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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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#include <trace.h>#include <utils.h>#include <rv.h>
static int config_has_id;static int config_is_container;static int config_my_pid;static int config_trace;
static char *config_initial_reactor;static char *config_reactor;
/* * __ikm_read_enable - reads monitor's enable status * * __does not log errors. * * Returns the current status, or -1 if the monitor does not exist, * __hence not logging errors. */static int __ikm_read_enable(char *monitor_name){ char path[MAX_PATH]; long long enabled; int retval;
snprintf(path, MAX_PATH, "rv/monitors/%s/enable", monitor_name);
retval = tracefs_instance_file_read_number(NULL, path, &enabled); if (retval < 0) return -1;
return enabled;}
/* * __ikm_find_monitor - find the full name of a possibly nested module * * __does not log errors. * * Returns 1 if we found the monitor, -1 on error and 0 if it does not exist. * The string out_name is populated with the full name, which can be * equal to monitor_name or container/monitor_name if nested */static int __ikm_find_monitor_name(char *monitor_name, char *out_name){ char *available_monitors, *cursor, *line; int len = strlen(monitor_name); int found = 0;
available_monitors = tracefs_instance_file_read(NULL, "rv/available_monitors", NULL); if (!available_monitors) return -1;
config_is_container = 0; cursor = available_monitors; while ((line = strsep(&cursor, "\n"))) { char *colon = strchr(line, ':');
if (strcmp(line, monitor_name) && (!colon || strcmp(colon + 1, monitor_name))) continue;
strncpy(out_name, line, 2 * MAX_DA_NAME_LEN); out_name[2 * MAX_DA_NAME_LEN - 1] = '\0';
if (colon) { out_name[colon - line] = '/'; } else { /* If there are children, they are on the next line. */ line = strsep(&cursor, "\n"); if (line && !strncmp(line, monitor_name, len) && line[len] == ':') config_is_container = 1; }
found = 1; break; }
free(available_monitors); return found;}
/* * ikm_read_enable - reads monitor's enable status * * Returns the current status, or -1 on error. */static int ikm_read_enable(char *monitor_name){ int enabled;
enabled = __ikm_read_enable(monitor_name); if (enabled < 0) { err_msg("ikm: fail read enabled: %d\n", enabled); return -1; }
debug_msg("ikm: read enabled: %d\n", enabled);
return enabled;}
/* * ikm_write_enable - write to the monitor's enable file * * Return the number of bytes written, -1 on error. */static int ikm_write_enable(char *monitor_name, char *enable_disable){ char path[MAX_PATH]; int retval;
debug_msg("ikm: writing enabled: %s\n", enable_disable);
snprintf(path, MAX_PATH, "rv/monitors/%s/enable", monitor_name); retval = tracefs_instance_file_write(NULL, path, enable_disable); if (retval < strlen(enable_disable)) { err_msg("ikm: writing enabled: %s\n", enable_disable); return -1; }
return retval;}
/* * ikm_enable - enable a monitor * * Returns -1 on failure. Success otherwise. */static int ikm_enable(char *monitor_name){ return ikm_write_enable(monitor_name, "1");}
/* * ikm_disable - disable a monitor * * Returns -1 on failure. Success otherwise. */static int ikm_disable(char *monitor_name){ return ikm_write_enable(monitor_name, "0");}
/* * ikm_read_desc - read monitors' description * * Return a dynamically allocated string with the monitor's * description, NULL otherwise. */static char *ikm_read_desc(char *monitor_name){ char path[MAX_PATH]; char *desc;
snprintf(path, MAX_PATH, "rv/monitors/%s/desc", monitor_name); desc = tracefs_instance_file_read(NULL, path, NULL); if (!desc) { err_msg("ikm: error reading monitor %s desc\n", monitor_name); return NULL; }
