command/server: remove env var requirement for sigusr2 pprof output (#25391)

* command/server: remove env var requirement for sigusr2 pprof output

* changelog

changelog/25391.txt

@@ -0,0 +1,4 @@
+```release-note:improvement
+command/server: Removed environment variable requirement to generate pprof 
+files using SIGUSR2. Added CPU profile support.
+```

command/server.go

@@ -1760,42 +1760,43 @@ func (c *ServerCommand) Run(args []string) int {
 			// We can only get pprof outputs via the API but sometimes Vault can get
 			// into a state where it cannot process requests so we can get pprof outputs
 			// via SIGUSR2.
-			if os.Getenv("VAULT_PPROF_WRITE_TO_FILE") != "" {
-				dir := ""
-				path := os.Getenv("VAULT_PPROF_FILE_PATH")
-				if path != "" {
-					if _, err := os.Stat(path); err != nil {
-						c.logger.Error("Checking pprof path failed", "error", err)
-						continue
-					}
-					dir = path
-				} else {
-					dir, err = os.MkdirTemp("", "vault-pprof")
-					if err != nil {
-						c.logger.Error("Could not create temporary directory for pprof", "error", err)
-						continue
-					}
+			pprofPath := filepath.Join(os.TempDir(), "vault-pprof")
+			err := os.MkdirAll(pprofPath, os.ModePerm)
+			if err != nil {
+				c.logger.Error("Could not create temporary directory for pprof", "error", err)
+				continue
+			}
+
+			dumps := []string{"goroutine", "heap", "allocs", "threadcreate", "profile"}
+			for _, dump := range dumps {
+				pFile, err := os.Create(filepath.Join(pprofPath, dump))
+				if err != nil {
+					c.logger.Error("error creating pprof file", "name", dump, "error", err)
+					break
 				}
 
-				dumps := []string{"goroutine", "heap", "allocs", "threadcreate"}
-				for _, dump := range dumps {
-					pFile, err := os.Create(filepath.Join(dir, dump))
-					if err != nil {
-						c.logger.Error("error creating pprof file", "name", dump, "error", err)
-						break
-					}
-
+				if dump != "profile" {
 					err = pprof.Lookup(dump).WriteTo(pFile, 0)
 					if err != nil {
 						c.logger.Error("error generating pprof data", "name", dump, "error", err)
 						pFile.Close()
 						break
 					}
-					pFile.Close()
+				} else {
+					// CPU profiles need to run for a duration so we're going to run it
+					// just for one second to avoid blocking here.
+					if err := pprof.StartCPUProfile(pFile); err != nil {
+						c.logger.Error("could not start CPU profile: ", err)
+						pFile.Close()
+						break
+					}
+					time.Sleep(time.Second * 1)
+					pprof.StopCPUProfile()
 				}
-
-				c.logger.Info(fmt.Sprintf("Wrote pprof files to: %s", dir))
+				pFile.Close()
 			}
+
+			c.logger.Info(fmt.Sprintf("Wrote pprof files to: %s", pprofPath))
 		}
 	}
 	// Notify systemd that the server is shutting down