From 308f9e88b28e75b1702112159d6894007372b355 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Alex=20Benn=C3=A9e?= Date: Mon, 16 Mar 2020 17:21:35 +0000 Subject: [PATCH] gdbstub: move str_buf to GDBState and use GString MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Rather than having a static buffer replace str_buf with a GString which we know can grow on demand. Convert the internal functions to take a GString instead of a char * and length. Signed-off-by: Alex Bennée Reviewed-by: Richard Henderson Reviewed-by: Damien Hedde Tested-by: Damien Hedde Message-Id: <20200316172155.971-9-alex.bennee@linaro.org> --- gdbstub.c | 197 +++++++++++++++++++++++++----------------------------- 1 file changed, 91 insertions(+), 106 deletions(-) diff --git a/gdbstub.c b/gdbstub.c index 7243a2f7af..f6b4282544 100644 --- a/gdbstub.c +++ b/gdbstub.c @@ -366,6 +366,7 @@ typedef struct GDBState { int process_num; char syscall_buf[256]; gdb_syscall_complete_cb current_syscall_cb; + GString *str_buf; } GDBState; /* By default use no IRQs and no timers while single stepping so as to @@ -380,6 +381,7 @@ static void init_gdbserver_state(void) g_assert(!gdbserver_state.init); memset(&gdbserver_state, 0, sizeof(GDBState)); gdbserver_state.init = true; + gdbserver_state.str_buf = g_string_new(NULL); } #ifndef CONFIG_USER_ONLY @@ -563,17 +565,15 @@ static inline int tohex(int v) } /* writes 2*len+1 bytes in buf */ -static void memtohex(char *buf, const uint8_t *mem, int len) +static void memtohex(GString *buf, const uint8_t *mem, int len) { int i, c; - char *q; - q = buf; for(i = 0; i < len; i++) { c = mem[i]; - *q++ = tohex(c >> 4); - *q++ = tohex(c & 0xf); + g_string_append_c(buf, tohex(c >> 4)); + g_string_append_c(buf, tohex(c & 0xf)); } - *q = '\0'; + g_string_append_c(buf, '\0'); } static void hextomem(uint8_t *mem, const char *buf, int len) @@ -667,25 +667,28 @@ static int put_packet(const char *buf) return put_packet_binary(buf, strlen(buf), false); } -/* Encode data using the encoding for 'x' packets. */ -static int memtox(char *buf, const char *mem, int len) +static void put_strbuf(void) +{ + put_packet(gdbserver_state.str_buf->str); +} + +/* Encode data using the encoding for 'x' packets. */ +static void memtox(GString *buf, const char *mem, int len) { - char *p = buf; char c; while (len--) { c = *(mem++); switch (c) { case '#': case '$': case '*': case '}': - *(p++) = '}'; - *(p++) = c ^ 0x20; + g_string_append_c(buf, '}'); + g_string_append_c(buf, c ^ 0x20); break; default: - *(p++) = c; + g_string_append_c(buf, c); break; } } - return p - buf; } static uint32_t gdb_get_cpu_pid(CPUState *cpu) @@ -1109,16 +1112,14 @@ static void gdb_set_cpu_pc(target_ulong pc) cpu_set_pc(cpu, pc); } -static char *gdb_fmt_thread_id(CPUState *cpu, char *buf, size_t buf_size) +static void gdb_append_thread_id(CPUState *cpu, GString *buf) { if (gdbserver_state.multiprocess) { - snprintf(buf, buf_size, "p%02x.%02x", - gdb_get_cpu_pid(cpu), cpu_gdb_index(cpu)); + g_string_append_printf(buf, "p%02x.