diff --git a/build-aux/syntax-check.mk b/build-aux/syntax-check.mk
index 3020921be8..2a38c03ba9 100644
--- a/build-aux/syntax-check.mk
+++ b/build-aux/syntax-check.mk
@@ -1987,7 +1987,7 @@ exclude_file_name_regexp--sc_flags_usage = \
 exclude_file_name_regexp--sc_libvirt_unmarked_diagnostics = \
   ^(src/rpc/gendispatch\.pl$$|tests/)
 
-exclude_file_name_regexp--sc_po_check = ^(docs/|src/rpc/gendispatch\.pl$$)
+exclude_file_name_regexp--sc_po_check = ^(docs/|src/rpc/gendispatch\.pl$$|tests/commandtest.c$$)
 
 exclude_file_name_regexp--sc_prohibit_VIR_ERR_NO_MEMORY = \
   ^(build-aux/syntax-check\.mk|include/libvirt/virterror\.h|src/remote/remote_daemon_dispatch\.c|src/util/virerror\.c|docs/internals/oomtesting\.html\.in)$$
diff --git a/src/util/virprocess.c b/src/util/virprocess.c
index 24135070b7..b126c3c9af 100644
--- a/src/util/virprocess.c
+++ b/src/util/virprocess.c
@@ -1126,6 +1126,23 @@ virProcessRunInMountNamespace(pid_t pid G_GNUC_UNUSED,
 
 
 #ifndef WIN32
+typedef struct {
+    int code;
+    int domain;
+    char message[VIR_ERROR_MAX_LENGTH];
+    virErrorLevel level;
+    char str1[VIR_ERROR_MAX_LENGTH];
+    char str2[VIR_ERROR_MAX_LENGTH];
+    char str3[VIR_ERROR_MAX_LENGTH];
+    int int1;
+    int int2;
+} errorData;
+
+typedef union {
+    errorData data;
+    char bindata[sizeof(errorData)];
+} errorDataBin;
+
 static int
 virProcessRunInForkHelper(int errfd,
                           pid_t ppid,
@@ -1134,9 +1151,24 @@ virProcessRunInForkHelper(int errfd,
 {
     if (cb(ppid, opaque) < 0) {
         virErrorPtr err = virGetLastError();
+
         if (err) {
-            size_t len = strlen(err->message) + 1;
-            ignore_value(safewrite(errfd, err->message, len));
+            g_autofree errorDataBin *bin = g_new0(errorDataBin, 1);
+
+            bin->data.code = err->code;
+            bin->data.domain = err->domain;
+            ignore_value(virStrcpy(bin->data.message, err->message, sizeof(bin->data.message)));
+            bin->data.level = err->level;
+            if (err->str1)
+                ignore_value(virStrcpy(bin->data.str1, err->str1, sizeof(bin->data.str1)));
+            if (err->str2)
+                ignore_value(virStrcpy(bin->data.str2, err->str2, sizeof(bin->data.str2)));
+            if (err->str3)
+                ignore_value(virStrcpy(bin->data.str3, err->str3, sizeof(bin->data.str3)));
+            bin->data.int1 = err->int1;
+            bin->data.int2 = err->int2;
+
+            ignore_value(safewrite(errfd, bin->bindata, sizeof(*bin)));
         }
 
         return -1;
@@ -1188,16 +1220,38 @@ virProcessRunInFork(virProcessForkCallback cb,
     } else {
         int status;
         g_autofree char *buf = NULL;
+        g_autofree errorDataBin *bin = NULL;
+        int nread;
 
         VIR_FORCE_CLOSE(errfd[1]);
-        ignore_value(virFileReadHeaderFD(errfd[0], 1024, &buf));
+        nread = virFileReadHeaderFD(errfd[0], sizeof(*bin), &buf);
         ret = virProcessWait(child, &status, false);
         if (ret == 0) {
             ret = status == EXIT_CANCELED ? -1 : status;
             if (ret) {
-                virReportError(VIR_ERR_INTERNAL_ERROR,
-                               _("child reported (status=%d): %s"),
-                               status, NULLSTR(buf));
+                if (nread == sizeof(*bin)) {
+                    bin = g_new0(errorDataBin, 1);
+                    memcpy(bin->bindata, buf, sizeof(*bin));
+
+                    virReportError(VIR_ERR_INTERNAL_ERROR,
+                                   _("child reported (status=%d): %s"),
+                                   status, NULLSTR(bin->data.message));
+
+                    virRaiseErrorFull(__FILE__, __FUNCTION__, __LINE__,
+                                      bin->data.domain,
+                                      bin->data.code,
+                                      bin->data.level,
+                                      bin->data.str1,
+                                      bin->data.str2,
+                                      bin->data.str3,
+                                      bin->data.int1,
+                                      bin->data.int2,
+                                      "%s", bin->data.message);
+                } else {
+                    virReportError(VIR_ERR_INTERNAL_ERROR,
+                                   _("child didn't write error (status=%d)"),
+                                   status);
+                }
             }
         }
     }
diff --git a/tests/commandtest.c b/tests/commandtest.c
index a64aa9ad33..f4a2c67c05 100644
--- a/tests/commandtest.c
+++ b/tests/commandtest.c
@@ -1257,6 +1257,48 @@ static int test27(const void *unused G_GNUC_UNUSED)
 }
 
 
+static int
+test28Callback(pid_t pid G_GNUC_UNUSED,
+               void *opaque G_GNUC_UNUSED)
+{
+    virReportSystemError(ENODATA, "%s", "some error message");
+    return -1;
+}
+
+
+static int
+test28(const void *unused G_GNUC_UNUSED)
+{
+    /* Not strictly a virCommand test, but this is the easiest place
+     * to test this lower-level interface. */
+    virErrorPtr err;
+
+    if (virProcessRunInFork(test28Callback, NULL) != -1) {
+        fprintf(stderr, "virProcessRunInFork did not fail\n");
+        return -1;
+    }
+
+    if (!(err = virGetLastError())) {
+        fprintf(stderr, "Expected error but got nothing\n");
+        return -1;
+    }
+
+    if (!(err->code == VIR_ERR_SYSTEM_ERROR &&
+          err->domain == 0 &&
+          STREQ(err->message, "some error message: No data available") &&
+          err->level == VIR_ERR_ERROR &&
+          STREQ(err->str1, "%s") &&
+          STREQ(err->str2, "some error message: No data available") &&
+          err->int1 == ENODATA &&
+          err->int2 == -1)) {
+        fprintf(stderr, "Unexpected error object\n");
+        return -1;
+    }
+
+    return 0;
+}
+
+
 static int
 mymain(void)
 {
@@ -1354,6 +1396,7 @@ mymain(void)
     DO_TEST(test25);
     DO_TEST(test26);
     DO_TEST(test27);
+    DO_TEST(test28);
 
     return ret == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
 }