perf tools: Generalize perf_header__adds_read()

Renaming it to perf_header__process_sections() and passing a
callback to handle each feature.

The next changesets will introduce 'perf buildid-list' that will
handle just the HEADER_BUILD_ID table, ignoring all the other
features.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <1258396365-29217-3-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 98 insertions, 56 deletions

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index ca0d657eefad..d8416f011179 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -128,26 +128,11 @@ static const char *__perf_magic = "PERFFILE";
 
 #define PERF_MAGIC      (*(u64 *)__perf_magic)
 
-struct perf_file_section {
-        u64 offset;
-        u64 size;
-};
-
 struct perf_file_attr {
         struct perf_event_attr  attr;
         struct perf_file_section        ids;
 };
 
-struct perf_file_header {
-        u64                             magic;
-        u64                             size;
-        u64                             attr_size;
-        struct perf_file_section        attrs;
-        struct perf_file_section        data;
-        struct perf_file_section        event_types;
-        DECLARE_BITMAP(adds_features, HEADER_FEAT_BITS);
-};
-
 void perf_header__set_feat(struct perf_header *self, int feat)
 {
         set_bit(feat, self->adds_features);
@@ -324,21 +309,23 @@ static void do_read(int fd, void *buf, size_t size)
         }
 }
 
-static void perf_header__adds_read(struct perf_header *self, int fd)
+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;
+                return 0;
 
         feat_sec = calloc(sizeof(*feat_sec), nr_sections);
         if (!feat_sec)
-                die("No memory");
+                return -1;
 
         sec_size = sizeof(*feat_sec) * nr_sections;
 
@@ -346,25 +333,73 @@ static void perf_header__adds_read(struct perf_header *self, int fd)
 
         do_read(fd, feat_sec, sec_size);
 
-        if (perf_header__has_feat(self, HEADER_TRACE_INFO)) {
-                struct perf_file_section *trace_sec;
+        while (idx < nr_sections && feat < HEADER_LAST_FEATURE) {
+                if (perf_header__has_feat(self, feat)) {
+                        struct perf_file_section *sec = &feat_sec[idx++];
 
-                trace_sec = &feat_sec[idx++];
-                lseek(fd, trace_sec->offset, SEEK_SET);
-                trace_report(fd);
+                        err = process(sec, feat, fd);
+                        if (err < 0)
+                                break;
+                }
+                ++feat;
         }
 
-        if (perf_header__has_feat(self, HEADER_BUILD_ID)) {
-                struct perf_file_section *buildid_sec;
+        free(feat_sec);
+        return err;
+};
 
-                buildid_sec = &feat_sec[idx++];
-                lseek(fd, buildid_sec->offset, SEEK_SET);
-                if (perf_header__read_build_ids(fd, buildid_sec->offset, buildid_sec->size))
-                        pr_debug("failed to read buildids, continuing...\n");
+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;
         }
 
-        free(feat_sec);
-};
+        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;
+}
 
 struct perf_header *perf_header__read(int fd)
 {
@@ -372,23 +407,11 @@ struct perf_header *perf_header__read(int fd)
         struct perf_file_header f_header;
         struct perf_file_attr   f_attr;
         u64                     f_id;
-
         int nr_attrs, nr_ids, i, j;
 
-        lseek(fd, 0, SEEK_SET);
-        do_read(fd, &f_header, sizeof(f_header));
-
-        if (f_header.magic      != PERF_MAGIC           ||
-            f_header.attr_size  != sizeof(f_attr))
+        if (perf_file_header__read(&f_header, self, fd) < 0)
                 die("incompatible file format");
 
-        if (f_header.size != sizeof(f_header)) {
-                /* Support the previous format */
-                if (f_header.size == offsetof(typeof(f_header), adds_features))
-                        bitmap_zero(f_header.adds_features, HEADER_FEAT_BITS);
-                else
-                        die("incompatible file format");
-        }
         nr_attrs = f_header.attrs.size / sizeof(f_attr);
         lseek(fd, f_header.attrs.offset, SEEK_SET);
 
@@ -422,15 +445,7 @@ struct perf_header *perf_header__read(int fd)
                 event_count =  f_header.event_types.size / sizeof(struct perf_trace_event_type);
         }
 
-        memcpy(&self->adds_features, &f_header.adds_features, sizeof(f_header.adds_features));
-
-        self->event_offset = f_header.event_types.offset;
-        self->event_size   = f_header.event_types.size;
-
-        self->data_offset = f_header.data.offset;
-        self->data_size   = f_header.data.size;
-
-        perf_header__adds_read(self, fd);
+        perf_header__process_sections(self, fd, perf_file_section__process);
 
         lseek(fd, self->data_offset, SEEK_SET);
 
diff --git a/tools/perf/util/header.h b/tools/perf/util/header.h
index a22d70b07571..f1b3bf7bdfc1 100644
--- a/tools/perf/util/header.h
+++ b/tools/perf/util/header.h
@@ -15,11 +15,34 @@ struct perf_header_attr {
         off_t id_offset;
 };
 
-#define HEADER_TRACE_INFO                       1
-#define HEADER_BUILD_ID                         2
+enum {
+        HEADER_TRACE_INFO = 1,
+        HEADER_BUILD_ID,
+        HEADER_LAST_FEATURE,
+};
 
 #define HEADER_FEAT_BITS                        256
 
+struct perf_file_section {
+        u64 offset;
+        u64 size;
+};
+
+struct perf_file_header {
+        u64                             magic;
+        u64                             size;
+        u64                             attr_size;
+        struct perf_file_section        attrs;
+        struct perf_file_section        data;
+        struct perf_file_section        event_types;
+        DECLARE_BITMAP(adds_features, HEADER_FEAT_BITS);
+};
+
+struct perf_header;
+
+int perf_file_header__read(struct perf_file_header *self,
+                           struct perf_header *ph, int fd);
+
 struct perf_header {
         int                     frozen;
         int                     attrs, size;
@@ -54,4 +77,8 @@ bool perf_header__has_feat(const struct perf_header *self, int feat);
 
 struct perf_header *perf_header__new(void);
 
+int perf_header__process_sections(struct perf_header *self, int fd,
+                                  int (*process)(struct perf_file_section *self,
+                                                 int feat, int fd));
+
 #endif /* __PERF_HEADER_H */