On 2/4/21 12:50 PM, Song Liu wrote:
The test dumps information similar to /proc/pid/maps. The first line of
the output is compared against the /proc file to make sure they match.
Signed-off-by: Song Liu <songliubraving@xxxxxx>
---
.../selftests/bpf/prog_tests/bpf_iter.c | 114 ++++++++++++++++--
tools/testing/selftests/bpf/progs/bpf_iter.h | 8 ++
.../selftests/bpf/progs/bpf_iter_task_vma.c | 58 +++++++++
3 files changed, 170 insertions(+), 10 deletions(-)
create mode 100644 tools/testing/selftests/bpf/progs/bpf_iter_task_vma.c
diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
index 0e586368948dd..9e8027685e859 100644
--- a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
@@ -7,6 +7,7 @@
#include "bpf_iter_task.skel.h"
#include "bpf_iter_task_stack.skel.h"
#include "bpf_iter_task_file.skel.h"
+#include "bpf_iter_task_vma.skel.h"
#include "bpf_iter_task_btf.skel.h"
#include "bpf_iter_tcp4.skel.h"
#include "bpf_iter_tcp6.skel.h"
@@ -64,6 +65,22 @@ static void do_dummy_read(struct bpf_program *prog)
bpf_link__destroy(link);
}
+static int read_fd_into_buffer(int fd, char *buf, int size)
+{
+ int bufleft = size;
+ int len;
+
+ do {
+ len = read(fd, buf, bufleft);
+ if (len > 0) {
+ buf += len;
+ bufleft -= len;
+ }
+ } while (len > 0);
+
+ return len < 0 ? len : size - bufleft;
+}
+
static void test_ipv6_route(void)
{
struct bpf_iter_ipv6_route *skel;
@@ -177,7 +194,7 @@ static int do_btf_read(struct bpf_iter_task_btf *skel)
{
struct bpf_program *prog = skel->progs.dump_task_struct;
struct bpf_iter_task_btf__bss *bss = skel->bss;
- int iter_fd = -1, len = 0, bufleft = TASKBUFSZ;
+ int iter_fd = -1, err;
struct bpf_link *link;
char *buf = taskbuf;
int ret = 0;
@@ -190,14 +207,7 @@ static int do_btf_read(struct bpf_iter_task_btf *skel)
if (CHECK(iter_fd < 0, "create_iter", "create_iter failed\n"))
goto free_link;
- do {
- len = read(iter_fd, buf, bufleft);
- if (len > 0) {
- buf += len;
- bufleft -= len;
- }
- } while (len > 0);
-
+ err = read_fd_into_buffer(iter_fd, buf, TASKBUFSZ);
if (bss->skip) {
printf("%s:SKIP:no __builtin_btf_type_id\n", __func__);
ret = 1;
@@ -205,7 +215,7 @@ static int do_btf_read(struct bpf_iter_task_btf *skel)
goto free_link;
}
- if (CHECK(len < 0, "read", "read failed: %s\n", strerror(errno)))
+ if (CHECK(err < 0, "read", "read failed: %s\n", strerror(errno)))
goto free_link;
CHECK(strstr(taskbuf, "(struct task_struct)") == NULL,
@@ -1133,6 +1143,88 @@ static void test_buf_neg_offset(void)
bpf_iter_test_kern6__destroy(skel);
}
+#define CMP_BUFFER_SIZE 1024
+static char task_vma_output[CMP_BUFFER_SIZE];
+static char proc_maps_output[CMP_BUFFER_SIZE];
+
+/* remove \0 and \t from str, and only keep the first line */
+static void str_strip_first_line(char *str)
+{
+ char *dst = str, *src = str;
+
+ do {
+ if (*src == ' ' || *src == '\t')
+ src++;
+ else
+ *(dst++) = *(src++);
+
+ } while (*src != '\0' && *src != '\n');
+
+ *dst = '\0';
+}
+
+#define min(a, b) ((a) < (b) ? (a) : (b))
+
+static void test_task_vma(void)
+{
+ int err, iter_fd = -1, proc_maps_fd = -1;
+ struct bpf_iter_task_vma *skel;
+ int len, read_size = 4;
+ char maps_path[64];
+
+ skel = bpf_iter_task_vma__open();
+ if (CHECK(!skel, "bpf_iter_task_vma__open", "skeleton open failed\n"))
+ return;
+
+ skel->bss->pid = getpid();
+
+ err = bpf_iter_task_vma__load(skel);
+ if (CHECK(err, "bpf_iter_task_vma__load", "skeleton load failed\n"))
+ goto out;
+
+ skel->links.proc_maps = bpf_program__attach_iter(
+ skel->progs.proc_maps, NULL);
+
+ if (CHECK(IS_ERR(skel->links.proc_maps), "bpf_program__attach_iter",
+ "attach iterator failed\n"))
+ goto out;
You need to set skel->links.proc_maps = NULL before goto out. Otherwise,
libbpf may segfault.
+
+ /* read CMP_BUFFER_SIZE (1kB) from bpf_iter */
This comment better right before
/* read in small chunks to trigger seq_file corner cases */
+ iter_fd = bpf_iter_create(bpf_link__fd(skel->links.proc_maps));
+ if (CHECK(iter_fd < 0, "create_iter", "create_iter failed\n"))
+ goto out;
+
+ /* read in small chunks to trigger seq_file corner cases */
+ len = 0;
+ while (len < CMP_BUFFER_SIZE) {
Some comment will be better to assure that we won't trigger infinite
loop here, e.g., err == 0 case.
+ err = read_fd_into_buffer(iter_fd, task_vma_output + len,
+ min(read_size, CMP_BUFFER_SIZE - len));
+ if (CHECK(err < 0, "read_iter_fd", "read_iter_fd failed\n"))
+ goto out;
+ len += err;
+ }
+
+ /* read CMP_BUFFER_SIZE (1kB) from /proc/pid/maps */
+ snprintf(maps_path, 64, "/proc/%u/maps", skel->bss->pid);
+ proc_maps_fd = open(maps_path, O_RDONLY);
+ if (CHECK(proc_maps_fd < 0, "open_proc_maps", "open_proc_maps failed\n"))
+ goto out;
+ err = read_fd_into_buffer(proc_maps_fd, proc_maps_output, CMP_BUFFER_SIZE);
+ if (CHECK(err < 0, "read_prog_maps_fd", "read_prog_maps_fd failed\n"))
+ goto out;
+
+ /* strip and compare the first line of the two files */
+ str_strip_first_line(task_vma_output);
+ str_strip_first_line(proc_maps_output);
+
+ CHECK(strcmp(task_vma_output, proc_maps_output), "compare_output",
+ "found mismatch\n");
+out:
+ close(proc_maps_fd);
+ close(iter_fd);
+ bpf_iter_task_vma__destroy(skel);
+}
+
void test_bpf_iter(void)
{
if (test__start_subtest("btf_id_or_null"))
@@ -1149,6 +1241,8 @@ void test_bpf_iter(void)
test_task_stack();
if (test__start_subtest("task_file"))
test_task_file();
+ if (test__start_subtest("task_vma"))
+ test_task_vma();
if (test__start_subtest("task_btf"))
test_task_btf();
if (test__start_subtest("tcp4"))
diff --git a/tools/testing/selftests/bpf/progs/bpf_iter.h b/tools/testing/selftests/bpf/progs/bpf_iter.h
index 6a1255465fd6d..3d83b185c4bcb 100644
--- a/tools/testing/selftests/bpf/progs/bpf_iter.h
+++ b/tools/testing/selftests/bpf/progs/bpf_iter.h
[...]
