test: pipe_overlong_path fails on AIX

[abmusse]

• Version: Current v1.x branch
• Platform: AIX

Discovered this failure while running the CI for a pull request:

Ref: #4229

https://ci.nodejs.org/job/libuv-test-commit-aix/nodes=aix72-ppc64/2279/console

not ok 199 - pipe_overlong_path
# exit code 393222
# Output from process `pipe_overlong_path`:
# Assertion failed in test/test-pipe-bind-error.c on line 175: `UV_EINVAL == uv_pipe_bind2(&pipe, path, sizeof(path), UV_PIPE_NO_TRUNCATE)` (-22 == -86)

libuv/test/test-pipe-bind-error.c

Line 175 in 6be130e

ASSERT_EQ(UV_EINVAL,

Looks like errno 86 maps to ENAMETOOLONG on AIX.

Looks like this passes as expected on IBM i:

ok 199 - pipe_overlong_path

https://ci.nodejs.org/job/libuv-test-commit-aix/nodes=aix72-ppc64/2279/console

[bnoordhuis]

What is the size of struct sockaddr_un.sun_path on AIX?

[abmusse]

@bnoordhuis

What is the size of struct sockaddr_un.sun_path on AIX?

Looks like its set to 1024 or 1023

From: /usr/include/sys/un.h

#if defined(COMPAT_43) && !defined(_KERNEL)
struct  sockaddr_un {
        ushort_t        sun_family;     /* AF_UNIX */
        char        sun_path[1024]; /* changed from 104 to PATH_MAX to support long user names. This value should be ch
anged manually if PATH_MAX changes in future */
};
#else
struct  sockaddr_un {
        uchar_t     sun_len;            /* sockaddr len including null */
        sa_family_t sun_family;         /* AF_UNIX */
        char        sun_path[1023]; /* changed from 104 to PATH_MAX to support long user names. This value should be ch
anged manually if PATH_MAX changes in future */
};
#endif /* COMPAT_43 && !_KERNEL */

[abmusse]

@bnoordhuis @richardlau

I got around to adding some debug print statements to get a better understanding of what is going on. My changes are here for ref: https://github.com/libuv/libuv/compare/v1.x...abmusse:libuv:debug-pipe-overlong-path?expand=1

not ok 200 - pipe_overlong_path
# exit code 393222
# Output from process `pipe_overlong_path`:
# Calling uv_pipe_init
# 
# Calling uv_pipe_bind2
# 
# flags & UV_PIPE_NO_TRUNCATE
# 
# namelen: 512
# 
# saddr.sun_path: 1023
# 
# malloc pipe_fname
# 
# failed to bind sockfs
# 
# goto err_socket
# 
# In err_socket, err: -86
# 

ref: https://ci.nodejs.org/job/libuv-test-commit-aix/nodes=aix72-ppc64/lastBuild/console

I confirmed that saddr.sun_path is set to 1023.

The namelen being passed in test case is 512 which is why its skipping the check

libuv/src/unix/pipe.c

Lines 84 to 86 in 6be130e

	if (flags & UV_PIPE_NO_TRUNCATE)
	if (namelen > sizeof(saddr.sun_path))
	return UV_EINVAL;

The weird part is that bind fails when setting saddr.sun_path to the long name.

libuv/src/unix/pipe.c

Lines 116 to 127 in 6be130e

	memset(&saddr, 0, sizeof saddr);
	memcpy(&saddr.sun_path, name, namelen);
	saddr.sun_family = AF_UNIX;
	if (bind(sockfd, (struct sockaddr*)&saddr, sizeof saddr)) {
	err = UV__ERR(errno);
	/* Convert ENOENT to EACCES for compatibility with Windows. */
	if (err == UV_ENOENT)
	err = UV_EACCES;
	uv__close(sockfd);
	goto err_socket;

We get back errno 86 which looks like it maps to ENAMETOOLONG on AIX.

From my previous comment:

#if defined(COMPAT_43) && !defined(_KERNEL)
struct  sockaddr_un {
        ushort_t        sun_family;     /* AF_UNIX */
        char        sun_path[1024]; /* changed from 104 to PATH_MAX to support long user names. This value should be ch
anged manually if PATH_MAX changes in future */
};
#else
struct  sockaddr_un {
        uchar_t     sun_len;            /* sockaddr len including null */
        sa_family_t sun_family;         /* AF_UNIX */
        char        sun_path[1023]; /* changed from 104 to PATH_MAX to support long user names. This value should be ch
anged manually if PATH_MAX changes in future */
};
#endif /* COMPAT_43 && !_KERNEL */

It seems like on AIX sun_path was increased from support for long user names?

I think we need to find the true max allowed name length for a socket since the current sun_path of 1023 looks too big.

[abmusse]

As a follow up I made a re-producible program in C

// unix-sock.c
// gcc -o unix-sock unix-sock.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/un.h>

int main() {
    int sockfd;
    struct sockaddr_un addr;
    printf( "addr.sun_path: %lu\n\n", sizeof(addr.sun_path));

    char SOCKET_PATH[512];
    memset(SOCKET_PATH, '@', sizeof(SOCKET_PATH));
    
    // Create a Unix domain socket
    sockfd = socket(AF_UNIX, SOCK_STREAM, 0);
    if (sockfd == -1) {
        perror("socket");
        exit(EXIT_FAILURE);
    }

    // Clear the structure
    memset(&addr, 0, sizeof(struct sockaddr_un));

    // Assign the socket family and the socket path
    addr.sun_family = AF_UNIX;
    strncpy(addr.sun_path, SOCKET_PATH, sizeof(addr.sun_path) - 1);

    // Bind the socket
    if (bind(sockfd, (struct sockaddr *)&addr, sizeof(struct sockaddr_un)) == -1) {
        perror("bind");
        close(sockfd);
        exit(EXIT_FAILURE);
    }

    printf("Socket bound to %s\n", SOCKET_PATH);

    close(sockfd);

    return 0;
}

I then compiled and ran it on AIX:

$ gcc -o unix-sock unix-sock.c 
$ ./unix-sock 
addr.sun_path: 1023

bind: File name too long

For fun I then compiled and ran it on IBM i to see if there would be a diff in behavior:

$ gcc -o unix-sock unix-sock.c
$ ./unix-sock                                                                                                  
addr.sun_path: 126                                                                                                    
                                                                                                                       
Socket bound to @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@                                                                   

There is a def a diff in behavior in relation to File name max length.