*strstr(desc, "\n") = '\0';
return desc;}
/* * ikm_fill_monitor_definition - fill monitor's definition * * Returns -1 on error, 1 if the monitor does not belong in the container, 0 otherwise. * container can be NULL */static int ikm_fill_monitor_definition(char *name, struct monitor *ikm, char *container){ int enabled; char *desc, *nested_name;
nested_name = strstr(name, ":"); if (nested_name) { /* it belongs in container if it starts with "container:" */ if (container) { int len = strlen(container);
if (strncmp(name, container, len) || name[len] != ':') return 1; } *nested_name = '/'; ++nested_name; ikm->nested = 1; } else { if (container) return 1; nested_name = name; ikm->nested = 0; }
enabled = ikm_read_enable(name); if (enabled < 0) { err_msg("ikm: monitor %s fail to read enable file, bug?\n", name); return -1; }
desc = ikm_read_desc(name); if (!desc) { err_msg("ikm: monitor %s does not have desc file, bug?\n", name); return -1; }
strncpy(ikm->name, nested_name, sizeof(ikm->name) - 1); ikm->name[sizeof(ikm->name) - 1] = '\0'; ikm->enabled = enabled; strncpy(ikm->desc, desc, sizeof(ikm->desc) - 1); ikm->desc[sizeof(ikm->desc) - 1] = '\0'; free(desc);
return 0;}
/* * ikm_write_reactor - switch the reactor to *reactor * * Return the number or characters written, -1 on error. */static int ikm_write_reactor(char *monitor_name, char *reactor){ char path[MAX_PATH]; int retval;
snprintf(path, MAX_PATH, "rv/monitors/%s/reactors", monitor_name); retval = tracefs_instance_file_write(NULL, path, reactor); debug_msg("ikm: write \"%s\" reactors: %d\n", reactor, retval);
return retval;}
/* * ikm_read_reactor - read the reactors file * * Returns a dynamically allocated string with monitor's * available reactors, or NULL on error. */static char *ikm_read_reactor(char *monitor_name){ char path[MAX_PATH]; char *reactors;
snprintf(path, MAX_PATH, "rv/monitors/%s/reactors", monitor_name); reactors = tracefs_instance_file_read(NULL, path, NULL); if (!reactors) { err_msg("ikm: fail reading monitor's %s reactors file\n", monitor_name); return NULL; }
return reactors;}
/* * ikm_get_current_reactor - get the current enabled reactor * * Reads the reactors file and find the currently enabled * [reactor]. * * Returns a dynamically allocated memory with the current * reactor. NULL otherwise. */static char *ikm_get_current_reactor(char *monitor_name){ char *reactors = ikm_read_reactor(monitor_name); char *curr_reactor = NULL; char *start; char *end;
if (!reactors) return NULL;
start = strstr(reactors, "["); if (!start) goto out_free;
start++;
end = strstr(start, "]"); if (!end) goto out_free;
*end = '\0';
curr_reactor = calloc(strlen(start) + 1, sizeof(char)); if (!curr_reactor) goto out_free;
strncpy(curr_reactor, start, strlen(start)); debug_msg("ikm: read current reactor %s\n", curr_reactor);
out_free: free(reactors);
return curr_reactor;}
static int ikm_has_id(char *monitor_name){ char path[MAX_PATH]; char *format; int has_id;
snprintf(path, MAX_PATH, "events/rv/event_%s/format", monitor_name); format = tracefs_instance_file_read(NULL, path, NULL); if (!format) { err_msg("ikm: fail reading monitor's %s format event file\n", monitor_name); return -1; }
/* print fmt: "%d: %s x %s -> %s %s", REC->id, ... */ has_id = !!strstr(format, "REC->id");
debug_msg("ikm: monitor %s has id: %s\n", monitor_name, has_id ? "yes" : "no");
free(format);
return has_id;}
