commit 4af9a30a1638f7ab527c150a9fe4e3b0ee01d1e8
Author: Alex Crichton <alex@alexcrichton.com>
Date:   Sat Nov 5 22:24:07 2016 -0700

    Initial commit

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..a9d37c5
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+target
+Cargo.lock
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..2eec003
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "openssl-probe"
+version = "0.1.0"
+authors = ["Alex Crichton <alex@alexcrichton.com>"]
+
+[dependencies]
diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..e3711b5
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,77 @@
+use std::env;
+use std::fs;
+use std::path::PathBuf;
+
+pub struct ProbeResult {
+    pub cert_file: Option<PathBuf>,
+    pub cert_dir: Option<PathBuf>,
+}
+
+/// Probe the system for the directory in which CA certificates should likely be
+/// found.
+///
+/// This will only search known system locations.
+pub fn find_certs_dirs() -> Vec<PathBuf> {
+    // see http://gagravarr.org/writing/openssl-certs/others.shtml
+    [
+        "/var/ssl",
+        "/usr/share/ssl",
+        "/usr/local/ssl",
+        "/usr/local/openssl",
+        "/usr/local/share",
+        "/usr/lib/ssl",
+        "/usr/ssl",
+        "/etc/openssl",
+        "/etc/pki/tls",
+        "/etc/ssl",
+    ].iter().map(|s| PathBuf::from(*s)).filter(|p| {
+        fs::metadata(p).is_ok()
+    }).collect()
+}
+
+pub fn init_ssl_cert_env_vars() {
+    let ProbeResult { cert_file, cert_dir } = probe();
+    match cert_file {
+        Some(path) => put("SSL_CERT_FILE", path),
+        None => {}
+    }
+    match cert_dir {
+        Some(path) => put("SSL_CERT_DIR", path),
+        None => {}
+    }
+
+    fn put(var: &str, path: PathBuf) {
+        // Don't stomp over what anyone else has set
+        match env::var(var) {
+            Ok(..) => {}
+            Err(..) => env::set_var(var, &path),
+        }
+    }
+}
+
+pub fn probe() -> ProbeResult {
+    let mut result = ProbeResult {
+        cert_file: env::var_os("SSL_CERT_FILE").map(PathBuf::from),
+        cert_dir: env::var_os("SSL_CERT_DIR").map(PathBuf::from),
+    };
+    for certs_dir in find_certs_dirs().iter() {
+        // cert.pem looks to be an openssl 1.0.1 thing, while
+        // certs/ca-certificates.crt appears to be a 0.9.8 thing
+        for cert in [
+            "cert.pem",
+            "certs.pem",
+            "certs/ca-certificates.crt",
+            "certs/ca-root-nss.crt"
+        ].iter() {
+            try(&mut result.cert_file, certs_dir.join(cert));
+        }
+        try(&mut result.cert_dir, certs_dir.join("certs"));
+    }
+    result
+}
+
+fn try(dst: &mut Option<PathBuf>, val: PathBuf) {
+    if dst.is_none() && fs::metadata(&val).is_ok() {
+        *dst = Some(val);
+    }
+}