conspy: code shrink ~200 bytes

Signed-off-by: Pascal Bellard <pascal.bellard@ads-lu.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 42 insertions, 45 deletions

diff --git a/miscutils/conspy.c b/miscutils/conspy.c
index ae471a3fa..0a5fdccad 100644
--- a/miscutils/conspy.c
+++ b/miscutils/conspy.c
@@ -63,6 +63,12 @@ struct globals {
         unsigned width;
         unsigned height;
         char last_attr;
+        int ioerror_count;
+        int key_count;
+        int escape_count;
+        int nokeys;
+        int current;
+        int vcsa_fd;
         struct screen_info info;
         struct termios term_orig;
 };
@@ -83,11 +89,12 @@ enum {
 #define FLAG(x) (1 << FLAG_##x)
 #define BW (option_mask32 & FLAG(n))
 
-static void screen_read_close(int fd, char *data)
+static void screen_read_close(void)
 {
         unsigned i, j;
+        char *data = G.data + G.current;
 
-        xread(fd, data, G.size);
+        xread(G.vcsa_fd, data, G.size);
         G.last_attr = 0;
         for (i = 0; i < G.info.lines; i++) {
                 for (j = 0; j < G.info.rows; j++, NEXT(data)) {
@@ -100,7 +107,7 @@ static void screen_read_close(int fd, char *data)
                                 DATA(data) = 0;
                 }
         }
-        close(fd);
+        close(G.vcsa_fd);
 }
 
 static void screen_char(char *data)
@@ -131,13 +138,13 @@ static void gotoxy(int row, int line)
         printf("\033[%u;%uH", line + 1, row + 1);
 }
 
-static void screen_dump(char *data)
+static void screen_dump(void)
 {
         int linefeed_cnt;
         int line, row;
         int linecnt = G.info.lines - G.y;
+        char *data = G.data + G.current + (2 * G.y * G.info.rows);
 
-        data += 2 * G.y * G.info.rows;
         linefeed_cnt = 0;
         for (line = 0; line < linecnt && line < G.height; line++) {
                 int space_cnt = 0;
@@ -197,12 +204,12 @@ static void cleanup(int code)
 static void get_initial_data(const char* vcsa_name)
 {
         int size;
-        int fd = xopen(vcsa_name, O_RDONLY);
-        xread(fd, &G.info, 4);
+        G.vcsa_fd = xopen(vcsa_name, O_RDONLY);
+        xread(G.vcsa_fd, &G.info, 4);
         G.size = size = G.info.rows * G.info.lines * 2;
         G.width = G.height = UINT_MAX;
         G.data = xzalloc(2 * size);
-        screen_read_close(fd, G.data);
+        screen_read_close();
 }
 
 static void create_cdev_if_doesnt_exist(const char* name, dev_t dev)
@@ -250,7 +257,6 @@ static NOINLINE void start_shell_in_child(const char* tty_name)
 int conspy_main(int argc UNUSED_PARAM, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int conspy_main(int argc UNUSED_PARAM, char **argv)
 {
-        char *buffer[2];
         char vcsa_name[sizeof("/dev/vcsa") + 2];
         char tty_name[sizeof("/dev/tty") + 2];
 #define keybuf bb_common_bufsiz1
@@ -258,11 +264,6 @@ int conspy_main(int argc UNUSED_PARAM, char **argv)
         unsigned opts;
         unsigned ttynum;
         int poll_timeout_ms;
-        int current;
-        int ioerror_count;
-        int key_count;
-        int escape_count;
-        int nokeys;
 #if ENABLE_LONG_OPTS
         static const char getopt_longopts[] ALIGN1 =
                 "viewonly\0"     No_argument "v"
@@ -276,7 +277,6 @@ int conspy_main(int argc UNUSED_PARAM, char **argv)
         applet_long_options = getopt_longopts;
 #endif
         INIT_G();
-        strcpy(vcsa_name, "/dev/vcsa");
 
         opt_complementary = "x+:y+"; // numeric params
         opts = getopt32(argv, "vcsndfx:y:", &G.x, &G.y);
@@ -284,8 +284,8 @@ int conspy_main(int argc UNUSED_PARAM, char **argv)
         ttynum = 0;
         if (argv[0]) {
                 ttynum = xatou_range(argv[0], 0, 63);
-                sprintf(vcsa_name + sizeof("/dev/vcsa")-1, "%u", ttynum);
         }
+        sprintf(vcsa_name, "/dev/vcsa%u", ttynum);
         sprintf(tty_name, "%s%u", "/dev/tty", ttynum);
         if (opts & FLAG(c)) {
                 if ((opts & (FLAG(s)|FLAG(v))) != FLAG(v))
@@ -299,7 +299,7 @@ int conspy_main(int argc UNUSED_PARAM, char **argv)
         get_initial_data(vcsa_name);
         G.kbd_fd = xopen(CURRENT_TTY, O_RDONLY);
         if (opts & FLAG(d)) {
-                screen_dump(G.data);
+                screen_dump();
                 bb_putchar('\n');
                 if (ENABLE_FEATURE_CLEAN_UP) {
                         free(ptr_to_globals);
@@ -318,23 +318,21 @@ int conspy_main(int argc UNUSED_PARAM, char **argv)
         termbuf.c_cc[VMIN] = 1;
         termbuf.c_cc[VTIME] = 0;
         tcsetattr(G.kbd_fd, TCSANOW, &termbuf);
-        buffer[0] = G.data;
-        buffer[1] = G.data + G.size;
         poll_timeout_ms = 250;
-        ioerror_count = key_count = escape_count = nokeys = current = 0;
         while (1) {
                 struct pollfd pfd;
-                int vcsa_handle;
                 int bytes_read;
                 int i, j;
-                int next = 1 - current;
-                char *data = buffer[next];
-                char *old  = buffer[current];
+                char *data, *old;
 
