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| 1 | +// SPDX-License-Identifier: GPL-2.0 |
| 2 | +#define _GNU_SOURCE |
| 3 | +#include <sys/sendfile.h> |
| 4 | +#include <tracefs.h> |
| 5 | +#include <signal.h> |
| 6 | +#include <stdlib.h> |
| 7 | +#include <unistd.h> |
| 8 | +#include <errno.h> |
| 9 | + |
| 10 | +#include "trace.h" |
| 11 | +#include "utils.h" |
| 12 | + |
| 13 | +/* |
| 14 | + * enable_tracer_by_name - enable a tracer on the given instance |
| 15 | + */ |
| 16 | +int enable_tracer_by_name(struct tracefs_instance *inst, const char *tracer_name) |
| 17 | +{ |
| 18 | + enum tracefs_tracers tracer; |
| 19 | + int retval; |
| 20 | + |
| 21 | + tracer = TRACEFS_TRACER_CUSTOM; |
| 22 | + |
| 23 | + debug_msg("enabling %s tracer\n", tracer_name); |
| 24 | + |
| 25 | + retval = tracefs_tracer_set(inst, tracer, tracer_name); |
| 26 | + if (retval < 0) { |
| 27 | + if (errno == ENODEV) |
| 28 | + err_msg("tracer %s not found!\n", tracer_name); |
| 29 | + |
| 30 | + err_msg("failed to enable the tracer %s\n", tracer_name); |
| 31 | + return -1; |
| 32 | + } |
| 33 | + |
| 34 | + return 0; |
| 35 | +} |
| 36 | + |
| 37 | +/* |
| 38 | + * disable_tracer - set nop tracer to the insta |
| 39 | + */ |
| 40 | +void disable_tracer(struct tracefs_instance *inst) |
| 41 | +{ |
| 42 | + enum tracefs_tracers t = TRACEFS_TRACER_NOP; |
| 43 | + int retval; |
| 44 | + |
| 45 | + retval = tracefs_tracer_set(inst, t); |
| 46 | + if (retval < 0) |
| 47 | + err_msg("oops, error disabling tracer\n"); |
| 48 | +} |
| 49 | + |
| 50 | +/* |
| 51 | + * create_instance - create a trace instance with *instance_name |
| 52 | + */ |
| 53 | +struct tracefs_instance *create_instance(char *instance_name) |
| 54 | +{ |
| 55 | + return tracefs_instance_create(instance_name); |
| 56 | +} |
| 57 | + |
| 58 | +/* |
| 59 | + * destroy_instance - remove a trace instance and free the data |
| 60 | + */ |
| 61 | +void destroy_instance(struct tracefs_instance *inst) |
| 62 | +{ |
| 63 | + tracefs_instance_destroy(inst); |
| 64 | + tracefs_instance_free(inst); |
| 65 | +} |
| 66 | + |
| 67 | +/* |
| 68 | + * save_trace_to_file - save the trace output of the instance to the file |
| 69 | + */ |
| 70 | +int save_trace_to_file(struct tracefs_instance *inst, const char *filename) |
| 71 | +{ |
| 72 | + const char *file = "trace"; |
| 73 | + mode_t mode = 0644; |
| 74 | + char buffer[4096]; |
| 75 | + int out_fd, in_fd; |
| 76 | + int retval = -1; |
| 77 | + |
| 78 | + in_fd = tracefs_instance_file_open(inst, file, O_RDONLY); |
| 79 | + if (in_fd < 0) { |
| 80 | + err_msg("Failed to open trace file\n"); |
| 81 | + return -1; |
| 82 | + } |
| 83 | + |
| 84 | + out_fd = creat(filename, mode); |
| 85 | + if (out_fd < 0) { |
| 86 | + err_msg("Failed to create output file %s\n", filename); |
| 87 | + goto out_close_in; |
| 88 | + } |
| 89 | + |
| 90 | + do { |
| 91 | + retval = read(in_fd, buffer, sizeof(buffer)); |
| 92 | + if (retval <= 0) |
| 93 | + goto out_close; |
| 94 | + |
| 95 | + retval = write(out_fd, buffer, retval); |
| 96 | + if (retval < 0) |
| 97 | + goto out_close; |
