Implement -xattrname

From macOS find.

12 files changed, 159 insertions, 20 deletions

diff --git a/RELEASES.md b/RELEASES.md
index e8e0b71..d80f1ee 100644
--- a/RELEASES.md
+++ b/RELEASES.md
@@ -38,6 +38,8 @@
 
 - Fixed an optimizer bug that could skip `-empty`/`-xtype` if they didn't always lead to an action
 
+- Implemented `-xattrname` to find files with a particular extended attribute (from macOS find)
+
 [#8]: https://github.com/tavianator/bfs/issues/8
 [#30]: https://github.com/tavianator/bfs/issues/30
 
diff --git a/bfs.1 b/bfs.1
index 4c78bde..abb4189 100644
--- a/bfs.1
+++ b/bfs.1
@@ -576,6 +576,10 @@ days after they were changed.
 Find files with extended attributes
 .RB ( xattr (7)).
 .TP
+\fB\-xattrname\fR \fINAME\fR
+Find files with the extended attribute
+.IR NAME .
+.TP
 \fB\-xtype\fR [\fIbcdlpfswD\fR]
 Find files of the given type, following links when
 .B \-type
diff --git a/eval.c b/eval.c
index dc859b7..f8b9a6d 100644
--- a/eval.c
+++ b/eval.c
@@ -864,6 +864,19 @@ bool eval_xattr(const struct expr *expr, struct eval_state *state) {
 }
 
 /**
+ * -xattr test.
+ */
+bool eval_xattrname(const struct expr *expr, struct eval_state *state) {
+	int ret = bfs_check_xattr_named(state->ftwbuf, expr->sdata);
+	if (ret >= 0) {
+		return ret;
+	} else {
+		eval_report_error(state);
+		return false;
+	}
+}
+
+/**
  * -xtype test.
  */
 bool eval_xtype(const struct expr *expr, struct eval_state *state) {
diff --git a/eval.h b/eval.h
index b31c0d5..a95c3ac 100644
--- a/eval.h
+++ b/eval.h
@@ -33,6 +33,7 @@ bool eval_acl(const struct expr *expr, struct eval_state *state);
 bool eval_capable(const struct expr *expr, struct eval_state *state);
 bool eval_perm(const struct expr *expr, struct eval_state *state);
 bool eval_xattr(const struct expr *expr, struct eval_state *state);
+bool eval_xattrname(const struct expr *expr, struct eval_state *state);
 
 bool eval_newer(const struct expr *expr, struct eval_state *state);
 bool eval_time(const struct expr *expr, struct eval_state *state);
diff --git a/fsade.c b/fsade.c
index acd39bb..efe5092 100644
--- a/fsade.c
+++ b/fsade.c
@@ -330,6 +330,45 @@ int bfs_check_xattrs(const struct BFTW *ftwbuf) {
 	}
 }
 
+int bfs_check_xattr_named(const struct BFTW *ftwbuf, const char *name) {
+	const char *path = fake_at(ftwbuf);
+	ssize_t len;
+
+#if BFS_HAS_SYS_EXTATTR
+	ssize_t (*extattr_get)(const char *, int, const char *, void*, size_t) =
+		ftwbuf->type == BFTW_LNK ? extattr_get_link : extattr_get_file;
+
+	len = extattr_get(path, EXTATTR_NAMESPACE_SYSTEM, name, NULL, 0);
+	if (len < 0) {
+		len = extattr_get(path, EXTATTR_NAMESPACE_USER, name, NULL, 0);
+	}
+#elif __APPLE__
+	int options = ftwbuf->type == BFTW_LNK ? XATTR_NOFOLLOW : 0;
+	len = getxattr(path, name, NULL, 0, 0, options);
+#else
+	if (ftwbuf->type == BFTW_LNK) {
+		len = lgetxattr(path, name, NULL, 0);
+	} else {
+		len = getxattr(path, name, NULL, 0);
+	}
+#endif
+
+	int error = errno;
+
+	free_fake_at(ftwbuf, path);
+
+	if (len >= 0) {
+		return 1;
+	} else if (is_absence_error(error)) {
+		return 0;
+	} else if (error == E2BIG) {
+		return 1;
+	} else {
+		errno = error;
+		return -1;
+	}
+}
+
 #else // !BFS_CAN_CHECK_XATTRS
 
 int bfs_check_xattrs(const struct BFTW *ftwbuf) {
@@ -337,4 +376,9 @@ int bfs_check_xattrs(const struct BFTW *ftwbuf) {
 	return -1;
 }
 
