[pbs-devel] [PATCH proxmox-backup 1/9] file-restore: add debug mode with serial access
Stefan Reiter
s.reiter at proxmox.com
Thu May 6 17:26:16 CEST 2021
Set PBS_QEMU_DEBUG=1 on a command that starts a VM and then connect to
the debug root shell via:
minicom -D \unix#/run/proxmox-backup/file-restore-serial-10.sock
or similar.
Note that this requires 'proxmox-backup-restore-image-debug' to work,
the postinst script is updated to also generate the corresponding image.
Signed-off-by: Stefan Reiter <s.reiter at proxmox.com>
---
debian/proxmox-backup-file-restore.postinst | 12 ++++-
src/bin/proxmox_file_restore/qemu_helper.rs | 55 ++++++++++++++++++---
src/buildcfg.rs | 4 ++
3 files changed, 62 insertions(+), 9 deletions(-)
diff --git a/debian/proxmox-backup-file-restore.postinst b/debian/proxmox-backup-file-restore.postinst
index 27eb87e9..feb0557b 100755
--- a/debian/proxmox-backup-file-restore.postinst
+++ b/debian/proxmox-backup-file-restore.postinst
@@ -6,6 +6,7 @@ update_initramfs() {
# regenerate initramfs for single file restore VM
INST_PATH="/usr/lib/x86_64-linux-gnu/proxmox-backup/file-restore"
CACHE_PATH="/var/cache/proxmox-backup/file-restore-initramfs.img"
+ CACHE_PATH_DBG="/var/cache/proxmox-backup/file-restore-initramfs-debug.img"
# cleanup first, in case proxmox-file-restore was uninstalled since we do
# not want an unuseable image lying around
@@ -20,7 +21,7 @@ update_initramfs() {
# avoid leftover temp file
cleanup() {
- rm -f "$CACHE_PATH.tmp"
+ rm -f "$CACHE_PATH.tmp" "$CACHE_PATH_DBG.tmp"
}
trap cleanup EXIT
@@ -34,6 +35,15 @@ update_initramfs() {
| cpio -o --format=newc -A -F "$CACHE_PATH.tmp" )
mv -f "$CACHE_PATH.tmp" "$CACHE_PATH"
+ if [ -f "$INST_PATH/initramfs-debug.img" ]; then
+ echo "Updating file-restore debug initramfs..."
+ cp "$INST_PATH/initramfs-debug.img" "$CACHE_PATH_DBG.tmp"
+ ( cd "$INST_PATH"; \
+ printf "./proxmox-restore-daemon" \
+ | cpio -o --format=newc -A -F "$CACHE_PATH_DBG.tmp" )
+ mv -f "$CACHE_PATH_DBG.tmp" "$CACHE_PATH_DBG"
+ fi
+
trap - EXIT
}
diff --git a/src/bin/proxmox_file_restore/qemu_helper.rs b/src/bin/proxmox_file_restore/qemu_helper.rs
index 9328addf..20b4f344 100644
--- a/src/bin/proxmox_file_restore/qemu_helper.rs
+++ b/src/bin/proxmox_file_restore/qemu_helper.rs
@@ -47,9 +47,13 @@ fn create_restore_log_dir() -> Result<String, Error> {
Ok(logpath)
}
-fn validate_img_existance() -> Result<(), Error> {
+fn validate_img_existance(debug: bool) -> Result<(), Error> {
let kernel = PathBuf::from(buildcfg::PROXMOX_BACKUP_KERNEL_FN);
- let initramfs = PathBuf::from(buildcfg::PROXMOX_BACKUP_INITRAMFS_FN);
+ let initramfs = PathBuf::from(if debug {
+ buildcfg::PROXMOX_BACKUP_INITRAMFS_DBG_FN
+ } else {
+ buildcfg::PROXMOX_BACKUP_INITRAMFS_FN
+ });
if !kernel.exists() || !initramfs.exists() {
bail!("cannot run file-restore VM: package 'proxmox-backup-restore-image' is not (correctly) installed");
}
@@ -79,7 +83,7 @@ fn try_kill_vm(pid: i32) -> Result<(), Error> {
Ok(())
}
-async fn create_temp_initramfs(ticket: &str) -> Result<(Fd, String), Error> {
+async fn create_temp_initramfs(ticket: &str, debug: bool) -> Result<(Fd, String), Error> {
use std::ffi::CString;
