bsd-user: Add FreeBSD socket helpers and sockaddr conversion

Add bsd-socket.c with target_to_host_sockaddr, host_to_target_sockaddr,
and target_to_host_ip_mreq helper functions, and add it to the build.

Signed-off-by: Stacey Son <sson@FreeBSD.org>
Assisted-by: Claude Opus 4.6 (1M context)
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com>
Acked-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Warner Losh <imp@bsdimp.com>

bsd-user/bsd-socket.c

@@ -0,0 +1,98 @@
+/*
+ * BSD socket system call related helpers
+ *
+ * Copyright (c) 2013 Stacey D. Son
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+#include "qemu/osdep.h"
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <netinet/in.h>
+
+#include "qemu.h"
+#include "qemu-bsd.h"
+
+/*
+ * socket conversion
+ */
+abi_long target_to_host_sockaddr(struct sockaddr *addr, abi_ulong target_addr,
+                                 socklen_t len)
+{
+    const socklen_t unix_maxlen = sizeof(struct sockaddr_un);
+    sa_family_t sa_family;
+    struct target_sockaddr *target_saddr;
+
+    target_saddr = lock_user(VERIFY_READ, target_addr, len, 1);
+    if (target_saddr == 0) {
+        return -TARGET_EFAULT;
+    }
+
+    sa_family = target_saddr->sa_family;
+
+    /*
+     * Oops. The caller might send a incomplete sun_path; sun_path
+     * must be terminated by \0 (see the manual page), but unfortunately
+     * it is quite common to specify sockaddr_un length as
+     * "strlen(x->sun_path)" while it should be "strlen(...) + 1". We will
+     * fix that here if needed.
+     */
+    if (target_saddr->sa_family == AF_UNIX) {
+        if (len < unix_maxlen && len > 0) {
+            char *cp = (char *)target_saddr;
+
+            if (cp[len - 1] && !cp[len]) {
+                len++;
+            }
+        }
+        if (len > unix_maxlen) {
+            len = unix_maxlen;
+        }
+    }
+
+    memcpy(addr, target_saddr, len);
+    addr->sa_family = sa_family;        /* type uint8_t */
+    addr->sa_len = target_saddr->sa_len;    /* type uint8_t */
+    unlock_user(target_saddr, target_addr, 0);
+
+    return 0;
+}
+
+abi_long host_to_target_sockaddr(abi_ulong target_addr, struct sockaddr *addr,
+                                 socklen_t len)
+{
+    struct target_sockaddr *target_saddr;
+
+    target_saddr = lock_user(VERIFY_WRITE, target_addr, len, 0);
+    if (target_saddr == 0) {
+        return -TARGET_EFAULT;
+    }
+    memcpy(target_saddr, addr, len);
+    target_saddr->sa_family = addr->sa_family;  /* type uint8_t */
+    target_saddr->sa_len = addr->sa_len;        /* type uint8_t */
+    unlock_user(target_saddr, target_addr, len);
+
+    return 0;
+}
+
+abi_long target_to_host_ip_mreq(struct ip_mreqn *mreqn, abi_ulong target_addr,
+                                socklen_t len)
+{
+    struct target_ip_mreqn *target_smreqn;
+
+    target_smreqn = lock_user(VERIFY_READ, target_addr, len, 1);
+    if (target_smreqn == 0) {
+        return -TARGET_EFAULT;
+    }
+    mreqn->imr_multiaddr.s_addr = target_smreqn->imr_multiaddr.s_addr;
+    mreqn->imr_address.s_addr = target_smreqn->imr_address.s_addr;
+    if (len == sizeof(struct target_ip_mreqn)) {
+        mreqn->imr_ifindex = tswap32(target_smreqn->imr_ifindex);
+    }
+    unlock_user(target_smreqn, target_addr, 0);
+
+    return 0;
+}
+

bsd-user/meson.build

@@ -11,6 +11,7 @@ bsd_user_ss.add(files(
   'bsd-mem.c',
   'bsd-misc.c',
   'bsd-proc.c',
+  'bsd-socket.c',
   'bsdload.c',
   'elfload.c',
   'main.c',

bsd-user/qemu-bsd.h

@@ -32,6 +32,14 @@ int host_to_target_waitstatus(int status);
 void h2g_rusage(const struct rusage *rusage,
         struct target_freebsd_rusage *target_rusage);
 
+/* bsd-socket.c */
+abi_long target_to_host_sockaddr(struct sockaddr *addr, abi_ulong target_addr,
+        socklen_t len);
+abi_long host_to_target_sockaddr(abi_ulong target_addr, struct sockaddr *addr,
+        socklen_t len);
+abi_long target_to_host_ip_mreq(struct ip_mreqn *mreqn, abi_ulong target_addr,
+        socklen_t len);
+
 /* bsd-mem.c */
 void target_to_host_ipc_perm__locked(struct ipc_perm *host_ip,
         struct target_ipc_perm *target_ip);

bsd-user/syscall_defs.h

@@ -203,6 +203,42 @@ struct target_freebsd__wrusage {
     struct target_freebsd_rusage wru_children;
 };
 
+/*
+ * sys/socket.h
+ */
+struct target_msghdr {
+    abi_long    msg_name;       /* Socket name */
+    int32_t     msg_namelen;    /* Length of name */
+    abi_long    msg_iov;        /* Data blocks */
+    int32_t     msg_iovlen;     /* Number of blocks */
+    abi_long    msg_control;    /* Per protocol magic (eg BSD fd passing) */
+    int32_t     msg_controllen; /* Length of cmsg list */
+    int32_t     msg_flags;      /* flags on received message */
+};
+
+struct target_sockaddr {
+    uint8_t sa_len;
+    uint8_t sa_family;
+    uint8_t sa_data[14];
+} QEMU_PACKED;
+
+struct target_in_addr {
+    uint32_t s_addr; /* big endian */
+};
+/*
+ * netinet/in.h
+ */
+struct target_ip_mreq {
+    struct target_in_addr   imr_multiaddr;
+    struct target_in_addr   imr_interface;
+};
+
+struct target_ip_mreqn {
+    struct target_in_addr   imr_multiaddr;
+    struct target_in_addr   imr_address;
+    int32_t                 imr_ifindex;
+};
+
 /*
  * sys/stat.h
  */
@@ -531,19 +567,6 @@ type safe_##name(type1 arg1, type2 arg2, type3 arg3, type4 arg4, \
     return safe_syscall(SYS_##name, arg1, arg2, arg3, arg4, arg5, arg6); \
 }
 
-/*
- * sys/socket.h
- */
-struct target_sockaddr {
-    uint8_t sa_len;
-    uint8_t sa_family;
-    uint8_t sa_data[14];
-} QEMU_PACKED;
-
-struct target_in_addr {
-    uint32_t s_addr; /* big endian */
-};
-
 #define safe_ioctl(...) safe_syscall(SYS_ioctl, __VA_ARGS__)
 #define safe_fcntl(...) safe_syscall(SYS_fcntl, __VA_ARGS__)