From: Jonathan Rajotte Date: Fri, 29 Nov 2019 21:12:28 +0000 (-0500) Subject: Allow run-as to generate filter bytecode. X-Git-Tag: v2.13.0-rc1~482 X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=commitdiff_plain;h=c73f064af78ce03f1f6d89b66a0e05b3d3b477aa;hp=8bd71deafbf1d15f47f4935280a6290368ec6224 Allow run-as to generate filter bytecode. Signed-off-by: Jonathan Rajotte Signed-off-by: Jérémie Galarneau Change-Id: I3742bb00b7c753b7d256cdff1889a5e90865608b --- diff --git a/src/common/runas.c b/src/common/runas.c index b1a4b4836..3c4c2ae0b 100644 --- a/src/common/runas.c +++ b/src/common/runas.c @@ -27,6 +27,7 @@ #include #include #include +#include #include #include #include @@ -34,6 +35,10 @@ #include +#include +#include +#include + #include "runas.h" struct run_as_data; @@ -57,6 +62,7 @@ enum run_as_cmd { RUN_AS_RENAMEAT, RUN_AS_EXTRACT_ELF_SYMBOL_OFFSET, RUN_AS_EXTRACT_SDT_PROBE_OFFSETS, + RUN_AS_GENERATE_FILTER_BYTECODE, }; struct run_as_mkdir_data { @@ -80,7 +86,7 @@ struct run_as_unlink_data { struct run_as_rmdir_data { int dirfd; char path[LTTNG_PATH_MAX]; - int flags; /* enum lttng_directory_handle_rmdir_recursive_flags */ + int flags; /* enum lttng_directory_handle_rmdir_recursive_flags. */ } LTTNG_PACKED; struct run_as_extract_elf_symbol_offset_data { @@ -94,6 +100,10 @@ struct run_as_extract_sdt_probe_offsets_data { char provider_name[LTTNG_SYMBOL_NAME_LEN]; } LTTNG_PACKED; +struct run_as_generate_filter_bytecode_data { + char filter_expression[LTTNG_FILTER_MAX_LEN]; +} LTTNG_PACKED; + struct run_as_rename_data { /* * [0] = old_dirfd @@ -117,6 +127,11 @@ struct run_as_extract_sdt_probe_offsets_ret { uint64_t offsets[LTTNG_KERNEL_MAX_UPROBE_NUM]; } LTTNG_PACKED; +struct run_as_generate_filter_bytecode_ret { + /* A lttng_bytecode_filter struct with 'dynamic' payload. */ + char bytecode[LTTNG_FILTER_MAX_LEN]; +} LTTNG_PACKED; + struct run_as_data { enum run_as_cmd cmd; union { @@ -127,6 +142,7 @@ struct run_as_data { struct run_as_rename_data rename; struct run_as_extract_elf_symbol_offset_data extract_elf_symbol_offset; struct run_as_extract_sdt_probe_offsets_data extract_sdt_probe_offsets; + struct run_as_generate_filter_bytecode_data generate_filter_bytecode; } u; uid_t uid; gid_t gid; @@ -153,6 +169,7 @@ struct run_as_ret { struct run_as_open_ret open; struct run_as_extract_elf_symbol_offset_ret extract_elf_symbol_offset; struct run_as_extract_sdt_probe_offsets_ret extract_sdt_probe_offsets; + struct run_as_generate_filter_bytecode_ret generate_filter_bytecode; } u; int _errno; bool _error; @@ -306,6 +323,13 @@ static const struct run_as_command_properties command_properties[] = { .out_fd_count = 0, .use_cwd_fd = false, }, + [RUN_AS_GENERATE_FILTER_BYTECODE] = { + .in_fds_offset = -1, + .in_fd_count = 0, + .out_fds_offset = -1, + .out_fd_count = 0, + .use_cwd_fd = false, + }, }; struct run_as_worker { @@ -619,6 +643,48 @@ int _extract_sdt_probe_offsets(struct run_as_data *data, } #endif +static +int _generate_filter_bytecode(struct run_as_data *data, + struct run_as_ret *ret_value) { + int ret = 0; + const char *filter_expression = NULL; + struct filter_parser_ctx *ctx = NULL; + + ret_value->_error = false; + + filter_expression = data->u.generate_filter_bytecode.filter_expression; + + if (lttng_strnlen(filter_expression, LTTNG_FILTER_MAX_LEN - 1) == LTTNG_FILTER_MAX_LEN - 1) { + ret_value->_error = true; + ret = -1; + goto end; + } + + ret = filter_parser_ctx_create_from_filter_expression(filter_expression, &ctx); + if (ret < 0) { + ret_value->_error = true; + ret = -1; + goto end; + } + + DBG("Size of bytecode generated: %u bytes.", + bytecode_get_len(&ctx->bytecode->b)); + + /* Copy the lttng_bytecode_filter object to the return structure. */ + memcpy(ret_value->u.generate_filter_bytecode.bytecode, + &ctx->bytecode->b, + sizeof(ctx->bytecode->b) + + bytecode_get_len(&ctx->bytecode->b)); + +end: + if (ctx) { + filter_bytecode_free(ctx); + filter_ir_free(ctx); + filter_parser_ctx_free(ctx); + } + + return ret; +} static run_as_fct run_as_enum_to_fct(enum run_as_cmd cmd) { @@ -648,6 +714,8 @@ run_as_fct run_as_enum_to_fct(enum run_as_cmd cmd) return _extract_elf_symbol_offset; case RUN_AS_EXTRACT_SDT_PROBE_OFFSETS: return _extract_sdt_probe_offsets; + case RUN_AS_GENERATE_FILTER_BYTECODE: + return _generate_filter_bytecode; default: ERR("Unknown command %d", (int) cmd); return NULL; @@ -794,6 +862,10 @@ int recv_fds_from_master(struct run_as_worker *worker, struct run_as_data *data) goto end; } + if (COMMAND_IN_FD_COUNT(data) == 0) { + goto end; + } + ret = do_recv_fds(worker->sockpair[1], COMMAND_IN_FDS(data), COMMAND_IN_FD_COUNT(data)); if (ret < 0) { @@ -1725,6 +1797,49 @@ error: return ret; } +LTTNG_HIDDEN +int run_as_generate_filter_bytecode(const char *filter_expression, + uid_t uid, + gid_t gid, + struct lttng_filter_bytecode **bytecode) +{ + int ret; + struct run_as_data data = {}; + struct run_as_ret run_as_ret = {}; + const struct lttng_filter_bytecode *view_bytecode = NULL; + struct lttng_filter_bytecode *local_bytecode = NULL; + + DBG3("generate_filter_bytecode() from expression=\"%s\" for uid %d and gid %d", + filter_expression, (int) uid, (int) gid); + + ret = lttng_strncpy(data.u.generate_filter_bytecode.filter_expression, filter_expression, + sizeof(data.u.generate_filter_bytecode.filter_expression)); + if (ret) { + goto error; + } + + run_as(RUN_AS_GENERATE_FILTER_BYTECODE, &data, &run_as_ret, uid, gid); + errno = run_as_ret._errno; + if (run_as_ret._error) { + ret = -1; + goto error; + } + + view_bytecode = (const struct lttng_filter_bytecode *) run_as_ret.u.generate_filter_bytecode.bytecode; + + local_bytecode = zmalloc(sizeof(*local_bytecode) + view_bytecode->len); + if (!local_bytecode) { + ret = -ENOMEM; + goto error; + } + + memcpy(local_bytecode, run_as_ret.u.generate_filter_bytecode.bytecode, + sizeof(*local_bytecode) + view_bytecode->len); + *bytecode = local_bytecode; +error: + return ret; +} + LTTNG_HIDDEN int run_as_create_worker(const char *procname, post_fork_cleanup_cb clean_up_func, diff --git a/src/common/runas.h b/src/common/runas.h index 619d3d0b3..398221708 100644 --- a/src/common/runas.h +++ b/src/common/runas.h @@ -14,6 +14,7 @@ #include #include +#include /* * The run-as process is launched by forking without an exec*() call. This means @@ -70,6 +71,11 @@ int run_as_extract_sdt_probe_offsets(int fd, const char *provider_name, const char* probe_name, uid_t uid, gid_t gid, uint64_t **offsets, uint32_t *num_offset); LTTNG_HIDDEN +int run_as_generate_filter_bytecode(const char *filter_expression, + uid_t uid, + gid_t gid, + struct lttng_filter_bytecode **bytecode); +LTTNG_HIDDEN int run_as_create_worker(const char *procname, post_fork_cleanup_cb clean_up_func, void *clean_up_user_data); LTTNG_HIDDEN