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 930839de3bbc63665551aaf635f1f299983f2d37..0c8ef3d5907b8f020b90a7780c964fe281c4e905 100644 (file)
--- a/head.c
+++ b/head.c
@@ -1,9 +1,10 @@
+/* vi: set sw=4 ts=4: */
 /*
  * Mini head implementation for busybox
  *
  *
- * Copyright (C) 1999 by Lineo, inc.
- * Written by John Beppu <beppu@line.com>
+ * 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
  * it under the terms of the GNU General Public License as published by
@@ -21,86 +22,78 @@
  *
  */
 
-#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[] =
-"Usage: head [OPTION]... [FILE]...\n"
-"Print first 10 lines of each FILE to standard output.\n"
-"With more than one FILE, precede each with a header giving the file name.\n"
-"With no FILE, or when FILE is -, read standard input.\n\n"
-"  -h  display this help and exit\n";
-
-int
-head(int len, FILE *src)
+static int head(int len, FILE *fp)
 {
-    int            i;
-    char    buffer[1024];
+       int i;
+       char *input;
 
-    for (i = 0; i < len; i++) {
-       fgets(buffer, 1024, src);
-       if (feof(src)) { break; }
-       fputs(buffer, stdout);
-    }
-    return 0;
+       for (i = 0; i < len; i++) {
+               if ((input = get_line_from_file(fp)) == NULL)
+                       break;
+               fputs(input, stdout);
+               free(input);
+       }
+       return 0;
 }
 
 /* BusyBoxed head(1) */
-int
-head_main(int argc, char **argv)
+int head_main(int argc, char **argv)
 {
-    int            i = 1;
-    char    opt;
-    int            len = 10;
-
-    /* 1st option is potentially special */
-    if ((argv[1][0] == '-') && isDecimal(argv[1][1])) {
-       int tmplen = atoi(&argv[1][1]);
-       if (tmplen) { len = tmplen; }
-       i = 2;
-    }
+       FILE *fp;
+       int need_headers, opt, len = 10, status = EXIT_SUCCESS;
 
-    /* parse argv[] */
-    for ( ; i < argc; i++) {
-       if (argv[i][0] == '-') {
-           opt = argv[i][1];
-           switch (opt) {
-               case 'h':
-                   usage(head_usage);
+       /* parse argv[] */
+       while ((opt = getopt(argc, argv, "n:")) > 0) {
+               switch (opt) {
+               case 'n':
+                       len = atoi(optarg);
+                       if (len >= 1)
+                               break;
+                       /* fallthrough */
                default:
-                   fprintf(stderr, "head: invalid option -- %c\n", opt);
-                   usage(head_usage);
-           }
-       } else {
-           break;
+                       show_usage();
+               }
        }
-    }
 
-    /* get rest of argv[] or stdin if nothing's left */
-    if (i >= argc) {
-       head(len, stdin);
+       /* get rest of argv[] or stdin if nothing's left */
+       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]);
+       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;
                }
-               head(len, src);
-               if (i < argc - 1) {
-                   fprintf(stdout, "\n");
+               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 1.1 1999/12/10 07:42:50 beppu Exp $ */
+       return status;
+}