diff --git a/Cargo.lock b/Cargo.lock
index a7363a44319..1e00a29762f 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -72,7 +72,7 @@ name = "atty"
 version = "0.2.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -88,7 +88,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "backtrace-sys 0.1.32 (registry+https://github.com/rust-lang/crates.io-index)",
  "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-demangle 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -98,7 +98,7 @@ version = "0.1.32"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cc 1.0.46 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -233,7 +233,7 @@ name = "chrono"
 version = "0.4.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
  "num-integer 0.1.41 (registry+https://github.com/rust-lang/crates.io-index)",
  "num-traits 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "time 0.1.42 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -272,7 +272,7 @@ version = "0.6.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "core-foundation-sys 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -299,7 +299,7 @@ version = "0.4.25"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "curl-sys 0.4.23 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
  "openssl-probe 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "openssl-sys 0.9.52 (registry+https://github.com/rust-lang/crates.io-index)",
  "schannel 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -313,7 +313,7 @@ version = "0.4.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cc 1.0.46 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
  "libz-sys 1.0.25 (registry+https://github.com/rust-lang/crates.io-index)",
  "openssl-sys 0.9.52 (registry+https://github.com/rust-lang/crates.io-index)",
  "pkg-config 0.3.16 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -412,7 +412,7 @@ version = "0.6.5"
 dependencies = [
  "curl 0.4.25 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_proxy 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "error-chain 0.12.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "error-chain 0.12.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "hyper 0.13.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "reqwest 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -437,6 +437,17 @@ dependencies = [
  "sha2 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "effective-limits"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "error-chain 0.12.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sys-info 0.5.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "encoding_rs"
 version = "0.8.20"
@@ -456,11 +467,11 @@ dependencies = [
 
 [[package]]
 name = "error-chain"
-version = "0.12.1"
+version = "0.12.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "backtrace 0.3.40 (registry+https://github.com/rust-lang/crates.io-index)",
- "version_check 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "version_check 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -494,7 +505,7 @@ version = "0.2.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
  "redox_syscall 0.1.56 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -506,7 +517,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "crc32fast 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
  "miniz_oxide 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -597,7 +608,7 @@ version = "0.1.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
  "wasi 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -746,7 +757,7 @@ name = "iovec"
 version = "0.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -786,7 +797,7 @@ dependencies = [
 
 [[package]]
 name = "libc"
-version = "0.2.65"
+version = "0.2.67"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -800,7 +811,7 @@ version = "1.0.25"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cc 1.0.46 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
  "pkg-config 0.3.16 (registry+https://github.com/rust-lang/crates.io-index)",
  "vcpkg 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -819,7 +830,7 @@ version = "0.1.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cc 1.0.46 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
