2 files changed, 68 insertions, 29 deletions

diff --git a/libbb/appletlib.c b/libbb/appletlib.c
index 51824f1b3..c90285ae9 100644
--- a/libbb/appletlib.c
+++ b/libbb/appletlib.c
@@ -1349,6 +1349,10 @@ int main(int argc UNUSED_PARAM, char **argv)
                         break;
                 }
         }
+
+        /* Have this process handle critical errors itself:  the default
+         * system-generated error dialogs may be inconvenient. */
+        SetErrorMode(SEM_FAILCRITICALERRORS);
 #endif
 
 #if defined(__MINGW64_VERSION_MAJOR)
diff --git a/win32/process.c b/win32/process.c
index caea87492..94a1e23a9 100644
--- a/win32/process.c
+++ b/win32/process.c
@@ -443,7 +443,65 @@ BOOL WINAPI kill_child_ctrl_handler(DWORD dwCtrlType)
         return FALSE;
 }
 
-static NORETURN void wait_for_child(HANDLE child)
+static int exit_code_to_wait_status_cmd(DWORD exit_code, const char *cmd)
+{
+        int sig, status;
+        DECLARE_PROC_ADDR(ULONG, RtlNtStatusToDosError, NTSTATUS);
+        DWORD flags, code;
+        char *msg = NULL;
+
+        if (exit_code == 0xc0000005)
+                return SIGSEGV;
+        else if (exit_code == 0xc000013a)
+                return SIGINT;
+
+        // When a process is terminated as if by a signal the Windows
+        // exit code is zero apart from the signal in its topmost byte.
+        // This is a busybox-w32 convention.
+        sig = exit_code >> 24;
+        if (sig != 0 && exit_code == sig << 24 && is_valid_signal(sig))
+                return sig;
+
+        // The exit code may be an NTSTATUS code.  Try to obtain a
+        // descriptive message for it.
+        if (exit_code > 0xff) {
+                flags = FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM;
+                if (INIT_PROC_ADDR(ntdll.dll, RtlNtStatusToDosError)) {
+                        code = RtlNtStatusToDosError(exit_code);
+                        if (FormatMessage(flags, NULL, code, 0, (char *)&msg, 0, NULL)) {
+                                char *cr = strrchr(msg, '\r');
+                                if (cr) {               // Replace CRLF with a space
+                                        cr[0] = ' ';
+                                        cr[1] = '\0';
+                                }
+                        }
+                }
+
+                if (cmd)
+                        bb_error_msg("%s: %sError 0x%lx", cmd, msg ?: "", exit_code);
+                else
+                        bb_error_msg("%s: %sError 0x%lx" + 4, msg ?: "", exit_code);
+                LocalFree(msg);
+        }
+
+        // Use least significant byte as exit code, but not if it's zero
+        // and the Windows exit code as a whole is non-zero.
+        status = exit_code & 0xff;
+        if (exit_code != 0 && status == 0)
+                status = 255;
+        return status << 8;
+}
+
+static int exit_code_to_posix_cmd(DWORD exit_code, const char *cmd)
+{
+        int status = exit_code_to_wait_status_cmd(exit_code, cmd);
+
+        if (WIFSIGNALED(status))
+                return 128 + WTERMSIG(status);
+        return WEXITSTATUS(status);
+}
+
+static NORETURN void wait_for_child(HANDLE child, const char *cmd)
 {
         DWORD code;
 
@@ -451,7 +509,7 @@ static NORETURN void wait_for_child(HANDLE child)
         SetConsoleCtrlHandler(kill_child_ctrl_handler, TRUE);
         WaitForSingleObject(child, INFINITE);
         GetExitCodeProcess(child, &code);
-        exit(exit_code_to_posix(code));
+        exit(exit_code_to_posix_cmd(code, cmd));
 }
 
 int
@@ -459,7 +517,7 @@ mingw_execvp(const char *cmd, char *const *argv)
 {
         intptr_t ret = mingw_spawnvp(P_NOWAIT, cmd, argv);
         if (ret != -1)
-                wait_for_child((HANDLE)ret);
+                wait_for_child((HANDLE)ret, cmd);
         return ret;
 }
 
@@ -468,7 +526,7 @@ mingw_execve(const char *cmd, char *const *argv, char *const *envp)
 {
         intptr_t ret = mingw_spawn_interpreter(P_NOWAIT, cmd, argv, envp, 0);
         if (ret != -1)
-                wait_for_child((HANDLE)ret);
+                wait_for_child((HANDLE)ret, cmd);
         return ret;
 }
 
@@ -896,33 +954,10 @@ int FAST_FUNC is_valid_signal(int number)
 
 int exit_code_to_wait_status(DWORD exit_code)
 {
-        int sig, status;
-
-        if (exit_code == 0xc0000005)
-                return SIGSEGV;
-        else if (exit_code == 0xc000013a)
-                return SIGINT;
-
-        // When a process is terminated as if by a signal the Windows
-        // exit code is zero apart from the signal in its topmost byte.
-        // This is a busybox-w32 convention.
-        sig = exit_code >> 24;
-        if (sig != 0 && exit_code == sig << 24 && is_valid_signal(sig))
-                return sig;
-
-        // Use least significant byte as exit code, but not if it's zero
-        // and the Windows exit code as a whole is non-zero.
-        status = exit_code & 0xff;
-        if (exit_code != 0 && status == 0)
-                status = 255;
-        return status << 8;
+        return exit_code_to_wait_status_cmd(exit_code, NULL);
 }
 
 int exit_code_to_posix(DWORD exit_code)
 {
-        int status = exit_code_to_wait_status(exit_code);
-
-        if (WIFSIGNALED(status))
-                return 128 + WTERMSIG(status);
-        return WEXITSTATUS(status);
+        return exit_code_to_posix_cmd(exit_code, NULL);
 }