/** * ikm_list_monitors - list all available monitors * * Returns 0 on success, -1 otherwise. */int ikm_list_monitors(char *container){ char *available_monitors; struct monitor ikm = {0}; char *curr, *next; int retval, list_monitor = 0;
available_monitors = tracefs_instance_file_read(NULL, "rv/available_monitors", NULL);
if (!available_monitors) { err_msg("ikm: available monitors is not available, is CONFIG_RV enabled?\n"); return -1; }
curr = available_monitors; do { next = strstr(curr, "\n"); *next = '\0';
retval = ikm_fill_monitor_definition(curr, &ikm, container); if (retval < 0) err_msg("ikm: error reading %d in kernel monitor, skipping\n", curr);
if (!retval) { int indent = ikm.nested && !container;
list_monitor = 1; printf("%s%-*s %s %s\n", indent ? " - " : "", indent ? MAX_DA_NAME_LEN - 3 : MAX_DA_NAME_LEN, ikm.name, ikm.desc, ikm.enabled ? "[ON]" : "[OFF]"); } curr = ++next;
} while (strlen(curr));
if (!list_monitor) { if (container) printf("-- No monitor found in container %s --\n", container); else printf("-- No monitor found --\n"); }
free(available_monitors);
return 0;}
static void ikm_print_header(struct trace_seq *s){ trace_seq_printf(s, "%16s-%-8s %5s %5s ", "<TASK>", "PID", "[CPU]", "TYPE"); if (config_has_id) trace_seq_printf(s, "%8s ", "ID");
trace_seq_printf(s, "%24s x %-24s -> %-24s %s\n", "STATE", "EVENT", "NEXT_STATE", "FINAL");
trace_seq_printf(s, "%16s %-8s %5s %5s ", " | ", " | ", " | ", " | ");
if (config_has_id) trace_seq_printf(s, "%8s ", " | ");
trace_seq_printf(s, "%24s %-24s %-24s %s\n", " | ", " | ", " | ", "|");
}
/* * ikm_event_handler - callback to handle event events * * Called any time a rv:"monitor"_event events is generated. * It parses and prints event. */static intikm_event_handler(struct trace_seq *s, struct tep_record *record, struct tep_event *trace_event, void *context){ /* if needed: struct trace_instance *inst = context; */ char *state, *event, *next_state; unsigned long long final_state; unsigned long long pid; unsigned long long id; int val; bool missing_id;
if (config_has_id) missing_id = tep_get_field_val(s, trace_event, "id", record, &id, 1);
tep_get_common_field_val(s, trace_event, "common_pid", record, &pid, 1);
if (config_has_id && (config_my_pid == id)) return 0; else if (config_my_pid == pid) return 0;
tep_print_event(trace_event->tep, s, record, "%16s-%-8d [%.3d] ", TEP_PRINT_COMM, TEP_PRINT_PID, TEP_PRINT_CPU);
if (config_is_container) tep_print_event(trace_event->tep, s, record, "%s ", TEP_PRINT_NAME); else trace_seq_printf(s, "event ");
if (config_has_id) { if (missing_id) /* placeholder if we are dealing with a mixed-type container*/ trace_seq_printf(s, " "); else trace_seq_printf(s, "%8llu ", id); }
state = tep_get_field_raw(s, trace_event, "state", record, &val, 0); event = tep_get_field_raw(s, trace_event, "event", record, &val, 0); next_state = tep_get_field_raw(s, trace_event, "next_state", record, &val, 0); tep_get_field_val(s, trace_event, "final_state", record, &final_state, 1);
trace_seq_printf(s, "%24s x %-24s -> %-24s %s\n", state, event, next_state, final_state ? "Y" : "N");
trace_seq_do_printf(s); trace_seq_reset(s);
return 0;}
/* * ikm_error_handler - callback to handle error events * * Called any time a rv:"monitor"_errors events is generated. * It parses and prints event. */static intikm_error_handler(struct trace_seq *s, struct tep_record *record, struct tep_event *trace_event, void *context){ unsigned long long pid, id; int cpu = record->cpu; char *state, *event; int val; bool missing_id;
if (config_has_id) missing_id = tep_get_field_val(s, trace_event, "id", record, &id, 1);
tep_get_common_field_val(s, trace_event, "common_pid", record, &pid, 1);
