X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=src%2Fbin%2Flttng-sessiond%2Fkernel.c;h=6eeb9b5b1b7824802bb2da554999ca2a46e26bce;hb=8936c33a1a322904bd631caff22358a0bb791cf5;hp=afa5e604fbefff9a9a2465fb5809cfe884d19f60;hpb=db7586006bc1a2b9057a2c108bf1e7d20fd6903f;p=lttng-tools.git

diff --git a/src/bin/lttng-sessiond/kernel.c b/src/bin/lttng-sessiond/kernel.c
index afa5e604f..6eeb9b5b1 100644
--- a/src/bin/lttng-sessiond/kernel.c
+++ b/src/bin/lttng-sessiond/kernel.c
@@ -28,6 +28,7 @@
 #include <common/kernel-ctl/kernel-ctl.h>
 
 #include "kernel.h"
+#include "kern-modules.h"
 
 /*
  * Add context on a kernel channel.
@@ -606,3 +607,65 @@ error_fp:
 error:
 	return -1;
 }
+
+/*
+ * Get kernel version and validate it.
+ */
+int kernel_validate_version(int tracer_fd)
+{
+	int ret;
+	struct lttng_kernel_tracer_version version;
+
+	ret = kernctl_tracer_version(tracer_fd, &version);
+	if (ret < 0) {
+		ERR("Failed at getting the lttng-modules version");
+		goto error;
+	}
+
+	/* Validate version */
+	if (version.version > KERN_MODULES_VERSION) {
+		goto error_version;
+	}
+
+	DBG2("Kernel tracer version validated (major version %d)", version.version);
+	return 0;
+
+error_version:
+	ERR("Kernel major version %d is not compatible (supporting <= %d)",
+			version.version, KERN_MODULES_VERSION)
+	ret = -1;
+
+error:
+	return ret;
+}
+
+/*
+ * Kernel work-arounds called at the start of sessiond main().
+ */
+int init_kernel_workarounds(void)
+{
+	int ret;
+	FILE *fp;
+
+	/*
+	 * boot_id needs to be read once before being used concurrently
+	 * to deal with a Linux kernel race. A fix is proposed for
+	 * upstream, but the work-around is needed for older kernels.
+	 */
+	fp = fopen("/proc/sys/kernel/random/boot_id", "r");
+	if (!fp) {
+		goto end_boot_id;
+	}
+	while (!feof(fp)) {
+		char buf[37] = "";
+
+		ret = fread(buf, 1, sizeof(buf), fp);
+		if (ret < 0) {
+			/* Ignore error, we don't really care */
+		}
+	}
+	fclose(fp);
+end_boot_id:
+
+	return 0;
+}