  "pkg-config 0.3.16 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -875,7 +886,7 @@ dependencies = [
  "fuchsia-zircon-sys 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "iovec 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "miow 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "net2 0.2.33 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -900,7 +911,7 @@ version = "0.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "openssl 0.10.25 (registry+https://github.com/rust-lang/crates.io-index)",
  "openssl-probe 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -917,7 +928,7 @@ version = "0.2.33"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -990,7 +1001,7 @@ name = "num_cpus"
 version = "1.10.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1015,7 +1026,7 @@ dependencies = [
  "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "foreign-types 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
  "openssl-sys 0.9.52 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1039,7 +1050,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "autocfg 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "cc 1.0.46 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
  "openssl-src 111.6.0+1.1.1d (registry+https://github.com/rust-lang/crates.io-index)",
  "pkg-config 0.3.16 (registry+https://github.com/rust-lang/crates.io-index)",
  "vcpkg 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1167,7 +1178,7 @@ version = "0.7.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "getrandom 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_chacha 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_hc 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1320,12 +1331,13 @@ dependencies = [
  "chrono 0.4.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "clap 2.33.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "download 0.6.5",
- "error-chain 0.12.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "effective-limits 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "error-chain 0.12.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "flate2 1.0.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "git-testament 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "home 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
  "opener 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "openssl 0.10.25 (registry+https://github.com/rust-lang/crates.io-index)",
  "pgp 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1392,7 +1404,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "core-foundation 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "core-foundation-sys 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
  "security-framework-sys 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1493,7 +1505,7 @@ version = "0.3.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
  "redox_syscall 0.1.56 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -1552,13 +1564,22 @@ dependencies = [
  "unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "sys-info"
+version = "0.5.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "cc 1.0.46 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "tar"
 version = "0.4.26"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "filetime 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
  "redox_syscall 0.1.56 (registry+https://github.com/rust-lang/crates.io-index)",
  "xattr 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -1569,7 +1590,7 @@ version = "3.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "redox_syscall 0.1.56 (registry+https://github.com/rust-lang/crates.io-index)",
  "remove_dir_all 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1614,7 +1635,7 @@ name = "time"
 version = "0.1.42"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
  "redox_syscall 0.1.56 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -1761,12 +1782,17 @@ name = "version_check"
 version = "0.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "version_check"
+version = "0.9.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "wait-timeout"
 version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1959,7 +1985,7 @@ name = "xattr"
 version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -2040,9 +2066,10 @@ dependencies = [
