From 9b50adaaaa4fedc8bda6fcf32595ecf7a682fa8b Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Tue, 19 Oct 2021 12:24:22 -0400
Subject: parse: Switch back to O_TRUNC from explicit ftruncate()

O_TRUNC is not equivalent to an unconditional ftruncate(), e.g. for
device files.

This reverts the behaviour change from 78944c81, which was never
released and is not supported in other find implementations.
---
 parse.c | 23 +++++++----------------
 1 file changed, 7 insertions(+), 16 deletions(-)

(limited to 'parse.c')

diff --git a/parse.c b/parse.c
index c257f4e..aea7b4f 100644
--- a/parse.c
+++ b/parse.c
@@ -336,9 +336,8 @@ static int expr_open(struct parser_state *state, struct expr *expr, const char *
 
 	FILE *file = NULL;
 	CFILE *cfile = NULL;
-	CFILE *dedup = NULL;
 
-	file = xfopen(path, O_WRONLY | O_CREAT | O_CLOEXEC);
+	file = xfopen(path, O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC);
 	if (!file) {
 		goto fail;
 	}
@@ -348,18 +347,12 @@ static int expr_open(struct parser_state *state, struct expr *expr, const char *
 		goto fail;
 	}
 
-	dedup = bfs_ctx_dedup(ctx, cfile, path);
+	CFILE *dedup = bfs_ctx_dedup(ctx, cfile, path);
 	if (!dedup) {
 		goto fail;
 	}
 
-	if (dedup == cfile) {
-		// O_TRUNC was omitted above to avoid repeatedly truncating the same file, so do it
-		// manually here
-		if (ftruncate(fileno(file), 0) != 0) {
-			goto fail;
-		}
-	} else {
+	if (dedup != cfile) {
 		cfclose(cfile);
 	}
 
@@ -368,12 +361,10 @@ static int expr_open(struct parser_state *state, struct expr *expr, const char *
 
 fail:
 	parse_error(state, "${blu}%s${rs} ${bld}%s${rs}: %m.\n", expr->argv[0], path);
-	if (!dedup) {
-		if (cfile) {
-			cfclose(cfile);
-		} else if (file) {
-			fclose(file);
-		}
+	if (cfile) {
+		cfclose(cfile);
+	} else if (file) {
+		fclose(file);
 	}
 	return -1;
 }
-- 
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