pkg/global: add the ability to call setrlimit(2) on startup

Recent versions of Go changed the logic for setting RLIMIT_NOFILE as
part of child processes:

https://go-review.googlesource.com/c/go/+/476097

This might cause build actions to run into file descriptor limits. Let's
solve this by adding the ability to override resource limits in
bb_runner's configuration.

pkg/global/BUILD.bazel

@@ -4,6 +4,11 @@ go_library(
     name = "global",
     srcs = [
         "apply_configuration.go",
+        "resource_limits_darwin.go",
+        "resource_limits_freebsd.go",
+        "resource_limits_linux.go",
+        "resource_limits_nonunix.go",
+        "resource_limits_unix.go",
         "umask_nonunix.go",
         "umask_unix.go",
     ],
@@ -36,5 +41,27 @@ go_library(
         "@org_golang_google_grpc//:go_default_library",
         "@org_golang_google_grpc//codes",
         "@org_golang_google_grpc//status",
-    ],
+    ] + select({
+        "@io_bazel_rules_go//go/platform:android": [
+            "@org_golang_google_protobuf//types/known/wrapperspb",
+            "@org_golang_x_sys//unix",
+        ],
+        "@io_bazel_rules_go//go/platform:darwin": [
+            "@org_golang_google_protobuf//types/known/wrapperspb",
+            "@org_golang_x_sys//unix",
+        ],
+        "@io_bazel_rules_go//go/platform:freebsd": [
+            "@org_golang_google_protobuf//types/known/wrapperspb",
+            "@org_golang_x_sys//unix",
+        ],
+        "@io_bazel_rules_go//go/platform:ios": [
+            "@org_golang_google_protobuf//types/known/wrapperspb",
+            "@org_golang_x_sys//unix",
+        ],
+        "@io_bazel_rules_go//go/platform:linux": [
+            "@org_golang_google_protobuf//types/known/wrapperspb",
+            "@org_golang_x_sys//unix",
+        ],
+        "//conditions:default": [],
+    }),
 )

pkg/global/apply_configuration.go

@@ -90,6 +90,13 @@ func ApplyConfiguration(configuration *pb.Configuration) (*LifecycleState, bb_gr
 		}
 	}
 
+	// Set resource limits, if provided.
+	for name, resourceLimit := range configuration.GetSetResourceLimits() {
+		if err := setResourceLimit(name, resourceLimit); err != nil {
+			return nil, nil, util.StatusWrapf(err, "Failed to set resource limit %#v", name)
+		}
+	}
+
 	// Logging.
 	logPaths := configuration.GetLogPaths()
 	logWriters := append(make([]io.Writer, 0, len(logPaths)+1), os.Stderr)

pkg/global/resource_limits_darwin.go

@@ -0,0 +1,23 @@
+//go:build darwin
+// +build darwin
+
+package global
+
+import (
+	"golang.org/x/sys/unix"
+)
+
+var resourceLimitNames = map[string]int{
+	"AS":      unix.RLIMIT_AS,
+	"CORE":    unix.RLIMIT_CORE,
+	"CPU":     unix.RLIMIT_CPU,
+	"DATA":    unix.RLIMIT_DATA,
+	"FSIZE":   unix.RLIMIT_FSIZE,
+	"MEMLOCK": unix.RLIMIT_MEMLOCK,
+	"NOFILE":  unix.RLIMIT_NOFILE,
+	"NPROC":   unix.RLIMIT_NPROC,
+	"RSS":     unix.RLIMIT_RSS,
+	"STACK":   unix.RLIMIT_STACK,
+}
+
+type resourceLimitValueType = uint64

pkg/global/resource_limits_freebsd.go

@@ -0,0 +1,23 @@
+//go:build freebsd
+// +build freebsd
+
+package global
+
+import (
+	"golang.org/x/sys/unix"
+)
+
+var resourceLimitNames = map[string]int{
+	"AS":      unix.RLIMIT_AS,
+	"CORE":    unix.RLIMIT_CORE,
+	"CPU":     unix.RLIMIT_CPU,
+	"DATA":    unix.RLIMIT_DATA,
+	"FSIZE":   unix.RLIMIT_FSIZE,
+	"MEMLOCK": unix.RLIMIT_MEMLOCK,
+	"NOFILE":  unix.RLIMIT_NOFILE,
+	"NPROC":   unix.RLIMIT_NPROC,
+	"RSS":     unix.RLIMIT_RSS,
+	"STACK":   unix.RLIMIT_STACK,
+}
+
+type resourceLimitValueType = int64

pkg/global/resource_limits_linux.go

@@ -0,0 +1,18 @@
+//go:build linux
+// +build linux
+
+package global
+
+import (
+	"golang.org/x/sys/unix"
+)
+
+var resourceLimitNames = map[string]int{
+	"AS":      unix.RLIMIT_AS,
+	"MEMLOCK": unix.RLIMIT_MEMLOCK,
+	"NOFILE":  unix.RLIMIT_NOFILE,
+	"NPROC":   unix.RLIMIT_NPROC,
+	"RSS":     unix.RLIMIT_RSS,
+}
+
+type resourceLimitValueType = uint64

pkg/global/resource_limits_nonunix.go

@@ -0,0 +1,15 @@
+//go:build windows
+// +build windows
+
+package global
+
+import (
+	"github.com/buildbarn/bb-storage/pkg/proto/configuration/global"
+
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+)
+
+func setResourceLimit(name string, resourceLimit *global.SetResourceLimitConfiguration) error {
+	return status.Error(codes.Unimplemented, "Resource limits cannot be adjusted on this operating system")
+}

pkg/global/resource_limits_unix.go

@@ -0,0 +1,35 @@
+//go:build darwin || freebsd || linux
+// +build darwin freebsd linux
+
+package global
+
+import (
+	"github.com/buildbarn/bb-storage/pkg/proto/configuration/global"
+
+	"golang.org/x/sys/unix"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+	"google.golang.org/protobuf/types/known/wrapperspb"
+)
+
+func convertResourceLimitValue(limit *wrapperspb.UInt64Value) resourceLimitValueType {
+	if limit == nil {
+		// No limit provided. Assume infinity.
+		return unix.RLIM_INFINITY
+	}
+	return resourceLimitValueType(limit.Value)
+}
+
+// setResourceLimit applies a single resource limit that is provided in
+// the configuration file against the current process using
+// setrlimit(2).
+func setResourceLimit(name string, resourceLimit *global.SetResourceLimitConfiguration) error {
+	resource, ok := resourceLimitNames[name]
+	if !ok {
+		return status.Error(codes.InvalidArgument, "Resource name is not supported by this operating system")
+	}
+	return unix.Setrlimit(resource, &unix.Rlimit{
+		Cur: convertResourceLimitValue(resourceLimit.SoftLimit),
+		Max: convertResourceLimitValue(resourceLimit.HardLimit),
+	})
+}

pkg/proto/configuration/global/BUILD.bazel

@@ -18,6 +18,7 @@ proto_library(
         "//pkg/proto/configuration/http:http_proto",
         "@com_google_protobuf//:duration_proto",
         "@com_google_protobuf//:empty_proto",
+        "@com_google_protobuf//:wrappers_proto",
         "@io_opentelemetry_proto//:common_proto",
     ],
 )