Add target-to-host and host-to-target control message conversion
functions (t2h_freebsd_cmsg and h2t_freebsd_cmsg) for sendmsg/recvmsg
support, and add os-socket.c to the FreeBSD build.

Signed-off-by: Stacey Son <[email protected]>
Signed-off-by: MikaĆ«l Urankar <[email protected]>
Signed-off-by: Kyle Evans <[email protected]>
Signed-off-by: Michal Meloun <[email protected]>
Signed-off-by: Warner Losh <[email protected]>
Assisted-by: Claude Opus 4.6 (1M context)
---
 bsd-user/freebsd/meson.build |   8 +-
 bsd-user/freebsd/os-socket.c | 235 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 241 insertions(+), 2 deletions(-)

diff --git a/bsd-user/freebsd/meson.build b/bsd-user/freebsd/meson.build
index 38f2debf7e..0fc779749d 100644
--- a/bsd-user/freebsd/meson.build
+++ b/bsd-user/freebsd/meson.build
@@ -4,9 +4,13 @@ bsd_syscall_nr = custom_target('bsd-syscall-h',
     command: [sh, meson.current_source_dir() / 'scripts/syscallhdr.sh', 
'@INPUT@', '@OUTPUT@', 'FREEBSD'])
 
 bsd_user_ss.add(files(
-  'os-stat.c',
+  'os-extattr.c',
   'os-proc.c',
+  'os-socket.c',
+  'os-stat.c',
   'os-sys.c',
-  'os-syscall.c'),
+  'os-syscall.c',
+  'os-thread.c',
+  'os-time.c'),
   bsd_syscall_nr
 )
diff --git a/bsd-user/freebsd/os-socket.c b/bsd-user/freebsd/os-socket.c
new file mode 100644
index 0000000000..543c9c10a6
--- /dev/null
+++ b/bsd-user/freebsd/os-socket.c
@@ -0,0 +1,235 @@
+/*
+ * FreeBSD socket related system call 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 <netinet/in.h>
+
+#include "qemu.h"
+#include "qemu-os.h"
+
+abi_long t2h_freebsd_cmsg(struct msghdr *msgh,
+        struct target_msghdr *target_msgh)
+{
+    struct cmsghdr *cmsg = CMSG_FIRSTHDR(msgh);
+    socklen_t msg_controllen;
+    abi_ulong target_cmsg_addr;
+    struct target_cmsghdr *target_cmsg, *target_cmsg_start;
+    socklen_t space = 0;
+
+    msg_controllen = tswap32(target_msgh->msg_controllen);
+    if (msg_controllen < sizeof(struct target_cmsghdr)) {
+        goto the_end;
+    }
+    target_cmsg_addr = tswapal(target_msgh->msg_control);
+    target_cmsg = lock_user(VERIFY_READ, target_cmsg_addr, msg_controllen, 1);
+    target_cmsg_start = target_cmsg;
+    if (!target_cmsg) {
+        return -TARGET_EFAULT;
+    }
+
+    while (cmsg && target_cmsg) {
+        void *data = CMSG_DATA(cmsg);
+        void *target_data = TARGET_CMSG_DATA(target_cmsg);
+        int len = (unsigned char *)(target_cmsg) +
+            tswap32(target_cmsg->cmsg_len) - (unsigned char *)target_data;
+
+        space += CMSG_SPACE(len);
+        if (space > msgh->msg_controllen) {
+            space -= CMSG_SPACE(len);
+            /*
+             * This is a QEMU bug, since we allocated the payload area 
ourselves
+             * (unlike overflow in host-to-target conversion, which is just the
+             * guest giving us a buffer that's too small). It can't happen for
+             * the payload types we currently support; if it becomes an issue 
in
+             * future we would need to improve our allocation strategy to
+             * something more intelligent than "twice the size of the target
+             * buffer we're reading from".
+             */
+            gemu_log("Host cmsg overflow\n");
+            break;
+        }
+
+        if (tswap32(target_cmsg->cmsg_level) == TARGET_SOL_SOCKET) {
+            cmsg->cmsg_level = SOL_SOCKET;
+        } else {
+            cmsg->cmsg_level = tswap32(target_cmsg->cmsg_level);
+        }
+        cmsg->cmsg_type = tswap32(target_cmsg->cmsg_type);
+        cmsg->cmsg_len = CMSG_LEN(len);
+
+        if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) {
+            int *fd = (int *)data;
+            int *target_fd = (int *)target_data;
+            int i, numfds = len / sizeof(int);
+
+            for (i = 0; i < numfds; i++) {
+                __get_user(fd[i], target_fd + i);
+            }
+        } else if ((cmsg->cmsg_level == TARGET_SOL_SOCKET) &&
+            (cmsg->cmsg_type == SCM_TIMESTAMP) &&
+            (len == sizeof(struct target_freebsd_timeval)))  {
+            /* copy struct timeval to host */
+            struct timeval *tv = (struct timeval *)data;
+            struct target_freebsd_timeval *target_tv =
+                (struct target_freebsd_timeval *)target_data;
+            __get_user(tv->tv_sec, &target_tv->tv_sec);
+            __get_user(tv->tv_usec, &target_tv->tv_usec);
+        } else {
+            gemu_log("Unsupported target ancillary data: %d/%d\n",
+                     cmsg->cmsg_level, cmsg->cmsg_type);
+            memcpy(data, target_data, len);
+        }
+
+        cmsg = CMSG_NXTHDR(msgh, cmsg);
+        target_cmsg = TARGET_CMSG_NXTHDR(target_msgh, target_cmsg,
+                                         target_cmsg_start);
+    }
+    unlock_user(target_cmsg, target_cmsg_addr, 0);
+the_end:
+    msgh->msg_controllen = space;
+    return 0;
