import: Handle small files

When systemd-pull encountered a file shorter than the compression magic
headers it looks for, then it would complete the download in the
analysis state and fail.
When we are still in the analysis state and the download is done, we
know there is no compression and we should leave the analysis state and
continue writing out to disk as usual.

src/import/pull-job.c

@@ -299,6 +299,29 @@ static int pull_job_open_disk(PullJob *j) {
         return 0;
 }
 
+static int pull_job_begin_running(PullJob *j) {
+        int r;
+
+        assert(j);
+        assert(j->state == PULL_JOB_ANALYZING);
+        assert(j->compress);
+
+        r = pull_job_open_disk(j);
+        if (r < 0)
+                return r;
+
+        /* Now, take the payload we read so far, and decompress it */
+        _cleanup_(iovec_done) struct iovec stub = TAKE_STRUCT(j->payload);
+
+        j->state = PULL_JOB_RUNNING;
+
+        r = pull_job_write_compressed(j, &stub);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
 static int pull_job_curl_on_finished(CurlSlot *slot, CURL *curl, CURLcode result, void *userdata) {
         PullJob *j = ASSERT_PTR(userdata);
         char *scheme = NULL;
@@ -382,6 +405,20 @@ static int pull_job_curl_on_finished(CurlSlot *slot, CURL *curl, CURLcode result
                         return pull_job_finish(j, log_error_errno(SYNTHETIC_ERRNO(EIO), "HTTP request to %s finished with unexpected code %li.", j->url, status));
         }
 
+        if (j->state == PULL_JOB_ANALYZING) {
+                /* When curl finished the download while we were still looking for a compression magic
+                 * header the content isn't compressed but should be written out as is. */
+                assert(result == CURLE_OK);
+
+                r = decompressor_force_off(&j->compress);
+                if (r < 0)
+                        return pull_job_finish(j, r);
+
+                r = pull_job_begin_running(j);
+                if (r < 0)
+                        return pull_job_finish(j, r);
+        }
+
         if (j->state != PULL_JOB_RUNNING)
                 return pull_job_finish(j, log_error_errno(SYNTHETIC_ERRNO(EIO), "Premature connection termination."));
 
@@ -483,20 +520,7 @@ static int pull_job_detect_compression(PullJob *j) {
 
         log_debug("Stream is compressed: %s", compression_to_string(compressor_type(j->compress)));
 
-        r = pull_job_open_disk(j);
-        if (r < 0)
-                return r;
-
-        /* Now, take the payload we read so far, and decompress it */
-        _cleanup_(iovec_done) struct iovec stub = TAKE_STRUCT(j->payload);
-
-        j->state = PULL_JOB_RUNNING;
-
-        r = pull_job_write_compressed(j, &stub);
-        if (r < 0)
-                return r;
-
-        return 0;
+        return pull_job_begin_running(j);
 }
 
 static size_t pull_job_write_callback(void *contents, size_t size, size_t nmemb, void *userdata) {

test/units/TEST-72-SYSUPDATE.sh

@@ -552,4 +552,28 @@ EOF
 done
 done
 
+# Make sure the processing of compressed streams still handles uncompressed streams shorter than
+# COMPRESSION_MAGIC_BYTES_MAX correctly.
+rm -rf "$CONFIGDIR" "$WORKDIR/blobs"
+mkdir -p "$CONFIGDIR" "$WORKDIR/blobs"
+printf 'xx' >"$WORKDIR/source/tiny-v1.bin"
+(cd "$WORKDIR/source" && sha256sum tiny-v1.bin >SHA256SUMS)
+cat >"$CONFIGDIR/01-tiny-url.transfer" <<EOF
+[Source]
+Type=url-file
+Path=file://$WORKDIR/source
+MatchPattern=tiny-@v.bin
+
+[Target]
+Type=regular-file
+Path=$WORKDIR/blobs
+MatchPattern=tiny-@v.bin
+InstancesMax=1
+EOF
+"$SYSUPDATE" --verify=no update
+cmp "$WORKDIR/source/tiny-v1.bin" "$WORKDIR/blobs/tiny-v1.bin"
+rm "$CONFIGDIR/01-tiny-url.transfer"
+rm "$WORKDIR/source/tiny-v1.bin"
+rm "$WORKDIR/source/SHA256SUMS"
+
 touch /testok