On Wed, 3 Jul 2019 14:51:34 +0300
tz.stoyanov@xxxxxxxxx wrote:
> From: "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@xxxxxxxxx>
>
> A new trace-cmd record option is added: "--mmap". When it is set with
> combination of -F or -P options, the memory map of the traced applications
> is stored in the trace.dat file. A new API tracecmd_search_task_mmap()
> can be used to look up into stored memory maps. The map is retrieved from
> /proc/<pid>/maps file.
>
I also have some notes below.
> diff --git a/Documentation/trace-cmd-record.1.txt b/Documentation/trace-cmd-record.1.txt
> index 26a8299..4a59de9 100644
> --- a/Documentation/trace-cmd-record.1.txt
> +++ b/Documentation/trace-cmd-record.1.txt
> @@ -119,6 +119,9 @@ OPTIONS
> Used with either *-F* (or *-P* if kernel supports it) to trace the process'
> children too.
>
> +*--mmap*::
> + Used with either *-F* or *-P*, save the traced process memory map into
> + the trace.dat file.
Do we need to use -F? If we want to record the proc/mmap of the process
that we execute (trace-cmd recode -e all some-program, where we save
the process map of some-program). Do we have to only record
some-program? Which is what -F will do.
> *-C* 'clock'::
> Set the trace clock to "clock".
>
> diff --git a/include/trace-cmd/trace-cmd.h b/include/trace-cmd/trace-cmd.h
> index 6f62ab9..17edb9d 100644
> --- a/include/trace-cmd/trace-cmd.h
> +++ b/include/trace-cmd/trace-cmd.h
> @@ -82,6 +82,7 @@ enum {
> TRACECMD_OPTION_OFFSET,
> TRACECMD_OPTION_CPUCOUNT,
> TRACECMD_OPTION_VERSION,
> + TRACECMD_OPTION_PIDMMAPS,
> };
>
> enum {
> @@ -97,6 +98,12 @@ struct tracecmd_ftrace {
> int long_size;
> };
>
> +struct lib_mem_map {
If this is going to be exported to external users, it needs to use the
tracecmd_ prefix. Probably should also add "proc" as well.
struct tracecmd_proc_mem_map ?
I'm also thinking of removing the "mem" as it's not really memory maps,
it's really called address mapping. Perhaps just drop the "mem", and
call it tracecmd_proc_map. And address may not even be pointing into
memory (It could have a device I/O mapping).
> + unsigned long long start;
> + unsigned long long end;
> + char *lib_name;
> +};
> +
> typedef void (*tracecmd_show_data_func)(struct tracecmd_input *handle,
> struct tep_record *record);
> typedef void (*tracecmd_handle_init_func)(struct tracecmd_input *handle,
> @@ -208,6 +215,8 @@ unsigned long long tracecmd_page_ts(struct tracecmd_input *handle,
> unsigned int tracecmd_record_ts_delta(struct tracecmd_input *handle,
> struct tep_record *record);
>
> +struct lib_mem_map *tracecmd_search_task_mmap(struct tracecmd_input *handle,
> + int pid, unsigned long long addr);
> #ifndef SWIG
> /* hack for function graph work around */
> extern __thread struct tracecmd_input *tracecmd_curr_thread_handle;
> diff --git a/lib/trace-cmd/trace-input.c b/lib/trace-cmd/trace-input.c
> index 61566ba..d9abbcf 100644
> --- a/lib/trace-cmd/trace-input.c
> +++ b/lib/trace-cmd/trace-input.c
> @@ -101,6 +101,7 @@ struct tracecmd_input {
> struct tracecmd_ftrace finfo;
>
> struct hook_list *hooks;
> + struct pid_mem_maps *pid_mmaps;
> /* file information */
> size_t header_files_start;
> size_t ftrace_files_start;
> @@ -2134,6 +2135,166 @@ void tracecmd_set_ts2secs(struct tracecmd_input *handle,
> handle->use_trace_clock = false;
> }
>
> +static int trace_pid_mmap_cmp(const void *a, const void *b)
> +{
> + struct lib_mem_map *map_a = (struct lib_mem_map *)a;
> + struct lib_mem_map *map_b = (struct lib_mem_map *)b;
> +
> + if (map_a->start > map_b->start)
> + return 1;
> + if (map_a->start < map_b->start)
> + return -1;
> + return 0;
> +}
> +
> +static void mmap_free(struct pid_mem_maps *maps)
> +{
> + int i;
> +
> + if (!maps)
> + return;
> + if (maps->lib_maps) {
> + for (i = 0; i < maps->nr_lib_maps; i++)
> + free(maps->lib_maps[i].lib_name);
> + free(maps->lib_maps);
> + }
> + free(maps->proc_name);
> + free(maps);
> +}
> +
> +#define STR_MMAP_LINE_MAX (PATH_MAX+34)
What's the reason for the +34?