+int bfs_check_xattr_named(const struct BFTW *ftwbuf, const char *name) {
+	errno = ENOTSUP;
+	return -1;
+}
+
 #endif
diff --git a/fsade.h b/fsade.h
index fedc8ed..3136608 100644
--- a/fsade.h
+++ b/fsade.h
@@ -67,4 +67,16 @@ int bfs_check_capabilities(const struct BFTW *ftwbuf);
  */
 int bfs_check_xattrs(const struct BFTW *ftwbuf);
 
+/**
+ * Check if a file has an extended attribute with the given name.
+ *
+ * @param ftwbuf
+ *         The file to check.
+ * @param name
+ *         The name of the xattr to check.
+ * @return
+ *         1 if it does, 0 if it doesn't, or -1 if an error occurred.
+ */
+int bfs_check_xattr_named(const struct BFTW *ftwbuf, const char *name);
+
 #endif // BFS_FSADE_H
diff --git a/parse.c b/parse.c
index 42dfc2e..155f10b 100644
--- a/parse.c
+++ b/parse.c
@@ -2505,6 +2505,23 @@ static struct expr *parse_xattr(struct parser_state *state, int arg1, int arg2)
 }
 
 /**
+ * Parse -xattrname.
+ */
+static struct expr *parse_xattrname(struct parser_state *state, int arg1, int arg2) {
+#if BFS_CAN_CHECK_XATTRS
+	struct expr *expr = parse_unary_test(state, eval_xattrname);
+	if (expr) {
+		expr->cost = STAT_COST;
+		expr->probability = 0.01;
+	}
+	return expr;
+#else
+	parse_error(state, "${blu}%s${rs} is missing platform support.\n", state->argv[0]);
+	return NULL;
+#endif
+}
+
+/**
  * Parse -xdev.
  */
 static struct expr *parse_xdev(struct parser_state *state, int arg1, int arg2) {
@@ -2814,6 +2831,8 @@ static struct expr *parse_help(struct parser_state *state, int arg1, int arg2) {
 #if BFS_CAN_CHECK_XATTRS
 	cfprintf(cout, "  ${blu}-xattr${rs}\n");
 	cfprintf(cout, "      Find files with extended attributes\n");
+	cfprintf(cout, "  ${blu}-xattrname${rs} ${bld}NAME${rs}\n");
+	cfprintf(cout, "      Find files with the extended attribute ${bld}NAME${rs}\n");
 #endif
 	cfprintf(cout, "  ${blu}-xtype${rs} ${bld}[bcdlpfswD]${rs}\n");
 	cfprintf(cout, "      Find files of the given type, following links when ${blu}-type${rs} would not, and\n");
@@ -3017,6 +3036,7 @@ static const struct table_entry parse_table[] = {
 	{"-writable", T_TEST, parse_access, W_OK},
 	{"-x", T_FLAG, parse_xdev},
 	{"-xattr", T_TEST, parse_xattr},
+	{"-xattrname", T_TEST, parse_xattrname},
 	{"-xdev", T_OPTION, parse_xdev},
 	{"-xtype", T_TEST, parse_type, true},
 	{0},
diff --git a/tests.sh b/tests.sh
index 88b6988..bbc823d 100755
--- a/tests.sh
+++ b/tests.sh
@@ -695,12 +695,18 @@ case "$UNAME" in
         bsd_tests+=(
             test_xattr
             test_L_xattr
+
+            test_xattrname
+            test_L_xattrname
         )
         ;;
     *)
         sudo_tests+=(
             test_xattr
             test_L_xattr
+
+            test_xattrname
+            test_L_xattrname
         )
         ;;
 esac
@@ -2562,53 +2568,84 @@ function test_L_capable() {
     bfs_diff -L scratch -capable
 }
 
