From 150f3bb5ea586563d0eb394d79f1c66d961adc45 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Th=C3=A9ophane=20Hufschmitt?=
 <theophane.hufschmitt@tweag.io>
Date: Mon, 26 Jun 2023 09:49:24 +0200
Subject: [PATCH] nix-find-roots: Cleanup

Based on an offline review by @mopleen (thanks!)
---
 src/nix-find-roots/lib/find-roots.hh | 14 ++------------
 src/nix-find-roots/main.cc           | 18 +++++++++++++-----
 2 files changed, 15 insertions(+), 17 deletions(-)

diff --git a/src/nix-find-roots/lib/find-roots.hh b/src/nix-find-roots/lib/find-roots.hh
index 504fdd768..25c24dd67 100644
--- a/src/nix-find-roots/lib/find-roots.hh
+++ b/src/nix-find-roots/lib/find-roots.hh
@@ -7,19 +7,9 @@ namespace nix::roots_tracer {
 namespace fs = std::filesystem;
 using std::set, std::map, std::string;
 
-class Error : public std::exception {
-private:
-    const string message;
-
+class Error : public std::runtime_error {
 public:
-    Error(std::string message)
-        : message(message)
-    {}
-
-    const char* what() const noexcept override
-    {
-        return message.c_str();
-    }
+    using std::runtime_error::runtime_error;
 };
 
 inline void logNone(std::string_view)
diff --git a/src/nix-find-roots/main.cc b/src/nix-find-roots/main.cc
index 0e8aabb91..e5597747d 100644
--- a/src/nix-find-roots/main.cc
+++ b/src/nix-find-roots/main.cc
@@ -80,11 +80,11 @@ std::string escape(std::string original)
 {
     map<string, string> replacements = {
         {"\n", "\\n"},
-        {"\n", "\\t"},
+        {"\t", "\\t"},
     };
     for (auto [oldStr, newStr] : replacements) {
         size_t currentPos = 0;
-        while ((currentPos = original.find(oldStr)) != std::string::npos) {
+        while ((currentPos = original.find(oldStr, currentPos)) != std::string::npos) {
             original.replace(currentPos, oldStr.length(), newStr);
             currentPos += newStr.length();
         }
@@ -109,19 +109,27 @@ int main(int argc, char * * argv)
     auto rawListenFds = std::getenv("LISTEN_FDS");
     if (rawListenFds) {
         auto listenFds = std::string(rawListenFds);
-        if (std::getenv("LISTEN_PID") != std::to_string(getpid()) || listenFds != "1")
+        auto listenPid = std::getenv("LISTEN_PID");
+        if (listenPid == nullptr || listenPid != std::to_string(getpid()) || listenFds != "1")
             throw Error("unexpected systemd environment variables");
         mySock = SD_LISTEN_FDS_START;
     } else {
         mySock = socket(PF_UNIX, SOCK_STREAM, 0);
-        if (mySock == 0) {
-            throw Error("Cannot create Unix domain socket");
+        if (mySock == -1) {
+            throw Error(std::string("Cannot create Unix domain socket, got") +
+                    std::strerror(errno));
         }
         struct sockaddr_un addr;
         addr.sun_family = AF_UNIX;
 
         auto socketDir = opts.socketPath.parent_path();
         auto socketFilename = opts.socketPath.filename();
+        if (socketFilename.string().size() > sizeof(addr.sun_path))
+            throw Error(
+                    "Socket filename " + socketFilename.string() +
+                    " is too long, should be at most " +
+                    std::to_string(sizeof(addr.sun_path))
+                    );
         chdir(socketDir.c_str());
 
         fs::remove(socketFilename);