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blockdev: use lsblk --json output format
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Fixes #516
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@sohankunkerkar
sohankunkerkar committed Oct 5, 2021
1 parent 46f9093 commit cf2bfcc
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Showing 2 changed files with 98 additions and 115 deletions.
28 changes: 14 additions & 14 deletions src/bin/rdcore/rootmap.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -65,8 +65,8 @@ pub fn rootmap(config: &RootmapConfig) -> Result<()> {
})
.context("appending rootmap kargs")?;
eprintln!("Injected kernel arguments into BLS: {}", kargs.join(" "));
// Note here we're not calling `zipl` on s390x; it will be called anyway on firstboot by
// `coreos-ignition-firstboot-complete.service`, so might as well batch them.
// Note here we're not calling `zipl` on s390x; it will be called anyway on firstboot by
// `coreos-ignition-firstboot-complete.service`, so might as well batch them.
} else {
// without /boot options, we just print the kargs; note we output to stdout here
println!("{}", kargs.join(" "));
Expand All @@ -83,13 +83,13 @@ pub fn get_boot_mount_from_cmdline_args(
if let Some(path) = boot_mount {
Ok(Some(Mount::from_existing(path)?))
} else if let Some(devpath) = boot_device {
let devinfo = lsblk_single(Path::new(devpath))?;
let devinfo = Device::lsblk(Path::new(devpath), false)?;
let fs = devinfo
.get("FSTYPE")
.with_context(|| format!("failed to query filesystem for {}", devpath))?;
.fstype
.ok_or_else(|| anyhow::anyhow!("failed to query filesystem for {}", devpath))?;
Ok(Some(Mount::try_mount(
devpath,
fs,
&fs,
mount::MsFlags::empty(),
)?))
} else {
Expand All @@ -98,19 +98,19 @@ pub fn get_boot_mount_from_cmdline_args(
}

fn device_to_kargs(root: &Mount, device: PathBuf) -> Result<Option<Vec<String>>> {
let blkinfo = lsblk_single(&device)?;
let blktype = blkinfo
.get("TYPE")
.with_context(|| format!("missing TYPE for {}", device.display()))?;
let blkinfo = Device::lsblk(&device, false)?;
let blktypeinfo = blkinfo
.blktype
.ok_or_else(|| anyhow::anyhow!("missing type for {}", device.display()))?;
// a `match {}` construct would be nice here, but for RAID it's a prefix match
if blktype.starts_with("raid") {
if blktypeinfo.starts_with("raid") {
Ok(Some(get_raid_kargs(&device)?))
} else if blktype == "crypt" {
} else if blktypeinfo == "crypt" {
Ok(Some(get_luks_kargs(root, &device)?))
} else if blktype == "part" || blktype == "disk" || blktype == "mpath" {
} else if blktypeinfo == "part" || blktypeinfo == "disk" || blktypeinfo == "mpath" {
Ok(None)
} else {
bail!("unknown block device type {}", blktype)
bail!("unknown block device type {}", blktypeinfo)
}
}

Expand Down
185 changes: 84 additions & 101 deletions src/blockdev.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -17,7 +17,7 @@ use gptman::{GPTPartitionEntry, GPT};
use nix::sys::stat::{major, minor};
use nix::{errno::Errno, mount, sched};
use regex::Regex;
use std::collections::HashMap;
use serde::Deserialize;
use std::convert::TryInto;
use std::env;
use std::fs::{
Expand All @@ -42,6 +42,50 @@ use crate::util::*;

use crate::{runcmd, runcmd_output};

#[derive(Debug, Deserialize)]
struct DevicesOutput {
blockdevices: Vec<Device>,
}

#[derive(Debug, Deserialize)]
pub struct Device {
pub name: String,
pub label: Option<String>,
pub fstype: Option<String>,
#[serde(rename = "type")]
pub blktype: Option<String>,
pub mountpoint: Option<String>,
pub uuid: Option<String>,
pub children: Option<Vec<Device>>,
}

impl Device {
pub fn lsblk(dev: &Path, with_children: bool) -> Result<Device> {
let mut cmd = Command::new("lsblk");
cmd.args(&[
"-J",
"--paths",
"-o",
"NAME,LABEL,FSTYPE,TYPE,MOUNTPOINT,UUID",
])
.arg(dev);
if !with_children {
cmd.arg("--nodeps");
}
let output = cmd_output(&mut cmd)?;
let devs: DevicesOutput = serde_json::from_str(&output)?;
if devs.blockdevices.len() > 1 {
bail!("found more than one device for {:?}", dev);
}
let devinfo = devs
.blockdevices
.into_iter()
.next()
.ok_or_else(|| anyhow!("failed to get device information"))?;
Ok(devinfo)
}
}

#[derive(Debug)]
pub struct Disk {
pub path: String,
Expand Down Expand Up @@ -100,29 +144,45 @@ impl Disk {
}
}

fn compute_partition(&self, devinfo: &Device) -> Result<Vec<Partition>> {
let mut result: Vec<Partition> = Vec::new();
// Only return partitions. Skip the whole-disk device, as well
// as holders like LVM or RAID devices using one of the partitions.
if !(devinfo.blktype != Some("part".to_string())) {
let (mountpoint, swap) = match &devinfo.mountpoint {
Some(mp) if mp == "[SWAP]" => (None, true),
Some(mp) => (Some(mp.to_string()), false),
None => (None, false),
};
result.push(Partition {
path: devinfo.name.to_owned(),
label: devinfo.label.clone(),
fstype: devinfo.fstype.clone(),
parent: self.path.to_owned(),
mountpoint,
swap,
});
}

