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From cb867d2fd64adc851f82be3c6eb6e38ec008930b Mon Sep 17 00:00:00 2001
From: Dominik Honnef <dominik@honnef.co>
Date: Sun, 21 Jun 2015 20:07:29 +0200
Subject: [PATCH] os/user: don't depend on _SC_GETPW_R_SIZE_MAX on Linux
Even Linux systems may not have _SC_GETPW_R_SIZE_MAX if using a
different libc than glibc (e.g. musl). Instead of having special-cases
for the BSDs, handle -1 correctly by always using a default buffer size.
Fixes #11319.
Change-Id: I8b1b260eb9830e6dbe7667f3f33d115ae4de4ce8
Reviewed-on: https://go-review.googlesource.com/13772
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
---
src/os/user/lookup_unix.go | 19 ++++++++-----------
1 file changed, 8 insertions(+), 11 deletions(-)
diff --git a/src/os/user/lookup_unix.go b/src/os/user/lookup_unix.go
index f4f603e..e8a1eb1 100644
--- a/src/os/user/lookup_unix.go
+++ b/src/os/user/lookup_unix.go
@@ -9,7 +9,6 @@ package user
import (
"fmt"
- "runtime"
"strconv"
"strings"
"syscall"
@@ -55,17 +54,15 @@ func lookupUnix(uid int, username string, lookupByName bool) (*User, error) {
var pwd C.struct_passwd
var result *C.struct_passwd
- var bufSize C.long
- if runtime.GOOS == "dragonfly" || runtime.GOOS == "freebsd" {
- // DragonFly and FreeBSD do not have _SC_GETPW_R_SIZE_MAX
- // and just return -1. So just use the same
- // size that Linux returns.
+ bufSize := C.sysconf(C._SC_GETPW_R_SIZE_MAX)
+ if bufSize == -1 {
+ // DragonFly and FreeBSD do not have _SC_GETPW_R_SIZE_MAX.
+ // Additionally, not all Linux systems have it, either. For
+ // example, the musl libc returns -1.
bufSize = 1024
- } else {
- bufSize = C.sysconf(C._SC_GETPW_R_SIZE_MAX)
- if bufSize <= 0 || bufSize > 1<<20 {
- return nil, fmt.Errorf("user: unreasonable _SC_GETPW_R_SIZE_MAX of %d", bufSize)
- }
+ }
+ if bufSize <= 0 || bufSize > 1<<20 {
+ return nil, fmt.Errorf("user: unreasonable _SC_GETPW_R_SIZE_MAX of %d", bufSize)
}
buf := C.malloc(C.size_t(bufSize))
defer C.free(buf)
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