fix(dns): parsing of `/etc/resolv.conf` by manually updating `resolv-conf` crate (#184)

* Show the error cause if initializing a DNS resolver fails

* Manually bump `resolv-conf` to `master` at rev `83c0f25`

This fixes the parsing of `/etc/resolv.conf` with `options trust-ad`
which is e.g. used in `systemd-resolved-v246`[1].

Refs #166

[1] https://github.com/systemd/systemd/commit/a742f9828ea73d9c2c9bafe701c10fe60f058012

3 files changed, 24 insertions, 18 deletions

diff --git a/Cargo.lock b/Cargo.lock
index caefc0e..2c0e8e2 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -99,6 +99,7 @@ dependencies = [
  "pnet_base 0.26.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "procfs 0.7.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "regex 1.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "resolv-conf 0.6.3 (git+https://github.com/tailhook/resolv-conf?rev=83c0f25ebcb0615550488692c5213ca1ae4acd8f)",
  "signal-hook 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)",
  "structopt 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "sysinfo 0.15.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -730,11 +731,12 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "hostname"
-version = "0.1.5"
+version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "libc 0.2.76 (registry+https://github.com/rust-lang/crates.io-index)",
- "winutil 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "match_cfg 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -909,6 +911,11 @@ version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
+name = "match_cfg"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
 name = "matches"
 version = "0.1.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -1570,10 +1577,10 @@ dependencies = [
 
 [[package]]
 name = "resolv-conf"
-version = "0.6.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
+version = "0.6.3"
+source = "git+https://github.com/tailhook/resolv-conf?rev=83c0f25ebcb0615550488692c5213ca1ae4acd8f#83c0f25ebcb0615550488692c5213ca1ae4acd8f"
 dependencies = [
- "hostname 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "hostname 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "quick-error 1.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1992,7 +1999,7 @@ dependencies = [
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "lru-cache 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "resolv-conf 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "resolv-conf 0.6.3 (git+https://github.com/tailhook/resolv-conf?rev=83c0f25ebcb0615550488692c5213ca1ae4acd8f)",
  "smallvec 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "trust-dns-proto 0.18.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2181,14 +2188,6 @@ dependencies = [
 ]
 