%02x", + gdb_get_cpu_pid(cpu), cpu_gdb_index(cpu)); } else { - snprintf(buf, buf_size, "%02x", cpu_gdb_index(cpu)); + g_string_append_printf(buf, "%02x", cpu_gdb_index(cpu)); } - - return buf; } typedef enum GDBThreadIdKind { @@ -1412,7 +1413,6 @@ typedef struct GdbCmdContext { GdbCmdVariant *params; int num_params; uint8_t mem_buf[MAX_PACKET_LENGTH]; - char str_buf[MAX_PACKET_LENGTH + 1]; } GdbCmdContext; typedef void (*GdbCmdHandler)(GdbCmdContext *gdb_ctx, void *user_ctx); @@ -1502,6 +1502,8 @@ static void run_cmd_parser(const char *data, const GdbCmdParseEntry *cmd) return; } + g_string_set_size(gdbserver_state.str_buf, 0); + /* In case there was an error during the command parsing we must * send a NULL packet to indicate the command is not supported */ if (process_string_cmd(NULL, data, cmd, 1)) { @@ -1740,8 +1742,8 @@ static void handle_get_reg(GdbCmdContext *gdb_ctx, void *user_ctx) return; } - memtohex(gdb_ctx->str_buf, gdb_ctx->mem_buf, reg_size); - put_packet(gdb_ctx->str_buf); + memtohex(gdbserver_state.str_buf, gdb_ctx->mem_buf, reg_size); + put_strbuf(); } static void handle_write_mem(GdbCmdContext *gdb_ctx, void *user_ctx) @@ -1789,8 +1791,8 @@ static void handle_read_mem(GdbCmdContext *gdb_ctx, void *user_ctx) return; } - memtohex(gdb_ctx->str_buf, gdb_ctx->mem_buf, gdb_ctx->params[1].val_ull); - put_packet(gdb_ctx->str_buf); + memtohex(gdbserver_state.str_buf, gdb_ctx->mem_buf, gdb_ctx->params[1].val_ull); + put_strbuf(); } static void handle_write_all_regs(GdbCmdContext *gdb_ctx, void *user_ctx) @@ -1827,8 +1829,8 @@ static void handle_read_all_regs(GdbCmdContext *gdb_ctx, void *user_ctx) addr); } - memtohex(gdb_ctx->str_buf, gdb_ctx->mem_buf, len); - put_packet(gdb_ctx->str_buf); + memtohex(gdbserver_state.str_buf, gdb_ctx->mem_buf, len); + put_strbuf(); } static void handle_file_io(GdbCmdContext *gdb_ctx, void *user_ctx) @@ -1889,9 +1891,8 @@ static void handle_v_attach(GdbCmdContext *gdb_ctx, void *user_ctx) { GDBProcess *process; CPUState *cpu; - char thread_id[16]; - pstrcpy(gdb_ctx->str_buf, sizeof(gdb_ctx->str_buf), "E22"); + g_string_assign(gdbserver_state.str_buf, "E22"); if (!gdb_ctx->num_params) { goto cleanup; } @@ -1910,11 +1911,11 @@ static void handle_v_attach(GdbCmdContext *gdb_ctx, void *user_ctx) gdbserver_state.g_cpu = cpu; gdbserver_state.c_cpu = cpu; - gdb_fmt_thread_id(cpu, thread_id, sizeof(thread_id)); - snprintf(gdb_ctx->str_buf, sizeof(gdb_ctx->str_buf), "T%02xthread:%s;", - GDB_SIGNAL_TRAP, thread_id); + g_string_printf(gdbserver_state.str_buf, "T%02xthread:", GDB_SIGNAL_TRAP); + gdb_append_thread_id(cpu, gdbserver_state.str_buf); + g_string_append_c(gdbserver_state.str_buf, ';'); cleanup: - put_packet(gdb_ctx->str_buf); + put_strbuf(); } static void handle_v_kill(GdbCmdContext *gdb_ctx, void *user_ctx) @@ -1966,10 +1967,9 @@ static void handle_v_commands(GdbCmdContext *gdb_ctx, void *user_ctx) static void handle_query_qemu_sstepbits(GdbCmdContext *gdb_ctx, void *user_ctx) { - snprintf(gdb_ctx->str_buf, sizeof(gdb_ctx->str_buf), - "ENABLE=%x,NOIRQ=%x,NOTIMER=%x", SSTEP_ENABLE, - SSTEP_NOIRQ, SSTEP_NOTIMER); - put_packet(gdb_ctx->str_buf); + g_string_printf(gdbserver_state.str_buf, "ENABLE=%x,NOIRQ=%x,NOTIMER=%x", + SSTEP_ENABLE, SSTEP_NOIRQ, SSTEP_NOTIMER); + put_strbuf(); } static