use tokio::fs::File;
@@ -88,8 +92,14 @@ async fn create_temp_initramfs(ticket: &str) -> Result<(Fd, String), Error> {
nix::unistd::unlink(&tmp_path)?;
tools::fd_change_cloexec(tmp_fd.0, false)?;
+ let initramfs = if debug {
+ buildcfg::PROXMOX_BACKUP_INITRAMFS_DBG_FN
+ } else {
+ buildcfg::PROXMOX_BACKUP_INITRAMFS_FN
+ };
+
let mut f = File::from_std(unsafe { std::fs::File::from_raw_fd(tmp_fd.0) });
- let mut base = File::open(buildcfg::PROXMOX_BACKUP_INITRAMFS_FN).await?;
+ let mut base = File::open(initramfs).await?;
tokio::io::copy(&mut base, &mut f).await?;
@@ -122,18 +132,24 @@ pub async fn start_vm(
files: impl Iterator<Item = String>,
ticket: &str,
) -> Result<(i32, i32), Error> {
- validate_img_existance()?;
-
if let Err(_) = std::env::var("PBS_PASSWORD") {
bail!("environment variable PBS_PASSWORD has to be set for QEMU VM restore");
}
+ let debug = if let Ok(val) = std::env::var("PBS_QEMU_DEBUG") {
+ !val.is_empty()
+ } else {
+ false
+ };
+
+ validate_img_existance(debug)?;
+
let pid;
let (pid_fd, pid_path) = make_tmp_file("/tmp/file-restore-qemu.pid.tmp", CreateOptions::new())?;
nix::unistd::unlink(&pid_path)?;
tools::fd_change_cloexec(pid_fd.0, false)?;
- let (_ramfs_pid, ramfs_path) = create_temp_initramfs(ticket).await?;
+ let (_ramfs_pid, ramfs_path) = create_temp_initramfs(ticket, debug).await?;
let logpath = create_restore_log_dir()?;
let logfile = &format!("{}/qemu.log", logpath);
@@ -174,7 +190,11 @@ pub async fn start_vm(
"-initrd",
&ramfs_path,
"-append",
- "quiet panic=1",
+ if debug {
+ "debug panic=1"
+ } else {
+ "quiet panic=1"
+ },
"-daemonize",
"-pidfile",
&format!("/dev/fd/{}", pid_fd.as_raw_fd()),
@@ -218,6 +238,19 @@ pub async fn start_vm(
cid
));
+ if debug {
+ let debug_args = [
+ "-chardev",
+ &format!(
+ "socket,id=debugser,path=/run/proxmox-backup/file-restore-serial-{}.sock,server,nowait",
+ cid
+ ),
+ "-serial",
+ "chardev:debugser",
+ ];
+ qemu_cmd.args(debug_args.iter());
+ }
+
qemu_cmd.stdout(std::process::Stdio::null());
qemu_cmd.stderr(std::process::Stdio::piped());
@@ -260,6 +293,12 @@ pub async fn start_vm(
if let Ok(Ok(_)) =
time::timeout(Duration::from_secs(2), client.get("api2/json/status", None)).await
{
+ if debug {
+ eprintln!(
+ "Connect to '/run/proxmox-backup/file-restore-serial-{}.sock' for shell access",
+ cid
+ )
+ }
return Ok((pid, cid as i32));
}
if kill(pid_t, None).is_err() {
diff --git a/src/buildcfg.rs b/src/buildcfg.rs
index b0f61efb..c70ab6ea 100644
--- a/src/buildcfg.rs
+++ b/src/buildcfg.rs
@@ -43,6 +43,10 @@ pub const PROXMOX_BACKUP_API_PID_FN: &str = concat!(PROXMOX_BACKUP_RUN_DIR_M!(),
pub const PROXMOX_BACKUP_INITRAMFS_FN: &str =
concat!(PROXMOX_BACKUP_CACHE_DIR_M!(), "/file-restore-initramfs.img");
+/// filename of the cached initramfs to use for debugging single file restore
+pub const PROXMOX_BACKUP_INITRAMFS_DBG_FN: &str =
+ concat!(PROXMOX_BACKUP_CACHE_DIR_M!(), "/file-restore-initramfs-debug.img");
+
/// filename of the kernel to use for booting single file restore VMs
pub const PROXMOX_BACKUP_KERNEL_FN: &str =
concat!(PROXMOX_BACKUP_FILE_RESTORE_BIN_DIR_M!(), "/bzImage");
--
2.20.1
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