BPF FS: add support for multiple processes (#211)

* BPF FS: add support for multiple processes * add entry to changelog * fix checks * Update pkg/instrumentors/bpffs/bpfsfs.go Co-authored-by: Mike Goldsmith <[email protected]> * rollback Dockerfile --------- Co-authored-by: Mike Goldsmith <[email protected]>
open-telemetry · Jul 23, 2023 · 298c38b · 298c38b
1 parent 6cf75fd
commit 298c38b
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Showing 9 changed files with 59 additions and 26 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -22,6 +22,7 @@ OpenTelemetry Go Automatic Instrumentation adheres to [Semantic Versioning](http
 - Remove the HTTP path from span names in `net/http`, `gin-gonic/gin`, and `gorilla/mux` instrumentations. ([#161](https://github.com/open-telemetry/opentelemetry-go-instrumentation/pull/161))
 - Update generated offsets. ([#186](https://github.com/open-telemetry/opentelemetry-go-instrumentation/pull/186))
 - Reduce Docker image size by using different base image. ([#182](https://github.com/open-telemetry/opentelemetry-go-instrumentation/pull/182))
+- Support for multiple processes in BPF FS. ([#211](https://github.com/open-telemetry/opentelemetry-go-instrumentation/pull/211))
 
 ## [v0.2.1-alpha] - 2023-05-15
 

diff --git a/pkg/instrumentors/allocator/allocator_linux.go b/pkg/instrumentors/allocator/allocator_linux.go
@@ -15,10 +15,6 @@
 package allocator
 
 import (
- "os"
-
- "golang.org/x/sys/unix"
-
  "go.opentelemetry.io/auto/pkg/instrumentors/bpffs"
  "go.opentelemetry.io/auto/pkg/instrumentors/context"
  "go.opentelemetry.io/auto/pkg/log"
@@ -42,24 +38,10 @@ func (a *Allocator) Load(ctx *context.InstrumentorContext) error {
  }
  logger.V(0).Info("Loading allocator")
 
- err := a.mountBPFFs()
+ err := bpffs.Mount(ctx.TargetDetails)
  if err != nil {
  return err
  }
 
  return nil
 }
-
-func (a *Allocator) mountBPFFs() error {
- _, err := os.Stat(bpffs.BPFFsPath)
- if err != nil {
- if !os.IsNotExist(err) {
- return err
- }
- if err := os.MkdirAll(bpffs.BPFFsPath, 0755); err != nil {
- return err
- }
- }
-
- return unix.Mount(bpffs.BPFFsPath, bpffs.BPFFsPath, "bpf", 0, "")
-}
diff --git a/pkg/instrumentors/bpf/github.com/gin-gonic/gin/probe.go b/pkg/instrumentors/bpf/github.com/gin-gonic/gin/probe.go
@@ -108,7 +108,7 @@ func (h *Instrumentor) Load(ctx *context.InstrumentorContext) error {
  h.bpfObjects = &bpfObjects{}
  err = utils.LoadEBPFObjects(spec, h.bpfObjects, &ebpf.CollectionOptions{
  Maps: ebpf.MapOptions{
- PinPath: bpffs.BPFFsPath,
+ PinPath: bpffs.PathForTargetApplication(ctx.TargetDetails),
  },
  })
  if err != nil {

diff --git a/pkg/instrumentors/bpf/github.com/gorilla/mux/probe.go b/pkg/instrumentors/bpf/github.com/gorilla/mux/probe.go
@@ -107,7 +107,7 @@ func (g *Instrumentor) Load(ctx *context.InstrumentorContext) error {
  g.bpfObjects = &bpfObjects{}
  err = utils.LoadEBPFObjects(spec, g.bpfObjects, &ebpf.CollectionOptions{
  Maps: ebpf.MapOptions{
- PinPath: bpffs.BPFFsPath,
+ PinPath: bpffs.PathForTargetApplication(ctx.TargetDetails),
  },
  })
  if err != nil {

