bftw: Pass a const struct BFTW * to the callback

7 files changed, 84 insertions, 83 deletions

diff --git a/bftw.c b/bftw.c
index 98ed341..2313fec 100644
--- a/bftw.c
+++ b/bftw.c
@@ -764,26 +764,27 @@ static const struct bfs_stat *bftw_stat_impl(struct BFTW *ftwbuf, struct bftw_st
 	return cache->buf;
 }
 
-const struct bfs_stat *bftw_stat(struct BFTW *ftwbuf, enum bfs_stat_flag flags) {
+const struct bfs_stat *bftw_stat(const struct BFTW *ftwbuf, enum bfs_stat_flag flags) {
+	struct BFTW *mutbuf = (struct BFTW *)ftwbuf;
 	const struct bfs_stat *ret;
 
 	if (flags & BFS_STAT_NOFOLLOW) {
-		ret = bftw_stat_impl(ftwbuf, &ftwbuf->lstat_cache, BFS_STAT_NOFOLLOW);
-		if (ret && !S_ISLNK(ret->mode) && !ftwbuf->stat_cache.buf) {
+		ret = bftw_stat_impl(mutbuf, &mutbuf->lstat_cache, BFS_STAT_NOFOLLOW);
+		if (ret && !S_ISLNK(ret->mode) && !mutbuf->stat_cache.buf) {
 			// Non-link, so share stat info
-			ftwbuf->stat_cache.buf = ret;
+			mutbuf->stat_cache.buf = ret;
 		}
 	} else {
-		ret = bftw_stat_impl(ftwbuf, &ftwbuf->stat_cache, BFS_STAT_FOLLOW);
+		ret = bftw_stat_impl(mutbuf, &mutbuf->stat_cache, BFS_STAT_FOLLOW);
 		if (!ret && (flags & BFS_STAT_TRYFOLLOW) && is_nonexistence_error(errno)) {
-			ret = bftw_stat_impl(ftwbuf, &ftwbuf->lstat_cache, BFS_STAT_NOFOLLOW);
+			ret = bftw_stat_impl(mutbuf, &mutbuf->lstat_cache, BFS_STAT_NOFOLLOW);
 		}
 	}
 
 	return ret;
 }
 
-enum bftw_typeflag bftw_typeflag(struct BFTW *ftwbuf, enum bfs_stat_flag flags) {
+enum bftw_typeflag bftw_typeflag(const struct BFTW *ftwbuf, enum bfs_stat_flag flags) {
 	if (ftwbuf->stat_flags & BFS_STAT_NOFOLLOW) {
 		if ((flags & BFS_STAT_NOFOLLOW) || ftwbuf->typeflag != BFTW_LNK) {
 			return ftwbuf->typeflag;
@@ -911,7 +912,7 @@ static bool bftw_need_stat(struct bftw_state *state) {
 		return true;
 	}
 
-	struct BFTW *ftwbuf = &state->ftwbuf;
+	const struct BFTW *ftwbuf = &state->ftwbuf;
 	if (ftwbuf->typeflag == BFTW_UNKNOWN) {
 		return true;
 	}
@@ -1036,7 +1037,8 @@ static void bftw_prepare_visit(struct bftw_state *state) {
  * Invoke the callback.
  */
 static enum bftw_action bftw_visit_path(struct bftw_state *state) {
-	if (state->reader.dir) {
+	const struct bftw_dir *dir = state->reader.dir;
+	if (dir) {
 		if (bftw_update_path(state) != 0) {
 			state->error = errno;
 			return BFTW_STOP;
@@ -1045,18 +1047,19 @@ static enum bftw_action bftw_visit_path(struct bftw_state *state) {
 
 	bftw_prepare_visit(state);
 
+	const struct BFTW *ftwbuf = &state->ftwbuf;
+
 	// Never give the callback BFTW_ERROR unless BFTW_RECOVER is specified
-	if (state->ftwbuf.typeflag == BFTW_ERROR && !(state->flags & BFTW_RECOVER)) {
-		state->error = state->ftwbuf.error;
+	if (ftwbuf->typeflag == BFTW_ERROR && !(state->flags & BFTW_RECOVER)) {
+		state->error = ftwbuf->error;
 		return BFTW_STOP;
 	}
 
