Check architecture compatibility during sysmerge(8)/sysupgrade(8).

sysinstall/fileops.c

@@ -17,6 +17,7 @@
  * File operation utility functions.
  */
 
+#include <sys/stat.h>
 #include <sys/types.h>
 
 #include <err.h>
@@ -129,3 +130,42 @@ void write_random_seed(const char* path)
 	}
 	close(fd);
 }
+
+char* read_string_file(const char* path)
+{
+	FILE* fp = fopen(path, "r");
+	if ( !fp )
+		return NULL;
+	struct stat st;
+	if ( fstat(fileno(fp), &st) < 0 )
+	{
+		fclose(fp);
+		return NULL;
+	}
+	size_t content_length;
+	if ( __builtin_add_overflow(1, st.st_size, &content_length) )
+	{
+		fclose(fp);
+		errno = EOVERFLOW;
+		return NULL;
+	}
+	char* content = malloc(content_length);
+	if ( !content )
+	{
+		fclose(fp);
+		return NULL;
+	}
+	size_t amount = fread(content, 1, content_length - 1, fp);
+	if ( ferror(fp) )
+	{
+		fclose(fp);
+		free(content);
+		return NULL;
+	}
+	fclose(fp);
+	if ( 0 < amount && content[amount - 1] == '\n' )
+		content[amount - 1] = '\0';
+	else
+		content[amount] = '\0';
+	return content;
+}

sysinstall/fileops.h

@@ -25,5 +25,6 @@ int mkdir_p(const char* path, mode_t mode);
 int access_or_die(const char* path, int mode);
 void mkdir_or_chmod_or_die(const char* path, mode_t mode);
 void write_random_seed(const char* path);
+char* read_string_file(const char* path);
 
 #endif

sysinstall/sysmerge.c

@@ -191,7 +191,23 @@ int main(int argc, char* argv[])
 	}
 	free(new_release_path);
 
-	// TODO: Check if /etc/machine matches the current architecture.
+	const char* old_machine_path = "/etc/machine";
+	char* old_machine = read_string_file(old_machine_path);
+	if ( !old_machine )
+		err(2, "%s", old_machine_path);
+	char* new_machine_path;
+	if ( asprintf(&new_machine_path, "%s/etc/machine", source) < 0 )
+		err(2, "asprintf");
+	char* new_machine = read_string_file(new_machine_path);
+	if ( !new_machine )
+		err(2, "%s", new_machine_path);
+	if ( strcmp(old_machine, new_machine) != 0 )
+		errx(2, "%s (%s) does not match %s (%s)", new_machine_path,
+		     new_machine, old_machine_path, old_machine);
+	free(old_machine);
+	free(new_machine_path);
+	free(new_machine);
+
 	// TODO: Check for version (skipping, downgrading).
 
 	struct conf conf;

sysinstall/sysupgrade.c

@@ -60,6 +60,7 @@ struct installation
 	struct release release;
 	struct mountpoint* mountpoints;
 	size_t mountpoints_used;
+	char* machine;
 };
 
 static struct installation* installations;
@@ -74,7 +75,8 @@ static char fs[] = "/tmp/fs.XXXXXX";
 static bool add_installation(struct blockdevice* bdev,
                              struct release* release,
                              struct mountpoint* mountpoints,
-                             size_t mountpoints_used)
+                             size_t mountpoints_used,
+                             char* machine)
 {
 	if ( installations_count == installations_length )
 	{
@@ -93,6 +95,7 @@ static bool add_installation(struct blockdevice* bdev,
 	installation->release = *release;
 	installation->mountpoints = mountpoints;
 	installation->mountpoints_used = mountpoints_used;
+	installation->machine = machine;
 	return true;
 }
 
@@ -135,7 +138,23 @@ static void search_installation_path(const char* mnt, struct blockdevice* bdev)
 		release_free(&release);
 		return;
 	}
-	if ( !add_installation(bdev, &release, mountpoints, mountpoints_used) )
+	char* machine_path;
+	if ( asprintf(&machine_path, "%s/etc/machine", mnt) < 0 )
+	{
+		warn("%s: malloc", path_of_blockdevice(bdev));
+		release_free(&release);
+		return;
+	}
+	char* machine = read_string_file(machine_path);
+	free(machine_path);
+	if ( !machine )
+	{
+		warn("%s/etc/machine", path_of_blockdevice(bdev));
+		release_free(&release);
+		return;
+	}
+	if ( !add_installation(bdev, &release, mountpoints, mountpoints_used,
+	                       machine) )
 	{
 		free_mountpoints(mountpoints, mountpoints_used);
 		release_free(&release);
@@ -516,9 +535,10 @@ int main(void)
 			for ( size_t i = 0; i < installations_count; i++ )
 			{
 				struct installation* installation = &installations[i];
-				printf("  %-16s  %s\n",
+				printf("  %-16s  %s (%s)\n",
 				       path_of_blockdevice(installation->bdev),
-					   installation->release.pretty_name);
+				       installation->release.pretty_name,
+				       installation->machine);
 			}
 			text("\n");
 
@@ -549,7 +569,27 @@ int main(void)
 
 	struct release* target_release = &target->release;
 
-	// TODO: Check if /etc/machine matches the current architecture.
+	char* source_machine = read_string_file("/etc/machine");
+	if ( !source_machine )
+		err(2, "/etc/machine");
+	if ( strcmp(target->machine, source_machine) != 0 )
+	{
+		textf("Warning: You are changing an existing installation to another "
+		      "architecture! (%s -> %s) This is not supported and there is no "
+		      "promise this will work!\n", target->machine, source_machine);
+		while ( true )
+		{
+			prompt(input, sizeof(input),
+			       "Change the existing installation to another architecture?",
+			       "no");
+			if ( !strcasecmp(input, "no") || !strcasecmp(input, "yes") )
+				break;
+		}
+		if ( !strcasecmp(input, "no") )
+			errx(2, "upgrade aborted because of architecture mismatch");
+		text("\n");
+	}
+	free(source_machine);
 
 	if ( downgrading_version(target_release, &new_release) )
 	{