if (config_has_id && config_my_pid == id) return 0; else if (config_my_pid == pid) return 0;
trace_seq_printf(s, "%8lld [%03d] ", pid, cpu);
if (config_is_container) tep_print_event(trace_event->tep, s, record, "%s ", TEP_PRINT_NAME); else trace_seq_printf(s, "error ");
if (config_has_id) { if (missing_id) /* placeholder if we are dealing with a mixed-type container*/ trace_seq_printf(s, " "); else trace_seq_printf(s, "%8llu ", id); }
state = tep_get_field_raw(s, trace_event, "state", record, &val, 0); event = tep_get_field_raw(s, trace_event, "event", record, &val, 0);
trace_seq_printf(s, "%24s x %s\n", state, event);
trace_seq_do_printf(s); trace_seq_reset(s);
return 0;}
static int ikm_enable_trace_events(char *monitor_name, struct trace_instance *inst){ char event[MAX_DA_NAME_LEN + 7]; /* max(error_,event_) + '0' = 7 */ int retval;
snprintf(event, sizeof(event), "event_%s", monitor_name); retval = tracefs_event_enable(inst->inst, "rv", event); if (retval) return -1;
tep_register_event_handler(inst->tep, -1, "rv", event, ikm_event_handler, NULL);
snprintf(event, sizeof(event), "error_%s", monitor_name); retval = tracefs_event_enable(inst->inst, "rv", event); if (retval) return -1;
tep_register_event_handler(inst->tep, -1, "rv", event, ikm_error_handler, NULL);
/* set if at least 1 monitor has id in case of a container */ config_has_id = ikm_has_id(monitor_name); if (config_has_id < 0) return -1;
return 0;}
static int ikm_enable_trace_container(char *monitor_name, struct trace_instance *inst){ DIR *dp; char *abs_path, rv_path[MAX_PATH]; struct dirent *ep; int retval = 0;
snprintf(rv_path, MAX_PATH, "rv/monitors/%s", monitor_name); abs_path = tracefs_instance_get_file(NULL, rv_path); if (!abs_path) return -1; dp = opendir(abs_path); if (!dp) goto out_free;
while (!retval && (ep = readdir(dp))) { if (ep->d_type != DT_DIR || ep->d_name[0] == '.') continue; retval = ikm_enable_trace_events(ep->d_name, inst); }
closedir(dp);out_free: free(abs_path); return retval;}
/* * ikm_setup_trace_instance - set up a tracing instance to collect data * * Create a trace instance, enable rv: events and enable the trace. * * Returns the trace_instance * with all set, NULL otherwise. */static struct trace_instance *ikm_setup_trace_instance(char *monitor_name){ struct trace_instance *inst; int retval;
if (!config_trace) return NULL;
/* alloc data */ inst = calloc(1, sizeof(*inst)); if (!inst) { err_msg("ikm: failed to allocate trace instance"); goto out_err; }
retval = trace_instance_init(inst, monitor_name); if (retval) goto out_free;
if (config_is_container) retval = ikm_enable_trace_container(monitor_name, inst); else retval = ikm_enable_trace_events(monitor_name, inst); if (retval) goto out_inst;
/* ready to enable */ tracefs_trace_on(inst->inst);
return inst;
out_inst: trace_instance_destroy(inst);out_free: free(inst);out_err: return NULL;}
/** * ikm_destroy_trace_instance - destroy a previously created instance */static void ikm_destroy_trace_instance(struct trace_instance *inst){ if (!inst) return;
trace_instance_destroy(inst); free(inst);}
/* * ikm_usage_print_reactors - print all available reactors, one per line. */static void ikm_usage_print_reactors(void){ char *reactors = tracefs_instance_file_read(NULL, "rv/available_reactors", NULL); char *start, *end;
if (!reactors) return;
fprintf(stderr, " available reactors:");
start = reactors; end = strstr(start, "\n");
while (end) { *end = '\0';
fprintf(stderr, " %s", start);
start = ++end; end = strstr(start, "\n"); }
fprintf(stderr, "\n");}/* * ikm_usage - print usage */static void ikm_usage(int exit_val, char *monitor_name, const char *fmt, ...){