-	// Defensive copy
-	struct BFTW ftwbuf = state->ftwbuf;
-
-	enum bftw_action action = state->callback(&ftwbuf, state->ptr);
+	enum bftw_action action = state->callback(ftwbuf, state->ptr);
 	switch (action) {
 	case BFTW_CONTINUE:
+		break;
+
 	case BFTW_SKIP_SIBLINGS:
 	case BFTW_SKIP_SUBTREE:
 	case BFTW_STOP:
@@ -1066,6 +1069,19 @@ static enum bftw_action bftw_visit_path(struct bftw_state *state) {
 		state->error = EINVAL;
 		return BFTW_STOP;
 	}
+
+	if (state->visit != BFTW_PRE || ftwbuf->typeflag != BFTW_DIR) {
+		return BFTW_SKIP_SUBTREE;
+	}
+
+	if (state->flags & BFTW_XDEV) {
+		const struct bfs_stat *statbuf = bftw_stat(ftwbuf, ftwbuf->stat_flags);
+		if (statbuf && dir && statbuf->dev != dir->dev) {
+			return BFTW_SKIP_SUBTREE;
+		}
+	}
+
+	return BFTW_CONTINUE;
 }
 
 /**
@@ -1214,10 +1230,6 @@ int bftw(const char *path, const struct bftw_args *args) {
 		break;
 	}
 
-	if (state.ftwbuf.typeflag != BFTW_DIR) {
-		goto done;
-	}
-
 	// Now start the breadth-first search
 
 	if (bftw_push(&state, path) != 0) {
@@ -1247,17 +1259,6 @@ int bftw(const char *path, const struct bftw_args *args) {
 				goto done;
 			}
 
-			if (state.ftwbuf.typeflag != BFTW_DIR) {
-				goto read;
-			}
-
-			if (args->flags & BFTW_XDEV) {
-				const struct bfs_stat *statbuf = bftw_stat(&state.ftwbuf, state.ftwbuf.stat_flags);
-				if (statbuf && statbuf->dev != reader->dir->dev) {
-					goto read;
-				}
-			}
-
 			if (bftw_push(&state, name) != 0) {
 				goto done;
 			}
diff --git a/bftw.h b/bftw.h
index 626a6d8..568db9a 100644
--- a/bftw.h
+++ b/bftw.h
@@ -127,7 +127,7 @@ struct BFTW {
  * @return
  *         A pointer to a bfs_stat() buffer, or NULL if the call failed.
  */
-const struct bfs_stat *bftw_stat(struct BFTW *ftwbuf, enum bfs_stat_flag flags);
+const struct bfs_stat *bftw_stat(const struct BFTW *ftwbuf, enum bfs_stat_flag flags);
 
 /**
  * Get the type of a file encountered during bftw(), with flags controlling
@@ -141,7 +141,7 @@ const struct bfs_stat *bftw_stat(struct BFTW *ftwbuf, enum bfs_stat_flag flags);
  * @return
  *         The type of the file, or BFTW_ERROR if an error occurred.
  */
-enum bftw_typeflag bftw_typeflag(struct BFTW *ftwbuf, enum bfs_stat_flag flags);
+enum bftw_typeflag bftw_typeflag(const struct BFTW *ftwbuf, enum bfs_stat_flag flags);
 
 /**
  * Walk actions returned by the bftw() callback.
@@ -167,7 +167,7 @@ enum bftw_action {
  * @return
  *         An action value.
  */
-typedef enum bftw_action bftw_callback(struct BFTW *ftwbuf, void *ptr);
+typedef enum bftw_action bftw_callback(const struct BFTW *ftwbuf, void *ptr);
 
 /**
  * Flags that control bftw() behavior.
diff --git a/color.c b/color.c
index 188e7ed..cf507fd 100644
--- a/color.c
+++ b/color.c
@@ -550,7 +550,7 @@ static bool is_link_broken(const struct BFTW *ftwbuf) {
 }
 
