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Wed, 21 Jun 2023 20:36:50 +0000 (GMT) Received: from smtpav03.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id B6E9B20040; Wed, 21 Jun 2023 20:36:49 +0000 (GMT) Received: from heavy.boeblingen.de.ibm.com (unknown [9.179.1.208]) by smtpav03.fra02v.mail.ibm.com (Postfix) with ESMTP; Wed, 21 Jun 2023 20:36:49 +0000 (GMT) From: Ilya Leoshkevich To: =?utf-8?q?Alex_Benn=C3=A9e?= , Laurent Vivier , Peter Maydell , Richard Henderson , David Hildenbrand Cc: =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= , qemu-devel@nongnu.org, qemu-arm@nongnu.org, qemu-s390x@nongnu.org, Ilya Leoshkevich , "Dominik 'Disconnect3d' Czarnota" Subject: [PATCH v4 6/8] gdbstub: Add support for info proc mappings Date: Wed, 21 Jun 2023 22:36:25 +0200 Message-Id: <20230621203627.1808446-7-iii@linux.ibm.com> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230621203627.1808446-1-iii@linux.ibm.com> References: <20230621203627.1808446-1-iii@linux.ibm.com> X-TM-AS-GCONF: 00 X-Proofpoint-GUID: 3KnuIU4Ai-9KmgKPHNT_6B_B8_4uigum X-Proofpoint-ORIG-GUID: XiEP9650TWIyHcFGih4pvr8Xf7-_8s7T X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.254,Aquarius:18.0.957,Hydra:6.0.591,FMLib:17.11.176.26 definitions=2023-06-21_12,2023-06-16_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxlogscore=999 bulkscore=0 lowpriorityscore=0 malwarescore=0 clxscore=1015 phishscore=0 suspectscore=0 mlxscore=0 priorityscore=1501 adultscore=0 impostorscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2305260000 definitions=main-2306210172 Received-SPF: pass client-ip=148.163.158.5; envelope-from=iii@linux.ibm.com; helo=mx0b-001b2d01.pphosted.com X-Spam_score_int: -19 X-Spam_score: -2.0 X-Spam_bar: -- X-Spam_report: (-2.0 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Currently the GDB's generate-core-file command doesn't work well with qemu-user: the resulting dumps are huge [1] and at the same time incomplete (argv and envp are missing). The reason is that GDB has no access to proc mappings and therefore has to fall back to using heuristics for discovering them. This is, in turn, because qemu-user does not implement the Host I/O feature of the GDB Remote Serial Protocol. Implement vFile:{open,close,pread,readlink} and also qXfer:exec-file:read+. With that, generate-core-file begins to work on aarch64 and s390x. [1] https://sourceware.org/pipermail/gdb-patches/2023-May/199432.html Co-developed-by: Dominik 'Disconnect3d' Czarnota Signed-off-by: Ilya Leoshkevich --- gdbstub/gdbstub.c | 45 +++++++++++++- gdbstub/internals.h | 5 ++ gdbstub/user-target.c | 139 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 187 insertions(+), 2 deletions(-) diff --git a/gdbstub/gdbstub.c b/gdbstub/gdbstub.c index c7e3ee71f2..d2efefd352 100644 --- a/gdbstub/gdbstub.c +++ b/gdbstub/gdbstub.c @@ -1337,6 +1337,36 @@ static const GdbCmdParseEntry gdb_v_commands_table[] = { .cmd = "Kill;", .cmd_startswith = 1 }, +#ifdef CONFIG_USER_ONLY + /* + * Host I/O Packets. See [1] for details. + * [1] https://sourceware.org/gdb/onlinedocs/gdb/Host-I_002fO-Packets.html + */ + { + .handler = gdb_handle_v_file_open, + .cmd = "File:open:", + .cmd_startswith = 1, + .schema = "s,L,L0" + }, + { + .handler = gdb_handle_v_file_close, + .cmd = "File:close:", + .cmd_startswith = 1, + .schema = "l0" + }, + { + .handler = gdb_handle_v_file_pread, + .cmd = "File:pread:", + .cmd_startswith = 1, + .schema = "l,L,L0" + }, + { + .handler = gdb_handle_v_file_readlink, + .cmd = "File:readlink:", + .cmd_startswith = 1, + .schema = "s0" + }, +#endif }; static void handle_v_commands(GArray *params, void *user_ctx) @@ -1482,11 +1512,14 @@ static void handle_query_supported(GArray *params, void *user_ctx) ";ReverseStep+;ReverseContinue+"); } -#if defined(CONFIG_USER_ONLY) && defined(CONFIG_LINUX) +#if defined(CONFIG_USER_ONLY) +#if defined(CONFIG_LINUX) if (gdbserver_state.c_cpu->opaque) { g_string_append(gdbserver_state.str_buf, ";qXfer:auxv:read+"); } #endif + g_string_append(gdbserver_state.str_buf, ";qXfer:exec-file:read+"); +#endif if (params->len && strstr(get_param(params, 0)->data, "multiprocess+")) { @@ -1625,13 +1658,21 @@ static const GdbCmdParseEntry gdb_gen_query_table[] = { .cmd_startswith = 1, .schema = "s:l,l0" }, -#if defined(CONFIG_USER_ONLY) && defined(CONFIG_LINUX) +#if defined(CONFIG_USER_ONLY) +#if defined(CONFIG_LINUX) { .handler = gdb_handle_query_xfer_auxv, .cmd = "Xfer:auxv:read::", .cmd_startswith = 1, .schema = "l,l0" }, +#endif + { + .handler = gdb_handle_query_xfer_exec_file, + .cmd = "Xfer:exec-file:read:", + .cmd_startswith = 1, + .schema = "l:l,l0" + }, #endif { .handler = gdb_handle_query_attached, diff --git a/gdbstub/internals.h b/gdbstub/internals.h index 25e4d5eeaa..f2b46cce41 100644 --- a/gdbstub/internals.h +++ b/gdbstub/internals.h @@ -189,6 +189,11 @@ typedef union GdbCmdVariant { void gdb_handle_query_rcmd(GArray *params, void *user_ctx); /* softmmu */ void gdb_handle_query_offsets(GArray *params, void *user_ctx); /* user */ void gdb_handle_query_xfer_auxv(GArray *params, void *user_ctx); /*user */ +void gdb_handle_v_file_open(GArray *params, void *user_ctx); /* user */ +void gdb_handle_v_file_close(GArray *params, void *user_ctx); /* user */ +void gdb_handle_v_file_pread(GArray *params, void *user_ctx); /* user */ +void gdb_handle_v_file_readlink(GArray *params, void *user_ctx); /* user */ +void gdb_handle_query_xfer_exec_file(GArray *params, void *user_ctx); /* user */ void gdb_handle_query_attached(GArray *params, void *user_ctx); /* both */ diff --git a/gdbstub/user-target.c b/gdbstub/user-target.c index fa0e59ec9a..5f0098c806 100644 --- a/gdbstub/user-target.c +++ b/gdbstub/user-target.c @@ -11,6 +11,10 @@ #include "exec/gdbstub.h" #include "qemu.h" #include "internals.h" +#ifdef CONFIG_LINUX +#include "linux-user/loader.h" +#include "linux-user/qemu.h" +#endif /* * Map target signal numbers to GDB protocol signal numbers and vice @@ -281,3 +285,138 @@ void gdb_handle_query_xfer_auxv(GArray *params, void *user_ctx) gdbserver_state.str_buf->len, true); } #endif + +static const char *get_filename_param(GArray *params, int i) +{ + const char *hex_filename = get_param(params, i)->data; + gdb_hextomem(gdbserver_state.mem_buf, hex_filename, + strlen(hex_filename) / 2); + g_byte_array_append(gdbserver_state.mem_buf, (const