 [[package]]
-name = "winutil"
-version = "0.1.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
-[[package]]
 name = "ws2_32-sys"
 version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -2300,7 +2299,7 @@ dependencies = [
 "checksum heck 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "20564e78d53d2bb135c343b3f47714a56af2061f1c928fdb541dc7b9fdd94205"
 "checksum hermit-abi 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)" = "3deed196b6e7f9e44a2ae8d94225d80302d81208b1bb673fd21fe634645c85a9"
 "checksum hex 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)" = "644f9158b2f133fd50f5fb3242878846d9eb792e445c893805ff0e3824006e35"
-"checksum hostname 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "21ceb46a83a85e824ef93669c8b390009623863b5c195d1ba747292c0c72f94e"
+"checksum hostname 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "3c731c3e10504cc8ed35cfe2f1db4c9274c3d35fa486e3b31df46f068ef3e867"
 "checksum http_req 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "83169a2c0f68280d1c88a4a1d514810006c181a53c40844563013ae86ed4c478"
 "checksum idna 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "02e2673c30ee86b5b96a9cb52ad15718aa1f966f5ab9ad54a8b95d5ca33120a9"
 "checksum insta 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "23f83ab4ee86f38b292f0420c27fd412690a4baa9ea0ad4e3fa624bf34379b76"
@@ -2322,6 +2321,7 @@ dependencies = [
 "checksum log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)" = "14b6052be84e6b71ab17edffc2eeabf5c2c3ae1fdb464aae35ac50c67a44e1f7"
 "checksum lru-cache 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "31e24f1ad8321ca0e8a1e0ac13f23cb668e6f5466c2c57319f6a5cf1cc8e3b1c"
 "checksum maplit 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "3e2e65a1a2e43cfcb47a895c4c8b10d1f4a61097f9f254f183aee60cad9c651d"
+"checksum match_cfg 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ffbee8634e0d45d258acb448e7eaab3fce7a0a467395d4d9f228e3c1f01fb2e4"
 "checksum matches 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)" = "7ffc5c5338469d4d3ea17d269fa8ea3512ad247247c30bd2df69e68309ed0a08"
 "checksum maybe-uninit 2.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "60302e4db3a61da70c0cb7991976248362f30319e88850c487b9b95bbf059e00"
 "checksum memchr 2.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "88579771288728879b57485cc7d6b07d648c9f0141eb955f8ab7f9d45394468e"
@@ -2395,7 +2395,7 @@ dependencies = [
 "checksum regex 1.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "dc220bd33bdce8f093101afe22a037b8eb0e5af33592e6a9caafff0d4cb81cbd"
 "checksum regex-syntax 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)" = "11a7e20d1cce64ef2fed88b66d347f88bd9babb82845b2b858f3edbf59a4f716"
 "checksum remove_dir_all 0.5.3 (registry+https://github.com/rust-lang/crates.io-index)" = "3acd125665422973a33ac9d3dd2df85edad0f4ae9b00dafb1a05e43a9f5ef8e7"
-"checksum resolv-conf 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)" = "b263b4aa1b5de9ffc0054a2386f96992058bb6870aab516f8cdeb8a667d56dcb"
+"checksum resolv-conf 0.6.3 (git+https://github.com/tailhook/resolv-conf?rev=83c0f25ebcb0615550488692c5213ca1ae4acd8f)" = "<none>"
 "checksum rle-decode-fast 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "cabe4fa914dec5870285fa7f71f602645da47c486e68486d2b4ceb4a343e90ac"
 "checksum rustc-demangle 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)" = "4c691c0e608126e00913e33f0ccf3727d5fc84573623b8d65b2df340b5201783"
 "checksum rustc-serialize 0.3.24 (registry+https://github.com/rust-lang/crates.io-index)" = "dcf128d1287d2ea9d80910b5f1120d0b8eede3fbf1abe91c40d39ea7d51e6fda"
@@ -2467,7 +2467,6 @@ dependencies = [
 "checksum winapi-util 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "7168bab6e1daee33b4557efd0e95d5ca70a03706d39fa5f3fe7a236f584b03c9"
 "checksum winapi-x86_64-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
 "checksum winreg 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)" = "b2986deb581c4fe11b621998a5e53361efe6b48a151178d0cd9eeffa4dc6acc9"
-"checksum winutil 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7daf138b6b14196e3830a588acf1e86966c694d3e8fb026fb105b8b5dca07e6e"
 "checksum ws2_32-sys 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "d59cefebd0c892fa2dd6de581e937301d8552cb44489cdff035c6187cb63fa5e"
 "checksum yaml-rust 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)" = "65923dd1784f44da1d2c3dbbc5e822045628c590ba72123e1c73d3c230c4434d"
 "checksum zip 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)" = "58287c28d78507f5f91f2a4cf1e8310e2c76fd4c6932f93ac60fd1ceb402db7d"
diff --git a/Cargo.toml b/Cargo.toml
index 32f055c..b2411ef 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -33,6 +33,7 @@ tokio = { version = "0.2", features = ["rt-core", "sync"] }
 trust-dns-resolver = "0.18.1"
 async-trait = "0.1.21"
 unicode-width = "0.1.8"
+resolv-conf = "0.6.3"
 
 [target.'cfg(target_os="windows")'.dependencies]
 netstat2 = "0.9.0"
@@ -51,3 +52,6 @@ regex = "1"
 [target.'cfg(target_os="windows")'.build-dependencies]
 http_req = "0.7.0"
 zip = "0.5.6"
+
+[patch.crates-io]
+resolv-conf = { git = 'https://github.com/tailhook/resolv-conf', rev = '83c0f25ebcb0615550488692c5213ca1ae4acd8f' }
diff --git a/src/os/shared.rs b/src/os/shared.rs
index 4cc0c24..ea0f44d 100644
--- a/src/os/shared.rs
+++ b/src/os/shared.rs
@@ -238,7 +238,10 @@ pub fn get_input(
         let mut runtime = Runtime::new()?;
         let resolver = match runtime.block_on(dns::Resolver::new(runtime.handle().clone())) {
             Ok(resolver) => resolver,
-            Err(_) => failure::bail!("Could not initialize the DNS resolver. Are you offline?"),
+            Err(err) => failure::bail!(
+                "Could not initialize the DNS resolver. Are you offline?\n\nReason: {:?}",
+                err
+            ),
         };
         let dns_client = dns::Client::new(resolver, runtime)?;
         Some(dns_client)