From 5a8d3bab6f492b3932299d9e80fb247ab00b8102 Mon Sep 17 00:00:00 2001

From: "Dmitry V. Levin" <ldv@strace.io>

Date: Sun, 7 Mar 2021 08:00:00 +0000

Subject: [PATCH 147/149] file_handle: print f_handle as a hexadecimal string

Printing the sequence of bytes as a hexadecimal number is misleading

because the latter depends on endianness.

* src/file_handle.c (print_f_handle): New function.

(SYS_FUNC(name_to_handle_at), SYS_FUNC(open_by_handle_at)): Use it

to print struct file_handle.f_handle.

* tests/file_handle.c (print_handle_data, do_open_by_handle_at, main):

Update expected output.

---

 file_handle.c       | 47 ++++++++++++++++++++++-------------------------

 tests/file_handle.c | 26 +++++++++++---------------

 2 files changed, 33 insertions(+), 40 deletions(-)

diff --git a/file_handle.c b/file_handle.c

index d82a1bc..343111f 100644

--- a/file_handle.c

+++ b/file_handle.c

@@ -19,6 +19,22 @@ typedef struct {

 	int handle_type;

 } file_handle_header;

+static void

+print_f_handle(struct tcb *tcp, kernel_ulong_t addr, unsigned int handle_bytes)

+{

+	unsigned int len = MIN(handle_bytes, MAX_HANDLE_SZ);

+	char f_handle[MAX_HANDLE_SZ];

+	addr += sizeof(file_handle_header);

+	if (addr > sizeof(file_handle_header) &&

+	    !umoven(tcp, addr, len, f_handle)) {

+		print_quoted_string(f_handle, len, QUOTE_FORCE_HEX);

+		if (handle_bytes > len)

+			tprints("...");

+	} else {

+		tprints("???");

+	}

+}

+

 SYS_FUNC(name_to_handle_at)

 {

 	file_handle_header h;

@@ -53,24 +69,15 @@ SYS_FUNC(name_to_handle_at)

 		return 0;

 	} else {

-		unsigned int i = get_tcb_priv_ulong(tcp);

-

 		if ((!syserror(tcp) || EOVERFLOW == tcp->u_error)

 		    && !umove(tcp, addr, &h)) {

-			unsigned char f_handle[MAX_HANDLE_SZ];

-			if (i != h.handle_bytes)

+			if (h.handle_bytes != get_tcb_priv_ulong(tcp))

 				tprintf(" => %u", h.handle_bytes);

 			if (!syserror(tcp)) {

-				tprintf(", handle_type=%d", h.handle_type);

-				if (h.handle_bytes > MAX_HANDLE_SZ)

-					h.handle_bytes = MAX_HANDLE_SZ;

-				if (!umoven(tcp, addr + sizeof(h), h.handle_bytes,

-					    f_handle)) {

-					tprints(", f_handle=0x");

-					for (i = 0; i < h.handle_bytes; ++i)

-						tprintf("%02x", f_handle[i]);

-				}

+				tprintf(", handle_type=%d, f_handle=",

+					h.handle_type);

+				print_f_handle(tcp, addr, h.handle_bytes);

 			}

 		}

 		tprints("}, ");

@@ -96,19 +103,9 @@ SYS_FUNC(open_by_handle_at)

 	/* handle */

 	if (!umove_or_printaddr(tcp, addr, &h)) {

-		unsigned char f_handle[MAX_HANDLE_SZ];

-

-		tprintf("{handle_bytes=%u, handle_type=%d",

+		tprintf("{handle_bytes=%u, handle_type=%d, f_handle=",

 			h.handle_bytes, h.handle_type);

-		if (h.handle_bytes > MAX_HANDLE_SZ)

-			h.handle_bytes = MAX_HANDLE_SZ;

-		if (!umoven(tcp, addr + sizeof(h), h.handle_bytes, &f_handle)) {

-			unsigned int i;

-

-			tprints(", f_handle=0x");

-			for (i = 0; i < h.handle_bytes; ++i)

-				tprintf("%02x", f_handle[i]);

