Add a listxattr tool for listing xattrs

Change-Id: Ib80bab2b605ce77cd8fdc717d8bcfa8085516679

Android.mk

@@ -678,7 +678,8 @@ include $(commands_recovery_local_path)/injecttwrp/Android.mk \
     $(commands_recovery_local_path)/toybox/Android.mk \
     $(commands_recovery_local_path)/simg2img/Android.mk \
     $(commands_recovery_local_path)/adbbu/Android.mk \
-    $(commands_recovery_local_path)/libpixelflinger/Android.mk
+    $(commands_recovery_local_path)/libpixelflinger/Android.mk \
+    $(commands_recovery_local_path)/attr/Android.mk
 
 ifeq ($(shell test $(PLATFORM_SDK_VERSION) -lt 24; echo $$?),0)
     include $(commands_recovery_local_path)/libmincrypt/Android.mk

attr/Android.mk

@@ -0,0 +1,22 @@
+LOCAL_PATH:= $(call my-dir)
+
+include $(CLEAR_VARS)
+LOCAL_SRC_FILES := listxattr.c
+LOCAL_CFLAGS := -c -W
+LOCAL_MODULE := listxattr
+LOCAL_MODULE_TAGS := eng
+LOCAL_MODULE_CLASS := RECOVERY_EXECUTABLES
+LOCAL_MODULE_PATH := $(TARGET_RECOVERY_ROOT_OUT)/sbin
+LOCAL_PACK_MODULE_RELOCATIONS := false
+
+ifneq ($(TARGET_ARCH), arm64)
+    ifneq ($(TARGET_ARCH), x86_64)
+        LOCAL_LDFLAGS += -Wl,-dynamic-linker,/sbin/linker
+    else
+        LOCAL_LDFLAGS += -Wl,-dynamic-linker,/sbin/linker64
+    endif
+else
+    LOCAL_LDFLAGS += -Wl,-dynamic-linker,/sbin/linker64
+endif
+
+include $(BUILD_EXECUTABLE)

