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-rw-r--r--samples/bpf/bpf_load.c33
1 files changed, 24 insertions, 9 deletions
diff --git a/samples/bpf/bpf_load.c b/samples/bpf/bpf_load.c
index 5c052b9ea63f..434ea34a5954 100644
--- a/samples/bpf/bpf_load.c
+++ b/samples/bpf/bpf_load.c
@@ -54,6 +54,23 @@ static int populate_prog_array(const char *event, int prog_fd)
return 0;
}
+static int write_kprobe_events(const char *val)
+{
+ int fd, ret, flags;
+
+ if ((val != NULL) && (val[0] == '\0'))
+ flags = O_WRONLY | O_TRUNC;
+ else
+ flags = O_WRONLY | O_APPEND;
+
+ fd = open("/sys/kernel/debug/tracing/kprobe_events", flags);
+
+ ret = write(fd, val, strlen(val));
+ close(fd);
+
+ return ret;
+}
+
static int load_and_attach(const char *event, struct bpf_insn *prog, int size)
{
bool is_socket = strncmp(event, "socket", 6) == 0;
@@ -165,10 +182,9 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size)
#ifdef __x86_64__
if (strncmp(event, "sys_", 4) == 0) {
- snprintf(buf, sizeof(buf),
- "echo '%c:__x64_%s __x64_%s' >> /sys/kernel/debug/tracing/kprobe_events",
- is_kprobe ? 'p' : 'r', event, event);
- err = system(buf);
+ snprintf(buf, sizeof(buf), "%c:__x64_%s __x64_%s",
+ is_kprobe ? 'p' : 'r', event, event);
+ err = write_kprobe_events(buf);
if (err >= 0) {
need_normal_check = false;
event_prefix = "__x64_";
@@ -176,10 +192,9 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size)
}
#endif
if (need_normal_check) {
- snprintf(buf, sizeof(buf),
- "echo '%c:%s %s' >> /sys/kernel/debug/tracing/kprobe_events",
- is_kprobe ? 'p' : 'r', event, event);
- err = system(buf);
+ snprintf(buf, sizeof(buf), "%c:%s %s",
+ is_kprobe ? 'p' : 'r', event, event);
+ err = write_kprobe_events(buf);
if (err < 0) {
printf("failed to create kprobe '%s' error '%s'\n",
event, strerror(errno));
@@ -519,7 +534,7 @@ static int do_load_bpf_file(const char *path, fixup_map_cb fixup_map)
return 1;
/* clear all kprobes */
- i = system("echo \"\" > /sys/kernel/debug/tracing/kprobe_events");
+ i = write_kprobe_events("");
/* scan over all elf sections to get license and map info */
for (i = 1; i < ehdr.e_shnum; i++) {