head(1): validate all line count arguments

We need to validate all line count option arguments, not just the last
such argument found.

While here, switch to the default strtonum(3) error message format:

	<argument-name> is <errstr>: <argument-string>

Thread: https://marc.info/?l=openbsd-tech&m=163383023212104&w=2

ok millert@

diff --git a/usr.bin/head/head.c b/usr.bin/head/head.c
index ccf1372..f0c10cd 100644 (file)
--- a/usr.bin/head/head.c
+++ b/usr.bin/head/head.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: head.c,v 1.21 2016/03/20 17:14:51 tb Exp $    */
+/*     $OpenBSD: head.c,v 1.22 2021/10/10 15:57:25 cheloha Exp $       */
 
 /*
  * Copyright (c) 1980, 1987 Regents of the University of California.
@@ -48,11 +48,11 @@ static void usage(void);
 int
 main(int argc, char *argv[])
 {
+       const char *errstr;
        FILE    *fp;
        long    cnt;
        int     ch, firsttime;
        long    linecnt = 10;
-       char    *p = NULL;
        int     status = 0;
 
        if (pledge("stdio rpath", NULL) == -1)
@@ -61,7 +61,9 @@ main(int argc, char *argv[])
        /* handle obsolete -number syntax */
        if (argc > 1 && argv[1][0] == '-' &&
            isdigit((unsigned char)argv[1][1])) {
-               p = argv[1] + 1;
+               linecnt = strtonum(argv[1] + 1, 1, LONG_MAX, &errstr);
+               if (errstr != NULL)
+                       errx(1, "count is %s: %s", errstr, argv[1] + 1);
                argc--;
                argv++;
        }
@@ -69,7 +71,9 @@ main(int argc, char *argv[])
        while ((ch = getopt(argc, argv, "n:")) != -1) {
                switch (ch) {
                case 'n':
-                       p = optarg;
+                       linecnt = strtonum(optarg, 1, LONG_MAX, &errstr);
+                       if (errstr != NULL)
+                               errx(1, "count is %s: %s", errstr, optarg);
                        break;
                default:
                        usage();
@@ -77,14 +81,6 @@ main(int argc, char *argv[])
        }
        argc -= optind, argv += optind;
 
-       if (p) {
-               const char *errstr;
-
-               linecnt = strtonum(p, 1, LONG_MAX, &errstr);
-               if (errstr)
-                       errx(1, "line count %s: %s", errstr, p);
-       }
-
        for (firsttime = 1; ; firsttime = 0) {
                if (!*argv) {
                        if (!firsttime)