From 22e3eec15302eac28c1a2ac3f9af29c2c9e82a3c Mon Sep 17 00:00:00 2001
From: Jakob Unterwurzacher
Date: Thu, 28 May 2020 23:21:35 +0200
Subject: getdents-debug: loop and stop on first error

Also try to improve and unify output a little.

$ ./getdents /usr/share/man/man1
  1: unix.Getdents: n=9984; n=9984; n=9968; n=9976; n=9984; n=9968; n=10000; n=9976; n=9992; n=10000; n=9976; n=9992; n=2312; n=0; err=<nil>; total 122112 bytes
  2: unix.Getdents: n=9984; n=48; n=9976; n=9968; n=9976; n=9976; n=9992; n=9984; n=9992; n=10000; n=9976; n=9968; n=10000; n=2272; n=0; err=<nil>; total 122112 bytes
  3: unix.Getdents: n=9984; n=9984; n=9968; n=704; n=10000; n=10000; n=9968; n=9968; n=9992; n=10000; n=9960; n=9992; n=9992; n=1600; n=0; err=<nil>; total 122112 bytes
  4: unix.Getdents: n=9984; n=9984; n=9968; n=9976; n=9984; n=32; n=9992; n=9984; n=9992; n=10000; n=9976; n=9968; n=10000; n=2272; n=0; err=<nil>; total 122112 bytes

$ ./getdents_c /usr/share/man/man1
  1: getdents64: n=9984; n=9984; n=9968; n=9976; n=9984; n=9968; n=10000; n=9976; n=9992; n=10000; n=9976; n=9992; n=2312; n=0; errno=0 total 122112 bytes
  2: getdents64: n=9984; n=9984; n=9968; n=9976; n=9984; n=9968; n=10000; n=9976; n=9992; n=10000; n=9976; n=9992; n=2312; n=0; errno=0 total 122112 bytes
  3: getdents64: n=9984; n=9984; n=9968; n=9976; n=9984; n=9968; n=10000; n=9976; n=9992; n=10000; n=9976; n=9992; n=2312; n=0; errno=0 total 122112 bytes
  4: getdents64: n=9984; n=9984; n=9968; n=9976; n=9984; n=9968; n=10000; n=9976; n=9992; n=10000; n=9976; n=9992; n=2312; n=0; errno=0 total 122112 bytes
---
 contrib/getdents-debug/getdents/getdents.go  | 18 ++++++------
 contrib/getdents-debug/getdents_c/getdents.c | 41 +++++++++++++++++-----------
 2 files changed, 33 insertions(+), 26 deletions(-)

(limited to 'contrib')

diff --git a/contrib/getdents-debug/getdents/getdents.go b/contrib/getdents-debug/getdents/getdents.go
index cd1e49d..d7dac78 100644
--- a/contrib/getdents-debug/getdents/getdents.go
+++ b/contrib/getdents-debug/getdents/getdents.go
@@ -40,6 +40,7 @@ import (
 	"flag"
 	"fmt"
 	"os"
+	"time"
 
 	"golang.org/x/sys/unix"
 )
@@ -50,11 +51,10 @@ const (
 
 func main() {
 	flag.Usage = func() {
-		fmt.Fprintf(os.Stderr, "Usage: %s [-loop] PATH\n", myName)
-		fmt.Fprintf(os.Stderr, "Run getdents(2) on PATH\n")
+		fmt.Fprintf(os.Stderr, "Usage: %s PATH\n", myName)
+		fmt.Fprintf(os.Stderr, "Run getdents(2) on PATH in a 100ms loop until we hit an error\n")
 		os.Exit(1)
 	}
-	loop := flag.Bool("loop", false, "Run in a loop")
 	flag.Parse()
 	if flag.NArg() != 1 {
 		flag.Usage()
@@ -62,14 +62,14 @@ func main() {
 	path := flag.Arg(0)
 
 	tmp := make([]byte, 10000)
-	for {
+	for i := 1; ; i++ {
 		sum := 0
 		fd, err := unix.Open(path, unix.O_RDONLY, 0)
 		if err != nil {
-			fmt.Printf("unix.Open returned err=%v\n", err)
-			continue
+			fmt.Printf("%3d: unix.Open returned err=%v\n", err)
+			os.Exit(1)
 		}
-		fmt.Printf("unix.Getdents: ")
+		fmt.Printf("%3d: unix.Getdents: ", i)
 		for {
 			n, err := unix.Getdents(fd, tmp)
 			fmt.Printf("n=%d; ", n)
@@ -83,8 +83,6 @@ func main() {
 			sum += n
 		}
 		unix.Close(fd)
-		if !*loop {
-			break
-		}
+		time.Sleep(100 * time.Millisecond)
 	}
 }
diff --git a/contrib/getdents-debug/getdents_c/getdents.c b/contrib/getdents-debug/getdents_c/getdents.c
index 98c2346..936bd0b 100644
--- a/contrib/getdents-debug/getdents_c/getdents.c
+++ b/contrib/getdents-debug/getdents_c/getdents.c
@@ -12,28 +12,37 @@
 
 int main(int argc, char *argv[])
 {
-    if(argc < 2) {
+    if(argc != 2) {
         printf("Usage: %s PATH\n", argv[0]);
-        printf("Run getdents(2) on PATH\n");
+        printf("Run getdents(2) on PATH in a 100ms loop\n");
         exit(1);
     }
 
     const char *path = argv[1];
-    int fd = open(path, O_RDONLY);
-    if (fd == -1) {
-        perror("open");
-        exit(1);
-    }
 
-    char tmp[10000];
-    int sum = 0;
-    for ( ; ; ) {
-        int n = syscall(SYS_getdents64, fd, tmp, sizeof(tmp));
-        printf("getdents64 fd%d: n=%d, errno=%d\n", fd, n, errno);
-        if (n <= 0) {
-            printf("total %d bytes\n", sum);
-            break;
+    for (int i = 1 ; ; i ++ ) {
+        int fd = open(path, O_RDONLY);
+        if (fd == -1) {
+            perror("open");
+            exit(1);
+        }
+
+        char tmp[10000];
+        int sum = 0;
+        printf("%3d: getdents64: ", i);
+        for ( ; ; ) {
+            int n = syscall(SYS_getdents64, fd, tmp, sizeof(tmp));
+            printf("n=%d; ", n);
+            if (n <= 0) {
+                printf("errno=%d total %d bytes\n", errno, sum);
+                if (n < 0) {
+                    exit(1);
+                }
+                break;
+            }
+            sum += n;
         }
-        sum += n;
+        close(fd);
+        usleep(100000);
     }
 }
-- 
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