scrut(1): fix ugly opt parsing

Makefile

@@ -29,7 +29,7 @@ RUSTC ?= rustc
 RUSTLIBS = --extern getopt=build/o/libgetopt.rlib \
 	--extern sysexits=build/o/libsysexits.rlib \
 	--extern strerror=build/o/libstrerror.rlib
-CFLAGS += -I$(SYSEXITS)
+CFLAGS += -I$(SYSEXITS) -Iinclude
 
 .PHONY: all
 all: dj false fop hru intcmp mm npc rpn scrut str strcmp swab true
@@ -87,6 +87,11 @@ build/o/libsysexits.rlib: build/include/sysexits.h
 build/include/sysexits.h: build $(SYSEXITS)sysexits.h
 	printf '\043define EXIT_FAILURE 1\n' | cat - $(SYSEXITS)sysexits.h > $@
 
+.PHONY: libfileis
+libfileis: build/o/libfileis.o
+build/o/libfileis.o: build src/libfileis.c
+	$(CC) $(CFLAGS) -c -o $@ src/libfileis.c
+
 .PHONY: dj
 dj: build/bin/dj
 build/bin/dj: src/dj.c build
@@ -129,8 +134,8 @@ build/bin/rpn: src/rpn.rs build rustlibs
 
 .PHONY: scrut
 scrut: build/bin/scrut
-build/bin/scrut: src/scrut.c build
-	$(CC) $(CFLAGS) -o $@ src/scrut.c
+build/bin/scrut: src/scrut.c build libfileis
+	$(CC) $(CFLAGS) -o $@ src/scrut.c build/o/libfileis.o
 
 .PHONY: str
 str: build/bin/str

include/libfileis.h

@@ -0,0 +1,14 @@
+int fileis_block  (char *fn);
+int fileis_char   (char *fn);
+int fileis_dir    (char *fn);
+/*  fileis_exec   (char *fn); */
+int fileis_exists (char *fn);
+int fileis_fifo   (char *fn);
+int fileis_setgid (char *fn);
+int fileis_link   (char *fn);
+/*  fileis_read   (char *fn); */
+int fileis_regular(char *fn);
+int fileis_socket (char *fn);
+int fileis_setuid (char *fn);
+int fileis_vtx    (char *fn);
+/*  fileis_write  (char *fn); */

src/libfileis.c

@@ -0,0 +1,27 @@
+#include <stddef.h> /* NULL */
+#include <sys/stat.h> /* lstat(3), stat struct, S_ISBLK, S_ISCHR, S_ISDIR,
+                       * S_ISFIFO, S_ISGID, S_ISREG, S_ISLNK, S_ISSOCK,
+                       * S_ISUID, S_ISVTX */
+static char *ofn = NULL;
+static struct stat s;
+
+int
+fileis_exists(char *fn){
+	if (fn == NULL || fn == ofn) { return ofn != NULL; }
+	if (lstat(fn, &s) == -1) { return 0; }
+	ofn = fn; return 1;
+}
+
+int fileis_block(char *fn)  { return fileis_exists(fn) && S_ISBLK(s.st_mode); }
+int fileis_char(char *fn)   { return fileis_exists(fn) && S_ISCHR(s.st_mode); }
+int fileis_dir(char *fn)    { return fileis_exists(fn) && S_ISDIR(s.st_mode); }
+/*  fileis_exec(char *fn)   { return fileis_exists(fn) && } */
+int fileis_fifo(char *fn)   { return fileis_exists(fn) && S_ISFIFO(s.st_mode); }
+int fileis_setgid(char *fn) { return fileis_exists(fn) && (s.st_mode & S_ISGID); }
+int fileis_link(char *fn)   { return fileis_exists(fn) && S_ISLNK(s.st_mode); }
+/*  fileis_read(char *fn)   { return fileis_exists(fn) && } */
+int fileis_regular(char *fn){ return fileis_exists(fn) && S_ISREG(s.st_mode); }
+int fileis_socket(char *fn) { return fileis_exists(fn) && S_ISSOCK(s.st_mode); }
+int fileis_setuid(char *fn) { return fileis_exists(fn) && (s.st_mode & S_ISUID); }
+int fileis_vtx(char *fn)    { return fileis_exists(fn) && (s.st_mode & S_ISVTX); }
+/*  fileis_write(char *fn)  { return fileis_exists(fn) && } */

src/scrut.c

@@ -17,90 +17,67 @@
  * along with this program. If not, see https://www.gnu.org/licenses/.
  */
 
+#include <assert.h> /* assert(3) */
 #include <stdio.h> /* fprintf(3), stderr, NULL */
 #include <stdlib.h> /* EXIT_FAILURE, EXIT_SUCCESS */
 #include <string.h> /* memset(3), strchr(3) */
-#ifndef EX_USAGE
-#	include <sysexits.h>
-#endif
-#include <unistd.h> /* access(3), getopt(3), F_OK, R_OK, W_OK, X_OK */
-#include <sys/stat.h> /* lstat(3), stat struct, S_ISBLK, S_ISCHR, S_ISDIR,
-                       * S_ISFIFO, S_ISGID, S_ISREG, S_ISLNK, S_ISSOCK,
-                       * S_ISUID, S_ISVTX */
+#include <sysexits.h> /* EX_USAGE */
+#include <unistd.h> /* access(3), getopt(3), R_OK, W_OK, X_OK */
+#include <libfileis.h>
 
