user: replace the MOUNT macro with MOUNT_AT

The old style could be confused with a regular function, where the
driver would be executed unconditionally. This should make it more
obvious that the driver doesn't get executed in the parent process.

3 files changed, 29 insertions, 12 deletions

diff --git a/src/user/app/init/init.c b/src/user/app/init/init.c
index bb92cce..519329c 100644
--- a/src/user/app/init/init.c
+++ b/src/user/app/init/init.c
@@ -28,10 +28,10 @@ int main(void) {
 	freopen("/kdev/com1", "a+", stdout);
 	printf("in init (stage 2), main at 0x%x\n", &main);
 
-	MOUNT("/tmp/", tmpfs_drv());
-	MOUNT("/keyboard", ps2_drv());
-	MOUNT("/vga_tty", ansiterm_drv());
-	MOUNT("/bin/", fs_passthru("/init/bin"));
+	MOUNT_AT("/tmp/") { tmpfs_drv(); }
+	MOUNT_AT("/keyboard") { ps2_drv(); }
+	MOUNT_AT("/vga_tty") { ansiterm_drv(); }
+	MOUNT_AT("/bin/") { fs_passthru("/init/bin"); }
 
 	if (fork()) {
 		/* used to trigger a kernel bug
diff --git a/src/user/bootstrap/main.c b/src/user/bootstrap/main.c
index e877b64..fc239cf 100644
--- a/src/user/bootstrap/main.c
+++ b/src/user/bootstrap/main.c
@@ -15,14 +15,16 @@ void _start(void) {
 	_syscall_memflag(&_bss_start, &_bss_end - &_bss_start, MEMFLAG_PRESENT);
 
 	/* move everything provided by the kernel to /kdev */
-	MOUNT("/kdev/", fs_passthru(NULL));
-	if (!fork2_n_mount("/")) {
+	MOUNT_AT("/kdev/") { fs_passthru(NULL); }
+	MOUNT_AT("/") {
 		const char *l[] = {"/kdev/", NULL};
 		fs_whitelist(l);
 	}
-	if (!fork2_n_mount("/")) fs_dir_inject("/kdev/"); // TODO should be part of fs_whitelist
+	MOUNT_AT("/") {
+		fs_dir_inject("/kdev/"); // TODO should be part of fs_whitelist
+	}
 
-	MOUNT("/init/", tar_driver(&_initrd));
+	MOUNT_AT("/init/") { tar_driver(&_initrd); }
 
 	void *init = tar_find("bin/init", 8, &_initrd, ~0) + 512;
 	if (init) {
diff --git a/src/user/lib/fs/misc.h b/src/user/lib/fs/misc.h
index 0d9eb20..00f3c04 100644
--- a/src/user/lib/fs/misc.h
+++ b/src/user/lib/fs/misc.h
@@ -1,6 +1,8 @@
 #pragma once
 #include <stdbool.h>
 #include <stdio.h>
+#include <string.h>
+#include <unistd.h>
 
 bool fork2_n_mount(const char *path);
 
@@ -9,8 +11,21 @@ void fs_whitelist(const char **list);
 
 void fs_dir_inject(const char *path);
 
+static bool mount_at_pred(const char *path) {
+	// TODO preprocess path - simplify & ensure trailing slash
+	if (!fork2_n_mount(path)) {
+		/* child -> go into the for body */
+		_klogf("%s: impl", path);
+		return true;
+	}
+
+	if (strcmp("/", path) && !fork2_n_mount("/")) {
+		_klogf("%s: dir", path);
+		fs_dir_inject(path);
+		exit(1);
+	}
+	return false; /* continue after the for loop */
+}
+
 /** Mounts something and injects its path into the fs */
-// TODO path needs to have a trailing slash
-#define MOUNT(path, impl) \
-	if (!fork2_n_mount(path)) {_klogf("impl %s", path); impl;} \
-	if (!fork2_n_mount("/"))  {_klogf("dir for %s", path); fs_dir_inject(path);}
+#define MOUNT_AT(path) for (; mount_at_pred(path); exit(1))