 /** Get the color for a file. */
-static const char *file_color(const struct colors *colors, const char *filename, struct BFTW *ftwbuf, enum bfs_stat_flag flags) {
+static const char *file_color(const struct colors *colors, const char *filename, const struct BFTW *ftwbuf, enum bfs_stat_flag flags) {
 	const struct bfs_stat *sb = bftw_stat(ftwbuf, flags);
 	if (!sb) {
 		if (colors->missing) {
@@ -692,7 +692,7 @@ static int print_colored(const struct colors *colors, const char *esc, const cha
 }
 
 /** Print a path with colors. */
-static int print_path_colored(CFILE *cfile, const char *path, struct BFTW *ftwbuf, enum bfs_stat_flag flags) {
+static int print_path_colored(CFILE *cfile, const char *path, const struct BFTW *ftwbuf, enum bfs_stat_flag flags) {
 	const struct colors *colors = cfile->colors;
 	FILE *file = cfile->file;
 
@@ -715,7 +715,7 @@ static int print_path_colored(CFILE *cfile, const char *path, struct BFTW *ftwbu
 }
 
 /** Print the path to a file with the appropriate colors. */
-static int print_path(CFILE *cfile, struct BFTW *ftwbuf) {
+static int print_path(CFILE *cfile, const struct BFTW *ftwbuf) {
 	const struct colors *colors = cfile->colors;
 	if (!colors) {
 		return fputs(ftwbuf->path, cfile->file) == EOF ? -1 : 0;
@@ -730,7 +730,7 @@ static int print_path(CFILE *cfile, struct BFTW *ftwbuf) {
 }
 
 /** Print a link target with the appropriate colors. */
-static int print_link_target(CFILE *cfile, struct BFTW *ftwbuf) {
+static int print_link_target(CFILE *cfile, const struct BFTW *ftwbuf) {
 	int ret = -1;
 
 	size_t len = 0;
@@ -828,13 +828,13 @@ int cvfprintf(CFILE *cfile, const char *format, va_list args) {
 			case 'p':
 				switch (*++i) {
 				case 'P':
-					if (print_path(cfile, va_arg(args, struct BFTW *)) != 0) {
+					if (print_path(cfile, va_arg(args, const struct BFTW *)) != 0) {
 						return -1;
 					}
 					break;
 
 				case 'L':
-					if (print_link_target(cfile, va_arg(args, struct BFTW *)) != 0) {
+					if (print_link_target(cfile, va_arg(args, const struct BFTW *)) != 0) {
 						return -1;
 					}
 					break;
diff --git a/color.h b/color.h
index 946358a..7df3785 100644
--- a/color.h
+++ b/color.h
@@ -106,8 +106,8 @@ int cfclose(CFILE *cfile);
  *         %s: A string
  *         %zu: A size_t
  *         %m: strerror(errno)
- *         %pP: A colored file path, from a struct BFTW * argument
- *         %pL: A colored link target, from a struct BFTW * argument
+ *         %pP: A colored file path, from a const struct BFTW * argument
+ *         %pL: A colored link target, from a const struct BFTW * argument
  *         %%: A literal '%'
  *         ${cc}: Change the color to 'cc'
  *         $$: A literal '$'
diff --git a/eval.c b/eval.c
index 3bcdfeb..0c4f9a9 100644
--- a/eval.c
+++ b/eval.c
@@ -50,7 +50,7 @@
 
 struct eval_state {
 	/** Data about the current file. */
-	struct BFTW *ftwbuf;
+	const struct BFTW *ftwbuf;
 	/** The parsed command line. */
 	const struct cmdline *cmdline;
 	/** The bftw() callback return value. */
@@ -102,7 +102,7 @@ static void eval_report_error(struct eval_state *state) {
  * Perform a bfs_stat() call if necessary.
  */
 static const struct bfs_stat *eval_stat(struct eval_state *state) {
-	struct BFTW *ftwbuf = state->ftwbuf;
+	const struct BFTW *ftwbuf = state->ftwbuf;
 	const struct bfs_stat *ret = bftw_stat(ftwbuf, ftwbuf->stat_flags);
 	if (!ret) {
 		eval_report_error(state);
@@ -152,7 +152,7 @@ bool eval_false(const struct expr *expr, struct eval_state *state) {
  * -executable, -readable, -writable tests.
  */
 bool eval_access(const struct expr *expr, struct eval_state *state) {
-	struct BFTW *ftwbuf = state->ftwbuf;
+	const struct BFTW *ftwbuf = state->ftwbuf;
 	return xfaccessat(ftwbuf->at_fd, ftwbuf->at_path, expr->idata) == 0;
 }
 