char message[1024]; va_list ap; int i;
static const char *const usage[] = { "", " -h/--help: print this menu and the reactor list", " -r/--reactor 'reactor': enables the 'reactor'", " -s/--self: when tracing (-t), also trace rv command", " -t/--trace: trace monitor's event", " -v/--verbose: print debug messages", "", NULL, };
va_start(ap, fmt); vsnprintf(message, sizeof(message), fmt, ap); va_end(ap);
fprintf(stderr, " %s\n", message);
fprintf(stderr, "\n usage: rv mon %s [-h] [-q] [-r reactor] [-s] [-v]", monitor_name);
for (i = 0; usage[i]; i++) fprintf(stderr, "%s\n", usage[i]);
ikm_usage_print_reactors(); exit(exit_val);}
/* * parse_arguments - parse arguments and set config */static int parse_arguments(char *monitor_name, int argc, char **argv){ int c, retval;
config_my_pid = getpid();
while (1) { static struct option long_options[] = { {"help", no_argument, 0, 'h'}, {"reactor", required_argument, 0, 'r'}, {"self", no_argument, 0, 's'}, {"trace", no_argument, 0, 't'}, {"verbose", no_argument, 0, 'v'}, {0, 0, 0, 0} };
/* getopt_long stores the option index here. */ int option_index = 0;
c = getopt_long(argc, argv, "hr:stv", long_options, &option_index);
/* detect the end of the options. */ if (c == -1) break;
switch (c) { case 'h': ikm_usage(0, monitor_name, "help:"); break; case 'r': config_reactor = optarg; break; case 's': config_my_pid = -1; break; case 't': config_trace = 1; break; case 'v': config_debug = 1; break; } }
if (config_reactor) { config_initial_reactor = ikm_get_current_reactor(monitor_name); if (!config_initial_reactor) ikm_usage(1, monitor_name, "ikm: failed to read current reactor, are reactors enabled?");
retval = ikm_write_reactor(monitor_name, config_reactor); if (retval <= 0) ikm_usage(1, monitor_name, "ikm: failed to set %s reactor, is it available?", config_reactor); }
debug_msg("ikm: my pid is %d\n", config_my_pid);
return 0;}
/** * ikm_run_monitor - apply configs and run the monitor * * Returns 1 if a monitor was found an executed, 0 if no * monitors were found, or -1 on error. */int ikm_run_monitor(char *monitor_name, int argc, char **argv){ struct trace_instance *inst = NULL; char *nested_name, full_name[2*MAX_DA_NAME_LEN]; int retval;
nested_name = strstr(monitor_name, ":"); if (nested_name) ++nested_name; else nested_name = monitor_name;
retval = __ikm_find_monitor_name(monitor_name, full_name); if (!retval) return 0; if (retval < 0) { err_msg("ikm: error finding monitor %s\n", nested_name); return -1; }
retval = __ikm_read_enable(full_name); if (retval) { err_msg("ikm: monitor %s (in-kernel) is already enabled\n", nested_name); return -1; }
/* we should be good to go */ retval = parse_arguments(full_name, argc, argv); if (retval) ikm_usage(1, nested_name, "ikm: failed parsing arguments");
if (config_trace) { inst = ikm_setup_trace_instance(nested_name); if (!inst) goto out_free_instance; }
retval = ikm_enable(full_name); if (retval < 0) goto out_free_instance;
if (config_trace) ikm_print_header(inst->seq);
while (!should_stop()) { if (config_trace) { retval = tracefs_iterate_raw_events(inst->tep, inst->inst, NULL, 0, collect_registered_events, inst); if (retval) { err_msg("ikm: error reading trace buffer\n"); break; } }
sleep(1); }
ikm_disable(full_name); ikm_destroy_trace_instance(inst);
if (config_reactor && config_initial_reactor) ikm_write_reactor(full_name, config_initial_reactor);
return 1;
out_free_instance: ikm_destroy_trace_instance(inst); if (config_reactor && config_initial_reactor) ikm_write_reactor(full_name, config_initial_reactor); return -1;}