[PULL 23/51] bsd-user: Implement wait4(2) and wait6(2) system calls.

[Warner Losh]

From: Stacey Son <sson@FreeBSD.org>

Signed-off-by: Stacey Son <sson@FreeBSD.org>
Signed-off-by: Karim Taha <kariem.taha2.7@gmail.com>
Reviewed-by: Warner Losh <imp@bsdimp.com>
Message-Id: <20230925182425.3163-24-kariem.taha2.7@gmail.com>
---
 bsd-user/freebsd/os-proc.h    | 84 +++++++++++++++++++++++++++++++++++
 bsd-user/freebsd/os-syscall.c | 15 +++++++
 2 files changed, 99 insertions(+)

diff --git a/bsd-user/freebsd/os-proc.h b/bsd-user/freebsd/os-proc.h
index 75ed39f8ddd..04bce755e58 100644
--- a/bsd-user/freebsd/os-proc.h
+++ b/bsd-user/freebsd/os-proc.h
@@ -30,6 +30,10 @@
 
 #include "target_arch_cpu.h"
 
+pid_t safe_wait4(pid_t wpid, int *status, int options, struct rusage *rusage);
+pid_t safe_wait6(idtype_t idtype, id_t id, int *status, int options,
+    struct __wrusage *wrusage, siginfo_t *infop);
+
 /* execve(2) */
 static inline abi_long do_freebsd_execve(abi_ulong path_or_fd, abi_ulong argp,
         abi_ulong envp)
@@ -46,4 +50,84 @@ static inline abi_long do_freebsd_fexecve(abi_ulong 
path_or_fd, abi_ulong argp,
     return freebsd_exec_common(path_or_fd, argp, envp, 1);
 }
 
+/* wait4(2) */
+static inline abi_long do_freebsd_wait4(abi_long arg1, abi_ulong target_status,
+        abi_long arg3, abi_ulong target_rusage)
+{
+    abi_long ret;
+    int status;
+    struct rusage rusage, *rusage_ptr = NULL;
+
+    if (target_rusage) {
+        rusage_ptr = &rusage;
+    }
+    ret = get_errno(safe_wait4(arg1, &status, arg3, rusage_ptr));
+
+    if (ret < 0) {
+        return ret;
+    }
+    if (target_status != 0) {
+        status = host_to_target_waitstatus(status);
+        if (put_user_s32(status, target_status) != 0) {
+            return -TARGET_EFAULT;
+        }
+    }
+    if (target_rusage != 0) {
+        host_to_target_rusage(target_rusage, &rusage);
+    }
+    return ret;
+}
+
+/* wait6(2) */
+static inline abi_long do_freebsd_wait6(void *cpu_env, abi_long idtype,
+    abi_long id1, abi_long id2,
+    abi_ulong target_status, abi_long options, abi_ulong target_wrusage,
+    abi_ulong target_infop, abi_ulong pad1)
+{
+    abi_long ret;
+    int status;
+    struct __wrusage wrusage, *wrusage_ptr = NULL;
+    siginfo_t info;
+    void *p;
+
+    if (regpairs_aligned(cpu_env) != 0) {
+        /* printf("shifting args\n"); */
+        /* 64-bit id is aligned, so shift all the arguments over by one */
+        id1 = id2;
+        id2 = target_status;
+        target_status = options;
+        options = target_wrusage;
+        target_wrusage = target_infop;
+        target_infop = pad1;
+    }
+
+    if (target_wrusage) {
+        wrusage_ptr = &wrusage;
+    }
+    ret = get_errno(safe_wait6(idtype, target_arg64(id1, id2),
+                               &status, options, wrusage_ptr, &info));
+
+    if (ret < 0) {
+        return ret;
+    }
+    if (target_status != 0) {
+        status = host_to_target_waitstatus(status);
+        if (put_user_s32(status, target_status) != 0) {
+            return -TARGET_EFAULT;
+        }
+    }
+    if (target_wrusage != 0) {
+        host_to_target_wrusage(target_wrusage, &wrusage);
+    }
+    if (target_infop != 0) {
+        p = lock_user(VERIFY_WRITE, target_infop, sizeof(target_siginfo_t), 0);
+        if (p == NULL) {
+            return -TARGET_EFAULT;
+        }
+        host_to_target_siginfo(p, &info);
+        unlock_user(p, target_infop, sizeof(target_siginfo_t));
+    }
+    return ret;
+}
+
 #endif /* BSD_USER_FREEBSD_OS_PROC_H */
diff --git a/bsd-user/freebsd/os-syscall.c b/bsd-user/freebsd/os-syscall.c
index 515eaaf31f1..55e68e48159 100644
--- a/bsd-user/freebsd/os-syscall.c
+++ b/bsd-user/freebsd/os-syscall.c
@@ -40,6 +40,12 @@
 #include "os-stat.h"
 #include "os-proc.h"
 
+/* used in os-proc */
+safe_syscall4(pid_t, wait4, pid_t, wpid, int *, status, int, options,
+    struct rusage *, rusage);
+safe_syscall6(pid_t, wait6, idtype_t, idtype, id_t, id, int *, status, int,
+    options, struct __wrusage *, wrusage, siginfo_t *, infop);
+
 /* I/O */
 safe_syscall3(int, open, const char *, path, int, flags, mode_t, mode);
 safe_syscall4(int, openat, int, fd, const char *, path, int, flags, mode_t,
@@ -228,6 +234,15 @@ static abi_long freebsd_syscall(void *cpu_env, int num, 
abi_long arg1,
         ret = do_freebsd_fexecve(arg1, arg2, arg3);
         break;
 
+    case TARGET_FREEBSD_NR_wait4: /* wait4(2) */
+        ret = do_freebsd_wait4(arg1, arg2, arg3, arg4);
+        break;
+
+    case TARGET_FREEBSD_NR_wait6: /* wait6(2) */
+        ret = do_freebsd_wait6(cpu_env, arg1, arg2, arg3,
+                               arg4, arg5, arg6, arg7, arg8);
+        break;
+
     case TARGET_FREEBSD_NR_exit: /* exit(2) */
         ret = do_bsd_exit(cpu_env, arg1);
         break;
-- 
2.41.0