@@ -317,7 +317,7 @@ bool eval_nouser(const struct expr *expr, struct eval_state *state) {
  * -delete action.
  */
 bool eval_delete(const struct expr *expr, struct eval_state *state) {
-	struct BFTW *ftwbuf = state->ftwbuf;
+	const struct BFTW *ftwbuf = state->ftwbuf;
 
 	// Don't try to delete the current directory
 	if (strcmp(ftwbuf->path, ".") == 0) {
@@ -395,7 +395,7 @@ bool eval_depth(const struct expr *expr, struct eval_state *state) {
  */
 bool eval_empty(const struct expr *expr, struct eval_state *state) {
 	bool ret = false;
-	struct BFTW *ftwbuf = state->ftwbuf;
+	const struct BFTW *ftwbuf = state->ftwbuf;
 
 	if (ftwbuf->typeflag == BFTW_DIR) {
 		int dfd = openat(ftwbuf->at_fd, ftwbuf->at_path, O_RDONLY | O_CLOEXEC | O_DIRECTORY);
@@ -459,7 +459,7 @@ bool eval_fstype(const struct expr *expr, struct eval_state *state) {
  * -hidden test.
  */
 bool eval_hidden(const struct expr *expr, struct eval_state *state) {
-	struct BFTW *ftwbuf = state->ftwbuf;
+	const struct BFTW *ftwbuf = state->ftwbuf;
 	return ftwbuf->nameoff > 0 && ftwbuf->path[ftwbuf->nameoff] == '.';
 }
 
@@ -506,7 +506,7 @@ bool eval_lname(const struct expr *expr, struct eval_state *state) {
 	bool ret = false;
 	char *name = NULL;
 
-	struct BFTW *ftwbuf = state->ftwbuf;
+	const struct BFTW *ftwbuf = state->ftwbuf;
 	if (ftwbuf->typeflag != BFTW_LNK) {
 		goto done;
 	}
@@ -533,7 +533,7 @@ done:
  * -i?name test.
  */
 bool eval_name(const struct expr *expr, struct eval_state *state) {
-	struct BFTW *ftwbuf = state->ftwbuf;
+	const struct BFTW *ftwbuf = state->ftwbuf;
 
 	const char *name = ftwbuf->path + ftwbuf->nameoff;
 	char *copy = NULL;
@@ -560,7 +560,7 @@ bool eval_name(const struct expr *expr, struct eval_state *state) {
  * -i?path test.
  */
 bool eval_path(const struct expr *expr, struct eval_state *state) {
-	struct BFTW *ftwbuf = state->ftwbuf;
+	const struct BFTW *ftwbuf = state->ftwbuf;
 	return fnmatch(expr->sdata, ftwbuf->path, expr->idata) == 0;
 }
 
