chpasswd: fixes and code shrink

update_passwd                                        732     734      +2
chpasswd_main                                        318     292     -26
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/1 up/down: 2/-26)             Total: -24 bytes
   text    data     bss     dec     hex filename
 781564    1168   11900  794632   c2008 busybox_old
 781548    1168   11900  794616   c1ff8 busybox_unstripped

5 files changed, 36 insertions, 39 deletions

diff --git a/libbb/update_passwd.c b/libbb/update_passwd.c
index 5572db5..8914b8b 100644
--- a/libbb/update_passwd.c
+++ b/libbb/update_passwd.c
@@ -18,18 +18,18 @@ int update_passwd(const char *filename, const char *username,
 	struct flock lock;
 	FILE *old_fp;
 	FILE *new_fp;
-	char *new_name;
-	char *last_char;
+	char *fnamesfx;
+	char *sfx_char;
 	unsigned user_len;
 	int old_fd;
 	int new_fd;
 	int i;
 	int cnt = 0;
-	int ret = 1; /* failure */
+	int ret = -1; /* failure */
 
 	/* New passwd file, "/etc/passwd+" for now */
-	new_name = xasprintf("%s+", filename);
-	last_char = &new_name[strlen(new_name)-1];
+	fnamesfx = xasprintf("%s+", filename);
+	sfx_char = &fnamesfx[strlen(fnamesfx)-1];
 	username = xasprintf("%s:", username);
 	user_len = strlen(username);
 
@@ -42,12 +42,12 @@ int update_passwd(const char *filename, const char *username,
 	i = 30;
 	do {
 		// FIXME: on last iteration try w/o O_EXCL but with O_TRUNC?
-		new_fd = open(new_name, O_WRONLY|O_CREAT|O_EXCL,0600);
+		new_fd = open(fnamesfx, O_WRONLY|O_CREAT|O_EXCL, 0600);
 		if (new_fd >= 0) goto created;
 		if (errno != EEXIST) break;
 		usleep(100000); /* 0.1 sec */
 	} while (--i);
-	bb_perror_msg("cannot create '%s'", new_name);
+	bb_perror_msg("cannot create '%s'", fnamesfx);
 	goto close_old_fp;
 
  created:
@@ -62,12 +62,13 @@ int update_passwd(const char *filename, const char *username,
 	}
 
 	/* Backup file is "/etc/passwd-" */
-	last_char[0] = '-';
-	/* Delete old one, create new as a hardlink to current */
-	i = (unlink(new_name) && errno != ENOENT);
-	if (i || link(filename, new_name))
-		bb_perror_msg("warning: cannot create backup copy '%s'", new_name);
-	last_char[0] = '+';
+	*sfx_char = '-';
+	/* Delete old backup */
+	i = (unlink(fnamesfx) && errno != ENOENT);
+	/* Create backup as a hardlink to current */
+	if (i || link(filename, fnamesfx))
+		bb_perror_msg("warning: cannot create backup copy '%s'", fnamesfx);
+	*sfx_char = '+';
 
 	/* Lock the password file before updating */
 	lock.l_type = F_WRLCK;
@@ -78,7 +79,7 @@ int update_passwd(const char *filename, const char *username,
 		bb_perror_msg("warning: cannot lock '%s'", filename);
 	lock.l_type = F_UNLCK;
 
-	/* Read current password file, write updated one */
+	/* Read current password file, write updated /etc/passwd+ */
 	while (1) {
 		char *line = xmalloc_fgets(old_fp);
 		if (!line) break; /* EOF/error */
@@ -86,8 +87,7 @@ int update_passwd(const char *filename, const char *username,
 			/* we have a match with "username:"... */
 			const char *cp = line + user_len;
 			/* now cp -> old passwd, skip it: */
-			cp = strchr(cp, ':');
-			if (!cp) cp = "";
+			cp = strchrnul(cp, ':');
 			/* now cp -> ':' after old passwd or -> "" */
 			fprintf(new_fp, "%s%s%s", username, new_pw, cp);
 			cnt++;
@@ -99,7 +99,7 @@ int update_passwd(const char *filename, const char *username,
 
