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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /tools/testing/selftests/bpf/urandom_read.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'tools/testing/selftests/bpf/urandom_read.c')
-rw-r--r--tools/testing/selftests/bpf/urandom_read.c88
1 files changed, 88 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/urandom_read.c b/tools/testing/selftests/bpf/urandom_read.c
new file mode 100644
index 000000000..e92644d0f
--- /dev/null
+++ b/tools/testing/selftests/bpf/urandom_read.c
@@ -0,0 +1,88 @@
+#include <stdbool.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <signal.h>
+
+#define _SDT_HAS_SEMAPHORES 1
+#include "sdt.h"
+
+#define SEC(name) __attribute__((section(name), used))
+
+#define BUF_SIZE 256
+
+/* defined in urandom_read_aux.c */
+void urand_read_without_sema(int iter_num, int iter_cnt, int read_sz);
+/* these are coming from urandom_read_lib{1,2}.c */
+void urandlib_read_with_sema(int iter_num, int iter_cnt, int read_sz);
+void urandlib_read_without_sema(int iter_num, int iter_cnt, int read_sz);
+
+unsigned short urand_read_with_sema_semaphore SEC(".probes");
+
+static __attribute__((noinline))
+void urandom_read(int fd, int count)
+{
+ char buf[BUF_SIZE];
+ int i;
+
+ for (i = 0; i < count; ++i) {
+ read(fd, buf, BUF_SIZE);
+
+ /* trigger USDTs defined in executable itself */
+ urand_read_without_sema(i, count, BUF_SIZE);
+ STAP_PROBE3(urand, read_with_sema, i, count, BUF_SIZE);
+
+ /* trigger USDTs defined in shared lib */
+ urandlib_read_without_sema(i, count, BUF_SIZE);
+ urandlib_read_with_sema(i, count, BUF_SIZE);
+ }
+}
+
+static volatile bool parent_ready;
+
+static void handle_sigpipe(int sig)
+{
+ parent_ready = true;
+}
+
+int main(int argc, char *argv[])
+{
+ int fd = open("/dev/urandom", O_RDONLY);
+ int count = 4;
+ bool report_pid = false;
+
+ if (fd < 0)
+ return 1;
+
+ if (argc >= 2)
+ count = atoi(argv[1]);
+ if (argc >= 3) {
+ report_pid = true;
+ /* install SIGPIPE handler to catch when parent closes their
+ * end of the pipe (on the other side of our stdout)
+ */
+ signal(SIGPIPE, handle_sigpipe);
+ }
+
+ /* report PID and wait for parent process to send us "signal" by
+ * closing stdout
+ */
+ if (report_pid) {
+ while (!parent_ready) {
+ fprintf(stdout, "%d\n", getpid());
+ fflush(stdout);
+ }
+ /* at this point stdout is closed, parent process knows our
+ * PID and is ready to trace us
+ */
+ }
+
+ urandom_read(fd, count);
+
+ close(fd);
+ return 0;
+}