@@ -601,7 +601,7 @@ bool eval_perm(const struct expr *expr, struct eval_state *state) {
 bool eval_fls(const struct expr *expr, struct eval_state *state) {
 	CFILE *cfile = expr->cfile;
 	FILE *file = cfile->file;
-	struct BFTW *ftwbuf = state->ftwbuf;
+	const struct BFTW *ftwbuf = state->ftwbuf;
 	const struct bfs_stat *statbuf = eval_stat(state);
 	if (!statbuf) {
 		goto done;
@@ -884,7 +884,7 @@ bool eval_type(const struct expr *expr, struct eval_state *state) {
  * -xtype test.
  */
 bool eval_xtype(const struct expr *expr, struct eval_state *state) {
-	struct BFTW *ftwbuf = state->ftwbuf;
+	const struct BFTW *ftwbuf = state->ftwbuf;
 	enum bfs_stat_flag flags = ftwbuf->stat_flags ^ (BFS_STAT_NOFOLLOW | BFS_STAT_TRYFOLLOW);
 	enum bftw_typeflag type = bftw_typeflag(ftwbuf, flags);
 	if (type == BFTW_ERROR) {
@@ -1168,7 +1168,7 @@ struct callback_args {
 /**
  * bftw() callback.
  */
-static enum bftw_action cmdline_callback(struct BFTW *ftwbuf, void *ptr) {
+static enum bftw_action cmdline_callback(const struct BFTW *ftwbuf, void *ptr) {
 	struct callback_args *args = ptr;
 
 	const struct cmdline *cmdline = args->cmdline;
diff --git a/printf.c b/printf.c
index f77ff92..80f54c9 100644
--- a/printf.c
+++ b/printf.c
@@ -33,7 +33,7 @@
 #include <string.h>
 #include <time.h>
 
-typedef int bfs_printf_fn(FILE *file, const struct bfs_printf *directive, struct BFTW *ftwbuf);
+typedef int bfs_printf_fn(FILE *file, const struct bfs_printf *directive, const struct BFTW *ftwbuf);
 
 struct bfs_printf {
 	/** The printing function to invoke. */
@@ -51,7 +51,7 @@ struct bfs_printf {
 };
 
 /** Print some text as-is. */
-static int bfs_printf_literal(FILE *file, const struct bfs_printf *directive, struct BFTW *ftwbuf) {
+static int bfs_printf_literal(FILE *file, const struct bfs_printf *directive, const struct BFTW *ftwbuf) {
 	size_t len = dstrlen(directive->str);
 	if (fwrite(directive->str, 1, len, file) == len) {
 		return 0;
@@ -61,7 +61,7 @@ static int bfs_printf_literal(FILE *file, const struct bfs_printf *directive, st
 }
 
 /** \c: flush */
-static int bfs_printf_flush(FILE *file, const struct bfs_printf *directive, struct BFTW *ftwbuf) {
+static int bfs_printf_flush(FILE *file, const struct bfs_printf *directive, const struct BFTW *ftwbuf) {
 	return fflush(file);
 }
 
@@ -75,7 +75,7 @@ static int bfs_printf_flush(FILE *file, const struct bfs_printf *directive, stru
 	(void)ret
 
 /** %a, %c, %t: ctime() */
-static int bfs_printf_ctime(FILE *file, const struct bfs_printf *directive, struct BFTW *ftwbuf) {
+static int bfs_printf_ctime(FILE *file, const struct bfs_printf *directive, const struct BFTW *ftwbuf) {
 	// Not using ctime() itself because GNU find adds nanoseconds
 	static const char *days[] = {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};
 	static const char *months[] = {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
@@ -109,7 +109,7 @@ static int bfs_printf_ctime(FILE *file, const struct bfs_printf *directive, stru
 }
 
 /** %A, %B/%W, %C, %T: strftime() */
-static int bfs_printf_strftime(FILE *file, const struct bfs_printf *directive, struct BFTW *ftwbuf) {
+static int bfs_printf_strftime(FILE *file, const struct bfs_printf *directive, const struct BFTW *ftwbuf) {
 	const struct bfs_stat *statbuf = bftw_stat(ftwbuf, ftwbuf->stat_flags);
 	if (!statbuf) {
 		return -1;
@@ -177,7 +177,7 @@ static int bfs_printf_strftime(FILE *file, const struct bfs_printf *directive, s
 }
 
 /** %b: blocks */
-static int bfs_printf_b(FILE *file, const struct bfs_printf *directive, struct BFTW *ftwbuf) {
+static int bfs_printf_b(FILE *file, const struct bfs_printf *directive, const struct BFTW *ftwbuf) {
 	const struct bfs_stat *statbuf = bftw_stat(ftwbuf, ftwbuf->stat_flags);
 	if (!statbuf) {
 		return -1;
@@ -189,12 +189,12 @@ static int bfs_printf_b(FILE *file, const struct bfs_printf *directive, struct B
 }
 