Ok(result)
}

fn get_partitions(&self) -> Result<Vec<Partition>> {
// walk each device in the output
let mut result: Vec<Partition> = Vec::new();
for devinfo in lsblk(Path::new(&self.path), true)? {
if let Some(name) = devinfo.get("NAME") {
// Only return partitions. Skip the whole-disk device, as well
// as holders like LVM or RAID devices using one of the partitions.
if devinfo.get("TYPE").map(|s| s.as_str()) != Some("part") {
continue;
let deviceinfo = Device::lsblk(Path::new(&self.path), true)?;
let mut partition = self.compute_partition(&deviceinfo)?;
if !partition.is_empty() {
result.append(&mut partition);
}
if let Some(children) = deviceinfo.children.as_ref() {
if !children.is_empty() {
for child in children {
let mut childpartition = self.compute_partition(child)?;
if !childpartition.is_empty() {
result.append(&mut childpartition);
}
}
let (mountpoint, swap) = match devinfo.get("MOUNTPOINT") {
Some(mp) if mp == "[SWAP]" => (None, true),
Some(mp) => (Some(mp.to_string()), false),
None => (None, false),
};
result.push(Partition {
path: name.to_owned(),
label: devinfo.get("LABEL").map(<_>::to_string),
fstype: devinfo.get("FSTYPE").map(<_>::to_string),
parent: self.path.to_owned(),
mountpoint,
swap,
});
}
}
Ok(result)
Expand Down Expand Up @@ -493,11 +553,10 @@ impl Mount {
}

pub fn get_filesystem_uuid(&self) -> Result<String> {
let devinfo = lsblk_single(Path::new(&self.device))?;
devinfo
.get("UUID")
.map(String::from)
.with_context(|| format!("filesystem {} has no UUID", self.device))
let uuid = Device::lsblk(Path::new(&self.device), false)?
.uuid
.ok_or_else(|| anyhow!("failed to get uuid"))?;
Ok(uuid)
}
}

Expand Down Expand Up @@ -800,46 +859,6 @@ fn read_sysfs_dev_block_value(maj: u64, min: u64, field: &str) -> Result<String>
Ok(read_to_string(&path)?.trim_end().into())
}

pub fn lsblk_single(dev: &Path) -> Result<HashMap<String, String>> {
let mut devinfos = lsblk(Path::new(dev), false)?;
if devinfos.is_empty() {
// this should never happen because `lsblk` itself would've failed
bail!("no lsblk results for {}", dev.display());
}
Ok(devinfos.remove(0))
}

pub fn lsblk(dev: &Path, with_deps: bool) -> Result<Vec<HashMap<String, String>>> {
let mut cmd = Command::new("lsblk");
// Older lsblk, e.g. in CentOS 7.6, doesn't support PATH, but --paths option
cmd.arg("--pairs")
.arg("--paths")
.arg("--output")
.arg("NAME,LABEL,FSTYPE,TYPE,MOUNTPOINT,UUID")
.arg(dev);
if !with_deps {
cmd.arg("--nodeps");
}
let output = cmd_output(&mut cmd)?;
let mut result: Vec<HashMap<String, String>> = Vec::new();
for line in output.lines() {
// parse key-value pairs
result.push(split_lsblk_line(line));
}
Ok(result)
}

/// Parse key-value pairs from lsblk --pairs.
/// Newer versions of lsblk support JSON but the one in CentOS 7 doesn't.
fn split_lsblk_line(line: &str) -> HashMap<String, String> {
let re = Regex::new(r#"([A-Z-]+)="([^"]+)""#).unwrap();
let mut fields: HashMap<String, String> = HashMap::new();
for cap in re.captures_iter(line) {
fields.insert(cap[1].to_string(), cap[2].to_string());
}
fields
}

pub fn get_blkdev_deps(device: &Path) -> Result<Vec<PathBuf>> {
let deps = {
let mut p = PathBuf::from("/sys/block");
Expand Down Expand Up @@ -1028,46 +1047,10 @@ mod ioctl {
#[cfg(test)]
mod tests {
use super::*;
use maplit::hashmap;
use std::io::copy;
use tempfile::tempfile;
use xz2::read::XzDecoder;

#[test]
fn lsblk_split() {
assert_eq!(
split_lsblk_line(r#"NAME="sda" LABEL="" FSTYPE="""#),
hashmap! {
String::from("NAME") => String::from("sda"),
}
);
assert_eq!(
split_lsblk_line(r#"NAME="sda1" LABEL="" FSTYPE="vfat""#),
hashmap! {
String::from("NAME") => String::from("sda1"),
String::from("FSTYPE") => String::from("vfat")
}
);
assert_eq!(
split_lsblk_line(r#"NAME="sda2" LABEL="boot" FSTYPE="ext4""#),
hashmap! {
String::from("NAME") => String::from("sda2"),
String::from("LABEL") => String::from("boot"),
String::from("FSTYPE") => String::from("ext4"),
}
);
assert_eq!(
split_lsblk_line(r#"NAME="sda3" LABEL="foo=\x22bar\x22 baz" FSTYPE="ext4""#),
hashmap! {
String::from("NAME") => String::from("sda3"),
// for now, we don't care about resolving lsblk's hex escapes,
// so we just pass them through
String::from("LABEL") => String::from(r#"foo=\x22bar\x22 baz"#),
String::from("FSTYPE") => String::from("ext4"),
}
);
}

#[test]
fn disk_sector_size_reader() {
struct Test {
Expand Down

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