Version 1.08 with public source code release.

src/main/hook/patch/mounts.c

@@ -0,0 +1,105 @@
+#define LOG_MODULE "patch-mounts"
+
+#include <assert.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <string.h>
+
+#include "capnhook/hook/filehook.h"
+
+#include "util/log.h"
+
+/* looks odd but hddd is intentional */
+static const char* patch_mount_proc_mount_file = "/dev/hddd /mnt/hd";
+
+static FILE* patch_mount_file = NULL;
+static bool patch_mount_eof;
+
+static enum cnh_result patch_hdd_check_filehook(struct cnh_filehook_irp *irp)
+{
+    enum cnh_result result;
+
+    result = CNH_RESULT_SUCCESS;
+
+    assert(irp);
+
+    if (irp->op != CNH_FILEHOOK_IRP_OP_OPEN && irp->file != patch_mount_file) {
+        return cnh_filehook_invoke_next(irp);
+    }
+
+    switch (irp->op) {
+        case CNH_FILEHOOK_IRP_OP_OPEN:
+        {
+            if (!strcmp(irp->open_filename, "/proc/mounts")) {
+                patch_mount_file = cnh_filehook_open_dummy_file_handle();
+                irp->file = patch_mount_file;
+
+                patch_mount_eof = false;
+
+                log_debug("/proc/mounts opened: %p", irp->file);
+            } else {
+                return cnh_filehook_invoke_next(irp);
+            }
+
+            break;
+        }
+
+        case CNH_FILEHOOK_IRP_OP_FGETS:
+        {
+            size_t size;
+
+            log_info("/proc/mounts fake read");
+
+            size = strlen(patch_mount_proc_mount_file) + 1;
+
+            /* +1: copy the null terminator, too */
+            memcpy(&irp->read.bytes[irp->read.pos], patch_mount_proc_mount_file, size);
+            irp->read.pos += size;
+
+            patch_mount_eof = true;
+
+            break;
+        }
+
+        case CNH_FILEHOOK_IRP_OP_SEEK:
+        {
+            /* Ignore seeking */
+
+            break;
+        }
+
+        case CNH_FILEHOOK_IRP_OP_TELL:
+        {
+            /* Return size */
+            irp->tell_offset = strlen(patch_mount_proc_mount_file) + 1;
+
+            break;
+        }
+
+        case CNH_FILEHOOK_IRP_OP_EOF:
+        {
+            irp->eof = patch_mount_eof;
+            break;
+        }
+
+        case CNH_FILEHOOK_IRP_OP_CLOSE:
+        {
+            patch_mount_file = NULL;
+
+            /* Actually close dummy handle */
+            return cnh_filehook_invoke_next(irp);
+        }
+
+        default:
+            log_warn("Unhandled file op: %d", irp->op);
+            break;
+    }
+
+    return result;
+}
+
+void patch_mounts_init(void)
+{
+    cnh_filehook_push_handler(patch_hdd_check_filehook);
+    log_info("Initialized");
+}