 /** %d: depth */
-static int bfs_printf_d(FILE *file, const struct bfs_printf *directive, struct BFTW *ftwbuf) {
+static int bfs_printf_d(FILE *file, const struct bfs_printf *directive, const struct BFTW *ftwbuf) {
 	return fprintf(file, directive->str, (intmax_t)ftwbuf->depth);
 }
 
 /** %D: device */
-static int bfs_printf_D(FILE *file, const struct bfs_printf *directive, struct BFTW *ftwbuf) {
+static int bfs_printf_D(FILE *file, const struct bfs_printf *directive, const struct BFTW *ftwbuf) {
 	const struct bfs_stat *statbuf = bftw_stat(ftwbuf, ftwbuf->stat_flags);
 	if (!statbuf) {
 		return -1;
@@ -205,12 +205,12 @@ static int bfs_printf_D(FILE *file, const struct bfs_printf *directive, struct B
 }
 
 /** %f: file name */
-static int bfs_printf_f(FILE *file, const struct bfs_printf *directive, struct BFTW *ftwbuf) {
+static int bfs_printf_f(FILE *file, const struct bfs_printf *directive, const struct BFTW *ftwbuf) {
 	return fprintf(file, directive->str, ftwbuf->path + ftwbuf->nameoff);
 }
 
 /** %F: file system type */
-static int bfs_printf_F(FILE *file, const struct bfs_printf *directive, struct BFTW *ftwbuf) {
+static int bfs_printf_F(FILE *file, const struct bfs_printf *directive, const struct BFTW *ftwbuf) {
 	const struct bfs_stat *statbuf = bftw_stat(ftwbuf, ftwbuf->stat_flags);
 	if (!statbuf) {
 		return -1;
@@ -221,7 +221,7 @@ static int bfs_printf_F(FILE *file, const struct bfs_printf *directive, struct B
 }
 
 /** %G: gid */
-static int bfs_printf_G(FILE *file, const struct bfs_printf *directive, struct BFTW *ftwbuf) {
+static int bfs_printf_G(FILE *file, const struct bfs_printf *directive, const struct BFTW *ftwbuf) {
 	const struct bfs_stat *statbuf = bftw_stat(ftwbuf, ftwbuf->stat_flags);
 	if (!statbuf) {
 		return -1;
@@ -232,7 +232,7 @@ static int bfs_printf_G(FILE *file, const struct bfs_printf *directive, struct B
 }
 
 /** %g: group name */
-static int bfs_printf_g(FILE *file, const struct bfs_printf *directive, struct BFTW *ftwbuf) {
+static int bfs_printf_g(FILE *file, const struct bfs_printf *directive, const struct BFTW *ftwbuf) {
 	const struct bfs_stat *statbuf = bftw_stat(ftwbuf, ftwbuf->stat_flags);
 	if (!statbuf) {
 		return -1;
@@ -247,7 +247,7 @@ static int bfs_printf_g(FILE *file, const struct bfs_printf *directive, struct B
 }
 
 /** %h: leading directories */
-static int bfs_printf_h(FILE *file, const struct bfs_printf *directive, struct BFTW *ftwbuf) {
+static int bfs_printf_h(FILE *file, const struct bfs_printf *directive, const struct BFTW *ftwbuf) {
 	char *copy = NULL;
 	const char *buf;
 
@@ -274,12 +274,12 @@ static int bfs_printf_h(FILE *file, const struct bfs_printf *directive, struct B
 }
 
 /** %H: current root */
-static int bfs_printf_H(FILE *file, const struct bfs_printf *directive, struct BFTW *ftwbuf) {
+static int bfs_printf_H(FILE *file, const struct bfs_printf *directive, const struct BFTW *ftwbuf) {
 	return fprintf(file, directive->str, ftwbuf->root);
 }
 
