[opentitantool] improve user experience

When 'opentitiantool image manifest update ...' fails due to any input
or output file name mistyped, or any of the input files does not
exist, the error message is the same:

  Error: No such file or directory (os error 2)

Which does not help much the operator. This patch adds some code which
will print the name of the file causing the error.

Tested by invoking 'image manifest update' with incorrectly specified
various input files.

The same improvement is being made to the bootstrap option, file name
is reported if file read attempt failed.

Signed-off-by: Vadim Bendebury <[email protected]>

sw/host/opentitanlib/src/image/manifest_def.rs

@@ -8,7 +8,7 @@ use crate::util::bigint::fixed_size_bigint;
 use crate::util::num_de::HexEncoded;
 use crate::util::parse_int::ParseInt;
 
-use anyhow::{bail, Result};
+use anyhow::{bail, Context, Result};
 use serde::{Deserialize, Serialize};
 use std::convert::{TryFrom, TryInto};
 use std::fmt;
@@ -96,7 +96,9 @@ macro_rules! manifest_def {
 
 impl ManifestSpec {
     pub fn read_from_file(path: &Path) -> Result<ManifestSpec> {
-        Ok(deser_hjson::from_str(&std::fs::read_to_string(path)?)?)
+        Ok(deser_hjson::from_str(
+            &std::fs::read_to_string(path).with_context(|| format!("Failed to open {path:?}"))?,
+        )?)
     }
 
     pub fn overwrite_fields(&mut self, other: ManifestSpec) {

sw/host/opentitanlib/src/util/file.rs

@@ -2,7 +2,7 @@
 // Licensed under the Apache License, Version 2.0, see LICENSE for details.
 // SPDX-License-Identifier: Apache-2.0
 
-use anyhow::{ensure, Result};
+use anyhow::{ensure, Context, Result};
 use pem_rfc7468::{Decoder, Encoder, LineEnding};
 use thiserror::Error;
 
@@ -72,7 +72,7 @@ pub trait FromReader: Sized {
 
     /// Reads an instance of `Self` from a binary file at `path`.
     fn read_from_file(path: &Path) -> Result<Self> {
-        let file = File::open(path)?;
+        let file = File::open(path).with_context(|| format!("Failed to open {path:?}"))?;
         Self::from_reader(file)
     }
 }
@@ -84,7 +84,7 @@ pub trait ToWriter: Sized {
 
     /// Writes `self` to a file at `path` in binary format.
     fn write_to_file(self, path: &Path) -> Result<()> {
-        let mut file = File::create(path)?;
+        let mut file = File::create(path).with_context(|| format!("Failed to create {path:?}"))?;
         self.to_writer(&mut file)
     }
 }

sw/host/opentitantool/src/command/bootstrap.rs

@@ -2,7 +2,7 @@
 // Licensed under the Apache License, Version 2.0, see LICENSE for details.
 // SPDX-License-Identifier: Apache-2.0
 
-use anyhow::{ensure, Result};
+use anyhow::{ensure, Context, Result};
 use clap::Args;
 use serde_annotate::Annotate;
 use std::any::Any;
@@ -51,7 +51,8 @@ impl BootstrapCommand {
             image.parse(&self.filename)?;
             image.assemble()
         } else {
-            Ok(std::fs::read(&self.filename[0])?)
+            Ok(std::fs::read(&self.filename[0])
+                .with_context(|| format!("Failed to read {}", self.filename[0]))?)
         }
     }
 }

sw/host/opentitantool/src/command/image.rs

@@ -2,7 +2,7 @@
 // Licensed under the Apache License, Version 2.0, see LICENSE for details.
 // SPDX-License-Identifier: Apache-2.0
 
-use anyhow::{ensure, Context, Result};
+use anyhow::{bail, ensure, Context, Result};
 use clap::{Args, Subcommand};
 use serde_annotate::Annotate;
 use std::any::Any;
@@ -26,7 +26,7 @@ use opentitanlib::image::manifest_def::ManifestSpec;
 use opentitanlib::image::manifest_ext::{ManifestExtEntry, ManifestExtId, ManifestExtSpec};
 use opentitanlib::util::file::{FromReader, ToWriter};
 use opentitanlib::util::parse_int::ParseInt;
-use sphincsplus::{DecodeKey, SpxDomain, SpxPublicKey, SpxSecretKey};
+use sphincsplus::{DecodeKey, SpxDomain, SpxError, SpxPublicKey, SpxSecretKey};
 
 /// Bootstrap the target device.
 #[derive(Debug, Args)]
@@ -232,11 +232,19 @@ impl CommandDispatch for ManifestUpdateCommand {
         // Load / write SPX+ public key.
         let mut spx_private_key: Option<SpxSecretKey> = None;
         if let Some(key) = &self.spx_key {
-            let (pk, sk) = if let Ok(sk) = SpxSecretKey::read_pem_file(key) {
-                (SpxPublicKey::from(&sk), Some(sk))
-            } else {
-                (SpxPublicKey::read_pem_file(key)?, None)
+            let (pk, sk) = match SpxSecretKey::read_pem_file(key.clone()) {
+                Ok(sk) => (SpxPublicKey::from(&sk), Some(sk)),
+                Err(SpxError::Io(_)) => {
+                    // Return error if file could not be read.
+                    bail!(std::io::Error::new(
+                        std::io::ErrorKind::NotFound,
+                        format!("{} not found", key.display())
+                    ));
+                }
+                // Maybe it is a public key, try reading it as such.
+                _ => (SpxPublicKey::read_pem_file(key)?, None),
             };
+
             let key_ext = ManifestExtEntry::new_spx_key_entry(&pk)?;
             image.add_manifest_extension(key_ext)?;
             spx_private_key = sk;