-		}

+		print_f_handle(tcp, addr, h.handle_bytes);

 		tprints("}");

 	}

 	tprints(", ");

diff --git a/tests/file_handle.c b/tests/file_handle.c

index edabde6..07af7ba 100644

--- a/tests/file_handle.c

+++ b/tests/file_handle.c

@@ -42,14 +42,10 @@ struct file_handle {

 void

 print_handle_data(unsigned char *bytes, unsigned int size)

 {

-	unsigned int i;

-

-	if (size > MAX_HANDLE_SZ)

-		size = MAX_HANDLE_SZ;

-

-	printf("0x");

-	for (i = 0; i < size; ++i)

-		printf("%02x", bytes[i]);

+	unsigned int len = MIN(size, MAX_HANDLE_SZ);

+	print_quoted_hex(bytes, len);

+	if (size > len)

+		printf("...");

 }

 void

@@ -111,11 +107,13 @@ do_open_by_handle_at(kernel_ulong_t mount_fd,

 		printf("{handle_bytes=%u, handle_type=%d", fh->handle_bytes,

 		       fh->handle_type);

+		printf(", f_handle=");

 		if (valid_data) {

-			printf(", f_handle=");

 			print_handle_data((unsigned char *) fh +

 					  sizeof(struct file_handle),

 					  fh->handle_bytes);

+		} else {

+			printf("???");

 		}

 		printf("}");

@@ -275,16 +273,14 @@ main(void)

 	assert(syscall(__NR_name_to_handle_at, fdcwd, ".", handle, &mount_id,

 		flags) == 0);

 	printf("name_to_handle_at(AT_FDCWD, \".\", {handle_bytes=%u"

-	       ", handle_type=%d, f_handle=0x",

+	       ", handle_type=%d, f_handle=",

 	       handle->handle_bytes, handle->handle_type);

-	for (i = 0; i < handle->handle_bytes; ++i)

-		printf("%02x", handle->f_handle[i]);

+	print_handle_data(handle->f_handle, handle->handle_bytes);

 	printf("}, [%d], AT_SYMLINK_FOLLOW) = 0\n", mount_id);

 	printf("open_by_handle_at(-1, {handle_bytes=%u, handle_type=%d"

-	       ", f_handle=0x", handle->handle_bytes, handle->handle_type);

-	for (i = 0; i < handle->handle_bytes; ++i)

-		printf("%02x", handle->f_handle[i]);

+	       ", f_handle=", handle->handle_bytes, handle->handle_type);

+	print_handle_data(handle->f_handle, handle->handle_bytes);

 	int rc = syscall(__NR_open_by_handle_at, -1, handle,

 		O_RDONLY | O_DIRECTORY);

 	printf("}, O_RDONLY|O_DIRECTORY) = %d %s (%m)\n", rc, errno2name());

diff --git a/tests-m32/file_handle.c b/tests-m32/file_handle.c

index edabde6..07af7ba 100644

--- a/tests-m32/file_handle.c

+++ b/tests-m32/file_handle.c

@@ -42,14 +42,10 @@ struct file_handle {

 void

 print_handle_data(unsigned char *bytes, unsigned int size)

 {

-	unsigned int i;

-

-	if (size > MAX_HANDLE_SZ)

-		size = MAX_HANDLE_SZ;

-

-	printf("0x");

-	for (i = 0; i < size; ++i)

-		printf("%02x", bytes[i]);

+	unsigned int len = MIN(size, MAX_HANDLE_SZ);

+	print_quoted_hex(bytes, len);

+	if (size > len)

+		printf("...");

 }

 void

@@ -111,11 +107,13 @@ do_open_by_handle_at(kernel_ulong_t mount_fd,

 		printf("{handle_bytes=%u, handle_type=%d", fh->handle_bytes,

 		       fh->handle_type);

+		printf(", f_handle=");

 		if (valid_data) {

-			printf(", f_handle=");

 			print_handle_data((unsigned char *) fh +

 					  sizeof(struct file_handle),

 					  fh->handle_bytes);

+		} else {

+			printf("???");

 		}

 		printf("}");

