linux-user: Trace rt_sigprocmask's sigsets

Add a function for formatting target sigsets. It can be useful for
other syscalls in the future, so put it into the beginning of strace.c.
For simplicity, do not implement the strace's ~[] output syntax.

Add a rt_sigprocmask return handler.

Example outputs:

    753914 rt_sigprocmask(SIG_BLOCK,[SIGCHLD SIGTSTP SIGTTIN SIGTTOU],0x00007f80fddfe380,8) = 0 (oldset=[SIGTTOU])
    753914 rt_sigprocmask(SIG_SETMASK,[SIGCHLD],NULL,8) = 0
    753914 rt_sigprocmask(SIG_BLOCK,NULL,0x00007f80fddff3c0,8) = 0 (oldset=[])

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Message-ID: <20241022102726.18520-1-iii@linux.ibm.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

linux-user/strace.c

@@ -161,19 +161,20 @@ static const char * const target_signal_name[] = {
 };
 
 static void
-print_signal(abi_ulong arg, int last)
+print_signal_1(abi_ulong arg)
 {
-    const char *signal_name = NULL;
-
     if (arg < ARRAY_SIZE(target_signal_name)) {
-        signal_name = target_signal_name[arg];
+        qemu_log("%s", target_signal_name[arg]);
+    } else {
+        qemu_log(TARGET_ABI_FMT_lu, arg);
     }
+}
 
-    if (signal_name == NULL) {
-        print_raw_param("%ld", arg, last);
-        return;
-    }
-    qemu_log("%s%s", signal_name, get_comma(last));
+static void
+print_signal(abi_ulong arg, int last)
+{
+    print_signal_1(arg);
+    qemu_log("%s", get_comma(last));
 }
 
 static void print_si_code(int arg)
@@ -718,6 +719,51 @@ print_ipc(CPUArchState *cpu_env, const struct syscallname *name,
 }
 #endif
 
+#ifdef TARGET_NR_rt_sigprocmask
+static void print_target_sigset_t_1(target_sigset_t *set, int last)
+{
+    bool first = true;
+    int i, sig = 1;
+
+    qemu_log("[");
+    for (i = 0; i < TARGET_NSIG_WORDS; i++) {
+        abi_ulong bits = 0;
+        int j;
+
+        __get_user(bits, &set->sig[i]);
+        for (j = 0; j < sizeof(bits) * 8; j++) {
+            if (bits & ((abi_ulong)1 << j)) {
+                if (first) {
+                    first = false;
+                } else {
+                    qemu_log(" ");
+                }
+                print_signal_1(sig);
+            }
+            sig++;
+        }
+    }
+    qemu_log("]%s", get_comma(last));
+}
+
+static void print_target_sigset_t(abi_ulong addr, abi_ulong size, int last)
+{
+    if (addr && size == sizeof(target_sigset_t)) {
+        target_sigset_t *set;
+
+        set = lock_user(VERIFY_READ, addr, sizeof(target_sigset_t), 1);
+        if (set) {
+            print_target_sigset_t_1(set, last);
+            unlock_user(set, addr, 0);
+        } else {
+            print_pointer(addr, last);
+        }
+    } else {
+        print_pointer(addr, last);
+    }
+}
+#endif
+
 /*
  * Variants for the return value output function
  */
@@ -3312,11 +3358,29 @@ print_rt_sigprocmask(CPUArchState *cpu_env, const struct syscallname *name,
     case TARGET_SIG_SETMASK: how = "SIG_SETMASK"; break;
     }
     qemu_log("%s,", how);
-    print_pointer(arg1, 0);
+    print_target_sigset_t(arg1, arg3, 0);
     print_pointer(arg2, 0);
     print_raw_param("%u", arg3, 1);
     print_syscall_epilogue(name);
 }
+
+static void
+print_rt_sigprocmask_ret(CPUArchState *cpu_env, const struct syscallname *name,
+                         abi_long ret, abi_long arg0, abi_long arg1,
+                         abi_long arg2, abi_long arg3, abi_long arg4,
+                         abi_long arg5)
+{
+    if (!print_syscall_err(ret)) {
+        qemu_log(TARGET_ABI_FMT_ld, ret);
+        if (arg2) {
+            qemu_log(" (oldset=");
+            print_target_sigset_t(arg2, arg3, 1);
+            qemu_log(")");
+        }
+    }
+
+    qemu_log("\n");
+}
 #endif
 
 #ifdef TARGET_NR_rt_sigqueueinfo

linux-user/strace.list

@@ -1189,7 +1189,8 @@
 { TARGET_NR_rt_sigpending, "rt_sigpending" , NULL, NULL, NULL },
 #endif
 #ifdef TARGET_NR_rt_sigprocmask
-{ TARGET_NR_rt_sigprocmask, "rt_sigprocmask" , NULL, print_rt_sigprocmask, NULL },
+{ TARGET_NR_rt_sigprocmask, "rt_sigprocmask" , NULL, print_rt_sigprocmask,
+                            print_rt_sigprocmask_ret },
 #endif
 #ifdef TARGET_NR_rt_sigqueueinfo
 { TARGET_NR_rt_sigqueueinfo, "rt_sigqueueinfo" , NULL, print_rt_sigqueueinfo, NULL },