:
- case GDB_BREAKPOINT_HW:
- CPU_FOREACH(cpu) {
- err = cpu_breakpoint_remove(cpu, addr, BP_GDB);
- if (err) {
- break;
- }
- }
- return err;
- default:
- /* user-mode doesn't support watchpoints */
- return -ENOSYS;
- }
- }
- void gdb_breakpoint_remove_all(CPUState *cs)
- {
- cpu_breakpoint_remove_all(cs, BP_GDB);
- }
- /*
- * For user-mode syscall support we send the system call immediately
- * and then return control to gdb for it to process the syscall request.
- * Since the protocol requires that gdb hands control back to us
- * using a "here are the results" F packet, we don't need to check
- * gdb_handlesig's return value (which is the signal to deliver if
- * execution was resumed via a continue packet).
- */
- void gdb_syscall_handling(const char *syscall_packet)
- {
- gdb_put_packet(syscall_packet);
- gdb_handlesig(gdbserver_state.c_cpu, 0);
- }
|