> +static int trace_pid_mmap_load(struct tracecmd_input *handle, char *buf)
> +{
> + struct pid_mem_maps *maps = NULL;
> + char mapname[STR_MMAP_LINE_MAX];
> + char *line;
> + int res;
> + int ret;
> + int i;
> +
> + maps = calloc(1, sizeof(*maps));
> + if (!maps)
> + return -ENOMEM;
> +
> + ret = -EINVAL;
> + line = strchr(buf, '\n');
> + if (!line)
> + goto out_fail;
> +
> + *line = '\0';
> + if (strlen(buf) > STR_MMAP_LINE_MAX)
> + goto out_fail;
> +
> + res = sscanf(buf, "%x %x %s", &maps->pid, &maps->nr_lib_maps, mapname);
> + if (res != 3)
> + goto out_fail;
> +
> + ret = -ENOMEM;
> + maps->proc_name = strdup(mapname);
> + if (!maps->proc_name)
> + goto out_fail;
> +
> + maps->lib_maps = calloc(maps->nr_lib_maps, sizeof(struct lib_mem_map));
> + if (!maps->lib_maps)
> + goto out_fail;
> +
> + buf = line + 1;
> + line = strchr(buf, '\n');
> + for (i = 0; i < maps->nr_lib_maps; i++) {
> + if (!line)
> + break;
> + *line = '\0';
> + if (strlen(buf) > STR_MMAP_LINE_MAX)
> + break;
> + res = sscanf(buf, "%llx %llx %s", &maps->lib_maps[i].start,
> + &maps->lib_maps[i].end, mapname);
> + if (res != 3)
> + break;
> + maps->lib_maps[i].lib_name = strdup(mapname);
> + if (!maps->lib_maps[i].lib_name)
> + goto out_fail;
> + buf = line + 1;
> + line = strchr(buf, '\n');
> + }
> +
> + ret = -EINVAL;
> + if (i != maps->nr_lib_maps)
> + goto out_fail;
> +
> + qsort(maps->lib_maps, maps->nr_lib_maps,
> + sizeof(*maps->lib_maps), trace_pid_mmap_cmp);
> +
> + maps->next = handle->pid_mmaps;
> + handle->pid_mmaps = maps;
> +
> + return 0;
> +
> +out_fail:
> + mmap_free(maps);
> + return ret;
> +}
> +
> +static void trace_pid_mmap_free(struct pid_mem_maps *mmaps)
> +{
> + struct pid_mem_maps *del;
> +
> + while (mmaps) {
> + del = mmaps;
> + mmaps = mmaps->next;
> + mmap_free(del);
> + }
> +}
> +
> +static int trace_pid_mmap_search(const void *a, const void *b)
> +{
> + struct lib_mem_map *key = (struct lib_mem_map *)a;
> + struct lib_mem_map *map = (struct lib_mem_map *)b;
> +
> + if (key->start >= map->end)
> + return 1;
> + if (key->start < map->start)
> + return -1;
> + return 0;
> +}
> +
> +/**
> + * tracecmd_search_task_mmap - Search task memory address map
> + * @handle: input handle to the trace.dat file
> + * @pid: pid of the task
> + * @addr: address from the task memory space.
> + *
> + * Map of the task memory can be saved in the trace.dat file, using the option
> + * "--mmap". If there is such information, this API can be used to look up into
> + * this memory map to find what library is loaded at the given @addr.
> + *
> + * A pointer to struct lib_mem_map is returned, containing the name of
> + * the library at given task @addr and the library start and end addresses.