 "checksum digest 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)" = "f3d0c8c8752312f9713efd397ff63acb9f85585afbf179282e720e7704954dd5"
 "checksum dtoa 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)" = "ea57b42383d091c85abcc2706240b94ab2a8fa1fc81c10ff23c4de06e2a90b5e"
 "checksum ed25519-dalek 1.0.0-pre.3 (registry+https://github.com/rust-lang/crates.io-index)" = "978710b352437433c97b2bff193f2fb1dfd58a093f863dd95e225a19baa599a2"
+"checksum effective-limits 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "0a9f83f5e74da97619a9c13722c22609ab82ee797a2d9985b2b3405c69f03cd7"
 "checksum encoding_rs 0.8.20 (registry+https://github.com/rust-lang/crates.io-index)" = "87240518927716f79692c2ed85bfe6e98196d18c6401ec75355760233a7e12e9"
 "checksum env_proxy 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "8731da06ff3731a69115a2910345ae5ee8d1fe09c846a9eca101b444a30ad454"
-"checksum error-chain 0.12.1 (registry+https://github.com/rust-lang/crates.io-index)" = "3ab49e9dcb602294bc42f9a7dfc9bc6e936fca4418ea300dbfb84fe16de0b7d9"
+"checksum error-chain 0.12.2 (registry+https://github.com/rust-lang/crates.io-index)" = "d371106cc88ffdfb1eabd7111e432da544f16f3e2d7bf1dfe8bf575f1df045cd"
 "checksum failure 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "f8273f13c977665c5db7eb2b99ae520952fe5ac831ae4cd09d80c4c7042b5ed9"
 "checksum failure_derive 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "0bc225b78e0391e4b8683440bf2e63c2deeeb2ce5189eab46e2b68c6d3725d08"
 "checksum fake-simd 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "e88a8acf291dafb59c2d96e8f59828f3838bb1a70398823ade51a84de6a6deed"
@@ -2081,7 +2108,7 @@ dependencies = [
 "checksum keccak 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "67c21572b4949434e4fc1e1978b99c5f77064153c59d998bf13ecd96fb5ecba7"
 "checksum kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "7507624b29483431c0ba2d82aece8ca6cdba9382bff4ddd0f7490560c056098d"
 "checksum lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
-"checksum libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)" = "1a31a0627fdf1f6a39ec0dd577e101440b7db22672c0901fe00a9a6fbb5c24e8"
+"checksum libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)" = "eb147597cdf94ed43ab7a9038716637d2d1bf2bc571da995d0028dec06bd3018"
 "checksum libm 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "c7d73b3f436185384286bd8098d17ec07c9a7d2388a6599f824d8502b529702a"
 "checksum libz-sys 1.0.25 (registry+https://github.com/rust-lang/crates.io-index)" = "2eb5e43362e38e2bca2fd5f5134c4d4564a23a5c28e9b95411652021a8675ebe"
 "checksum log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)" = "14b6052be84e6b71ab17edffc2eeabf5c2c3ae1fdb464aae35ac50c67a44e1f7"
@@ -2160,6 +2187,7 @@ dependencies = [
 "checksum subtle 2.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "ab3af2eb31c42e8f0ccf43548232556c42737e01a96db6e1777b0be108e79799"
 "checksum syn 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)" = "66850e97125af79138385e9b88339cbcd037e3f28ceab8c5ad98e64f0f1f80bf"
 "checksum synstructure 0.12.1 (registry+https://github.com/rust-lang/crates.io-index)" = "3f085a5855930c0441ca1288cf044ea4aecf4f43a91668abdb870b4ba546a203"
+"checksum sys-info 0.5.8 (registry+https://github.com/rust-lang/crates.io-index)" = "0079fe39cec2c8215e21b0bc4ccec9031004c160b88358f531b601e96b77f0df"
 "checksum tar 0.4.26 (registry+https://github.com/rust-lang/crates.io-index)" = "b3196bfbffbba3e57481b6ea32249fbaf590396a52505a2615adbb79d9d826d3"
 "checksum tempfile 3.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "7a6e24d9338a0a5be79593e2fa15a648add6138caa803e2d5bc782c371732ca9"
 "checksum term 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "5e6b677dd1e8214ea1ef4297f85dbcbed8e8cdddb561040cc998ca2551c37561"
@@ -2186,6 +2214,7 @@ dependencies = [
 "checksum vcpkg 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)" = "33dd455d0f96e90a75803cfeb7f948768c08d70a6de9a8d2362461935698bf95"
 "checksum vec_map 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)" = "05c78687fb1a80548ae3250346c3db86a80a7cdd77bda190189f2d0a0987c81a"
 "checksum version_check 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "914b1a6776c4c929a602fafd8bc742e06365d4bcbe48c30f9cca5824f70dc9dd"
