libbpf_0_6_1: Apply patch to keep compatiblity with legacy kernels

This is needed for composite actions with conditional steps.

Fixes #416.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>

src/libbpf.c

@@ -812,6 +812,93 @@ bpf_object__add_programs(struct bpf_object *obj, Elf_Data *sec_data,
 	return 0;
 }
 
+static __u32 choose_specific_version0(int fd, __u32 current)
+{
+	char ver[256];
+	__u32 v_major, v_minor, v_patch;
+	ssize_t len = read(fd, ver, sizeof(ver));
+	if (len < 0) {
+		return 0;
+	}
+	ver[len] = '\0';
+
+	char *first = strchr(ver, ' ');
+	if (!first) {
+		return 0;
+	}
+
+	first++;
+	char *version = strchr(first, ' ');
+	if (!version) {
+		return 0;
+	}
+
+	version++;
+	if (sscanf(version, "%u.%u.%u", &v_major, &v_minor, &v_patch) != 3)
+		return current;
+
+	return KERNEL_VERSION(v_major, v_minor, v_patch);
+}
+
+static __u32 choose_kernel_version(__u32 current)
+{
+	FILE *fp_d = fopen("/etc/debian_version","r");
+	int fp_u = open("/proc/version_signature", O_RDONLY);
+	FILE *fp_rh = fopen("/etc/redhat-release","r");
+	char tmp[32];
+	int de = 0;
+	__u32 ret;
+
+	if (!fp_d && !fp_rh && fp_u == -1)
+		return current;
+
+	struct utsname u;
+	uname(&u);
+
+	if (fp_d) {
+		fclose(fp_d);
+		de = 1;
+	}
+
+	if (fp_rh) {
+		fclose(fp_rh);
+		de = 0;
+	}
+
+	if ( fp_u > 0 ) {
+		ret = choose_specific_version0(fp_u, current);
+		close(fp_u);
+		return (!ret)?current:ret;
+	}
+
+	__u32 v_kernel,v_major, v_minor, v_patch;
+	__u32 r_kernel,r_major, r_minor, r_patch;
+
+	if (sscanf(u.release, "%u.%u.%u-%u", &v_kernel, &v_major, &v_minor, &v_patch) != 4)
+		return current;
+
+	int length = snprintf(tmp, 31, "%u.%u", v_kernel, v_major);
+	tmp[length] = '\0';
+
+	char *parse = strstr(u.version, tmp);
+	if (!parse) {
+		return current;
+	}
+
+	char *space = strchr(parse, ' ');
+	if(space) {
+		length = (int)(space - parse);
+		strncpy(tmp, parse, (size_t)length);
+		tmp[length] = '\0';
+	}
+
+	if (sscanf(tmp, "%u.%u.%u-%u", &r_kernel, &r_major, &r_minor, &r_patch) != 4)
+		return current;
+
+	ret = (de)?KERNEL_VERSION(r_kernel, r_major, r_minor):KERNEL_VERSION(r_kernel, r_major, r_minor) + r_patch;
+	return (ret > current)?ret:current;
+}
+
 static __u32 get_kernel_version(void)
 {
 	__u32 major, minor, patch;
@@ -820,7 +907,11 @@ static __u32 get_kernel_version(void)
 	uname(&info);
 	if (sscanf(info.release, "%u.%u.%u", &major, &minor, &patch) != 3)
 		return 0;
-	return KERNEL_VERSION(major, minor, patch);
+
+	if (major < 5)
+		return choose_kernel_version(KERNEL_VERSION(major, minor, patch));
+        else
+		return KERNEL_VERSION(major, minor, patch);
 }
 
 static const struct btf_member *

travis-ci/vmtest/s390x-self-hosted-builder/README.md

@@ -62,8 +62,8 @@ $ sudo systemctl restart actions-runner-libbpf
 The `actions-runner-libbpf` service stores various temporary data, such as
 runner  registration information, work directories and logs, in the
 `actions-runner-libbpf` volume. In order to remove it and start from scratch,
-e.g. when switching the runner to a different repository, use the following
+e.g. when upgrading the runner or switching it to a different repository, use
-commands:
+the following commands:
 
 ```
 $ sudo systemctl stop actions-runner-libbpf

travis-ci/vmtest/s390x-self-hosted-builder/actions-runner-libbpf.Dockerfile

@@ -33,13 +33,14 @@ RUN ln -fs /etc/resolv.conf /usr/x86_64-linux-gnu/etc/
 ENV QEMU_LD_PREFIX=/usr/x86_64-linux-gnu
 
 # amd64 Github Actions Runner.
+ARG version=2.285.0
 RUN useradd -m actions-runner
 RUN echo "actions-runner ALL=(ALL) NOPASSWD: ALL" >>/etc/sudoers
 RUN echo "Defaults env_keep += \"DEBIAN_FRONTEND\"" >>/etc/sudoers
 USER actions-runner
 ENV USER=actions-runner
 WORKDIR /home/actions-runner
-RUN curl -L https://github.com/actions/runner/releases/download/v2.283.2/actions-runner-linux-x64-2.283.2.tar.gz | tar -xz
+RUN curl -L https://github.com/actions/runner/releases/download/v${version}/actions-runner-linux-x64-${version}.tar.gz | tar -xz
 VOLUME /home/actions-runner
 
 # Scripts.