> + */
> +struct lib_mem_map *tracecmd_search_task_mmap(struct tracecmd_input *handle,
> + int pid, unsigned long long addr)
> +{
> + struct pid_mem_maps *maps;
> + struct lib_mem_map *lib;
> + struct lib_mem_map key;
> +
> + if (!handle || !handle->pid_mmaps)
> + return NULL;
> +
> + maps = handle->pid_mmaps;
> + while (maps) {
> + if (maps->pid == pid)
> + break;
> + maps = maps->next;
> + }
> + if (!maps || !maps->nr_lib_maps || !maps->lib_maps)
> + return NULL;
> + key.start = addr;
> + lib = bsearch(&key, maps->lib_maps, maps->nr_lib_maps,
> + sizeof(*maps->lib_maps), trace_pid_mmap_search);
> +
> + return lib;
> +}
> +
> static int handle_options(struct tracecmd_input *handle)
> {
> unsigned long long offset;
> @@ -2221,9 +2382,6 @@ static int handle_options(struct tracecmd_input *handle)
> case TRACECMD_OPTION_UNAME:
> handle->uname = strdup(buf);
> break;
> - case TRACECMD_OPTION_VERSION:
> - handle->version = strdup(buf);
> - break;
> case TRACECMD_OPTION_HOOK:
> hook = tracecmd_create_event_hook(buf);
> hook->next = handle->hooks;
> @@ -2233,6 +2391,10 @@ static int handle_options(struct tracecmd_input *handle)
> cpus = *(int *)buf;
> handle->cpus = tep_read_number(handle->pevent, &cpus, 4);
> break;
> + case TRACECMD_OPTION_PIDMMAPS:
OPTION_PROCMAPS ?
> + if (buf[size] == '\0')
> + trace_pid_mmap_load(handle, buf);
> + break;
> default:
> warning("unknown option %d", option);
> break;
> @@ -2842,10 +3004,12 @@ void tracecmd_close(struct tracecmd_input *handle)
> free(handle->cpu_data);
> free(handle->uname);
> close(handle->fd);
> -
I wouldn't remove this blank line.
> tracecmd_free_hooks(handle->hooks);
> handle->hooks = NULL;
>
> + trace_pid_mmap_free(handle->pid_mmaps);
> + handle->pid_mmaps = NULL;
> +
> if (handle->flags & TRACECMD_FL_BUFFER_INSTANCE)
> tracecmd_close(handle->parent);
> else {
> diff --git a/tracecmd/include/trace-local.h b/tracecmd/include/trace-local.h
> index 1cad3cc..ae1632c 100644
> --- a/tracecmd/include/trace-local.h
> +++ b/tracecmd/include/trace-local.h
> @@ -157,6 +157,14 @@ struct func_list {
> const char *mod;
> };
>
> +struct pid_mem_maps {
> + struct pid_mem_maps *next;
> + struct lib_mem_map *lib_maps;
> + unsigned int nr_lib_maps;
> + char *proc_name;
> + int pid;
> +};
> +
> struct buffer_instance {
> struct buffer_instance *next;
> const char *name;
> @@ -183,6 +191,8 @@ struct buffer_instance {
> struct tracecmd_msg_handle *msg_handle;
> struct tracecmd_output *network_handle;
>
> + struct pid_mem_maps *mem_maps;
> +
> char *max_graph_depth;
>
> int flags;
> diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
> index 5dc6f17..48081d4 100644
> --- a/tracecmd/trace-record.c
> +++ b/tracecmd/trace-record.c
> @@ -84,6 +84,7 @@ static int max_kb;
> static bool use_tcp;
>
> static int do_ptrace;
> +static int get_mmap;
>
> static int filter_task;
> static int filter_pid = -1;
> @@ -1062,6 +1063,120 @@ static char *make_pid_filter(char *curr_filter, const char *field)
> return filter;
> }
>
> +static int get_pid_mmaps(int pid)
Should probably remove all references to anything with 'mmap' here and
even remove "mem" as well. Again, these are technically not memory
maps but address mappings. Subtle difference, but a solid difference
none the less.