-function set_xattr() {
+function make_xattrs() {
+    rm -rf scratch/*
+
+    touch scratch/{normal,xattr,xattr_2}
+    ln -s xattr scratch/link
+    ln -s normal scratch/xattr_link
+
     case "$UNAME" in
         Darwin)
-            xattr -w bfs_test true "$1"
-            xattr -s -w bfs_test true "$2"
+            xattr -w bfs_test true scratch/xattr
+            xattr -w bfs_test_2 true scratch/xattr_2
+            xattr -s -w bfs_test true scratch/xattr_link
             ;;
         FreeBSD)
-            setextattr user bfs_test true "$1"
-            setextattr -h user bfs_test true "$2"
+            setextattr user bfs_test true scratch/xattr
+            setextattr user bfs_test_2 true scratch/xattr_2
+            setextattr -h user bfs_test true scratch/xattr_link
             ;;
         *)
             # Linux tmpfs doesn't support the user.* namespace, so we use the security.*
             # namespace, which is writable by root and readable by others
-            sudo setfattr -n security.bfs_test "$1"
-            sudo setfattr -h -n security.bfs_test "$2"
+            sudo setfattr -n security.bfs_test scratch/xattr
+            sudo setfattr -n security.bfs_test_2 scratch/xattr_2
+            sudo setfattr -h -n security.bfs_test scratch/xattr_link
             ;;
     esac
 }
 
 function test_xattr() {
-    rm -rf scratch/*
-
     if ! invoke_bfs scratch -quit -xattr 2>/dev/null; then
         return 0
     fi
 
-    touch scratch/{normal,xattr}
-    ln -s xattr scratch/link
-    ln -s normal scratch/xattr_link
-    set_xattr scratch/xattr scratch/xattr_link
-
+    make_xattrs
     bfs_diff scratch -xattr
 }
 
 function test_L_xattr() {
-    rm -rf scratch/*
+    if ! invoke_bfs scratch -quit -xattr 2>/dev/null; then
+        return 0
+    fi
 
+    make_xattrs
+    bfs_diff -L scratch -xattr
+}
+
+function test_xattrname() {
     if ! invoke_bfs scratch -quit -xattr 2>/dev/null; then
         return 0
     fi
 
-    touch scratch/{normal,xattr}
-    ln -s xattr scratch/link
-    ln -s normal scratch/xattr_link
-    set_xattr scratch/xattr scratch/xattr_link
+    make_xattrs
 
-    bfs_diff -L scratch -xattr
+    case "$UNAME" in
+        Darwin|FreeBSD)
+            bfs_diff scratch -xattrname bfs_test
+            ;;
+        *)
+            bfs_diff scratch -xattrname security.bfs_test
+            ;;
+    esac
+}
+
+function test_L_xattrname() {
+    if ! invoke_bfs scratch -quit -xattr 2>/dev/null; then
+        return 0
+    fi
+
+    make_xattrs
+
+    case "$UNAME" in
+        Darwin|FreeBSD)
+            bfs_diff -L scratch -xattrname bfs_test
+            ;;
+        *)
+            bfs_diff -L scratch -xattrname security.bfs_test
+            ;;
+    esac
 }
 
 function test_help() {
diff --git a/tests/test_L_xattr.out b/tests/test_L_xattr.out
index 4dc4836..12fac95 100644
--- a/tests/test_L_xattr.out
+++ b/tests/test_L_xattr.out
@@ -1,2 +1,3 @@
 scratch/link
 scratch/xattr
+scratch/xattr_2
diff --git a/tests/test_L_xattrname.out b/tests/test_L_xattrname.out
new file mode 100644
index 0000000..4dc4836
--- /dev/null
+++ b/tests/test_L_xattrname.out
@@ -0,0 +1,2 @@
+scratch/link
+scratch/xattr
diff --git a/tests/test_xattr.out b/tests/test_xattr.out
index 0285ac1..109e7c9 100644
--- a/tests/test_xattr.out
+++ b/tests/test_xattr.out
@@ -1,2 +1,3 @@
 scratch/xattr
+scratch/xattr_2
 scratch/xattr_link
diff --git a/tests/test_xattrname.out b/tests/test_xattrname.out
new file mode 100644
index 0000000..0285ac1
--- /dev/null
+++ b/tests/test_xattrname.out
@@ -0,0 +1,2 @@
+scratch/xattr
+scratch/xattr_link