A new command "--container <container-id>" is added to "trace-cmd record" sub command. It creates a ftrace instance and runs the tracing of container's PIDs into it. Multiple "--container" options can be specified, to trace multiple containers at the same time. The new option behaves as "-B": all trace-cmd options specified after "--container" affect only the tracing related to this container. The patch is a POC, it introduces the infrastructure and helper functions for container tracing. Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@xxxxxxxxx> --- include/trace-cmd/trace-cmd.h | 3 + lib/trace-cmd/Makefile | 1 + lib/trace-cmd/trace-containers.c | 141 +++++++++++++++++++++++++++++++ tracecmd/include/trace-local.h | 1 + tracecmd/trace-record.c | 59 ++++++++++--- 5 files changed, 192 insertions(+), 13 deletions(-) create mode 100644 lib/trace-cmd/trace-containers.c diff --git a/include/trace-cmd/trace-cmd.h b/include/trace-cmd/trace-cmd.h index f3c95f30..6db719e6 100644 --- a/include/trace-cmd/trace-cmd.h +++ b/include/trace-cmd/trace-cmd.h @@ -501,4 +501,7 @@ void *tracecmd_record_page(struct tracecmd_input *handle, void *tracecmd_record_offset(struct tracecmd_input *handle, struct tep_record *record); +/* --- Containers --- */ +int tracecmd_get_container_pids(char *cont_id, int **pids, int *pids_count); + #endif /* _TRACE_CMD_H */ diff --git a/lib/trace-cmd/Makefile b/lib/trace-cmd/Makefile index ab7440ac..b68334b3 100644 --- a/lib/trace-cmd/Makefile +++ b/lib/trace-cmd/Makefile @@ -17,6 +17,7 @@ OBJS += trace-filter-hash.o OBJS += trace-msg.o OBJS += trace-plugin.o OBJS += trace-timesync.o +OBJS += trace-containers.o # Additional util objects OBJS += trace-blk-hack.o diff --git a/lib/trace-cmd/trace-containers.c b/lib/trace-cmd/trace-containers.c new file mode 100644 index 00000000..f082a921 --- /dev/null +++ b/lib/trace-cmd/trace-containers.c @@ -0,0 +1,141 @@ +// SPDX-License-Identifier: LGPL-2.1 +/* + * Copyright (C) 2008, 2009, 2010 Red Hat Inc, Steven Rostedt <srostedt@xxxxxxxxxx> + * + * Updates: + * Copyright (C) 2020, VMware, Tzvetomir Stoyanov <tz.stoyanov@xxxxxxxxx> + * + */ + +#include <stdlib.h> +#include <stdio.h> +#include <fcntl.h> +#include <string.h> +#include <sys/types.h> +#include <dirent.h> +#include <unistd.h> + +#include "trace-cmd-local.h" + +#define CGROUPV1_CPUSET_DOCKER "/sys/fs/cgroup/cpuset/docker/" +#define CGROUPV1_PID_FILE "cgroup.procs" + +static char *read_text_file(char *file) +{ + char stbuf[BUFSIZ]; + char *buf = NULL; + int size = 0; + int fd = -1; + + fd = open(file, O_RDONLY); + if (fd < 0) + goto out; + + size = read(fd, stbuf, BUFSIZ); + if (size <= 0) + goto out; + buf = malloc(size + 1); + if (!buf) + goto out; + memcpy(buf, stbuf, size); + buf[size] = '\0'; + +out: + if (fd >= 0) + close(fd); + + return buf; +} + +static char *match_in_dir(char *path, char *match) +{ + char *match_path = NULL; + struct dirent *dent; + char *name = NULL; + DIR *dir; + + dir = opendir(path); + if (!dir) + return NULL; + + while ((dent = readdir(dir))) { + name = dent->d_name; + + if (!strncmp(name, match, strlen(match))) + break; + name = NULL; + } + + closedir(dir); + if (name) + asprintf(&match_path, "%s/%s", path, name); + + return match_path; +} + +static int get_v1_docker_pids(char *cont_id, int **pids, int *pids_count) +{ + char *cont_dir = NULL; + char *pid_file = NULL; + char *pid_buf = NULL; + int *pid_array = NULL; + char *savestr; + char *pid_str; + int pcount = 0; + int ret = -1; + + cont_dir = match_in_dir(CGROUPV1_CPUSET_DOCKER, cont_id); + if (!cont_dir) + goto out; + if (asprintf(&pid_file, "%s/%s", cont_dir, CGROUPV1_PID_FILE) < 0) + goto out; + pid_buf = read_text_file(pid_file); + if (!pid_buf) + goto out; + + *pids = NULL; + *pids_count = 0; + pid_str = strtok_r(pid_buf, " \t\r\n\v\f", &savestr); + while (pid_str) { + pid_array = realloc(pid_array, (pcount + 1) * sizeof(int)); + if (!pid_array) + break; + pid_array[pcount++] = atoi(pid_str); + pid_str = strtok_r(NULL, " \t\r\n\v\f", &savestr); + } + + if (!pid_str) { + *pids = pid_array; + *pids_count = pcount; + ret = 0; + } else + free(pid_array); + +out: + free(cont_dir); + free(pid_file); + free(pid_buf); + + return ret; +} + +/* + * tracecmd_get_container_pids - Get PIDs associated with a given container + * + *@cont_id - container identifier + *@pids - returns allocated array of size @pids_count with PIDs + *@pids_count - size of returned array @pids + * + * Returns -1 in case of an error, 0 otherwise + * In case of success, returned array @pids must be freed by free() + */ +int tracecmd_get_container_pids(char *cont_id, int **pids, int *pids_count) +{ + int ret; + + ret = get_v1_docker_pids(cont_id, pids, pids_count); + if (!ret) + return ret; + + return -1; +} diff --git a/tracecmd/include/trace-local.h b/tracecmd/include/trace-local.h index 4c6a63d0..13e5afc6 100644 --- a/tracecmd/include/trace-local.h +++ b/tracecmd/include/trace-local.h @@ -168,6 +168,7 @@ enum buffer_instance_flags { BUFFER_FL_GUEST = 1 << 2, BUFFER_FL_AGENT = 1 << 3, BUFFER_FL_HAS_CLOCK = 1 << 4, + BUFFER_FL_CONTAINER = 1 << 5, }; struct func_list { diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c index d0619ba6..219cebb7 100644 --- a/tracecmd/trace-record.c +++ b/tracecmd/trace-record.c @@ -5442,6 +5442,7 @@ void init_top_instance(void) } enum { + OPT_container = 241, OPT_tsyncinterval = 242, OPT_user = 243, OPT_procmap = 244, @@ -5705,6 +5706,46 @@ static void add_arg(struct buffer_instance *instance, /* Not found? */ } +static void set_trace_child(struct buffer_instance *instance) +{ + test_set_event_pid(instance); + if (!instance->have_event_fork) { +#ifdef NO_PTRACE + die("trace child: ptrace not supported"); +#endif + instance->ptrace_child = 1; + do_ptrace = 1; + } else { + save_option(instance, "event-fork"); + } + if (instance->have_func_fork) + save_option(instance, "function-fork"); +} + +static struct buffer_instance *parse_container(char *container) +{ + struct buffer_instance *instance; + int pids_count = 0; + int *pids = NULL; + int ret; + + ret = tracecmd_get_container_pids(container, &pids, &pids_count); + if (ret < 0 || !pids_count) + die("Failed to get container %s PIDs", container); + + instance = create_instance(container); + if (!instance) + die("Failed to create instance %s", container); + add_instance(instance, local_cpu_count); + instance->flags |= BUFFER_FL_CONTAINER; + set_trace_child(instance); + for (int i = 0; i < pids_count; i++) + add_filter_pid(instance, pids[i], 0); + + free(pids); + return instance; +} + static void parse_record_options(int argc, char **argv, enum trace_cmd curr_cmd, @@ -5750,6 +5791,7 @@ static void parse_record_options(int argc, {"user", required_argument, NULL, OPT_user}, {"module", required_argument, NULL, OPT_module}, {"tsync-interval", required_argument, NULL, OPT_tsyncinterval}, + {"container", required_argument, NULL, OPT_container}, {NULL, 0, NULL, 0} }; @@ -5870,20 +5912,8 @@ static void parse_record_options(int argc, free(pids); break; case 'c': - test_set_event_pid(ctx->instance); + set_trace_child(ctx->instance); do_children = 1; - if (!ctx->instance->have_event_fork) { -#ifdef NO_PTRACE - die("-c invalid: ptrace not supported"); -#endif - do_ptrace = 1; - ctx->instance->ptrace_child = 1; - - } else { - save_option(ctx->instance, "event-fork"); - } - if (ctx->instance->have_func_fork) - save_option(ctx->instance, "function-fork"); break; case 'C': ctx->instance->clock = optarg; @@ -6100,6 +6130,9 @@ static void parse_record_options(int argc, top_instance.tsync.loop_interval = atoi(optarg); guest_sync_set = true; break; + case OPT_container: + ctx->instance = parse_container(optarg); + break; case OPT_quiet: case 'q': quiet = true; -- 2.26.2