linux-user: Make TARGET_NR_setgroups affect only the current thread

Like TARGET_NR_setuid, TARGET_NR_setgroups should affect only the
calling thread, and not the entire process. Therefore, implement it
using a syscall, and not a libc call.

Cc: [email protected]
Fixes: 19b84f3 ("added setgroups and getgroups syscalls")
Signed-off-by: Ilya Leoshkevich <[email protected]>
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
Message-Id: <[email protected]>
Reviewed-by: Richard Henderson <[email protected]>
Signed-off-by: Richard Henderson <[email protected]>

Author: iii-i

linux-user/syscall.c

@@ -7209,11 +7209,17 @@ static inline int tswapid(int id)
 #else
 #define __NR_sys_setresgid __NR_setresgid
 #endif
+#ifdef __NR_setgroups32
+#define __NR_sys_setgroups __NR_setgroups32
+#else
+#define __NR_sys_setgroups __NR_setgroups
+#endif
 
 _syscall1(int, sys_setuid, uid_t, uid)
 _syscall1(int, sys_setgid, gid_t, gid)
 _syscall3(int, sys_setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
 _syscall3(int, sys_setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
+_syscall2(int, sys_setgroups, int, size, gid_t *, grouplist)
 
 void syscall_init(void)
 {
@@ -11891,7 +11897,7 @@ static abi_long do_syscall1(CPUArchState *cpu_env, int num, abi_long arg1,
                 unlock_user(target_grouplist, arg2,
                             gidsetsize * sizeof(target_id));
             }
-            return get_errno(setgroups(gidsetsize, grouplist));
+            return get_errno(sys_setgroups(gidsetsize, grouplist));
         }
     case TARGET_NR_fchown:
         return get_errno(fchown(arg1, low2highuid(arg2), low2highgid(arg3)));
@@ -12227,7 +12233,7 @@ static abi_long do_syscall1(CPUArchState *cpu_env, int num, abi_long arg1,
                 }
                 unlock_user(target_grouplist, arg2, 0);
             }
-            return get_errno(setgroups(gidsetsize, grouplist));
+            return get_errno(sys_setgroups(gidsetsize, grouplist));
         }
 #endif
 #ifdef TARGET_NR_fchown32