This patch modifies `bpftool map dump [-j|-p] id <map-id>` to json-
print and pretty-json-print map dump. It calls btf_dumper introduced in
previous patch to accomplish this.
The patch only prints debug info when -j or -p flags are supplied. Then
too, if the map has associated btf data loaded. Otherwise the usual
debug-less output is printed.
Signed-off-by: Okash Khawaja <o...@fb.com>
Acked-by: Martin KaFai Lau <ka...@fb.com>
---
tools/bpf/bpftool/map.c | 94 ++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 91 insertions(+), 3 deletions(-)
--- a/tools/bpf/bpftool/map.c
+++ b/tools/bpf/bpftool/map.c
@@ -43,9 +43,13 @@
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
+#include <linux/err.h>
#include <bpf.h>
+#include "json_writer.h"
+#include "btf.h"
+#include "btf_dumper.h"
#include "main.h"
static const char * const map_type_name[] = {
@@ -508,6 +512,83 @@ static int do_show(int argc, char **argv
return errno == ENOENT ? 0 : -1;
}
+
+static int do_dump_btf(struct btf *btf, struct bpf_map_info *map_info,
+ void *key, void *value)
+{
+ int ret;
+
+ jsonw_start_object(json_wtr);
+ jsonw_name(json_wtr, "key");
+
+ ret = btf_dumper_type(btf, json_wtr, map_info->btf_key_type_id, key);
+ if (ret)
+ goto out;
+
+ jsonw_end_object(json_wtr);
+
+ jsonw_start_object(json_wtr);
+ jsonw_name(json_wtr, "value");
+
+ ret = btf_dumper_type(btf, json_wtr, map_info->btf_value_type_id,
+ value);
+
+out:
+ /* end of root object */
+ jsonw_end_object(json_wtr);
+
+ return ret;
+}
+
+static struct btf *get_btf(struct bpf_map_info *map_info)
+{
+ int btf_fd = bpf_btf_get_fd_by_id(map_info->btf_id);
+ struct bpf_btf_info btf_info = { 0 };
+ __u32 len = sizeof(btf_info);
+ uint32_t last_size;
+ int err;
+ struct btf *btf = NULL;
+ void *ptr = NULL, *temp_ptr;
+
+ if (btf_fd < 0)
+ return NULL;
+
+ btf_info.btf_size = 4096;
+ do {
+ last_size = btf_info.btf_size;
+ temp_ptr = realloc(ptr, last_size);
+ if (!temp_ptr) {
+ p_err("unable allocate memory for debug info.");
+ goto exit_free;
+ }
+
+ ptr = temp_ptr;
+ bzero(ptr, last_size);
+ btf_info.btf = ptr_to_u64(ptr);
+ err = bpf_obj_get_info_by_fd(btf_fd, &btf_info, &len);
+ } while (!err && btf_info.btf_size > last_size && last_size == 4096);
+
+ if (err || btf_info.btf_size > last_size) {
+ p_info("can't get btf info. debug info won't be displayed.
error: %s",
+ err ? strerror(errno) : "exceeds size retry");
+ goto exit_free;
+ }
+
+ btf = btf__new((uint8_t *) btf_info.btf,
+ btf_info.btf_size, NULL);
+ if (IS_ERR(btf)) {
+ printf("error when initialising btf: %s\n",
+ strerror(PTR_ERR(btf)));
+ btf = NULL;
+ }
+
+exit_free:
+ close(btf_fd);
+ free(ptr);
+
+ return btf;
+}
+
static int do_dump(int argc, char **argv)
{
void *key, *value, *prev_key;
@@ -516,6 +597,7 @@ static int do_dump(int argc, char **argv
__u32 len = sizeof(info);
int err;
int fd;
+ struct btf *btf = NULL;
if (argc != 2)
usage();
@@ -538,6 +620,8 @@ static int do_dump(int argc, char **argv
goto exit_free;
}
+ btf = get_btf(&info);
+
prev_key = NULL;
if (json_output)
jsonw_start_array(json_wtr);
@@ -550,9 +634,12 @@ static int do_dump(int argc, char **argv
}
if (!bpf_map_lookup_elem(fd, key, value)) {
- if (json_output)
- print_entry_json(&info, key, value);
- else
+ if (json_output) {
+ if (btf)
+ do_dump_btf(btf, &info, key, value);
+ else
+ print_entry_json(&info, key, value);
+ } else
print_entry_plain(&info, key, value);
} else {
if (json_output) {
@@ -584,6 +671,7 @@ exit_free:
free(key);
free(value);
close(fd);
+ btf__free(btf);
return err;
}