+"checksum version_check 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)" = "078775d0255232fb988e6fccf26ddc9d1ac274299aaedcedce21c6f72cc533ce"
 "checksum wait-timeout 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "9f200f5b12eb75f8c1ed65abd4b2db8a6e1b138a20de009dacee265a2498f3f6"
 "checksum walkdir 2.2.9 (registry+https://github.com/rust-lang/crates.io-index)" = "9658c94fa8b940eab2250bd5a457f9c48b748420d71293b165c8cdbe2f55f71e"
 "checksum want 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "1ce8a968cb1cd110d136ff8b819a556d6fb6d919363c61534f6860c7eb172ba0"
diff --git a/Cargo.toml b/Cargo.toml
index 1280be537b6..b46552f07be 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -25,6 +25,7 @@ chrono = "0.4"
 clap = "2"
 download = { path = "download" }
 error-chain = "0.12"
+effective-limits = "0.3"
 flate2 = "1"
 git-testament = "0.1.4"
 home = "0.5"
diff --git a/src/dist/component/package.rs b/src/dist/component/package.rs
index d8dfb31a33c..c88e9f02335 100644
--- a/src/dist/component/package.rs
+++ b/src/dist/component/package.rs
@@ -8,6 +8,7 @@ use crate::dist::component::transaction::*;
 use crate::dist::temp;
 use crate::errors::*;
 use crate::utils::notifications::Notification;
+use crate::utils::units;
 use crate::utils::utils;
 
 use std::collections::{HashMap, HashSet};
@@ -17,7 +18,9 @@ use std::io::{self, ErrorKind as IOErrorKind, Read};
 use std::iter::FromIterator;
 use std::mem;
 use std::path::{Path, PathBuf};
+use std::sync::atomic::{AtomicBool, Ordering};
 
+use lazy_static::lazy_static;
 use tar::EntryType;
 
 /// The current metadata revision used by rust-installer
@@ -163,19 +166,40 @@ struct MemoryBudget {
     used: usize,
 }
 
+lazy_static! {
+    static ref RAM_NOTICE_SHOWN: AtomicBool = AtomicBool::new(false);
+}
+
 // Probably this should live in diskio but ¯\_(ツ)_/¯
 impl MemoryBudget {
-    fn new(max_file_size: usize) -> Self {
-        const DEFAULT_UNPACK_RAM: usize = 400 * 1024 * 1024;
-        let unpack_ram = if let Ok(budget_str) = env::var("RUSTUP_UNPACK_RAM") {
-            if let Ok(budget) = budget_str.parse::<usize>() {
-                budget
-            } else {
-                DEFAULT_UNPACK_RAM
+    fn new(max_file_size: usize, effective_max_ram: usize) -> Self {
+        const DEFAULT_UNPACK_RAM_MAX: usize = 500 * 1024 * 1024;
+        const RAM_ALLOWANCE_FOR_RUSTUP_AND_BUFFERS: usize = 100 * 1024 * 1024;
+        let ram_for_unpacking = effective_max_ram - RAM_ALLOWANCE_FOR_RUSTUP_AND_BUFFERS;
+        let default_max_unpack_ram = std::cmp::min(DEFAULT_UNPACK_RAM_MAX, ram_for_unpacking);
+        let unpack_ram = match env::var("RUSTUP_UNPACK_RAM")
+            .ok()
+            .and_then(|budget_str| budget_str.parse::<usize>().ok())
+        {
+            // Note: In future we may want to add a warning or even an override if a user
+            // supplied budget is larger than effective_max_ram.
+            Some(budget) => budget,
+            None => {
+                if RAM_NOTICE_SHOWN.load(Ordering::Acquire) {
+                    eprintln!(
+                        "Defaulting to {} unpack ram",
+                        units::Size::new(
+                            default_max_unpack_ram,
+                            units::Unit::B,
+                            units::UnitMode::Norm
+                        )
+                    );
+                    RAM_NOTICE_SHOWN.store(true, Ordering::Release);
+                }
+                default_max_unpack_ram
             }
-        } else {
-            DEFAULT_UNPACK_RAM
         };
+
         if max_file_size > unpack_ram {
             panic!("RUSTUP_UNPACK_RAM must be larger than {}", max_file_size);
         }
@@ -278,7 +302,8 @@ fn unpack_without_first_dir<'a, R: Read>(
         .entries()
         .chain_err(|| ErrorKind::ExtractingPackage)?;
     const MAX_FILE_SIZE: u64 = 200_000_000;
-    let mut budget = MemoryBudget::new(MAX_FILE_SIZE as usize);
+    let effective_max_ram = effective_limits::memory_limit()?;
+    let mut budget = MemoryBudget::new(MAX_FILE_SIZE as usize, effective_max_ram as usize);
 
     let mut directories: HashMap<PathBuf, DirStatus> = HashMap::new();
     // Path is presumed to exist. Call it a precondition.
