rust: adapt to new systemd journal API

The next/previous functions were renamed, and the journal is no longer
seeked to the head on open, so we have to do it manually. We did that
already in most places, except one.

For more information, see:
https://github.com/jmesmon/rust-systemd/pull/121

rust/src/history.rs

@@ -191,7 +191,7 @@ fn history_get_oldest_deployment_msg_timestamp() -> Result<Option<u64>> {
     let mut journal = journal::Journal::open(journal::JournalFiles::System, false, true)?;
     journal.seek(journal::JournalSeek::Head)?;
     journal.match_add("MESSAGE_ID", RPMOSTREE_DEPLOY_MSG)?;
-    while let Some(rec) = journal.next_record()? {
+    while let Some(rec) = journal.next_entry()? {
         if let Some(ts) = map_to_u64(rec.get("DEPLOYMENT_TIMESTAMP")) {
             return Ok(Some(ts));
         }
@@ -306,7 +306,7 @@ impl HistoryCtx {
     /// Goes to the next OSTree boot msg in the journal and returns its marker.
     fn find_next_boot_marker(&mut self) -> Result<Option<BootMarker>> {
         self.set_search_mode(JournalSearchMode::BootMsgs)?;
-        while let Some(rec) = self.journal.previous_record()? {
+        while let Some(rec) = self.journal.previous_entry()? {
             if let Some(Marker::Boot(m)) = self.boot_record_to_marker(&rec)? {
                 return Ok(Some(m));
             }
@@ -327,7 +327,7 @@ impl HistoryCtx {
     /// marker for it, and returns it.
     fn find_next_marker(&mut self) -> Result<Option<Marker>> {
         self.set_search_mode(JournalSearchMode::BootAndDeploymentMsgs)?;
-        while let Some(rec) = self.journal.previous_record()? {
+        while let Some(rec) = self.journal.previous_entry()? {
             if let Some(marker) = self.record_to_marker(&rec)? {
                 return Ok(Some(marker));
             }
@@ -473,7 +473,7 @@ mod mock_journal {
             self.msg_ids.push(msg_id.into());
             Ok(())
         }
-        pub fn previous_record(&mut self) -> Result<Option<JournalRecord>> {
+        pub fn previous_entry(&mut self) -> Result<Option<JournalRecord>> {
             while let Some((timestamp, record)) = self.entries.pop() {
                 if self.msg_ids.contains(record.get("MESSAGE_ID").unwrap()) {
                     self.current_timestamp = Some(timestamp);
@@ -483,7 +483,7 @@ mod mock_journal {
             Ok(None)
         }
         // This is only used by the prune path, which we're not unit testing.
-        pub fn next_record(&mut self) -> Result<Option<JournalRecord>> {
+        pub fn next_entry(&mut self) -> Result<Option<JournalRecord>> {
             unimplemented!();
         }
     }

rust/src/journal.rs

@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: Apache-2.0 OR MIT
  */
 
-use anyhow::Result;
+use anyhow::{bail, Result};
 use systemd::id128::Id128;
 use systemd::journal;
 
@@ -27,11 +27,14 @@ fn print_staging_failure_msg(msg: Option<&str>) -> Result<()> {
 /// Look for a failure from ostree-finalized-stage.service in the journal of the previous boot.
 fn journal_print_staging_failure() -> Result<()> {
     let mut j = journal::Journal::open(journal::JournalFiles::System, false, true)?;
+    j.seek(journal::JournalSeek::Head)?;
 
     // first, go to the first entry of the current boot
     let boot_id = Id128::from_boot()?;
     j.match_add("_BOOT_ID", boot_id.to_string().as_str())?;
-    j.seek(journal::JournalSeek::Head)?;
+    if j.next_entry()?.is_none() {
+        bail!("couldn't find current boot in journal");
+    }
     j.match_flush()?;
 
     // Now, go backwards until we hit the first entry from the previous boot. In theory that should
@@ -39,7 +42,7 @@ fn journal_print_staging_failure() -> Result<()> {
     // https://github.com/systemd/systemd/commit/dc00966228ff90c554fd034e588ea55eb605ec52
     let mut previous_boot_id: Id128 = boot_id.clone();
     while previous_boot_id == boot_id {
-        match j.previous_record()? {
+        match j.previous_entry()? {
             Some(_) => previous_boot_id = j.monotonic_timestamp()?.1,
             None => return Ok(()), // no previous boot!
         }
@@ -54,7 +57,7 @@ fn journal_print_staging_failure() -> Result<()> {
     j.match_add("MESSAGE_ID", OSTREE_DEPLOYMENT_FINALIZING_MSG_ID)?;
     j.match_add("SYSLOG_IDENTIFIER", "ostree")?;
     j.match_add("_BOOT_ID", previous_boot_id.as_str())?;
-    let ostree_pid = match j.previous_record()? {
+    let ostree_pid = match j.previous_entry()? {
         None => return Ok(()), // didn't run (or staged deployment was cleaned up)
         Some(mut rec) => rec.remove("_PID").unwrap(),
     };
@@ -69,7 +72,7 @@ fn journal_print_staging_failure() -> Result<()> {
     j.match_add("_PID", ostree_pid.as_str())?;
     j.match_add("_BOOT_ID", previous_boot_id.as_str())?;
 
-    if j.next_record()? != None {
+    if j.next_entry()? != None {
         return Ok(()); // finished successfully!
     }
 
@@ -86,7 +89,7 @@ fn journal_print_staging_failure() -> Result<()> {
     j.match_add("_BOOT_ID", previous_boot_id.as_str())?;
 
     let mut exited = false;
-    while let Some(rec) = j.next_record()? {
+    while let Some(rec) = j.next_entry()? {
         if let Some(msg) = rec.get("MESSAGE") {
             if msg.contains("Failed with result") || msg.contains("control process exited") {
                 if !msg.contains("exit-code") && !msg.contains("code=exited") {
@@ -118,7 +121,7 @@ fn journal_print_staging_failure() -> Result<()> {
     // systemd can be timestamped *after* the error msg (stdout transport)...
     j.match_add("_TRANSPORT", "stdout")?;
 
-    if let Some(rec) = j.previous_record()? {
+    if let Some(rec) = j.previous_entry()? {
         if let Some(msg) = rec.get("MESSAGE") {
             // only print the msg if it starts with 'error:', otherwise some other really
             // weird thing happened that might span multiple lines?