+int perf_header__process_sections(struct perf_header *self, int fd,
+ int (*process)(struct perf_file_section *self,
+ int feat, int fd))
+{
+ struct perf_file_section *feat_sec;
+ int nr_sections;
+ int sec_size;
+ int idx = 0;
+ int err = 0, feat = 1;
+
+ nr_sections = bitmap_weight(self->adds_features, HEADER_FEAT_BITS);
+ if (!nr_sections)
+ return 0;
+
+ feat_sec = calloc(sizeof(*feat_sec), nr_sections);
+ if (!feat_sec)
+ return -1;
+
+ sec_size = sizeof(*feat_sec) * nr_sections;
+
+ lseek(fd, self->data_offset + self->data_size, SEEK_SET);
+
+ do_read(fd, feat_sec, sec_size);
+
+ while (idx < nr_sections && feat < HEADER_LAST_FEATURE) {
+ if (perf_header__has_feat(self, feat)) {
+ struct perf_file_section *sec = &feat_sec[idx++];
+
+ err = process(sec, feat, fd);
+ if (err < 0)
+ break;
+ }
+ ++feat;
+ }
+
+ free(feat_sec);
+ return err;
+};
+
+int perf_file_header__read(struct perf_file_header *self,
+ struct perf_header *ph, int fd)
+{
+ lseek(fd, 0, SEEK_SET);
+ do_read(fd, self, sizeof(*self));
+
+ if (self->magic != PERF_MAGIC ||
+ self->attr_size != sizeof(struct perf_file_attr))
+ return -1;
+
+ if (self->size != sizeof(*self)) {
+ /* Support the previous format */
+ if (self->size == offsetof(typeof(*self), adds_features))
+ bitmap_zero(self->adds_features, HEADER_FEAT_BITS);
+ else
+ return -1;
+ }
+
+ memcpy(&ph->adds_features, &self->adds_features,
+ sizeof(self->adds_features));
+
+ ph->event_offset = self->event_types.offset;
+ ph->event_size = self->event_types.size;
+ ph->data_offset = self->data.offset;
+ ph->data_size = self->data.size;
+ return 0;
+}
+
+static int perf_file_section__process(struct perf_file_section *self,
+ int feat, int fd)
+{
+ if (lseek(fd, self->offset, SEEK_SET) < 0) {
+ pr_debug("Failed to lseek to %Ld offset for feature %d, "
+ "continuing...\n", self->offset, feat);
+ return 0;
+ }
+
+ switch (feat) {
+ case HEADER_TRACE_INFO:
+ trace_report(fd);
+ break;
+
+ case HEADER_BUILD_ID:
+ if (perf_header__read_build_ids(fd, self->offset, self->size))
+ pr_debug("Failed to read buildids, continuing...\n");
+ break;
+ default:
+ pr_debug("unknown feature %d, continuing...\n", feat);
+ }
+
+ return 0;
+}
+