diff --git a/src/errors.rs b/src/errors.rs
index d0d5c534a15..13c4dc4c816 100644
--- a/src/errors.rs
+++ b/src/errors.rs
@@ -22,6 +22,7 @@ pub const TOOLSTATE_MSG: &str =
 error_chain! {
     links {
         Download(download::Error, download::ErrorKind);
+        Limits(effective_limits::Error, effective_limits::ErrorKind);
     }
 
     foreign_links {
diff --git a/tests/cli-exact.rs b/tests/cli-exact.rs
index dfbddf30813..b0dc52d9055 100644
--- a/tests/cli-exact.rs
+++ b/tests/cli-exact.rs
@@ -38,6 +38,7 @@ info: downloading component 'rust-docs'
 info: downloading component 'rust-std'
 info: downloading component 'rustc'
 info: installing component 'cargo'
+Defaulting to 500.0 MiB unpack ram
 info: installing component 'rust-docs'
 info: installing component 'rust-std'
 info: installing component 'rustc'
@@ -172,6 +173,7 @@ info: downloading component 'rust-docs'
 info: downloading component 'rust-std'
 info: downloading component 'rustc'
 info: installing component 'cargo'
+Defaulting to 500.0 MiB unpack ram
 info: installing component 'rust-docs'
 info: installing component 'rust-std'
 info: installing component 'rustc'
@@ -504,6 +506,7 @@ fn cross_install_indicates_target() {
             &format!(
                 r"info: downloading component 'rust-std' for '{0}'
 info: installing component 'rust-std' for '{0}'
+Defaulting to 500.0 MiB unpack ram
 ",
                 clitools::CROSS_ARCH1
             ),
diff --git a/tests/cli-rustup.rs b/tests/cli-rustup.rs
index 77d70f90fa4..17ca87fe657 100644
--- a/tests/cli-rustup.rs
+++ b/tests/cli-rustup.rs
@@ -56,6 +56,7 @@ info: removing previous version of component 'rust-docs'
 info: removing previous version of component 'rust-std'
 info: removing previous version of component 'rustc'
 info: installing component 'cargo'
+Defaulting to 500.0 MiB unpack ram
 info: installing component 'rust-docs'
 info: installing component 'rust-std'
 info: installing component 'rustc'
@@ -96,6 +97,7 @@ info: removing previous version of component 'rust-docs'
 info: removing previous version of component 'rust-std'
 info: removing previous version of component 'rustc'
 info: installing component 'cargo'
+Defaulting to 500.0 MiB unpack ram
 info: installing component 'rust-docs'
 info: installing component 'rust-std'
 info: installing component 'rustc'
@@ -160,6 +162,7 @@ info: removing previous version of component 'rust-docs'
 info: removing previous version of component 'rust-std'
 info: removing previous version of component 'rustc'
 info: installing component 'cargo'
+Defaulting to 500.0 MiB unpack ram
 info: installing component 'rust-docs'
 info: installing component 'rust-std'
 info: installing component 'rustc'
@@ -230,6 +233,7 @@ info: removing previous version of component 'rust-docs'
 info: removing previous version of component 'rust-std'
 info: removing previous version of component 'rustc'
 info: installing component 'cargo'
+Defaulting to 500.0 MiB unpack ram
 info: installing component 'rust-docs'
 info: installing component 'rust-std'
 info: installing component 'rustc'
@@ -291,6 +295,7 @@ info: downloading component 'rust-docs'
 info: downloading component 'rust-std'
 info: downloading component 'rustc'
 info: installing component 'cargo'
+Defaulting to 500.0 MiB unpack ram
 info: installing component 'rust-docs'
 info: installing component 'rust-std'
 info: installing component 'rustc'
diff --git a/tests/cli-self-upd.rs b/tests/cli-self-upd.rs
index d27dac8b0b8..f0f7ff135b7 100644
--- a/tests/cli-self-upd.rs
+++ b/tests/cli-self-upd.rs
@@ -883,6 +883,7 @@ info: downloading component 'rust-docs'
 info: downloading component 'rust-std'
 info: downloading component 'rustc'
 info: installing component 'cargo'
+Defaulting to 500.0 MiB unpack ram
 info: installing component 'rust-docs'
 info: installing component 'rust-std'
 info: installing component 'rustc'
diff --git a/tests/cli-v2.rs b/tests/cli-v2.rs
index a7ad3a9a389..78b2786c89e 100644
--- a/tests/cli-v2.rs
+++ b/tests/cli-v2.rs
@@ -1342,6 +1342,7 @@ info: downloading component 'cargo'
 info: downloading component 'rust-docs'
 info: downloading component 'rustc'
 info: installing component 'cargo'
+Defaulting to 500.0 MiB unpack ram
 info: installing component 'rust-docs'
 info: installing component 'rustc'
 "