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Don't call open("") (#1336)

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strings.Split(s, sep) returns a slice of a single element containing s
if sep is not found in s. This is true even if s is empty.

As a result, every call to flagFromEnvOrFile results in an attempt to
open a file with empty name. This is seen from strace as

[pid 3287620] openat(AT_FDCWD, "", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
[pid 3287620] openat(AT_FDCWD, "", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
...

To fix, check if the string is empty before calling ReadFile.

This also fixes cases where filePath is non-empty but has extra commas.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
This commit is contained in:
Kir Kolyshkin 2022-02-15 05:28:44 -08:00 committed by GitHub
parent 1bf639b391
commit 3df9a3cd86
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 4 additions and 2 deletions
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6
flag.go
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@ -434,8 +434,10 @@ func flagFromEnvOrFile(envVars []string, filePath string) (val string, ok bool)
}
}
for _, fileVar := range strings.Split(filePath, ",") {
if data, err := ioutil.ReadFile(fileVar); err == nil {
return string(data), true
if fileVar != "" {
if data, err := ioutil.ReadFile(fileVar); err == nil {
return string(data), true
}
}
}
return "", false