coredump,basic: generalize O_TMPFILE handling a bit

This moves the O_TMPFILE handling from the coredumping code into common library
code, and generalizes it as open_tmpfile_linkable() + link_tmpfile(). The
existing open_tmpfile() function (which creates an unlinked temporary file that
cannot be linked into the fs) is renamed to open_tmpfile_unlinkable(), to make
the distinction clear. Thus, code may now choose between:

 a) open_tmpfile_linkable() + link_tmpfile()
 b) open_tmpfile_unlinkable()

Depending on whether they want a file that may be linked back into the fs later
on or not.

In a later commit we should probably convert fopen_temporary() to make use of
open_tmpfile_linkable().

Followup for: #3065

2 files changed, 4 insertions, 4 deletions

diff --git a/src/journal/journal-send.c b/src/journal/journal-send.c
index a79846146a..f0959b6237 100644
--- a/src/journal/journal-send.c
+++ b/src/journal/journal-send.c
@@ -316,7 +316,7 @@ _public_ int sd_journal_sendv(const struct iovec *iov, int n) {
         buffer_fd = memfd_new(NULL);
         if (buffer_fd < 0) {
                 if (buffer_fd == -ENOSYS) {
-                        buffer_fd = open_tmpfile("/dev/shm", O_RDWR | O_CLOEXEC);
+                        buffer_fd = open_tmpfile_unlinkable("/dev/shm", O_RDWR | O_CLOEXEC);
                         if (buffer_fd < 0)
                                 return buffer_fd;
 
diff --git a/src/journal/journal-verify.c b/src/journal/journal-verify.c
index a1241c9bcf..26572ddd76 100644
--- a/src/journal/journal-verify.c
+++ b/src/journal/journal-verify.c
@@ -838,19 +838,19 @@ int journal_file_verify(
         } else if (f->seal)
                 return -ENOKEY;
 
-        data_fd = open_tmpfile("/var/tmp", O_RDWR | O_CLOEXEC);
+        data_fd = open_tmpfile_unlinkable("/var/tmp", O_RDWR | O_CLOEXEC);
         if (data_fd < 0) {
                 r = log_error_errno(data_fd, "Failed to create data file: %m");
                 goto fail;
         }
 
-        entry_fd = open_tmpfile("/var/tmp", O_RDWR | O_CLOEXEC);
+        entry_fd = open_tmpfile_unlinkable("/var/tmp", O_RDWR | O_CLOEXEC);
         if (entry_fd < 0) {
                 r = log_error_errno(entry_fd, "Failed to create entry file: %m");
                 goto fail;
         }
 
-        entry_array_fd = open_tmpfile("/var/tmp", O_RDWR | O_CLOEXEC);
+        entry_array_fd = open_tmpfile_unlinkable("/var/tmp", O_RDWR | O_CLOEXEC);
         if (entry_array_fd < 0) {
                 r = log_error_errno(entry_array_fd,
                                     "Failed to create entry array file: %m");