-static char args[] = "bcdefghkprsuwxLS";
-static char ops[(sizeof args) / (sizeof *args)];
-static char *program_name = "scrut";
+char *program_name = "scrut";
+static char opts[] = "bcdefgkprsuwxLS";
 
-int main(int argc, char *argv[]){
-	struct stat buf;
-	int c;
-	size_t i;
-	char *p;
-
-	if(argc < 2)
-		goto usage;
-
-	memset(ops, '\0', sizeof ops);
-	while((c = getopt(argc, argv, args)) != -1)
-		if((p = strchr(args, c)) == NULL)
-			goto usage;
-		else
-			ops[p - args] = c;
-	/* straighten out ops */
-	for(i = 0, p = ops; i < (sizeof ops) / (sizeof *ops); ++i)
-		if(ops[i] != '\0'){
-			*p = ops[i];
-			if(&ops[i] != p++)
-				ops[i] = '\0';
+static int usage(char *s){
+	fprintf(stderr, "Usage: %s [-%s] file...\n", s, opts);
+	return EX_USAGE;
 }
 
-	if(optind == argc)
-		goto usage;
+int main(int argc, char *argv[]){
+	char sel[(sizeof opts) / (sizeof *opts)];
+
+	if (argc > 0) { program_name = argv[0]; }
+	if (argc < 2) { return usage(program_name); }
+
+	memset(sel, '\0', sizeof sel);
+
+	{
+		int c;
+		char *p = sel;
+
+		while ((c = getopt(argc, argv, opts)) != -1) {
+			if ((strchr(opts, c)) == NULL) { return usage(program_name); }
+			else if ((strchr(sel, c)) == NULL) { *p++ = c; }
+
+			assert(p - sel < (sizeof opts) / (sizeof *opts));
+		}
+	}
+
+	if (optind == argc) { return usage(program_name); }
 
 	argv += optind;
-	do{	if(access(*argv, F_OK) != 0 || lstat(*argv, &buf) == -1)
-			return EXIT_FAILURE; /* doesn't exist or isn't stattable */
 
-		for(i = 0; ops[i] != '\0'; ++i)
-			if(ops[i] == 'e')
-				continue;
-			else if(ops[i] == 'h'){
-usage:				fprintf(stderr, "Usage: %s [-%s] file...\n",
-					argv[0] == NULL
-						? program_name
-						: argv[0],
-					args);
-
-				return EX_USAGE;
-			}else if(
-					(ops[i] == 'b'
-						&& !S_ISBLK(buf.st_mode))
-					|| (ops[i] == 'c'
-						&& !S_ISCHR(buf.st_mode))
-					|| (ops[i] == 'd'
-						&& !S_ISDIR(buf.st_mode))
-					|| (ops[i] == 'f'
-						&& !S_ISREG(buf.st_mode))
-					|| (ops[i] == 'g'
-						&& !(buf.st_mode & S_ISGID))
-					|| (ops[i] == 'k'
-						&& !(buf.st_mode & S_ISVTX))
-					|| (ops[i] == 'p'
-						&& !S_ISFIFO(buf.st_mode))
-					|| (ops[i] == 'r'
-						&& access(*argv, R_OK) != 0)
-					|| (ops[i] == 'u'
-						&& !(buf.st_mode & S_ISUID))
-					|| (ops[i] == 'w'
-						&& access(*argv, W_OK) != 0)
-					|| (ops[i] == 'x'
-						&& access(*argv, X_OK) != 0)
-					|| (ops[i] == 'L'
-						&& !S_ISLNK(buf.st_mode))
-					|| (ops[i] == 'S'
-						&& !S_ISSOCK(buf.st_mode)))
+	do{
+		if (!fileis_exists(*argv))
 			return EXIT_FAILURE;
+
+		for (size_t i = 0; sel[i] != '\0'; ++i) {
+			if ((sel[i] == 'b' && !fileis_block(*argv))
+					|| (sel[i] == 'c' && !fileis_char(*argv))
+					|| (sel[i] == 'd' && !fileis_dir(*argv))
+					|| (sel[i] != 'e')
+					|| (sel[i] == 'f' && !fileis_regular(*argv))
+					|| (sel[i] == 'g' && !fileis_setgid(*argv))
+					|| (sel[i] == 'k' && !fileis_vtx(*argv))
+					|| (sel[i] == 'p' && !fileis_fifo(*argv))
+					|| (sel[i] == 'r' && access(*argv, R_OK) != 0)
+					|| (sel[i] == 'u' && !fileis_setuid(*argv))
+					|| (sel[i] == 'w' && access(*argv, W_OK) != 0)
+					|| (sel[i] == 'x' && access(*argv, X_OK) != 0)
+					|| (sel[i] == 'L' && !fileis_link(*argv))
+					|| (sel[i] == 'S' && !fileis_socket(*argv))
+			) { return EXIT_FAILURE; }
+		}
 	} while (*++argv != NULL);
 
 	return EXIT_SUCCESS;