+}
+
+abi_long h2t_freebsd_cmsg(struct target_msghdr *target_msgh,
+        struct msghdr *msgh)
+{
+    struct cmsghdr *cmsg = CMSG_FIRSTHDR(msgh);
+    socklen_t msg_controllen;
+    abi_ulong target_cmsg_addr;
+    struct target_cmsghdr *target_cmsg, *target_cmsg_start;
+    socklen_t space = 0;
+
+    msg_controllen = tswap32(target_msgh->msg_controllen);
+    if (msg_controllen < sizeof(struct target_cmsghdr)) {
+        goto the_end;
+    }
+    target_cmsg_addr = tswapal(target_msgh->msg_control);
+    target_cmsg = lock_user(VERIFY_WRITE, target_cmsg_addr, msg_controllen, 0);
+    target_cmsg_start = target_cmsg;
+    if (!target_cmsg) {
+        return -TARGET_EFAULT;
+    }
+
+    while (cmsg && target_cmsg) {
+        void *data = CMSG_DATA(cmsg);
+        void *target_data = TARGET_CMSG_DATA(target_cmsg);
+        int len = (unsigned char *)(cmsg) + cmsg->cmsg_len -
+            (unsigned char *)data;
+
+        int tgt_len, tgt_space;
+
+        /*
+         * We never copy a half-header but may copy half-data; this is Linux's
+         * behaviour in put_cmsg(). Note that truncation here is a guest 
problem
+         * (which we report to the guest via the CTRUNC bit), unlike truncation
+         * in target_to_host_cmsg, which is a QEMU bug.
+         */
+        if (msg_controllen < sizeof(struct target_cmsghdr)) {
+            target_msgh->msg_flags |= tswap32(MSG_CTRUNC);
+            break;
+        }
+
+        if (cmsg->cmsg_level == SOL_SOCKET) {
+            target_cmsg->cmsg_level = tswap32(TARGET_SOL_SOCKET);
+        } else {
+            target_cmsg->cmsg_level = tswap32(cmsg->cmsg_level);
+        }
+        target_cmsg->cmsg_type = tswap32(cmsg->cmsg_type);
+
+        /*
+         * Payload types which need a different size of payload on the target
+         * must adjust tgt_len here.
+         */
+        tgt_len = len;
+        switch (cmsg->cmsg_level) {
+        case SOL_SOCKET:
+            switch (cmsg->cmsg_type) {
+            case SCM_TIMESTAMP:
+                tgt_len = sizeof(struct target_freebsd_timeval);
+                break;
+            default:
+                break;
+            }
+            break;
+        default:
+            break;
+        }
+
+        if (msg_controllen < TARGET_CMSG_LEN(tgt_len)) {
+            target_msgh->msg_flags |= tswap32(MSG_CTRUNC);
+            tgt_len = msg_controllen - sizeof(struct target_cmsghdr);
+        }
+
+        /*
+         * We must now copy-and-convert len bytes of payload into tgt_len bytes
+         * of destination space. Bear in mind that in both source and
+         * destination we may be dealing with a truncated value!
+         */
+        switch (cmsg->cmsg_level) {
+        case SOL_SOCKET:
+            switch (cmsg->cmsg_type) {
+            case SCM_RIGHTS:
+            {
+                int *fd = (int *)data;
+                int *target_fd = (int *)target_data;
+                int i, numfds = tgt_len / sizeof(int);
+
+                for (i = 0; i < numfds; i++) {
+                    __put_user(fd[i], target_fd + i);
+                }
+                break;
+            }
+            case SO_TIMESTAMP:
+            {
+                struct timeval *tv = (struct timeval *)data;
+                struct target_freebsd_timeval *target_tv =
+                    (struct target_freebsd_timeval *)target_data;
+
+                if (len != sizeof(struct timeval) ||
+                    tgt_len != sizeof(struct target_freebsd_timeval)) {
+                    goto unimplemented;
+                }
+
+                /* copy struct timeval to target */
+                __put_user(tv->tv_sec, &target_tv->tv_sec);
+                __put_user(tv->tv_usec, &target_tv->tv_usec);
+                break;
+            }
+            default:
+                goto unimplemented;
+            }
+            break;
+        default:
+        unimplemented:
+            gemu_log("Unsupported host ancillary data: %d/%d\n",
+                     cmsg->cmsg_level, cmsg->cmsg_type);
+            memcpy(target_data, data, MIN(len, tgt_len));
+            if (tgt_len > len) {
+                memset(target_data + len, 0, tgt_len - len);
+            }
+        }
+
+        target_cmsg->cmsg_len = tswap32(TARGET_CMSG_LEN(tgt_len));
+        tgt_space = TARGET_CMSG_SPACE(tgt_len);
+        if (msg_controllen < tgt_space) {
+            tgt_space = msg_controllen;
+        }
+        msg_controllen -= tgt_space;
+        space += tgt_space;
+        cmsg = CMSG_NXTHDR(msgh, cmsg);
+        target_cmsg = TARGET_CMSG_NXTHDR(target_msgh, target_cmsg,
+                                         target_cmsg_start);
+    }
+    unlock_user(target_cmsg, target_cmsg_addr, space);
+the_end:
+    target_msgh->msg_controllen = tswap32(space);
+    return 0;
+}
+

-- 
2.52.0


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