From: Lennart Poettering <lennart@poettering.net>
Date: Fri, 13 Dec 2024 17:55:00 +0000 (+0100)
Subject: memfd-util: simplify memfd_new_and_seal()
X-Git-Tag: v258-rc1~1831^2~12
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=db5381c49c671df28136a7025454bf85e555c0d9;p=thirdparty%2Fsystemd.git

memfd-util: simplify memfd_new_and_seal()

Let's use pwrite() to write the contents of the memfd. This has the
benefit of not moving the file offset, which means we don't have to
reset it after at all.
---

diff --git a/src/basic/memfd-util.c b/src/basic/memfd-util.c
index 0ae9a4f777f..9ceb18cc2f3 100644
--- a/src/basic/memfd-util.c
+++ b/src/basic/memfd-util.c
@@ -171,8 +171,6 @@ int memfd_new_and_map(const char *name, size_t sz, void **p) {
 
 int memfd_new_and_seal(const char *name, const void *data, size_t sz) {
         _cleanup_close_ int fd = -EBADF;
-        ssize_t n;
-        off_t f;
         int r;
 
         assert(data || sz == 0);
@@ -185,15 +183,11 @@ int memfd_new_and_seal(const char *name, const void *data, size_t sz) {
                 return fd;
 
         if (sz > 0) {
-                n = write(fd, data, sz);
+                ssize_t n = pwrite(fd, data, sz, 0);
                 if (n < 0)
                         return -errno;
                 if ((size_t) n != sz)
                         return -EIO;
-
-                f = lseek(fd, 0, SEEK_SET);
-                if (f != 0)
-                        return -errno;
         }
 
         r = memfd_set_sealed(fd);