Re: [PATCH v2 1/2] t: add a test helper to truncate files
From: Eric Sunshine <hidden>
Date: 2023-10-12 17:49:30
On Thu, Oct 12, 2023 at 12:10 PM brian m. carlson [off-list ref] wrote:
quoted hunk ↗ jump to hunk
In a future commit, we're going to work with some large files which will be at least 4 GiB in size. To take advantage of the sparseness functionality on most Unix systems and avoid running the system out of disk, it would be convenient to use truncate(2) to simply create a sparse file of sufficient size. However, the GNU truncate(1) utility isn't portable, so let's write a tiny test helper that does the work for us. Signed-off-by: brian m. carlson <redacted> ---diff --git a/t/helper/test-truncate.c b/t/helper/test-truncate.c@@ -0,0 +1,27 @@ +int cmd__truncate(int argc, const char **argv) +{ + char *p = NULL; + uintmax_t sz = 0; + int fd = -1; + + if (argc != 3) + die("expected filename and size"); + + sz = strtoumax(argv[2], &p, 0); + if (*p) + die("invalid size");
Do you want to check 'errno' here, as well (probably before the '*p' check)? Or is that being too defensive for a 'test-tool' command?
+ fd = open(argv[1], O_WRONLY | O_CREAT, 0600);
+ if (fd < 0)
+ die_errno("failed to open file %s", argv[1]);
+
+ if (ftruncate(fd, (off_t) sz) < 0)
+ die_errno("failed to truncate file");
+ return 0;
+}