2 files changed, 50 insertions, 15 deletions

diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index fbf6cc98b8a9..db634383156c 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -205,6 +205,7 @@ static void close_data_fd(struct dso *dso)
         if (dso->data.fd >= 0) {
                 close(dso->data.fd);
                 dso->data.fd = -1;
+                dso->data.file_size = 0;
                 dso__list_del(dso);
         }
 }
@@ -373,16 +374,10 @@ dso_cache__memcpy(struct dso_cache *cache, u64 offset,
 }
 
 static ssize_t
-dso_cache__read(struct dso *dso, struct machine *machine,
-                 u64 offset, u8 *data, ssize_t size)
+dso_cache__read(struct dso *dso, u64 offset, u8 *data, ssize_t size)
 {
         struct dso_cache *cache;
         ssize_t ret;
-        int fd;
-
-        fd = dso__data_fd(dso, machine);
-        if (fd < 0)
-                return -1;
 
         do {
                 u64 cache_offset;
@@ -396,10 +391,10 @@ dso_cache__read(struct dso *dso, struct machine *machine,
                 cache_offset = offset & DSO__DATA_CACHE_MASK;
                 ret = -EINVAL;
 
-                if (-1 == lseek(fd, cache_offset, SEEK_SET))
+                if (-1 == lseek(dso->data.fd, cache_offset, SEEK_SET))
                         break;
 
-                ret = read(fd, cache->data, DSO__DATA_CACHE_SIZE);
+                ret = read(dso->data.fd, cache->data, DSO__DATA_CACHE_SIZE);
                 if (ret <= 0)
                         break;
 
@@ -417,8 +412,8 @@ dso_cache__read(struct dso *dso, struct machine *machine,
         return ret;
 }
 
-static ssize_t dso_cache_read(struct dso *dso, struct machine *machine,
-                              u64 offset, u8 *data, ssize_t size)
+static ssize_t dso_cache_read(struct dso *dso, u64 offset,
+                              u8 *data, ssize_t size)
 {
         struct dso_cache *cache;
 
@@ -426,11 +421,10 @@ static ssize_t dso_cache_read(struct dso *dso, struct machine *machine,
         if (cache)
                 return dso_cache__memcpy(cache, offset, data, size);
         else
-                return dso_cache__read(dso, machine, offset, data, size);
+                return dso_cache__read(dso, offset, data, size);
 }
 
-ssize_t dso__data_read_offset(struct dso *dso, struct machine *machine,
-                              u64 offset, u8 *data, ssize_t size)
+static ssize_t cached_read(struct dso *dso, u64 offset, u8 *data, ssize_t size)
 {
         ssize_t r = 0;
         u8 *p = data;
@@ -438,7 +432,7 @@ ssize_t dso__data_read_offset(struct dso *dso, struct machine *machine,
         do {
                 ssize_t ret;
 
-                ret = dso_cache_read(dso, machine, offset, p, size);
+                ret = dso_cache_read(dso, offset, p, size);
                 if (ret < 0)
                         return ret;
 
@@ -458,6 +452,46 @@ ssize_t dso__data_read_offset(struct dso *dso, struct machine *machine,
         return r;
 }
 
+static int data_file_size(struct dso *dso)
+{
+        struct stat st;
+
+        if (!dso->data.file_size) {
+                if (fstat(dso->data.fd, &st)) {
+                        pr_err("dso mmap failed, fstat: %s\n", strerror(errno));
+                        return -1;
+                }
+                dso->data.file_size = st.st_size;
+        }
+
+        return 0;
+}
+
+static ssize_t data_read_offset(struct dso *dso, u64 offset,
+                                u8 *data, ssize_t size)
+{
+        if (data_file_size(dso))
+                return -1;
+
+        /* Check the offset sanity. */
+        if (offset > dso->data.file_size)
+                return -1;
+
+        if (offset + size < offset)
+                return -1;
+
+        return cached_read(dso, offset, data, size);
+}
+
+ssize_t dso__data_read_offset(struct dso *dso, struct machine *machine,
+                              u64 offset, u8 *data, ssize_t size)
+{
+        if (dso__data_fd(dso, machine) < 0)
+                return -1;
+
+        return data_read_offset(dso, offset, data, size);
+}
+
 ssize_t dso__data_read_addr(struct dso *dso, struct map *map,
                             struct machine *machine, u64 addr,
                             u8 *data, ssize_t size)
diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
index 90988bf06641..da47b13595f3 100644
--- a/tools/perf/util/dso.h
+++ b/tools/perf/util/dso.h
@@ -103,6 +103,7 @@ struct dso {
         struct {
                 struct rb_root   cache;
                 int              fd;
+                size_t           file_size;
                 struct list_head open_entry;
         } data;