From 0f91c5861cacaeb17729b7727d07260273345393 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Thu, 4 Feb 2016 23:12:08 -0500
Subject: Implement -P and -H.

---
 bftw.c   | 18 ++++++++++++++----
 bftw.h   |  8 +++++---
 parse.c  | 20 +++++++++++++++++++-
 tests.sh | 20 +++++++++++++++++++-
 4 files changed, 57 insertions(+), 9 deletions(-)

diff --git a/bftw.c b/bftw.c
index 99e26e1..a49cbed 100644
--- a/bftw.c
+++ b/bftw.c
@@ -471,8 +471,8 @@ static void ftwbuf_use_dirent(struct BFTW *ftwbuf, const struct dirent *de) {
 #endif
 }
 
-static int ftwbuf_stat(struct BFTW *ftwbuf, struct stat *sb) {
-	int ret = fstatat(ftwbuf->at_fd, ftwbuf->at_path, sb, AT_SYMLINK_NOFOLLOW);
+static int ftwbuf_stat(struct BFTW *ftwbuf, struct stat *sb, int flags) {
+	int ret = fstatat(ftwbuf->at_fd, ftwbuf->at_path, sb, flags);
 	if (ret != 0) {
 		return ret;
 	}
@@ -620,8 +620,18 @@ static void bftw_init_buffers(struct bftw_state *state, const struct dirent *de)
 		ftwbuf->typeflag = BFTW_UNKNOWN;
 	}
 
-	if ((state->flags & BFTW_STAT) || ftwbuf->typeflag == BFTW_UNKNOWN) {
-		if (ftwbuf_stat(ftwbuf, &state->statbuf) != 0) {
+	bool follow;
+	if (state->flags & BFTW_FOLLOW_ROOT) {
+		follow = !state->current;
+	} else {
+		follow = false;
+	}
+
+	if ((state->flags & BFTW_STAT)
+	    || ftwbuf->typeflag == BFTW_UNKNOWN
+	    || (ftwbuf->typeflag == BFTW_LNK && follow)) {
+		int flags = follow ? 0 : AT_SYMLINK_NOFOLLOW;
+		if (ftwbuf_stat(ftwbuf, &state->statbuf, flags) != 0) {
 			state->error = errno;
 			ftwbuf_set_error(ftwbuf, state->error);
 		}
diff --git a/bftw.h b/bftw.h
index 1375594..4b81123 100644
--- a/bftw.h
+++ b/bftw.h
@@ -105,11 +105,13 @@ typedef enum bftw_action bftw_fn(struct BFTW *ftwbuf, void *ptr);
  */
 enum bftw_flags {
 	/** stat() each encountered file. */
-	BFTW_STAT    = 1 << 0,
+	BFTW_STAT        = 1 << 0,
 	/** Attempt to recover from encountered errors. */
-	BFTW_RECOVER = 1 << 1,
+	BFTW_RECOVER     = 1 << 1,
 	/** Visit directories in post-order as well as pre-order. */
-	BFTW_DEPTH   = 1 << 2,
+	BFTW_DEPTH       = 1 << 2,
+	/** If the initial path is a symbolic link, follow it. */
+	BFTW_FOLLOW_ROOT = 1 << 3,
 };
 
 /**
diff --git a/parse.c b/parse.c
index 413282a..93657c8 100644
--- a/parse.c
+++ b/parse.c
@@ -344,7 +344,11 @@ static struct expr *parse_acnewer(struct parser_state *state, const char *option
 	}
 
 	struct stat sb;
-	if (fstatat(AT_FDCWD, expr->sdata, &sb, AT_SYMLINK_NOFOLLOW) != 0) {
+
+	bool follow = state->cl->flags & BFTW_FOLLOW_ROOT;
+	int flags = follow ? 0 : AT_SYMLINK_NOFOLLOW;
+
+	if (fstatat(AT_FDCWD, expr->sdata, &sb, flags) != 0) {
 		print_error(NULL, expr->sdata, errno);
 		free_expr(expr);
 		return NULL;
@@ -465,6 +469,20 @@ static struct expr *parse_literal(struct parser_state *state) {
 	}
 
 	switch (arg[1]) {
+	case 'P':
+		if (strcmp(arg, "-P") == 0) {
+			state->cl->flags &= ~BFTW_FOLLOW_ROOT;
+			return new_option(state, arg);
+		}
+		break;
+
+	case 'H':
+		if (strcmp(arg, "-H") == 0) {
+			state->cl->flags |= BFTW_FOLLOW_ROOT;
+			return new_option(state, arg);
+		}
+		break;
+
 	case 'a':
 		if (strcmp(arg, "-amin") == 0) {
 			return parse_acmtime(state, arg, ATIME, MINUTES);
diff --git a/tests.sh b/tests.sh
index ffb110d..0a2f60a 100755
--- a/tests.sh
+++ b/tests.sh
@@ -35,6 +35,7 @@ function links_structure() {
     ln "$1/a" "$1/c"
     mkdir -p "$1/d/e"
     ln -s ../../d "$1/d/e/f"
+    touchp "$1/d/e/g"
 }
 
 # Checks for any (order-independent) differences between bfs and find
@@ -150,7 +151,24 @@ function test_0020() {
         find_diff "$1" -links +1
 }
 
-for i in {1..20}; do
+function test_0021() {
+    links_structure "$1"
+    find_diff -P "$1/d/e/f" && \
+        find_diff -P "$1/d/e/f/"
+}
+
+function test_0022() {
+    links_structure "$1"
+    find_diff -H "$1/d/e/f" && \
+        find_diff -H "$1/d/e/f/"
+}
+
+function test_0023() {
+    links_structure "$1"
+    find_diff -H "$1" -newer "$1/d/e/f"
+}
+
+for i in {1..23}; do
     dir="$(mktemp -d "${TMPDIR:-/tmp}"/bfs.XXXXXXXXXX)"
     test="test_$(printf '%04d' $i)"
     "$test" "$dir"
-- 
cgit v1.2.3