moved file resolution code to a shared library

Makefile

@@ -7,10 +7,10 @@
 
 .POSIX:
 
-PREFIX=/usr/local/bin
+PREFIX=/usr/local
-CFLAGS=-O3 -s -Wl,-z,noseparate-code,-z,nosectionheader -flto
+CFLAGS=-O3 -s -Wl,-z,noseparate-code,-z,nosectionheader -flto -Lbuild -lyac
 
-build: build_dir cat false true
+build: build_dir lib cat false tail true
 
 clean: build_dir
 	rm -rf build/
@@ -21,12 +21,20 @@ cat: build_dir
 false: build_dir
 	cc $(CFLAGS) -o build/false src/false.c
 
+tail: build_dir
+	cc $(CFLAGS) -o build/tail src/tail.c
+
 true: build_dir
 	cc $(CFLAGS) -o build/true src/true.c
 
+lib:
+	cc -c -fPIC $(CFLAGS) -o build/yac.o src/yac.c
+	cc $(CFLAGS) -shared -o build/libyac.so build/yac.o
+
 build_dir:
 	mkdir -p build
 
 install: build
 	mkdir -p $(PREFIX)
-	cp -f build/* $(PREFIX)/
+	cp -f build/*.so $(PREFIX)/lib/
+	cp -f build/* $(PREFIX)/bin/

src/cat.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023 Emma Tebibyte
+ * Copyright (c) 2023 Emma Tebibyte <emma@tebibyte.media>
  * SPDX-License-Identifier: AGPL-3.0-or-later
  *
  * This file is part of YAC coreutils.
@@ -25,6 +25,8 @@
 #include <stdio.h>
 #include <unistd.h>
 
+#include "yac.h"
+
 void cat(FILE *file, bool u) {
 	int byte = 0; /* variable for storing bytes as they are read */
 	int p = 0; /* index counter for bytes in buffered reading */
@@ -89,55 +91,13 @@ int main(int argc, char *argv[]) {
 	}
 	
 	FILE *file;
-	struct stat stats;
 
 	for (i = optind; i < argc; i++) {
-		if (argv[i][0] == '-') {
+		file = rpath(argv[0], argv[i]);
-			switch (argv[i][1]) {
+		if (file != NULL) {
-				case '\0':
-					file = stdin;
-					break;
-				default:
-					continue;
-			}
-		} else if (stat(argv[i], &stats) == 0 && S_ISDIR(stats.st_mode)) {
-			fprintf(stderr, "%s: %s: Is a directory.\n", argv[0], argv[i]);
-			return EX_NOINPUT;
-		} else if ((file = fopen(argv[i], "r")) == NULL) {
-			switch (errno) {
-				case EACCES:
-					fprintf(stderr, "%s: %s: Permission denied.\n", argv[0], argv[i]);
-					return EX_NOINPUT;
-				case EISDIR:
-					fprintf(stderr, "%s: %s: Is a directory.\n", argv[0], argv[i]);
-					return EX_NOINPUT;
-				case ELOOP:
-					fprintf(
-						stderr,
-						"%s: %s: Is a symbolic link loop.\n",
-						argv[0],
-						argv[i]
-					);
-					return EX_UNAVAILABLE;
-				case EMFILE:
-					fprintf(stderr, "%s: Internal error.\n", argv[0]);
-					return EX_SOFTWARE;
-				case ENOENT: case ENOTDIR: case ENXIO:
-					fprintf(
-						stderr,
-						"%s: %s: No such file or directory.\n",
-						argv[0],
-						argv[i]
-					);
-					return EX_NOINPUT;
-				default:
-					fprintf(stderr, "%s: Unknown error.\n", argv[0]);
-					return EX_UNAVAILABLE;
-			}
-		}
-
 			cat(file, u);
 			if (file != stdin) { fclose(file); }
+		} else { continue; }
 	}
 
 	return EX_OK;

src/false.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023 Emma Tebibyte
+ * Copyright (c) 2023 Emma Tebibyte <emma@tebibyte.media>
  * SPDX-License-Identifier: AGPL-3.0-or-later
  *
  * This file is part of YAC coreutils.

src/true.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023 Emma Tebibyte
+ * Copyright (c) 2023 Emma Tebibyte <emma@tebibyte.media>
  * SPDX-License-Identifier: AGPL-3.0-or-later
  *
  * This file is part of YAC coreutils.

src/yac.c

@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2023 Emma Tebibyte <emma@tebibyte.media>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ *
+ * This file is part of YAC coreutils.
+ *
+ * YAC coreutils is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Affero General Public License as published by the
+ * Free Software Foundation, either version 3 of the License, or (at your
+ * option) any later version.
+ * 
+ * YAC coreutils is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see https://www.gnu.org/licenses/.
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sysexits.h>
+#include <sys/stat.h>
+
+/* Resolve a file from a path */
+FILE *rpath(char *argv0, char *path) { 
+	struct stat stats;
+	FILE *file;
+
+	if (path[0] == '-') {
+		switch (path[1]) {
+			case '\0':
+				file = stdin;
+				break;
+			default:
+				file = NULL;
+				break;
+		}
+	} else if (stat(path, &stats) == 0 && S_ISDIR(stats.st_mode)) {
+		fprintf(stderr, "%s: %s: Is a directory.\n", argv0, path);
+		exit(EX_NOINPUT);
+	} else if ((file = fopen(path, "r")) == NULL) {
+		switch (errno) {
+			case EACCES:
+				fprintf(stderr, "%s: %s: Permission denied.\n", argv0, path);
+				exit(EX_NOINPUT);
+			case EISDIR:
+				fprintf(stderr, "%s: %s: Is a directory.\n", argv0, path);
+				exit(EX_NOINPUT);
+			case ELOOP:
+				fprintf(
+					stderr,
+					"%s: %s: Is a symbolic link loop.\n",
+					argv0,
+					path
+				);
+				exit(EX_UNAVAILABLE);
+			case EMFILE:
+				fprintf(stderr, "%s: Internal error.\n", argv0);
+				exit(EX_SOFTWARE);
+			case ENOENT: case ENOTDIR: case ENXIO:
+				fprintf(
+					stderr,
+					"%s: %s: No such path or directory.\n",
+					argv0,
+					path
+				);
+				exit(EX_NOINPUT);
+			default:
+				fprintf(stderr, "%s: Unknown error.\n", argv0);
+				exit(EX_UNAVAILABLE);
+		}
+	}
+	return file;
+}

src/yac.h

@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) 2023 Emma Tebibyte <emma@tebibyte.media>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ *
+ * This file is part of YAC coreutils.
+ *
+ * YAC coreutils is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Affero General Public License as published by the
+ * Free Software Foundation, either version 3 of the License, or (at your
+ * option) any later version.
+ * 
+ * YAC coreutils is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see https://www.gnu.org/licenses/.
+ */
+
+#ifndef YAC_H
+#define YAC_H
+
+FILE *rpath(char *argv0, char *path);
+
+#endif