flashrom_tester: Fix cmd read_region to read only the region

read_region for the CLI implementation was writing a file the size of
the whole flash, with only the region filled with real data. Now write
only the region to the file. This fixes the Coreboot_ELOG_sanity test
which regressed in 4342cc0f14e2945d7642e75e44346c13ca23089b.

BUG=b:241486407
BRANCH=None
TEST=flashrom_tester /usr/sbin/flashrom host Coreboot_ELOG_sanity

Change-Id: I97ff8c71861f1d0282a7d6173e196e3d0b41d746
Signed-off-by: Evan Benn <evanbenn@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/flashrom/+/3812722
Tested-by: Edward O'Callaghan <quasisec@chromium.org>
Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/66588
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

1 files changed, 10 insertions, 11 deletions

diff --git a/util/flashrom_tester/flashrom/src/cmd.rs b/util/flashrom_tester/flashrom/src/cmd.rs
index b5aacf48..1fbb9444 100644
--- a/util/flashrom_tester/flashrom/src/cmd.rs
+++ b/util/flashrom_tester/flashrom/src/cmd.rs
@@ -60,11 +60,11 @@ pub struct WPOpt {
 
 #[derive(Default)]
 pub struct IOOpt<'a> {
-    pub read: Option<&'a str>,   // -r <file>
-    pub write: Option<&'a str>,  // -w <file>
-    pub verify: Option<&'a str>, // -v <file>
-    pub erase: bool,             // -E
-    pub region: Option<&'a str>, // --image
+    pub read: Option<&'a str>,              // -r <file>
+    pub write: Option<&'a str>,             // -w <file>
+    pub verify: Option<&'a str>,            // -v <file>
+    pub erase: bool,                        // -E
+    pub region: Option<(&'a str, &'a str)>, // --image
 }
 
 #[derive(PartialEq, Debug)]
@@ -243,8 +243,7 @@ impl crate::Flashrom for FlashromCmd {
     fn read_region(&self, path: &str, region: &str) -> Result<(), FlashromError> {
         let opts = FlashromOpt {
             io_opt: IOOpt {
-                read: Some(path),
-                region: Some(region),
+                region: Some((region, path)),
                 ..Default::default()
             },
             ..Default::default()
@@ -322,11 +321,11 @@ fn flashrom_decode_opts(opts: FlashromOpt) -> Vec<String> {
     }
 
     // io_opt
-    if let Some(region) = opts.io_opt.region {
+    if let Some((region, path)) = opts.io_opt.region {
         params.push("--image".to_string());
-        params.push(region.to_string());
-    }
-    if opts.io_opt.read.is_some() {
+        params.push(format!("{}:{}", region, path));
+        params.push("-r".to_string());
+    } else if opts.io_opt.read.is_some() {
         params.push("-r".to_string());
         params.push(opts.io_opt.read.unwrap().to_string());
     } else if opts.io_opt.write.is_some() {