void handle_set_qemu_sstep(GdbCmdContext *gdb_ctx, void *user_ctx) @@ -1984,15 +1984,14 @@ static void handle_set_qemu_sstep(GdbCmdContext *gdb_ctx, void *user_ctx) static void handle_query_qemu_sstep(GdbCmdContext *gdb_ctx, void *user_ctx) { - snprintf(gdb_ctx->str_buf, sizeof(gdb_ctx->str_buf), "0x%x", sstep_flags); - put_packet(gdb_ctx->str_buf); + g_string_printf(gdbserver_state.str_buf, "0x%x", sstep_flags); + put_strbuf(); } static void handle_query_curr_tid(GdbCmdContext *gdb_ctx, void *user_ctx) { CPUState *cpu; GDBProcess *process; - char thread_id[16]; /* * "Current thread" remains vague in the spec, so always return @@ -2001,24 +2000,21 @@ static void handle_query_curr_tid(GdbCmdContext *gdb_ctx, void *user_ctx) */ process = gdb_get_cpu_process(gdbserver_state.g_cpu); cpu = get_first_cpu_in_process(process); - gdb_fmt_thread_id(cpu, thread_id, sizeof(thread_id)); - snprintf(gdb_ctx->str_buf, sizeof(gdb_ctx->str_buf), "QC%s", thread_id); - put_packet(gdb_ctx->str_buf); + g_string_assign(gdbserver_state.str_buf, "QC"); + gdb_append_thread_id(cpu, gdbserver_state.str_buf); + put_strbuf(); } static void handle_query_threads(GdbCmdContext *gdb_ctx, void *user_ctx) { - char thread_id[16]; - if (!gdbserver_state.query_cpu) { put_packet("l"); return; } - gdb_fmt_thread_id(gdbserver_state.query_cpu, thread_id, - sizeof(thread_id)); - snprintf(gdb_ctx->str_buf, sizeof(gdb_ctx->str_buf), "m%s", thread_id); - put_packet(gdb_ctx->str_buf); + g_string_assign(gdbserver_state.str_buf, "m"); + gdb_append_thread_id(gdbserver_state.query_cpu, gdbserver_state.str_buf); + put_strbuf(); gdbserver_state.query_cpu = gdb_next_attached_cpu(gdbserver_state.query_cpu); } @@ -2030,8 +2026,8 @@ static void handle_query_first_threads(GdbCmdContext *gdb_ctx, void *user_ctx) static void handle_query_thread_extra(GdbCmdContext *gdb_ctx, void *user_ctx) { + g_autoptr(GString) rs = g_string_new(NULL); CPUState *cpu; - int len; if (!gdb_ctx->num_params || gdb_ctx->params[0].thread_id.kind == GDB_READ_THREAD_ERR) { @@ -2051,20 +2047,17 @@ static void handle_query_thread_extra(GdbCmdContext *gdb_ctx, void *user_ctx) /* Print the CPU model and name in multiprocess mode */ ObjectClass *oc = object_get_class(OBJECT(cpu)); const char *cpu_model = object_class_get_name(oc); - char *cpu_name = object_get_canonical_path_component(OBJECT(cpu)); - len = snprintf((char *)gdb_ctx->mem_buf, sizeof(gdb_ctx->str_buf) / 2, - "%s %s [%s]", cpu_model, cpu_name, - cpu->halted ? "halted " : "running"); - g_free(cpu_name); + g_autofree char *cpu_name; + cpu_name = object_get_canonical_path_component(OBJECT(cpu)); + g_string_printf(rs, "%s %s [%s]", cpu_model, cpu_name, + cpu->halted ? "halted " : "running"); } else { - /* memtohex() doubles the required space */ - len = snprintf((char *)gdb_ctx->mem_buf, sizeof(gdb_ctx->str_buf) / 2, - "CPU#%d [%s]", cpu->cpu_index, + g_string_printf(rs, "CPU#%d [%s]", cpu->cpu_index, cpu->halted ? "halted " : "running"); } - trace_gdbstub_op_extra_info((char *)gdb_ctx->mem_buf); - memtohex(gdb_ctx->str_buf, gdb_ctx->mem_buf, len); - put_packet(gdb_ctx->str_buf); + trace_gdbstub_op_extra_info(rs->str); + memtohex(gdbserver_state.str_buf, (uint8_t *)rs->str, rs->len); + put_strbuf(); } #ifdef CONFIG_USER_ONLY @@ -2073,13 +2066,14 @@ static void handle_query_offsets(GdbCmdContext *gdb_ctx, void *user_ctx) TaskState *ts; ts = gdbserver_state.c_cpu->opaque; - snprintf(gdb_ctx->str_buf, sizeof(gdb_ctx->str_buf), - "Text=" TARGET_ABI_FMT_lx ";Data=" TARGET_ABI_FMT_lx - ";Bss=" TARGET_ABI_FMT_lx, - ts->info->code_offset, - ts->info->data_offset, - ts->info->data_offset); - put_packet(gdb_ctx->str_buf); + g_string_printf(gdbserver_state.str_buf, + "Text=" TARGET_ABI_FMT_lx + ";Data=" TARGET_ABI_FMT_lx + ";Bss=" TARGET_ABI_FMT_lx, + ts->info->code_offset, + ts->info->data_offset, + ts->info->data_offset); + put_strbuf(); } #else static void handle_query_rcmd(GdbCmdContext *gdb_ctx, void *user_ctx) @@ -2110,12 +2104,10 @@ static void handle_query_supported(GdbCmdContext *gdb_ctx, void *user_ctx) { CPUClass *cc; - snprintf(gdb_ctx->str_buf, sizeof(gdb_ctx->str_buf), "PacketSize=%x", - MAX_PACKET_LENGTH); + g_string_printf(gdbserver_state.str_buf, "PacketSize=%x", MAX_PACKET_LENGTH); cc = CPU_GET_CLASS(first_cpu); if (cc->gdb_core_xml_file) { - pstrcat(gdb_ctx->str_buf, sizeof(gdb_ctx->str_buf), - ";qXfer:features:read+"); + g_string_append(gdbserver_state.str_buf, ";qXfer:features:read+"); } if (gdb_ctx->num_params && @@ -2123,8 +2115,8 @@ static void handle_query_supported(GdbCmdContext *gdb_ctx, void *user_ctx) gdbserver_state.multiprocess = true; } - pstrcat(gdb_ctx->str_buf, sizeof(gdb_ctx->str_buf), ";multiprocess+"); - put_packet(gdb_ctx->str_buf); + g_string_append(gdbserver_state.str_buf, ";multiprocess+"); + put_strbuf(); } static void handle_query_xfer_features(GdbCmdContext *gdb_ctx, void *user_ctx) @@ -2168,14 +2160,15 @@ static void handle_query_xfer_features(GdbCmdContext *gdb_ctx, void *user_ctx) } if (len < total_len - addr) { - gdb_ctx->str_buf[0] = 'm'; - len = memtox(gdb_ctx->str_buf + 1, xml + addr, len); + g_string_assign(gdbserver_state.str_buf, "m"); + memtox(gdbserver_state.str_buf, xml + addr, len); } else { - gdb_ctx->str_buf[0] = 'l'; - len = memtox(gdb_ctx->str_buf + 1, xml + addr, total_len - addr); + g_string_assign(gdbserver_state.str_buf, "l"); + memtox(gdbserver_state.str_buf, xml + addr, total_len - addr); } - put_packet_binary(gdb_ctx->str_buf, len + 1, true); + put_packet_binary(gdbserver_state.str_buf->str, + gdbserver_state.str_buf->len, true); } static void handle_query_attached(GdbCmdContext *gdb_ctx, void *user_ctx) @@ -2185,19 +2178,19 @@ static void handle_query_attached(GdbCmdContext *gdb_ctx, void *user_ctx) static void handle_query_qemu_supported(GdbCmdContext *gdb_ctx, void *user_ctx) { - snprintf(gdb_ctx->str_buf, sizeof(gdb_ctx->str_buf), "sstepbits;sstep"); + g_string_printf(gdbserver_state.str_buf, "sstepbits;sstep"); #ifndef CONFIG_USER_ONLY - pstrcat(gdb_ctx->str_buf, sizeof(gdb_ctx->str_buf), ";PhyMemMode"); + g_string_append(gdbserver_state.str_buf, ";PhyMemMode"); #endif - put_packet(gdb_ctx->str_buf); + put_strbuf(); } #ifndef