> +{
> + struct buffer_instance *instance = &top_instance;
> + struct pid_mem_maps *maps = instance->mem_maps;
> + struct pid_mem_maps *m;
> + unsigned long long begin, end, inode, tmp;
> + struct lib_mem_map *map;
> + char mapname[PATH_MAX+1];
> + char fname[PATH_MAX+1];
> + char buf[PATH_MAX+100];
What's the reason for the +100?
> + char perm[5];
> + char dev[6];
> + FILE *f;
> + int ret;
> + int res;
> + int i;
> +
> + sprintf(fname, "/proc/%d/exe", pid);
> + ret = readlink(fname, mapname, PATH_MAX);
> + if (ret >= PATH_MAX || ret < 0)
> + return -ENOENT;
> + mapname[ret] = 0;
> +
> + sprintf(fname, "/proc/%d/maps", pid);
> + f = fopen(fname, "r");
> + if (!f)
> + return -ENOENT;
> +
> + while (maps) {
> + if (pid == maps->pid)
> + break;
> + maps = maps->next;
> + }
> +
> + ret = -ENOMEM;
> + if (!maps) {
> + maps = calloc(1, sizeof(*maps));
> + if (!maps)
> + goto out_fail;
> + maps->pid = pid;
> + maps->next = instance->mem_maps;
> + instance->mem_maps = maps;
> + } else {
> + for (i = 0; i < maps->nr_lib_maps; i++)
> + free(maps->lib_maps[i].lib_name);
> + free(maps->lib_maps);
> + maps->lib_maps = NULL;
> + maps->nr_lib_maps = 0;
> + free(maps->proc_name);
> + }
> +
> + maps->proc_name = strdup(mapname);
> + if (!maps->proc_name)
> + goto out;
> +
> + while (fgets(buf, sizeof(buf), f)) {
> + mapname[0] = '\0';
> + res = sscanf(buf, "%llx-%llx %s %llx %s %lld %s",
> + &begin, &end, perm, &tmp, dev, &inode, mapname);
This is dangerous with perm and dev, as if either string is bigger than
their size, you just created an overflow bug.
buf, "%llx-%llx %4s %llx %5s %lld %" STRINGIFY(PATH_MAX) "s"
Which will keep sscanf from overwriting the size of the variables.
Note, the STRINGIFY() is defined as:
#define _STRINGIFY(x) #x
#define STRINGIFY(x) _STRINGIFY(x)
-- Steve
> + if (res == 7 && mapname[0] != '\0') {
> + map = realloc(maps->lib_maps,
> + (maps->nr_lib_maps + 1) * sizeof(*map));
> + if (!map)
> + goto out_fail;
> + map[maps->nr_lib_maps].end = end;
> + map[maps->nr_lib_maps].start = begin;
> + map[maps->nr_lib_maps].lib_name = strdup(mapname);
> + if (!map[maps->nr_lib_maps].lib_name)
> + goto out_fail;
> + maps->lib_maps = map;
> + maps->nr_lib_maps++;
> + }
> + }
> +out:
> + fclose(f);
> + return 0;
> +
> +out_fail:
> + fclose(f);
> + if (maps) {
> + for (i = 0; i < maps->nr_lib_maps; i++)
> + free(maps->lib_maps[i].lib_name);
> + if (instance->mem_maps != maps) {
> + m = instance->mem_maps;
> + while (m) {
> + if (m->next == maps) {
> + m->next = maps->next;
> + break;
> + }
> + m = m->next;
> + }
> + } else
> + instance->mem_maps = maps->next;
> + free(maps->lib_maps);
> + maps->lib_maps = NULL;
> + maps->nr_lib_maps = 0;
> + free(maps->proc_name);
> + maps->proc_name = NULL;
> + free(maps);
> + }
> + return ret;
> +}
> +
> +static void get_filter_pid_mmaps(void)
> +{
> + struct filter_pids *p;
> +
> + for (p = filter_pids; p; p = p->next) {
> + if (p->exclude)
> + continue;
> + get_pid_mmaps(p->pid);
> + }
> +}
> +
> static void update_task_filter(void)
> {
> struct buffer_instance *instance;
> @@ -1070,6 +1185,9 @@ static void update_task_filter(void)
> if (no_filter)
> return;
>
> + if (get_mmap && filter_pids)
> + get_filter_pid_mmaps();
