id = 1394
title = "Byte-swapping issue in getresuid on qemu-user-sparc64"
state = "closed"
created_at = "2022-12-25T13:24:39.830Z"
closed_at = "2023-03-31T11:59:20.559Z"
labels = ["TestCase", "linux-user", "target: sparc"]
url = "https://gitlab.com/qemu-project/qemu/-/issues/1394"
host-os = "Debian bookworm/sid"
host-arch = "x86_64"
qemu-version = "qemu-sparc64 version 7.1.0 (Debian 1:7.1+dfsg-2+b3)"
guest-os = "Debian sid"
guest-arch = "sparc64"
description = """When calling getresuid() in the big-endian sparc64 guest, the uid_t values are written with their 16-bit halves reversed.

For example, the UID 0x000003e8 (1000) becomes 0x03e80000."""
reproduce = """A minimal test case looks like this:
```c
#define _GNU_SOURCE
#include <stdio.h>
#include <sys/types.h>
#include <pwd.h>
#include <unistd.h>

int main(int argc, char **argv) {
\tstruct passwd *pw = getpwuid(geteuid());
\tif (pw == NULL) {
\t\tperror("getpwuid failure");
\t\treturn 1;
\t}
\tprintf("getpwuid()->pw_uid=0x%08x\\n", pw->pw_uid);

\tuid_t ruid = 0, euid = 0, suid = 0;
\tif (getresuid(&ruid, &euid, &suid) != 0) {
\t\tperror("getresuid failure");
\t\treturn 1;
\t}
\tprintf("getresuid()->suid=0x%08x\\n", suid);

\treturn 0;
}
```

Compile and run with:
```
$ sparc64-linux-gnu-gcc -Wall -O0 -g -o sid-sparc64/test test.c
$ sudo chroot sid-sparc64
[chroot] $ qemu-sparc64-static ./test
```

Alternatively, static compilation without a chroot is also possible (despite a warning about `getpwuid()`):
```
$ sparc64-linux-gnu-gcc -static -Wall -O0 -g -o test test.c
$ qemu-sparc64-static ./test
```

Expected output:
```
$ ./test 
getpwuid()->pw_uid=0x000003e8
getresuid()->suid=0x000003e8
```

Actual output:
```
$ ./test 
getpwuid()->pw_uid=0x000003e8
getresuid()->suid=0x03e80000
```"""
additional = """I'm not sure if this is a glibc, qemu or kernel issue, but it doesn't occur outside qemu."""