 /** %i: inode */
-static int bfs_printf_i(FILE *file, const struct bfs_printf *directive, struct BFTW *ftwbuf) {
+static int bfs_printf_i(FILE *file, const struct bfs_printf *directive, const struct BFTW *ftwbuf) {
 	const struct bfs_stat *statbuf = bftw_stat(ftwbuf, ftwbuf->stat_flags);
 	if (!statbuf) {
 		return -1;
@@ -290,7 +290,7 @@ static int bfs_printf_i(FILE *file, const struct bfs_printf *directive, struct B
 }
 
 /** %k: 1K blocks */
-static int bfs_printf_k(FILE *file, const struct bfs_printf *directive, struct BFTW *ftwbuf) {
+static int bfs_printf_k(FILE *file, const struct bfs_printf *directive, const struct BFTW *ftwbuf) {
 	const struct bfs_stat *statbuf = bftw_stat(ftwbuf, ftwbuf->stat_flags);
 	if (!statbuf) {
 		return -1;
@@ -302,7 +302,7 @@ static int bfs_printf_k(FILE *file, const struct bfs_printf *directive, struct B
 }
 
 /** %l: link target */
-static int bfs_printf_l(FILE *file, const struct bfs_printf *directive, struct BFTW *ftwbuf) {
+static int bfs_printf_l(FILE *file, const struct bfs_printf *directive, const struct BFTW *ftwbuf) {
 	if (ftwbuf->typeflag != BFTW_LNK) {
 		return 0;
 	}
@@ -318,7 +318,7 @@ static int bfs_printf_l(FILE *file, const struct bfs_printf *directive, struct B
 }
 
 /** %m: mode */
-static int bfs_printf_m(FILE *file, const struct bfs_printf *directive, struct BFTW *ftwbuf) {
+static int bfs_printf_m(FILE *file, const struct bfs_printf *directive, const struct BFTW *ftwbuf) {
 	const struct bfs_stat *statbuf = bftw_stat(ftwbuf, ftwbuf->stat_flags);
 	if (!statbuf) {
 		return -1;
@@ -328,7 +328,7 @@ static int bfs_printf_m(FILE *file, const struct bfs_printf *directive, struct B
 }
 
 /** %M: symbolic mode */
-static int bfs_printf_M(FILE *file, const struct bfs_printf *directive, struct BFTW *ftwbuf) {
+static int bfs_printf_M(FILE *file, const struct bfs_printf *directive, const struct BFTW *ftwbuf) {
 	const struct bfs_stat *statbuf = bftw_stat(ftwbuf, ftwbuf->stat_flags);
 	if (!statbuf) {
 		return -1;
@@ -340,7 +340,7 @@ static int bfs_printf_M(FILE *file, const struct bfs_printf *directive, struct B
 }
 
 /** %n: link count */
-static int bfs_printf_n(FILE *file, const struct bfs_printf *directive, struct BFTW *ftwbuf) {
+static int bfs_printf_n(FILE *file, const struct bfs_printf *directive, const struct BFTW *ftwbuf) {
 	const struct bfs_stat *statbuf = bftw_stat(ftwbuf, ftwbuf->stat_flags);
 	if (!statbuf) {
 		return -1;
@@ -351,12 +351,12 @@ static int bfs_printf_n(FILE *file, const struct bfs_printf *directive, struct B
 }
 
 /** %p: full path */
-static int bfs_printf_p(FILE *file, const struct bfs_printf *directive, struct BFTW *ftwbuf) {
+static int bfs_printf_p(FILE *file, const struct bfs_printf *directive, const struct BFTW *ftwbuf) {
 	return fprintf(file, directive->str, ftwbuf->path);
 }
 
 /** %P: path after root */
-static int bfs_printf_P(FILE *file, const struct bfs_printf *directive, struct BFTW *ftwbuf) {
+static int bfs_printf_P(FILE *file, const struct bfs_printf *directive, const struct BFTW *ftwbuf) {
 	const char *path = ftwbuf->path + strlen(ftwbuf->root);
 	if (path[0] == '/') {
 		++path;
@@ -365,7 +365,7 @@ static int bfs_printf_P(FILE *file, const struct bfs_printf *directive, struct B
 }
 
