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Handle symlinking edge cases #1660

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Handle symlinking edge cases #1660

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581859b
fix #1637
withinboredom Jun 18, 2025
fd60f48
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withinboredom Jun 18, 2025
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5 changes: 4 additions & 1 deletion caddy/module.go
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Original file line number Diff line number Diff line change
Expand Up @@ -148,7 +148,10 @@ func (f *FrankenPHPModule) ServeHTTP(w http.ResponseWriter, r *http.Request, _ c
if documentRoot == "" && frankenphp.EmbeddedAppPath != "" {
documentRoot = frankenphp.EmbeddedAppPath
}
documentRootOption = frankenphp.WithRequestDocumentRoot(documentRoot, *f.ResolveRootSymlink)
//If we do not have a resolved document root, then we cannot resolve the symlink of our cwd because it may
//resolve to a different directory than the one we are currently in.
//This is especially important if there are workers running.
Comment on lines +151 to +153
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//If we do not have a resolved document root, then we cannot resolve the symlink of our cwd because it may
//resolve to a different directory than the one we are currently in.
//This is especially important if there are workers running.
// If we do not have a resolved document root, then we cannot resolve the symlink of our cwd because it may
// resolve to a different directory than the one we are currently in.
// This is especially important if there are workers running.

documentRootOption = frankenphp.WithRequestDocumentRoot(documentRoot, false)
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Not checking for symlinks here seems like it might break some setups. Definitely would be nice to test all the edge cases somehow (should be possible with caddy_tests?).

Tbh though, I don't know what the current edge cases with symlinks are

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I’m pretty sure we don’t want to evaluate symlinks here. In the case where a document root was expressly given (such as prod setups), we will never even enter this branch. In the case where a document root isn’t given, we need to be compatible with how we resolve workers. There is an edge case here that I didn’t cover, and I’m working out how to handle it: chained symlinks.

I suspect I’ll have to go back to the drawing board.

} else {
documentRoot = f.resolvedDocumentRoot
documentRootOption = frankenphp.WithRequestResolvedDocumentRoot(documentRoot)
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10 changes: 9 additions & 1 deletion worker.go
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Expand Up @@ -4,6 +4,7 @@ package frankenphp
import "C"
import (
"fmt"
"path/filepath"
"strings"
"sync"
"time"
Expand Down Expand Up @@ -74,7 +75,14 @@ func getWorkerKey(name string, filename string) string {
}

func newWorker(o workerOpt) (*worker, error) {
absFileName, err := fastabs.FastAbs(o.fileName)
//Order is important!
//This order ensures that FrankenPHP started from inside a symlinked directory will properly resolve any paths.
//If it is started from outside a symlinked directory, it is resolved to the same path that we use in the Caddy module.
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//Order is important!
//This order ensures that FrankenPHP started from inside a symlinked directory will properly resolve any paths.
//If it is started from outside a symlinked directory, it is resolved to the same path that we use in the Caddy module.
// Order is important!
// This order ensures that FrankenPHP started from inside a symlinked directory will properly resolve any paths.
// If it is started from outside a symlinked directory, it is resolved to the same path that we use in the Caddy module.

absFileName, err := filepath.EvalSymlinks(o.fileName)
if err != nil {
return nil, fmt.Errorf("worker filename is invalid %q: %w", o.fileName, err)
}
Comment on lines +81 to +84
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I like it 👍 explicitly checking if a worker exists is something I actually wanted to do for a long time

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Or wait, evalSymlinks will just evaluate symlinks. In that case it would also be nice to error right away if there's no file there. Can also be done in another PR though

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it errors if the file doesn't exist (I had to update a failing test -- haven't pushed the commit yet)

absFileName, err = fastabs.FastAbs(absFileName)
if err != nil {
return nil, fmt.Errorf("worker filename is invalid %q: %w", o.fileName, err)
}
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