attr/listxattr.c

@@ -0,0 +1,202 @@
+/****************************************************************************
+ |  (C) Copyright 2008 Novell, Inc. All Rights Reserved.
+ |
+ |  GPLv2: This program is free software; you can redistribute it
+ |  and/or modify it under the terms of version 2 of the GNU General
+ |  Public License as published by the Free Software Foundation.
+ |
+ |  This program is distributed in the hope that it will be useful,
+ |  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ |  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ |  GNU General Public License for more details.
+ +-------------------------------------------------------------------------*/
+/*
+ * NOTE from Dees_Troy: modified source to display values along with xattr names
+ * Below code comments about usage are no longer accurate but came from the
+ * original source code from the chromium project and combine features of
+ * listxattr and getfattr:
+ * https://chromium.googlesource.com/chromiumos/platform/punybench/+/factory-1235.B/file.m/listxattr.c
+ * https://chromium.googlesource.com/chromiumos/platform/punybench/+/factory-1235.B/file.m/getxattr.c
+ */
+/*
+ * LISTXATTR(2)             Linux Programmer's Manual            LISTXATTR(2)
+ *
+ *
+ *
+ * NAME
+ *        listxattr, llistxattr, flistxattr - list extended attribute names
+ *
+ * SYNOPSIS
+ *        #include <sys/types.h>
+ *        #include <attr/xattr.h>
+ *
+ *        ssize_t listxattr (const char *path,
+ *                             char *list, size_t size);
+ *        ssize_t llistxattr (const char *path,
+ *                             char *list, size_t size);
+ *        ssize_t flistxattr (int filedes,
+ *                             char *list, size_t size);
+ *
+ * DESCRIPTION
+ *        Extended  attributes  are  name:value  pairs associated with inodes
+ *        (files, directories, symlinks, etc).  They are  extensions  to  the
+ *        normal  attributes which are associated with all inodes in the sys-
+ *        tem (i.e. the stat(2)  data).   A  complete  overview  of  extended
+ *        attributes concepts can be found in attr(5).
+ *
+ *        listxattr retrieves the list of extended attribute names associated
+ *        with the given path in the filesystem.  The  list  is  the  set  of
+ *        (NULL-terminated)  names,  one  after the other.  Names of extended
+ *        attributes to which the calling process does not have access may be
+ *        omitted  from  the  list.  The length of the attribute name list is
+ *        returned.
+ *
+ *        llistxattr is identical to listxattr, except in the case of a  sym-
+ *        bolic  link, where the list of names of extended attributes associ-
+ *        ated with the link itself is retrieved, not the file that it refers
+ *        to.
+ *
+ *        flistxattr is identical to listxattr, only the open file pointed to
+ *        by filedes (as returned by open(2)) is  interrogated  in  place  of
+ *        path.
+ *
+ *        A  single  extended  attribute  name  is  a  simple NULL-terminated
+ *        string.  The name includes a namespace prefix; there  may  be  sev-
+ *        eral, disjoint namespaces associated with an individual inode.
+ *
+ *        An  empty  buffer  of  size  zero can be passed into these calls to
+ *        return the current size of the list of  extended  attribute  names,
+ *        which  can be used to estimate the size of a buffer which is suffi-
+ *        ciently large to hold the list of names.
+ *
+ * EXAMPLES
+ *        The list of names is returned as an unordered array of  NULL-termi-
+ *        nated  character  strings  (attribute  names  are separated by NULL
+ *        characters), like this:
+ *               user.name1\0system.name1\0user.name2\0
+ *
+ *        Filesystems like ext2, ext3 and  XFS  which  implement  POSIX  ACLs
+ *        using extended attributes, might return a list like this:
+ *               system.posix_acl_access\0system.posix_acl_default\0
+ *
+ * RETURN VALUE
+ *        On  success,  a  positive number is returned indicating the size of
+ *        the extended attribute name list.  On failure, -1 is  returned  and
+ *        errno is set appropriately.
+ *
+ *        If  the  size  of  the list buffer is too small to hold the result,
+ *        errno is set to ERANGE.
+ *
+ *        If extended attributes are not supported by the filesystem, or  are
+ *        disabled, errno is set to ENOTSUP.
+ *
+ *        The errors documented for the stat(2) system call are also applica-
+ *        ble here.
+ *
+ * AUTHORS
+ *        Andreas Gruenbacher, <[email protected]> and the  SGI  XFS
+ *        development  team,  <[email protected]>.   Please  send any bug
+ *        reports or comments to these addresses.
+ *
+ * SEE ALSO
+ *        getfattr(1),  setfattr(1),  getxattr(2),  open(2),  removexattr(2),
+ *        setxattr(2), stat(2), attr(5)
+ *
+ *
+ *
+ * Dec 2001                    Extended Attributes               LISTXATTR(2)
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <sys/types.h>
+#include <sys/xattr.h>
+//#include <eprintf.h>
+//#include <puny.h>
+
+/* dumpmem: dumps an n byte area of memory to screen */
+void dumpmem (const void *mem, unsigned int n)
+{
+	const char *c = mem;
+	unsigned i;
+	int all_text = 1;
+	if (n == 0) {
+		printf("<empty>");
+		return;
+	}
+	for (i = 0; i < n - 1; i++, c++) {
+		if (!isprint(*c)) {
+			all_text = 0;
+			break;
+		}
+	}
+	c = mem;
+	if (all_text) {
+		for (i = 0; i < n - 1; i++, c++) {
+			putchar(*c);
+		}
+		return;
+	} else {
+		char hex[(n * 2) + 1];
+		for(i = 0; i < n; i++, c++)
+			sprintf(hex + (i * 2), "%02X", *c);
+		hex[n] = 0;
+		printf("0x%s", hex);
+		return;
+	}
+}
+
+void dump_list (char *file, char *list, ssize_t size)
+{
+	int	c;
+	int	i;
+	int	first = 1;
+	int j = 0;
+	char xattr[1024];
+	char value[1024];
+	ssize_t	size2;
+	for (i = 0; i < size; i++) {
+		c = list[i];
+		if (c) {
+			if (first) {
+				putchar('\t');
+				first = 0;
+				j = 0;
+			}
+			putchar(c);
+			xattr[j++] = list[i];
+		} else {
+			xattr[j] = '\0';
+			size2 = getxattr(file, xattr, value, sizeof(value));
+			if (size2 < 0) {
+				printf("file=%s xattr=%s returned:", file, xattr);
+			} else {
+				putchar('=');
+				dumpmem(value, size2);
+			}
+			putchar('\n');
+			first = 1;
+		}
+	}
+}
+void usage (void)
+{
+	printf("listxattr <file>");
+}
+char	List[1<<17];
+int main (int argc, char *argv[])
+{
+	ssize_t	size;
+	if (argc < 2) {
+		usage();
+		exit(2);
+	}
+	size = listxattr(argv[1], List, sizeof(List));
+	if (size == -1) {
+		perror(argv[1]);
+		exit(2);
+	}
+	printf("xattrs for %s:\n", argv[1]);
+	dump_list(argv[1], List, size);
+	return 0;
+}