perf symbols: Add interface to read DSO image data

Adding following interface for DSO object to allow
reading of DSO image data:

  dso__data_fd
    - opens DSO and returns file descriptor
      Binary types are used to locate/open DSO in following order:
        DSO_BINARY_TYPE__BUILD_ID_CACHE
        DSO_BINARY_TYPE__SYSTEM_PATH_DSO
      In other word we first try to open DSO build-id path,
      and if that fails we try to open DSO system path.

  dso__data_read_offset
    - reads DSO data from specified offset

  dso__data_read_addr
    - reads DSO data from specified address/map.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Arun Sharma <asharma@fb.com>
Cc: Benjamin Redelings <benjamin.redelings@nescent.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Ulrich Drepper <drepper@gmail.com>
Link: http://lkml.kernel.org/r/1342959280-5361-11-git-send-email-jolsa@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

2 files changed, 117 insertions, 0 deletions

diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 60677a63bc7d..8131949d10f3 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -65,6 +65,14 @@ static enum dso_binary_type binary_type_symtab[] = {
 
 #define DSO_BINARY_TYPE__SYMTAB_CNT sizeof(binary_type_symtab)
 
+static enum dso_binary_type binary_type_data[] = {
+        DSO_BINARY_TYPE__BUILD_ID_CACHE,
+        DSO_BINARY_TYPE__SYSTEM_PATH_DSO,
+        DSO_BINARY_TYPE__NOT_FOUND,
+};
+
+#define DSO_BINARY_TYPE__DATA_CNT sizeof(binary_type_data)
+
 int dso__name_len(const struct dso *dso)
 {
         if (!dso)
@@ -336,6 +344,7 @@ struct dso *dso__new(const char *name)
                 for (i = 0; i < MAP__NR_TYPES; ++i)
                         dso->symbols[i] = dso->symbol_names[i] = RB_ROOT;
                 dso->symtab_type = DSO_BINARY_TYPE__NOT_FOUND;
+                dso->data_type   = DSO_BINARY_TYPE__NOT_FOUND;
                 dso->loaded = 0;
                 dso->sorted_by_name = 0;
                 dso->has_build_id = 0;
@@ -2953,3 +2962,103 @@ struct map *dso__new_map(const char *name)
 
         return map;
 }
+
+static int open_dso(struct dso *dso, struct machine *machine)
+{
+        char *root_dir = (char *) "";
+        char *name;
+        int fd;
+
+        name = malloc(PATH_MAX);
+        if (!name)
+                return -ENOMEM;
+
+        if (machine)
+                root_dir = machine->root_dir;
+
+        if (dso__binary_type_file(dso, dso->data_type,
+                                  root_dir, name, PATH_MAX)) {
+                free(name);
+                return -EINVAL;
+        }
+
+        fd = open(name, O_RDONLY);
+        free(name);
+        return fd;
+}
+
+int dso__data_fd(struct dso *dso, struct machine *machine)
+{
+        int i = 0;
+
+        if (dso->data_type != DSO_BINARY_TYPE__NOT_FOUND)
+                return open_dso(dso, machine);
+
+        do {
+                int fd;
+
+                dso->data_type = binary_type_data[i++];
+
+                fd = open_dso(dso, machine);
+                if (fd >= 0)
+                        return fd;
+
+        } while (dso->data_type != DSO_BINARY_TYPE__NOT_FOUND);
+
+        return -EINVAL;
+}
+
+static ssize_t dso_cache_read(struct dso *dso __used, u64 offset __used,
+                              u8 *data __used, ssize_t size __used)
+{
+        return -EINVAL;
+}
+
+static int dso_cache_add(struct dso *dso __used, u64 offset __used,
+                         u8 *data __used, ssize_t size __used)
+{
+        return 0;
+}
+
+static ssize_t read_dso_data(struct dso *dso, struct machine *machine,
+                     u64 offset, u8 *data, ssize_t size)
+{
+        ssize_t rsize = -1;
+        int fd;
+
+        fd = dso__data_fd(dso, machine);
+        if (fd < 0)
+                return -1;
+
+        do {
+                if (-1 == lseek(fd, offset, SEEK_SET))
+                        break;
+
+                rsize = read(fd, data, size);
+                if (-1 == rsize)
+                        break;
+
+                if (dso_cache_add(dso, offset, data, size))
+                        pr_err("Failed to add data int dso cache.");
+
+        } while (0);
+
+        close(fd);
+        return rsize;
+}
+
+ssize_t dso__data_read_offset(struct dso *dso, struct machine *machine,
+                              u64 offset, u8 *data, ssize_t size)
+{
+        if (dso_cache_read(dso, offset, data, size))
+                return read_dso_data(dso, machine, offset, data, size);
+        return 0;
+}
+
+ssize_t dso__data_read_addr(struct dso *dso, struct map *map,
+                            struct machine *machine, u64 addr,
+                            u8 *data, ssize_t size)
+{
+        u64 offset = map->map_ip(map, addr);
+        return dso__data_read_offset(dso, machine, offset, data, size);
+}
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index dc474f07bb2d..9b9ea00173af 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -189,6 +189,7 @@ struct dso {
         enum dso_kernel_type    kernel;
         enum dso_swap_type      needs_swap;
         enum dso_binary_type    symtab_type;
+        enum dso_binary_type    data_type;
         u8               adjust_symbols:1;
         u8               has_build_id:1;
         u8               hit:1;
@@ -306,4 +307,11 @@ size_t machine__fprintf_vmlinux_path(struct machine *machine, FILE *fp);
 
 int dso__binary_type_file(struct dso *dso, enum dso_binary_type type,
                           char *root_dir, char *file, size_t size);
+
+int dso__data_fd(struct dso *dso, struct machine *machine);
+ssize_t dso__data_read_offset(struct dso *dso, struct machine *machine,
+                              u64 offset, u8 *data, ssize_t size);
+ssize_t dso__data_read_addr(struct dso *dso, struct map *map,
+                            struct machine *machine, u64 addr,
+                            u8 *data, ssize_t size);
 #endif /* __PERF_SYMBOL */