 /** %s: size */
-static int bfs_printf_s(FILE *file, const struct bfs_printf *directive, struct BFTW *ftwbuf) {
+static int bfs_printf_s(FILE *file, const struct bfs_printf *directive, const struct BFTW *ftwbuf) {
 	const struct bfs_stat *statbuf = bftw_stat(ftwbuf, ftwbuf->stat_flags);
 	if (!statbuf) {
 		return -1;
@@ -376,7 +376,7 @@ static int bfs_printf_s(FILE *file, const struct bfs_printf *directive, struct B
 }
 
 /** %S: sparseness */
-static int bfs_printf_S(FILE *file, const struct bfs_printf *directive, struct BFTW *ftwbuf) {
+static int bfs_printf_S(FILE *file, const struct bfs_printf *directive, const struct BFTW *ftwbuf) {
 	const struct bfs_stat *statbuf = bftw_stat(ftwbuf, ftwbuf->stat_flags);
 	if (!statbuf) {
 		return -1;
@@ -392,7 +392,7 @@ static int bfs_printf_S(FILE *file, const struct bfs_printf *directive, struct B
 }
 
 /** %U: uid */
-static int bfs_printf_U(FILE *file, const struct bfs_printf *directive, struct BFTW *ftwbuf) {
+static int bfs_printf_U(FILE *file, const struct bfs_printf *directive, const struct BFTW *ftwbuf) {
 	const struct bfs_stat *statbuf = bftw_stat(ftwbuf, ftwbuf->stat_flags);
 	if (!statbuf) {
 		return -1;
@@ -403,7 +403,7 @@ static int bfs_printf_U(FILE *file, const struct bfs_printf *directive, struct B
 }
 
 /** %u: user name */
-static int bfs_printf_u(FILE *file, const struct bfs_printf *directive, struct BFTW *ftwbuf) {
+static int bfs_printf_u(FILE *file, const struct bfs_printf *directive, const struct BFTW *ftwbuf) {
 	const struct bfs_stat *statbuf = bftw_stat(ftwbuf, ftwbuf->stat_flags);
 	if (!statbuf) {
 		return -1;
@@ -441,13 +441,13 @@ static const char *bfs_printf_type(enum bftw_typeflag typeflag) {
 }
 
 /** %y: type */
-static int bfs_printf_y(FILE *file, const struct bfs_printf *directive, struct BFTW *ftwbuf) {
+static int bfs_printf_y(FILE *file, const struct bfs_printf *directive, const struct BFTW *ftwbuf) {
 	const char *type = bfs_printf_type(ftwbuf->typeflag);
 	return fprintf(file, directive->str, type);
 }
 
 /** %Y: target type */
-static int bfs_printf_Y(FILE *file, const struct bfs_printf *directive, struct BFTW *ftwbuf) {
+static int bfs_printf_Y(FILE *file, const struct bfs_printf *directive, const struct BFTW *ftwbuf) {
 	int error = 0;
 
 	if (ftwbuf->typeflag != BFTW_LNK) {
@@ -839,7 +839,7 @@ error:
 	return NULL;
 }
 
-int bfs_printf(FILE *file, const struct bfs_printf *command, struct BFTW *ftwbuf) {
+int bfs_printf(FILE *file, const struct bfs_printf *command, const struct BFTW *ftwbuf) {
 	int ret = 0, error = 0;
 
 	for (const struct bfs_printf *directive = command; directive; directive = directive->next) {
diff --git a/printf.h b/printf.h
index d62770e..3bbbcd2 100644
--- a/printf.h
+++ b/printf.h
@@ -54,7 +54,7 @@ struct bfs_printf *parse_bfs_printf(const char *format, struct cmdline *cmdline)
  *         must be non-NULL.
  * @return 0 on success, -1 on failure.
  */
-int bfs_printf(FILE *file, const struct bfs_printf *command, struct BFTW *ftwbuf);
+int bfs_printf(FILE *file, const struct bfs_printf *command, const struct BFTW *ftwbuf);
 
 /**
  * Free a parsed format string.