diff --git a/pkg/instrumentors/bpf/google/golang/org/grpc/probe.go b/pkg/instrumentors/bpf/google/golang/org/grpc/probe.go
@@ -98,7 +98,7 @@ func (g *Instrumentor) Load(ctx *context.InstrumentorContext) error {
  g.bpfObjects = &bpfObjects{}
  err = utils.LoadEBPFObjects(spec, g.bpfObjects, &ebpf.CollectionOptions{
  Maps: ebpf.MapOptions{
- PinPath: bpffs.BPFFsPath,
+ PinPath: bpffs.PathForTargetApplication(ctx.TargetDetails),
  },
  })
 

diff --git a/pkg/instrumentors/bpf/google/golang/org/grpc/server/probe.go b/pkg/instrumentors/bpf/google/golang/org/grpc/server/probe.go
@@ -116,7 +116,7 @@ func (g *Instrumentor) Load(ctx *context.InstrumentorContext) error {
  g.bpfObjects = &bpfObjects{}
  err = utils.LoadEBPFObjects(spec, g.bpfObjects, &ebpf.CollectionOptions{
  Maps: ebpf.MapOptions{
- PinPath: bpffs.BPFFsPath,
+ PinPath: bpffs.PathForTargetApplication(ctx.TargetDetails),
  },
  })
  if err != nil {

diff --git a/pkg/instrumentors/bpf/net/http/client/probe.go b/pkg/instrumentors/bpf/net/http/client/probe.go
@@ -109,7 +109,7 @@ func (h *Instrumentor) Load(ctx *context.InstrumentorContext) error {
  h.bpfObjects = &bpfObjects{}
  err = spec.LoadAndAssign(h.bpfObjects, &ebpf.CollectionOptions{
  Maps: ebpf.MapOptions{
- PinPath: bpffs.BPFFsPath,
+ PinPath: bpffs.PathForTargetApplication(ctx.TargetDetails),
  },
  })
 

diff --git a/pkg/instrumentors/bpf/net/http/server/probe.go b/pkg/instrumentors/bpf/net/http/server/probe.go
@@ -112,7 +112,7 @@ func (h *Instrumentor) Load(ctx *context.InstrumentorContext) error {
  h.bpfObjects = &bpfObjects{}
  err = utils.LoadEBPFObjects(spec, h.bpfObjects, &ebpf.CollectionOptions{
  Maps: ebpf.MapOptions{
- PinPath: bpffs.BPFFsPath,
+ PinPath: bpffs.PathForTargetApplication(ctx.TargetDetails),
  },
  })
  if err != nil {

diff --git a/pkg/instrumentors/bpffs/bpfsfs.go b/pkg/instrumentors/bpffs/bpfsfs.go
@@ -14,5 +14,55 @@
 
 package bpffs
 
+import (
+ "fmt"
+ "os"
+
+ "go.opentelemetry.io/auto/pkg/log"
+
+ "golang.org/x/sys/unix"
+
+ "go.opentelemetry.io/auto/pkg/process"
+)
+
 // BPFFsPath is the system path to the BPF file-system.
-const BPFFsPath = "/sys/fs/bpf"
+const bpfFsPath = "/sys/fs/bpf"
+
+// PathForTargetApplication returns the path to the BPF file-system for the given target.
+func PathForTargetApplication(target *process.TargetDetails) string {
+ return fmt.Sprintf("%s/%d", bpfFsPath, target.PID)
+}
+
+// Mount mounts the BPF file-system for the given target.
+func Mount(target *process.TargetDetails) error {
+ if !isBPFFSMounted() {
+ // Directory does not exist, create it and mount
+ if err := os.MkdirAll(bpfFsPath, 0755); err != nil {
+ return err
+ }
+
+ err := unix.Mount(bpfFsPath, bpfFsPath, "bpf", 0, "")
+ if err != nil {
+ return err
+ }
+ }
+
+ // create directory with read, write and execute permissions
+ return os.Mkdir(PathForTargetApplication(target), 0755)
+}
+
+func isBPFFSMounted() bool {
+ var stat unix.Statfs_t
+ err := unix.Statfs(bpfFsPath, &stat)
+ if err != nil {
+ log.Logger.Error(err, "failed to statfs bpf filesystem")
+ return false
+ }
+
+ return stat.Type == unix.BPF_FS_MAGIC
+}
+
+// Cleanup removes the BPF file-system for the given target.
+func Cleanup(target *process.TargetDetails) error {
+ return os.RemoveAll(PathForTargetApplication(target))
+}