*: shrink by using [f]open_or_warn_stdin where appropriate

function                                             old     new   delta
lsattr_main                                           62     143     +81
open_or_warn_stdin                                     -      36     +36
fclose_if_not_stdin                                   20      47     +27
xfopen_stdin                                           -      20     +20
tac_main                                             336     356     +20
cksum_main                                           249     259     +10
bb_argv_dash                                           -       8      +8
su_main                                              448     455      +7
cmp_main                                             630     633      +3
passwd_main                                         1072    1074      +2
uudecode_main                                        317     315      -2
text_yank                                            110     108      -2
handle_incoming_and_exit                            2653    2651      -2
flags                                                  5       1      -4
write_leases                                         235     230      -5
fopen_or_warn_stdin                                   48      42      -6
fold_main                                            648     642      -6
static.argv_dash                                       8       -      -8
sum_main                                             142     128     -14
tail_main                                           1237    1221     -16
sed_main                                             711     695     -16
cmp_xfopen_input                                      17       -     -17
bb_cat                                               113      96     -17
catv_main                                            328     306     -22
strings_main                                         457     434     -23
hash_file                                            298     274     -24
sum_file                                             353     325     -28
sort_main                                            904     859     -45
expand_main                                          736     686     -50
cut_main                                            1116    1065     -51
md5_sha1_sum_main                                    549     493     -56
lsattr_args                                           90       -     -90
read_stduu                                           408     255    -153
------------------------------------------------------------------------------
(add/remove: 3/3 grow/shrink: 7/20 up/down: 214/-657)        Total: -443 bytes
   text    data     bss     dec     hex filename
 797417     658    7428  805503   c4a7f busybox_old
 796973     658    7428  805059   c48c3 busybox_unstripped

1 files changed, 9 insertions, 13 deletions

diff --git a/coreutils/tail.c b/coreutils/tail.c
index 340697f..52aa8f6 100644
--- a/coreutils/tail.c
+++ b/coreutils/tail.c
@@ -101,16 +101,12 @@ int tail_main(int argc, char **argv)
 
 #if ENABLE_INCLUDE_SUSv2 || ENABLE_FEATURE_FANCY_TAIL
 	/* Allow legacy syntax of an initial numeric option without -n. */
-	if (argc >= 2 && (argv[1][0] == '+' || argv[1][0] == '-')
+	if (argv[1] && (argv[1][0] == '+' || argv[1][0] == '-')
 	 && isdigit(argv[1][1])
 	) {
-		/* replacing arg[0] with "-n" can segfault, so... */
-		argv[1] = xasprintf("-n%s", argv[1]);
-#if 0 /* If we ever decide to make tail NOFORK */
-		char *s = alloca(strlen(argv[1]) + 3);
-		sprintf(s, "-n%s", argv[1]);
-		argv[1] = s;
-#endif
+		count = eat_num(&argv[1][1]);
+		argv++;
+		argc--;
 	}
 #endif
 
@@ -133,8 +129,7 @@ int tail_main(int argc, char **argv)
 
 	/* open all the files */
 	fds = xmalloc(sizeof(int) * (argc + 1));
-	nfiles = i = 0;
-	if (argc == 0) {
+	if (!argv[0]) {
 		struct stat statbuf;
 
 		if (!fstat(STDIN_FILENO, &statbuf) && S_ISFIFO(statbuf.st_mode)) {
@@ -142,13 +137,14 @@ int tail_main(int argc, char **argv)
 		}
 		*argv = (char *) bb_msg_standard_input;
 	}
+	nfiles = i = 0;
 	do {
-		FILE* fil = fopen_or_warn_stdin(argv[i]);
-		if (!fil) {
+		int fd = open_or_warn_stdin(argv[i]);
+		if (fd < 0) {
 			G.status = EXIT_FAILURE;
 			continue;
 		}
-		fds[nfiles] = fileno(fil);
+		fds[nfiles] = fd;
 		argv[nfiles++] = argv[i];
 	} while (++i < argc);