@@ -275,16 +273,14 @@ main(void)

 	assert(syscall(__NR_name_to_handle_at, fdcwd, ".", handle, &mount_id,

 		flags) == 0);

 	printf("name_to_handle_at(AT_FDCWD, \".\", {handle_bytes=%u"

-	       ", handle_type=%d, f_handle=0x",

+	       ", handle_type=%d, f_handle=",

 	       handle->handle_bytes, handle->handle_type);

-	for (i = 0; i < handle->handle_bytes; ++i)

-		printf("%02x", handle->f_handle[i]);

+	print_handle_data(handle->f_handle, handle->handle_bytes);

 	printf("}, [%d], AT_SYMLINK_FOLLOW) = 0\n", mount_id);

 	printf("open_by_handle_at(-1, {handle_bytes=%u, handle_type=%d"

-	       ", f_handle=0x", handle->handle_bytes, handle->handle_type);

-	for (i = 0; i < handle->handle_bytes; ++i)

-		printf("%02x", handle->f_handle[i]);

+	       ", f_handle=", handle->handle_bytes, handle->handle_type);

+	print_handle_data(handle->f_handle, handle->handle_bytes);

 	int rc = syscall(__NR_open_by_handle_at, -1, handle,

 		O_RDONLY | O_DIRECTORY);

 	printf("}, O_RDONLY|O_DIRECTORY) = %d %s (%m)\n", rc, errno2name());

diff --git a/tests-mx32/file_handle.c b/tests-mx32/file_handle.c

index edabde6..07af7ba 100644

--- a/tests-mx32/file_handle.c

+++ b/tests-mx32/file_handle.c

@@ -42,14 +42,10 @@ struct file_handle {

 void

 print_handle_data(unsigned char *bytes, unsigned int size)

 {

-	unsigned int i;

-

-	if (size > MAX_HANDLE_SZ)

-		size = MAX_HANDLE_SZ;

-

-	printf("0x");

-	for (i = 0; i < size; ++i)

-		printf("%02x", bytes[i]);

+	unsigned int len = MIN(size, MAX_HANDLE_SZ);

+	print_quoted_hex(bytes, len);

+	if (size > len)

+		printf("...");

 }

 void

@@ -111,11 +107,13 @@ do_open_by_handle_at(kernel_ulong_t mount_fd,

 		printf("{handle_bytes=%u, handle_type=%d", fh->handle_bytes,

 		       fh->handle_type);

+		printf(", f_handle=");

 		if (valid_data) {

-			printf(", f_handle=");

 			print_handle_data((unsigned char *) fh +

 					  sizeof(struct file_handle),

 					  fh->handle_bytes);

+		} else {

+			printf("???");

 		}

 		printf("}");

@@ -275,16 +273,14 @@ main(void)

 	assert(syscall(__NR_name_to_handle_at, fdcwd, ".", handle, &mount_id,

 		flags) == 0);

 	printf("name_to_handle_at(AT_FDCWD, \".\", {handle_bytes=%u"

-	       ", handle_type=%d, f_handle=0x",

+	       ", handle_type=%d, f_handle=",

 	       handle->handle_bytes, handle->handle_type);

-	for (i = 0; i < handle->handle_bytes; ++i)

-		printf("%02x", handle->f_handle[i]);

+	print_handle_data(handle->f_handle, handle->handle_bytes);

 	printf("}, [%d], AT_SYMLINK_FOLLOW) = 0\n", mount_id);

 	printf("open_by_handle_at(-1, {handle_bytes=%u, handle_type=%d"

-	       ", f_handle=0x", handle->handle_bytes, handle->handle_type);

-	for (i = 0; i < handle->handle_bytes; ++i)

-		printf("%02x", handle->f_handle[i]);

+	       ", f_handle=", handle->handle_bytes, handle->handle_type);

+	print_handle_data(handle->f_handle, handle->handle_bytes);

 	int rc = syscall(__NR_open_by_handle_at, -1, handle,

 		O_RDONLY | O_DIRECTORY);

 	printf("}, O_RDONLY|O_DIRECTORY) = %d %s (%m)\n", rc, errno2name());

-- 

2.1.4