From: Stacey Son <sson@FreeBSD.org>

Signed-off-by: Stacey Son <sson@FreeBSD.org>
Signed-off-by: Karim Taha <kariem.taha2.7@gmail.com>
---
 bsd-user/bsd-mem.h            | 76 +++++++++++++++++++++++++++++++++++
 bsd-user/freebsd/os-syscall.c |  8 ++++
 2 files changed, 84 insertions(+)

diff --git a/bsd-user/bsd-mem.h b/bsd-user/bsd-mem.h
index dd506b8a15..c01b009326 100644
--- a/bsd-user/bsd-mem.h
+++ b/bsd-user/bsd-mem.h
@@ -337,4 +337,80 @@ static inline abi_long do_bsd_shmctl(abi_long shmid, abi_long cmd,
     return ret;
 }
 
+/* shmat(2) */
+static inline abi_long do_bsd_shmat(int shmid, abi_ulong shmaddr, int shmflg)
+{
+    abi_ulong raddr;
+    abi_long ret;
+    void *host_raddr;
+    struct shmid_ds shm_info;
+    int i;
+
+    /* Find out the length of the shared memory segment. */
+    ret = get_errno(shmctl(shmid, IPC_STAT, &shm_info));
+    if (is_error(ret)) {
+        /* Can't get the length */
+        return ret;
+    }
+
+    if (!guest_range_valid_untagged(shmaddr, shm_info.shm_segsz)) {
+        return -TARGET_EINVAL;
+    }
+
+    mmap_lock();
+
+    if (shmaddr) {
+        host_raddr = shmat(shmid, (void *)g2h_untagged(shmaddr), shmflg);
+    } else {
+        abi_ulong mmap_start;
+
+        mmap_start = mmap_find_vma(0, shm_info.shm_segsz);
+
+        if (mmap_start == -1) {
+            errno = ENOMEM;
+            host_raddr = (void *)-1;
+        } else {
+            host_raddr = shmat(shmid, g2h_untagged(mmap_start),
+                shmflg | SHM_REMAP);
+        }
+    }
+
+    if (host_raddr == (void *)-1) {
+        mmap_unlock();
+        return get_errno((long)host_raddr);
+    }
+    raddr = h2g((unsigned long)host_raddr);
+
+    page_set_flags(raddr, raddr + shm_info.shm_segsz,
+        PAGE_VALID | PAGE_READ | ((shmflg & SHM_RDONLY) ? 0 : PAGE_WRITE));
+
+    for (i = 0; i < N_BSD_SHM_REGIONS; i++) {
+        if (bsd_shm_regions[i].start == 0) {
+            bsd_shm_regions[i].start = raddr;
+            bsd_shm_regions[i].size = shm_info.shm_segsz;
+            break;
+        }
+    }
+
+    mmap_unlock();
+    return raddr;
+}
+
+/* shmdt(2) */
+static inline abi_long do_bsd_shmdt(abi_ulong shmaddr)
+{
+    int i;
+
+    for (i = 0; i < N_BSD_SHM_REGIONS; ++i) {
+        if (bsd_shm_regions[i].start == shmaddr) {
+            bsd_shm_regions[i].start = 0;
+            page_set_flags(shmaddr,
+                shmaddr + bsd_shm_regions[i].size, 0);
+            break;
+        }
+    }
+
+    return get_errno(shmdt(g2h_untagged(shmaddr)));
+}
+
 #endif /* BSD_USER_BSD_MEM_H */
diff --git a/bsd-user/freebsd/os-syscall.c b/bsd-user/freebsd/os-syscall.c
index 35f94f51fc..fe0968773e 100644
--- a/bsd-user/freebsd/os-syscall.c
+++ b/bsd-user/freebsd/os-syscall.c
@@ -559,6 +559,14 @@ static abi_long freebsd_syscall(void *cpu_env, int num, abi_long arg1,
         ret = do_bsd_shmctl(arg1, arg2, arg3);
         break;
 
+    case TARGET_FREEBSD_NR_shmat: /* shmat(2) */
+        ret = do_bsd_shmat(arg1, arg2, arg3);
+        break;
+
+    case TARGET_FREEBSD_NR_shmdt: /* shmdt(2) */
+        ret = do_bsd_shmdt(arg1);
+        break;
+
         /*
          * Misc
          */
-- 
2.42.0