CONFIG_USER_ONLY static void handle_query_qemu_phy_mem_mode(GdbCmdContext *gdb_ctx, void *user_ctx) { - snprintf(gdb_ctx->str_buf, sizeof(gdb_ctx->str_buf), "%d", phy_memory_mode); - put_packet(gdb_ctx->str_buf); + g_string_printf(gdbserver_state.str_buf, "%d", phy_memory_mode); + put_strbuf(); } static void handle_set_qemu_phy_mem_mode(GdbCmdContext *gdb_ctx, void *user_ctx) @@ -2362,13 +2355,10 @@ static void handle_gen_set(GdbCmdContext *gdb_ctx, void *user_ctx) static void handle_target_halt(GdbCmdContext *gdb_ctx, void *user_ctx) { - char thread_id[16]; - - gdb_fmt_thread_id(gdbserver_state.c_cpu, thread_id, - sizeof(thread_id)); - snprintf(gdb_ctx->str_buf, sizeof(gdb_ctx->str_buf), "T%02xthread:%s;", - GDB_SIGNAL_TRAP, thread_id); - put_packet(gdb_ctx->str_buf); + g_string_printf(gdbserver_state.str_buf, "T%02xthread:", GDB_SIGNAL_TRAP); + gdb_append_thread_id(gdbserver_state.c_cpu, gdbserver_state.str_buf); + g_string_append_c(gdbserver_state.str_buf, ';'); + put_strbuf(); /* * Remove all the breakpoints when this query is issued, * because gdb is doing an initial connect and the state @@ -2631,8 +2621,8 @@ void gdb_set_stop_cpu(CPUState *cpu) static void gdb_vm_state_change(void *opaque, int running, RunState state) { CPUState *cpu = gdbserver_state.c_cpu; - char buf[256]; - char thread_id[16]; + g_autoptr(GString) buf = g_string_new(NULL); + g_autoptr(GString) tid = g_string_new(NULL); const char *type; int ret; @@ -2650,7 +2640,7 @@ static void gdb_vm_state_change(void *opaque, int running, RunState state) return; } - gdb_fmt_thread_id(cpu, thread_id, sizeof(thread_id)); + gdb_append_thread_id(cpu, tid); switch (state) { case RUN_STATE_DEBUG: @@ -2668,10 +2658,9 @@ static void gdb_vm_state_change(void *opaque, int running, RunState state) } trace_gdbstub_hit_watchpoint(type, cpu_gdb_index(cpu), (target_ulong)cpu->watchpoint_hit->vaddr); - snprintf(buf, sizeof(buf), - "T%02xthread:%s;%swatch:" TARGET_FMT_lx ";", - GDB_SIGNAL_TRAP, thread_id, type, - (target_ulong)cpu->watchpoint_hit->vaddr); + g_string_printf(buf, "T%02xthread:%s;%swatch:" TARGET_FMT_lx ";", + GDB_SIGNAL_TRAP, tid->str, type, + (target_ulong)cpu->watchpoint_hit->vaddr); cpu->watchpoint_hit = NULL; goto send_packet; } else { @@ -2712,10 +2701,10 @@ static void gdb_vm_state_change(void *opaque, int running, RunState state) break; } gdb_set_stop_cpu(cpu); - snprintf(buf, sizeof(buf), "T%02xthread:%s;", ret, thread_id); + g_string_printf(buf, "T%02xthread:%s;", ret, tid->str); send_packet: - put_packet(buf); + put_packet(buf->str); /* disable single step if it was enabled */ cpu_single_step(cpu, 0); @@ -3196,13 +3185,9 @@ static void gdb_chr_event(void *opaque, QEMUChrEvent event) static void gdb_monitor_output(const char *msg, int len) { - char buf[MAX_PACKET_LENGTH]; - - buf[0] = 'O'; - if (len > (MAX_PACKET_LENGTH/2) - 1) - len = (MAX_PACKET_LENGTH/2) - 1; - memtohex(buf + 1, (uint8_t *)msg, len); - put_packet(buf); + g_autoptr(GString) buf = g_string_new("O"); + memtohex(buf, (uint8_t *)msg, len); + put_packet(buf->str); } static int gdb_monitor_write(Chardev *chr, const uint8_t *buf, int len)