libbb: introduce and use is_prefixed_with()

function                                             old     new   delta
is_prefixed_with                                       -      18     +18
complete_username                                     78      77      -1
man_main                                             737     735      -2
fsck_device                                          429     427      -2
unpack_ar_archive                                     80      76      -4
strip_unsafe_prefix                                  105     101      -4
singlemount                                         1054    1050      -4
rtc_adjtime_is_utc                                    90      86      -4
resolve_mount_spec                                    88      84      -4
parse_one_line                                      1029    1025      -4
parse_conf                                          1460    1456      -4
may_wakeup                                            83      79      -4
loadkmap_main                                        219     215      -4
get_irqs_from_stat                                   103      99      -4
get_header_cpio                                      913     909      -4
findfs_main                                           79      75      -4
fbsplash_main                                       1230    1226      -4
load_crontab                                         776     771      -5
expand_vars_to_list                                 1151    1146      -5
date_main                                            881     876      -5
skip_dev_pfx                                          30      24      -6
make_device                                         2199    2193      -6
complete_cmd_dir_file                                773     767      -6
run_applet_and_exit                                  715     708      -7
uudecode_main                                        321     313      -8
pwdx_main                                            197     189      -8
execute                                              568     560      -8
i2cdetect_main                                      1186    1176     -10
procps_scan                                         1242    1230     -12
procps_read_smaps                                   1017    1005     -12
process_module                                       746     734     -12
patch_main                                          1903    1891     -12
nfsmount                                            3572    3560     -12
stack_machine                                        126     112     -14
process_timer_stats                                  449     435     -14
match_fstype                                         111      97     -14
do_ipaddr                                           1344    1330     -14
open_list_and_close                                  359     343     -16
get_header_tar                                      1795    1779     -16
prepend_new_eth_table                                340     323     -17
fsck_main                                           1811    1794     -17
find_iface_state                                      56      38     -18
dnsd_main                                           1321    1303     -18
base_device                                          179     158     -21
find_keyword                                         104      82     -22
handle_incoming_and_exit                            2785    2762     -23
parse_and_put_prompt                                 774     746     -28
modinfo                                              347     317     -30
find_action                                          204     171     -33
update_passwd                                       1470    1436     -34
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 0/49 up/down: 18/-540)         Total: -522 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 9 insertions, 8 deletions

diff --git a/libbb/lineedit.c b/libbb/lineedit.c
index 249b401..a83e07c 100644
--- a/libbb/lineedit.c
+++ b/libbb/lineedit.c
@@ -681,7 +681,7 @@ static NOINLINE unsigned complete_username(const char *ud)
 	setpwent();
 	while ((pw = getpwent()) != NULL) {
 		/* Null usernames should result in all users as possible completions. */
-		if (/*!userlen || */ strncmp(ud, pw->pw_name, userlen) == 0) {
+		if (/* !ud[0] || */ is_prefixed_with(pw->pw_name, ud)) {
 			add_match(xasprintf("~%s/", pw->pw_name));
 		}
 	}
@@ -792,7 +792,7 @@ static NOINLINE unsigned complete_cmd_dir_file(const char *command, int type)
 			if (!pfind[0] && DOT_OR_DOTDOT(name_found))
 				continue;
 			/* match? */
-			if (strncmp(name_found, pfind, pf_len) != 0)
+			if (!is_prefixed_with(name_found, pfind))
 				continue; /* no */
 
 			found = concat_path_file(paths[i], name_found);
@@ -1879,15 +1879,16 @@ static void parse_and_put_prompt(const char *prmt_ptr)
 						cwd_buf = xrealloc_getcwd_or_warn(NULL);
 						if (!cwd_buf)
 							cwd_buf = (char *)bb_msg_unknown;
-						else {
+						else if (home_pwd_buf[0]) {
+							char *after_home_user;
+
 							/* /home/user[/something] -> ~[/something] */
-							l = strlen(home_pwd_buf);
-							if (l != 0
-							 && strncmp(home_pwd_buf, cwd_buf, l) == 0
-							 && (cwd_buf[l] == '/' || cwd_buf[l] == '\0')
+							after_home_user = is_prefixed_with(cwd_buf, home_pwd_buf);
+							if (after_home_user
+							 && (*after_home_user == '/' || *after_home_user == '\0')
 							) {
 								cwd_buf[0] = '~';
-								overlapping_strcpy(cwd_buf + 1, cwd_buf + l);
+								overlapping_strcpy(cwd_buf + 1, after_home_user);
 							}
 						}
 					}