From 38b29fb72ca4a07afbec1fd5067f59ca7d7f0fab Mon Sep 17 00:00:00 2001 From: Profpatsch Date: Thu, 12 Dec 2019 15:15:18 +0100 Subject: libstore/ssh: Improve error message on failing `execvp` MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit If the `throw` is reached, this means that execvp into `ssh` wasn’t successful. We can hint at a usual problem, which is a missing `ssh` executable. Test with: ``` env PATH= ./result/bin/nix-copy-closure --builders '' unusedhost ``` and the bash version with ``` env PATH= ./result/bin/nix-copy-closure --builders '' localhost ``` --- src/libstore/ssh.cc | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'src') diff --git a/src/libstore/ssh.cc b/src/libstore/ssh.cc index ac3ccd63d..ddc99a6cd 100644 --- a/src/libstore/ssh.cc +++ b/src/libstore/ssh.cc @@ -47,10 +47,13 @@ std::unique_ptr SSHMaster::startCommand(const std::string throw SysError("duping over stderr"); Strings args; + const char * execInto; if (fakeSSH) { + execInto = "bash"; args = { "bash", "-c" }; } else { + execInto = "ssh"; args = { "ssh", host.c_str(), "-x", "-a" }; addCommonSSHOpts(args); if (socketPath != "") @@ -62,7 +65,8 @@ std::unique_ptr SSHMaster::startCommand(const std::string args.push_back(command); execvp(args.begin()->c_str(), stringsToCharPtrs(args).data()); - throw SysError("executing '%s' on '%s'", command, host); + // could not exec ssh/bash + throw SysError("Failed to exec into %s. Is it in PATH?", execInto); }); @@ -108,7 +112,7 @@ Path SSHMaster::startMaster() addCommonSSHOpts(args); execvp(args.begin()->c_str(), stringsToCharPtrs(args).data()); - throw SysError("starting SSH master"); + throw SysError("Failed to exec into ssh. Is it in PATH?"); }); out.writeSide = -1; -- cgit v1.2.3