Fix the behavior of local shell variables to match that of bash and ash.

[oweals/busybox.git] / head.c

diff --git a/head.c b/head.c
index 82a73de2a2e35b7fe2d766057b98e305b8ce6fcf..0c8ef3d5907b8f020b90a7780c964fe281c4e905 100644 (file)
--- a/head.c
+++ b/head.c
@@ -3,7 +3,7 @@
  * Mini head implementation for busybox
  *
  *
- * Copyright (C) 1999 by Lineo, inc.
+ * Copyright (C) 1999,2000,2001 by Lineo, inc.
  * Written by John Beppu <beppu@lineo.com>
  *
  * This program is free software; you can redistribute it and/or modify
@@ -22,29 +22,23 @@
  *
  */
 
-#include "internal.h"
 #include <errno.h>
 #include <stdio.h>
+#include <getopt.h>
+#include <stdlib.h>
+#include <string.h>
+#include "busybox.h"
 
-const char head_usage[] =
-       "head [OPTION] [FILE]...\n\n"
-       "Print first 10 lines of each FILE to standard output.\n"
-       "With more than one FILE, precede each with a header giving the\n"
-       "file name. With no FILE, or when FILE is -, read standard input.\n\n"
-
-       "Options:\n" "\t-n NUM\t\tPrint first NUM lines instead of first 10\n";
-
-int head(int len, FILE * src)
+static int head(int len, FILE *fp)
 {
        int i;
-       char buffer[1024];
+       char *input;
 
        for (i = 0; i < len; i++) {
-               fgets(buffer, 1024, src);
-               if (feof(src)) {
+               if ((input = get_line_from_file(fp)) == NULL)
                        break;
-               }
-               fputs(buffer, stdout);
+               fputs(input, stdout);
+               free(input);
        }
        return 0;
 }
@@ -52,61 +46,54 @@ int head(int len, FILE * src)
 /* BusyBoxed head(1) */
 int head_main(int argc, char **argv)
 {
-       char opt;
-       int len = 10, tmplen, i;
+       FILE *fp;
+       int need_headers, opt, len = 10, status = EXIT_SUCCESS;
 
        /* parse argv[] */
-       for (i = 1; i < argc; i++) {
-               if (argv[i][0] == '-') {
-                       opt = argv[i][1];
-                       switch (opt) {
-                       case 'n':
-                               tmplen = 0;
-                               if (++i < argc)
-                                       tmplen = atoi(argv[i]);
-                               if (tmplen < 1)
-                                       usage(head_usage);
-                               len = tmplen;
+       while ((opt = getopt(argc, argv, "n:")) > 0) {
+               switch (opt) {
+               case 'n':
+                       len = atoi(optarg);
+                       if (len >= 1)
                                break;
-                       case '-':
-                       case 'h':
-                               usage(head_usage);
-                       default:
-                               fprintf(stderr, "head: invalid option -- %c\n", opt);
-                               usage(head_usage);
-                       }
-               } else {
-                       break;
+                       /* fallthrough */
+               default:
+                       show_usage();
                }
        }
 
        /* get rest of argv[] or stdin if nothing's left */
-       if (i >= argc) {
+       if (argv[optind] == NULL) {
                head(len, stdin);
+               return status;
+       } 
 
-       } else {
-               int need_headers = ((argc - i) > 1);
-
-               for (; i < argc; i++) {
-                       FILE *src;
-
-                       src = fopen(argv[i], "r");
-                       if (!src) {
-                               fprintf(stderr, "head: %s: %s\n", argv[i],
-                                               strerror(errno));
-                       } else {
-                               /* emulating GNU behaviour */
-                               if (need_headers) {
-                                       fprintf(stdout, "==> %s <==\n", argv[i]);
-                               }
-                               head(len, src);
-                               if (i < argc - 1) {
-                                       fprintf(stdout, "\n");
-                               }
+       need_headers = optind != (argc - 1);
+       while (argv[optind]) {
+               if (strcmp(argv[optind], "-") == 0) {
+                       fp = stdin;
+                       argv[optind] = "standard input";
+               } else {
+                       if ((fp = wfopen(argv[optind], "r")) == NULL)
+                               status = EXIT_FAILURE;
+               }
+               if (fp) {
+                       if (need_headers) {
+                               printf("==> %s <==\n", argv[optind]);
                        }
+                       head(len, fp);
+                       if (errno) {
+                               perror_msg("%s", argv[optind]);
+                               status = EXIT_FAILURE;
+                               errno = 0;
+                       }
+                       if (optind < argc - 1)
+                               putchar('\n');
+                       if (fp != stdin)
+                               fclose(fp);
                }
+               optind++;
        }
-       exit(0);
-}
 
-/* $Id: head.c,v 1.8 2000/02/08 19:58:47 erik Exp $ */
+       return status;
+}