| 98 | + } while (retval > 0); |
| 99 | + |
| 100 | + retval = 0; |
| 101 | +out_close: |
| 102 | + close(out_fd); |
| 103 | +out_close_in: |
| 104 | + close(in_fd); |
| 105 | + return retval; |
| 106 | +} |
| 107 | + |
| 108 | +/* |
| 109 | + * collect_registered_events - call the existing callback function for the event |
| 110 | + * |
| 111 | + * If an event has a registered callback function, call it. |
| 112 | + * Otherwise, ignore the event. |
| 113 | + */ |
| 114 | +int |
| 115 | +collect_registered_events(struct tep_event *event, struct tep_record *record, |
| 116 | + int cpu, void *context) |
| 117 | +{ |
| 118 | + struct trace_instance *trace = context; |
| 119 | + struct trace_seq *s = trace->seq; |
| 120 | + |
| 121 | + if (!event->handler) |
| 122 | + return 0; |
| 123 | + |
| 124 | + event->handler(s, record, event, context); |
| 125 | + |
| 126 | + return 0; |
| 127 | +} |
| 128 | + |
| 129 | +/* |
| 130 | + * trace_instance_destroy - destroy and free a rtla trace instance |
| 131 | + */ |
| 132 | +void trace_instance_destroy(struct trace_instance *trace) |
| 133 | +{ |
| 134 | + if (trace->inst) { |
| 135 | + disable_tracer(trace->inst); |
| 136 | + destroy_instance(trace->inst); |
| 137 | + } |
| 138 | + |
| 139 | + if (trace->seq) |
| 140 | + free(trace->seq); |
| 141 | + |
| 142 | + if (trace->tep) |
| 143 | + tep_free(trace->tep); |
| 144 | +} |
| 145 | + |
| 146 | +/* |
| 147 | + * trace_instance_init - create an rtla trace instance |
| 148 | + * |
| 149 | + * It is more than the tracefs instance, as it contains other |
| 150 | + * things required for the tracing, such as the local events and |
| 151 | + * a seq file. |
| 152 | + * |
| 153 | + * Note that the trace instance is returned disabled. This allows |
| 154 | + * the tool to apply some other configs, like setting priority |
| 155 | + * to the kernel threads, before starting generating trace entries. |
| 156 | + */ |
| 157 | +int trace_instance_init(struct trace_instance *trace, char *tool_name) |
| 158 | +{ |
| 159 | + trace->seq = calloc(1, sizeof(*trace->seq)); |
| 160 | + if (!trace->seq) |
| 161 | + goto out_err; |
| 162 | + |
| 163 | + trace_seq_init(trace->seq); |
| 164 | + |
| 165 | + trace->inst = create_instance(tool_name); |
| 166 | + if (!trace->inst) |
| 167 | + goto out_err; |
| 168 | + |
| 169 | + trace->tep = tracefs_local_events(NULL); |
| 170 | + if (!trace->tep) |
| 171 | + goto out_err; |
| 172 | + |
| 173 | + /* |
| 174 | + * Let the main enable the record after setting some other |
| 175 | + * things such as the priority of the tracer's threads. |
| 176 | + */ |
| 177 | + tracefs_trace_off(trace->inst); |
| 178 | + |
| 179 | + return 0; |
| 180 | + |
| 181 | +out_err: |
| 182 | + trace_instance_destroy(trace); |
| 183 | + return 1; |
| 184 | +} |
| 185 | + |
| 186 | +/* |
| 187 | + * trace_instance_start - start tracing a given rtla instance |
| 188 | + */ |
| 189 | +int trace_instance_start(struct trace_instance *trace) |
| 190 | +{ |
| 191 | + return tracefs_trace_on(trace->inst); |
| 192 | +} |
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