> +
> if (filter_task)
> add_filter_pid(pid, 0);
>
> @@ -1264,6 +1382,8 @@ static void ptrace_wait(enum trace_type type, int main_pid)
> break;
>
> case PTRACE_EVENT_EXIT:
> + if (get_mmap)
> + get_pid_mmaps(main_pid);
> ptrace(PTRACE_GETEVENTMSG, pid, NULL, &cstatus);
> ptrace(PTRACE_DETACH, pid, NULL, NULL);
> break;
> @@ -3094,6 +3214,33 @@ static void append_buffer(struct tracecmd_output *handle,
> }
> }
>
> +
> +static void
> +add_pid_mem_maps(struct tracecmd_output *handle, struct buffer_instance *instance)
> +{
> + struct pid_mem_maps *maps = instance->mem_maps;
> + struct trace_seq s;
> + int i;
> +
> + trace_seq_init(&s);
> + while (maps) {
> + if (!maps->nr_lib_maps)
> + continue;
> + trace_seq_reset(&s);
> + trace_seq_printf(&s, "%x %x %s\n",
> + maps->pid, maps->nr_lib_maps, maps->proc_name);
> + for (i = 0; i < maps->nr_lib_maps; i++)
> + trace_seq_printf(&s, "%llx %llx %s\n",
> + maps->lib_maps[i].start,
> + maps->lib_maps[i].end,
> + maps->lib_maps[i].lib_name);
> + tracecmd_add_option(handle, TRACECMD_OPTION_PIDMMAPS,
> + s.len + 1, s.buffer);
> + maps = maps->next;
> + }
> + trace_seq_destroy(&s);
> +}
> +
> static void
> add_buffer_stat(struct tracecmd_output *handle, struct buffer_instance *instance)
> {
> @@ -3287,6 +3434,10 @@ static void record_data(struct common_record_context *ctx)
> if (!no_top_instance() && !top_instance.msg_handle)
> print_stat(&top_instance);
>
> + for_all_instances(instance) {
> + add_pid_mem_maps(handle, instance);
> + }
> +
> tracecmd_append_cpu_data(handle, local_cpu_count, temp_files);
>
> for (i = 0; i < max_cpu_count; i++)
> @@ -4397,6 +4548,7 @@ void update_first_instance(struct buffer_instance *instance, int topt)
> }
>
> enum {
> + OPT_mmap = 244,
> OPT_quiet = 245,
> OPT_debug = 246,
> OPT_no_filter = 247,
> @@ -4627,6 +4779,7 @@ static void parse_record_options(int argc,
> {"debug", no_argument, NULL, OPT_debug},
> {"quiet", no_argument, NULL, OPT_quiet},
> {"help", no_argument, NULL, '?'},
> + {"mmap", no_argument, NULL, OPT_mmap},
> {"module", required_argument, NULL, OPT_module},
> {NULL, 0, NULL, 0}
> };
> @@ -4858,6 +5011,9 @@ static void parse_record_options(int argc,
> case 'i':
> ignore_event_not_found = 1;
> break;
> + case OPT_mmap:
> + get_mmap = 1;
> + break;
> case OPT_date:
> ctx->date = 1;
> if (ctx->data_flags & DATA_FL_OFFSET)
> @@ -4924,6 +5080,9 @@ static void parse_record_options(int argc,
> add_func(&ctx->instance->filter_funcs,
> ctx->instance->filter_mod, "*");
>
> + if (filter_task && get_mmap)
> + do_ptrace = 1;
> +
> if (do_ptrace && !filter_task && (filter_pid < 0))
> die(" -c can only be used with -F (or -P with event-fork support)");
> if (ctx->do_child && !filter_task &&! filter_pid)
> diff --git a/tracecmd/trace-usage.c b/tracecmd/trace-usage.c
> index 406384c..c658ede 100644
> --- a/tracecmd/trace-usage.c
> +++ b/tracecmd/trace-usage.c
> @@ -57,6 +57,7 @@ static struct usage_help usage_help[] = {
> " (use with caution)\n"
> " --max-graph-depth limit function_graph depth\n"
> " --no-filter include trace-cmd threads in the trace\n"
> + " --mmap used with -F or -P, save the traced process memory map into the trace.dat file\n"
> },
> {
> "start",
|