[PATCH 08/15] perf, tool: Add interface to read DSO image data

From: Jiri Olsa
Date: Wed Mar 28 2012 - 08:37:08 EST


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 addres/map.

TODO:
Implement read cache. Currently following no-op hooks are added:
dso_cache_add/dso_cache_read to store/retrieve dso read data.

Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
---
tools/perf/util/symbol.c | 107 ++++++++++++++++++++++++++++++++++++++++++++++
tools/perf/util/symbol.h | 8 +++
2 files changed, 115 insertions(+), 0 deletions(-)

diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 49f7042..2b8fa4b 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 (verbose)
@@ -334,6 +342,7 @@ 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;
@@ -2822,3 +2831,101 @@ int machine__load_vmlinux_path(struct machine *machine, enum map_type type,

return ret;
}
+
+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))
+ 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 13c3618..b62321f 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -175,6 +175,7 @@ struct dso {
struct rb_root symbol_names[MAP__NR_TYPES];
enum dso_kernel_type kernel;
enum dso_binary_type symtab_type;
+ enum dso_binary_type data_type;
u8 adjust_symbols:1;
u8 has_build_id:1;
u8 hit:1;
@@ -269,4 +270,11 @@ 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 */
--
1.7.1

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