libbb: switch bb_ask_noecho() to "mallocing" string return API

[oweals/busybox.git] / libbb / bb_askpass.c

diff --git a/libbb/bb_askpass.c b/libbb/bb_askpass.c
index aadc6910811bad1449ec2e5ee1c478469bbb2466..2dcead35ab2149d47de280f562259f81edf67f4e 100644 (file)
--- a/libbb/bb_askpass.c
+++ b/libbb/bb_askpass.c
@@ -13,16 +13,9 @@ static void askpass_timeout(int UNUSED_PARAM ignore)
 {
 }
 
-char* FAST_FUNC bb_ask_noecho_stdin(const char *prompt)
-{
-       return bb_ask_noecho(STDIN_FILENO, 0, prompt);
-}
-char* FAST_FUNC bb_ask_noecho(const int fd, int timeout, const char *prompt)
+char* FAST_FUNC bb_ask_noecho(int fd, int timeout, const char *prompt)
 {
-       /* Was static char[BIGNUM] */
-       enum { sizeof_passwd = 128 };
-
-       char *passwd;
+#define MAX_LINE 0xfff
        char *ret;
        int i;
        struct sigaction sa, oldsa;
@@ -37,7 +30,17 @@ char* FAST_FUNC bb_ask_noecho(const int fd, int timeout, const char *prompt)
 
        tcgetattr(fd, &oldtio);
        tio = oldtio;
-       /* Switch off echo */
+       /* Switch off echo. ECHOxyz meaning:
+        * ECHO    echo input chars
+        * ECHOE   echo BS-SP-BS on erase character
+        * ECHOK   echo kill char specially, not as ^c (ECHOKE controls how exactly)
+        * ECHOKE  erase all input via BS-SP-BS on kill char (else go to next line)
+        * ECHOCTL Echo ctrl chars as ^c (else echo verbatim:
+        *         e.g. up arrow emits "ESC-something" and thus moves cursor up!)
+        * ECHONL  Echo NL even if ECHO is not set
+        * ECHOPRT On erase, echo erased chars
+        *         [qwe<BS><BS><BS> input looks like "qwe\ewq/" on screen]
+        */
        tio.c_lflag &= ~(ECHO|ECHOE|ECHOK|ECHONL);
        tcsetattr(fd, TCSANOW, &tio);
 
@@ -51,20 +54,30 @@ char* FAST_FUNC bb_ask_noecho(const int fd, int timeout, const char *prompt)
                alarm(timeout);
        }
 
-       passwd = auto_string(xmalloc(sizeof_passwd));
-       ret = passwd;
+       ret = NULL;
        i = 0;
        while (1) {
-               int r = read(fd, &ret[i], 1);
+               int r;
+
+               /* User input is uber-slow, no need to optimize reallocs.
+                * Grow it on every char.
+                */
+               ret = xrealloc(ret, i + 2);
+               r = read(fd, &ret[i], 1);
+
                if ((i == 0 && r == 0) /* EOF (^D) with no password */
                 || r < 0 /* read is interrupted by timeout or ^C */
                ) {
+                       ret[i] = '\0'; /* paranoia */
+                       nuke_str(ret); /* paranoia */
+                       free(ret);
                        ret = NULL;
                        break;
                }
+
                if (r == 0 /* EOF */
                 || ret[i] == '\r' || ret[i] == '\n' /* EOL */
-                || ++i == sizeof_passwd-1 /* line limit */
+                || ++i == MAX_LINE /* line limit */
                ) {
                        ret[i] = '\0';
                        break;
@@ -80,3 +93,7 @@ char* FAST_FUNC bb_ask_noecho(const int fd, int timeout, const char *prompt)
        fflush_all();
        return ret;
 }
+char* FAST_FUNC bb_ask_noecho_stdin(const char *prompt)
+{
+       return bb_ask_noecho(STDIN_FILENO, 0, prompt);
+}