 	/* We do want all of them to execute, thus | instead of || */
 	if ((ferror(old_fp) | fflush(new_fp) | fsync(new_fd) | fclose(new_fp))
-	 || rename(new_name, filename)
+	 || rename(fnamesfx, filename)
 	) {
 		/* At least one of those failed */
 		goto unlink_new;
@@ -107,13 +107,13 @@ int update_passwd(const char *filename, const char *username,
 	ret = cnt; /* whee, success! */
 
  unlink_new:
-	if (ret) unlink(new_name);
+	if (ret < 0) unlink(fnamesfx);
 
  close_old_fp:
 	fclose(old_fp);
 
  free_mem:
-	if (ENABLE_FEATURE_CLEAN_UP) free(new_name);
-	if (ENABLE_FEATURE_CLEAN_UP) free((char*)username);
+	free(fnamesfx);
+	free((char*)username);
 	return ret;
 }
diff --git a/loginutils/chpasswd.c b/loginutils/chpasswd.c
index 124fc86..d5de424 100644
--- a/loginutils/chpasswd.c
+++ b/loginutils/chpasswd.c
@@ -26,19 +26,13 @@ int chpasswd_main(int argc, char **argv)
 {
 	char *name, *pass;
 	char salt[sizeof("$N$XXXXXXXX")];
-	int opt, rc;
+	int opt;
 	int rnd = rnd; /* we *want* it to be non-initialized! */
-	const char *pwfile = bb_path_passwd_file;
 
-	if (getuid() != 0)
+	if (getuid())
 		bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);
 
-#if ENABLE_FEATURE_SHADOWPASSWDS
-	if (access(bb_path_shadow_file, F_OK) == 0)
-		pwfile = bb_path_shadow_file;
-#endif
-
- 	opt_complementary = "m--e";
+ 	opt_complementary = "?m--e:e--m";
 	USE_GETOPT_LONG(applet_long_options = chpasswd_opts;)
 	opt = getopt32(argc, argv, "em");
 
@@ -48,8 +42,7 @@ int chpasswd_main(int argc, char **argv)
 			bb_error_msg_and_die("missing new password");
 		*pass++ = '\0';
 
-		//if (!getpwnam(name))
-		//	bb_error_msg_and_die("unknown user %s", name);
+		xuname2uid(name); /* dies if there is no such user */
 
 		if (!(opt & OPT_ENC)) {
 			rnd = crypt_make_salt(salt, 1, rnd);
@@ -60,15 +53,17 @@ int chpasswd_main(int argc, char **argv)
 			pass = pw_encrypt(pass, salt);
 		}
 
-		rc = update_passwd(pwfile, name, pass);
 		/* LOGMODE_BOTH logs to syslog */
 		logmode = LOGMODE_BOTH;
-		if (rc < 0)
-			bb_error_msg_and_die("an error occurred updating %s", pwfile);
-		if (rc > 0)
+
+		if ((ENABLE_FEATURE_SHADOWPASSWDS 
+			&& !update_passwd(bb_path_shadow_file, name, pass))
+			|| !update_passwd(bb_path_passwd_file, name, pass)
+		) {
+			bb_error_msg_and_die("an error occurred updating password for %s", name);
+		} else {
 			bb_info_msg("Password for '%s' changed", name);
-		else
-			bb_info_msg("User '%s' not found", name);
+		}
 		logmode = LOGMODE_STDIO;
 		free(name);
 	}
diff --git a/runit/runit_lib.c b/runit/runit_lib.c
index fcb66c3..295b45f 100644
--- a/runit/runit_lib.c
+++ b/runit/runit_lib.c
@@ -382,7 +382,6 @@ int seek_set(int fd,seek_pos pos)
 {
 	if (lseek(fd,(off_t) pos,SEEK_SET) == -1) return -1; return 0;
 }
-#endif
 
 
 /*** str_chr.c ***/
@@ -402,3 +401,4 @@ unsigned str_chr(const char *s,int c)
 	}
 	return t - s;
 }
+#endif
diff --git a/runit/runit_lib.h b/runit/runit_lib.h
index 25aeeaf..1dadb6e 100644
--- a/runit/runit_lib.h
+++ b/runit/runit_lib.h
@@ -125,7 +125,7 @@ extern unsigned pmatch(const char *, const char *, unsigned);
 
 /*** str.h ***/
 
-extern unsigned str_chr(const char *,int);  /* never returns NULL */
+//extern unsigned str_chr(const char *,int);  /* never returns NULL */
 
 #define str_diff(s,t) strcmp((s), (t))
 #define str_equal(s,t) (!strcmp((s), (t)))
diff --git a/scripts/trylink b/scripts/trylink
index cbd7023..bfc67bf 100755
--- a/scripts/trylink
+++ b/scripts/trylink
@@ -22,6 +22,8 @@ try "-Wl,--start-group $l_list -Wl,--end-group" "$@" \
     cat busybox_ld.err
     exit 1
 }
+# Hack: we are not supposed to know executable name,
+# but this hack cuts down link time
 mv busybox_unstripped busybox_unstripped.tmp
 
 # Now try to remove each lib and build without.