guint8 *)"", 1); + return (const char *)gdbserver_state.mem_buf->data; +} + +static void hostio_reply_with_data(const void *buf, size_t n) +{ + g_string_printf(gdbserver_state.str_buf, "F%zx;", n); + gdb_memtox(gdbserver_state.str_buf, buf, n); + gdb_put_packet_binary(gdbserver_state.str_buf->str, + gdbserver_state.str_buf->len, true); +} + +void gdb_handle_v_file_open(GArray *params, void *user_ctx) +{ + const char *filename = get_filename_param(params, 0); + uint64_t flags = get_param(params, 1)->val_ull; + uint64_t mode = get_param(params, 2)->val_ull; + +#ifdef CONFIG_LINUX + int fd = do_guest_openat(gdbserver_state.g_cpu->env_ptr, 0, filename, + flags, mode, false); +#else + int fd = open(filename, flags, mode); +#endif + if (fd < 0) { + g_string_printf(gdbserver_state.str_buf, "F-1,%d", errno); + } else { + g_string_printf(gdbserver_state.str_buf, "F%d", fd); + } + gdb_put_strbuf(); +} + +void gdb_handle_v_file_close(GArray *params, void *user_ctx) +{ + int fd = get_param(params, 0)->val_ul; + + if (close(fd) == -1) { + g_string_printf(gdbserver_state.str_buf, "F-1,%d", errno); + gdb_put_strbuf(); + return; + } + + gdb_put_packet("F00"); +} + +#define BUFSIZ 8192 + +void gdb_handle_v_file_pread(GArray *params, void *user_ctx) +{ + int fd = get_param(params, 0)->val_ul; + size_t count = get_param(params, 1)->val_ull; + off_t offset = get_param(params, 2)->val_ull; + + size_t bufsiz = MIN(count, BUFSIZ); + g_autofree char *buf = g_try_malloc(bufsiz); + if (buf == NULL) { + gdb_put_packet("E12"); + return; + } + + ssize_t n = pread(fd, buf, bufsiz, offset); + if (n < 0) { + g_string_printf(gdbserver_state.str_buf, "F-1,%d", errno); + gdb_put_strbuf(); + return; + } + hostio_reply_with_data(buf, n); +} + +void gdb_handle_v_file_readlink(GArray *params, void *user_ctx) +{ + const char *filename = get_filename_param(params, 0); + + g_autofree char *buf = g_try_malloc(BUFSIZ); + if (buf == NULL) { + gdb_put_packet("E12"); + return; + } + +#ifdef CONFIG_LINUX + ssize_t n = do_guest_readlink(filename, buf, BUFSIZ); +#else + ssize_t n = readlink(filename, buf, BUFSIZ); +#endif + if (n < 0) { + g_string_printf(gdbserver_state.str_buf, "F-1,%d", errno); + gdb_put_strbuf(); + return; + } + hostio_reply_with_data(buf, n); +} + +void gdb_handle_query_xfer_exec_file(GArray *params, void *user_ctx) +{ + uint32_t pid = get_param(params, 0)->val_ul; + uint32_t offset = get_param(params, 1)->val_ul; + uint32_t length = get_param(params, 2)->val_ul; + + GDBProcess *process = gdb_get_process(pid); + if (!process) { + gdb_put_packet("E00"); + return; + } + + CPUState *cpu = gdb_get_first_cpu_in_process(process); + if (!cpu) { + gdb_put_packet("E00"); + return; + } + + TaskState *ts = cpu->opaque; + if (!ts || !ts->bprm || !ts->bprm->filename) { + gdb_put_packet("E00"); + return; + } + + size_t total_length = strlen(ts->bprm->filename); + if (offset > total_length) { + gdb_put_packet("E00"); + return; + } + if (offset + length > total_length) { + length = total_length - offset; + } + + g_string_printf(gdbserver_state.str_buf, "l%.*s", length, + ts->bprm->filename + offset); + gdb_put_strbuf(); +}