+                old = G.data + G.current;
+                G.current = G.size - G.current;
+                data = G.data + G.current;
+                
                 // Close & re-open vcsa in case they have
                 // swapped virtual consoles
-                vcsa_handle = xopen(vcsa_name, O_RDONLY);
-                xread(vcsa_handle, &G.info, 4);
+                G.vcsa_fd = xopen(vcsa_name, O_RDONLY);
+                xread(G.vcsa_fd, &G.info, 4);
                 if (G.size != (G.info.rows * G.info.lines * 2)) {
                         cleanup(1);
                 }
@@ -364,10 +362,10 @@ int conspy_main(int argc UNUSED_PARAM, char **argv)
                 }
 
                 // Scan console data and redraw our tty where needed
-                screen_read_close(vcsa_handle, data);
+                screen_read_close();
                 if (i != G.width || j != G.height) {
                         clrscr();
-                        screen_dump(data);
+                        screen_dump();
                 }
                 else for (i = 0; i < G.info.lines; i++) {
                         char *last = last;
@@ -399,7 +397,6 @@ int conspy_main(int argc UNUSED_PARAM, char **argv)
                         for (; first < last; NEXT(first))
                                 screen_char(first);
                 }
-                current = next;
                 curmove();
 
                 // Wait for local user keypresses
@@ -407,26 +404,26 @@ int conspy_main(int argc UNUSED_PARAM, char **argv)
                 pfd.events = POLLIN;
                 bytes_read = 0;
                 switch (poll(&pfd, 1, poll_timeout_ms)) {
+                        char *k;
                 case -1:
                         if (errno != EINTR)
                                 cleanup(1);
                         break;
                 case 0:
-                        if (++nokeys >= 4)
-                                nokeys = escape_count = 0;
+                        if (++G.nokeys >= 4)
+                                G.nokeys = G.escape_count = 0;
                         break;
                 default:
                         // Read the keys pressed
-                        bytes_read = read(G.kbd_fd, keybuf + key_count,
-                                        sizeof(keybuf) - key_count);
+                        k = keybuf + G.key_count;
+                        bytes_read = read(G.kbd_fd, k, sizeof(keybuf) - G.key_count);
                         if (bytes_read < 0)
                                 cleanup(1);
 
                         // Do exit processing
                         for (i = 0; i < bytes_read; i++) {
-                                if (keybuf[key_count + i] != '\033')
-                                        escape_count = 0;
-                                else if (++escape_count >= 3)
+                                if (k[i] != '\033') G.escape_count = 0;
+                                else if (++G.escape_count >= 3)
                                         cleanup(0);
                         }
                 }
@@ -436,23 +433,23 @@ int conspy_main(int argc UNUSED_PARAM, char **argv)
                 // buffer.  Don't do this if the virtual console is in scan
                 // code mode - giving ASCII characters to a program expecting
                 // scan codes will confuse it.
-                if (!(option_mask32 & FLAG(v)) && escape_count == 0) {
+                if (!(option_mask32 & FLAG(v)) && G.escape_count == 0) {
                         int handle, result;
                         long kbd_mode;
 
-                        key_count += bytes_read;
+                        G.key_count += bytes_read;
                         handle = xopen(tty_name, O_WRONLY);
                         result = ioctl(handle, KDGKBMODE, &kbd_mode);
                         if (result == -1)
                                 /* nothing */;
                         else if (kbd_mode != K_XLATE && kbd_mode != K_UNICODE)
-                                key_count = 0; // scan code mode
+                                G.key_count = 0; // scan code mode
                         else {
-                                for (i = 0; i < key_count && result != -1; i++)
+                                for (i = 0; i < G.key_count && result != -1; i++)
                                         result = ioctl(handle, TIOCSTI, keybuf + i);
-                                key_count -= i;
-                                if (key_count)
-                                        memmove(keybuf, keybuf + i, key_count);
+                                G.key_count -= i;
+                                if (G.key_count)
+                                        memmove(keybuf, keybuf + i, G.key_count);
                                 // If there is an application on console which reacts
                                 // to keypresses, we need to make our first sleep
                                 // shorter to quickly redraw whatever it printed there.
@@ -465,8 +462,8 @@ int conspy_main(int argc UNUSED_PARAM, char **argv)
                         // We sometimes get spurious IO errors on the TTY
                         // as programs close and re-open it
                         if (result != -1)
-                                ioerror_count = 0;
-                        else if (errno != EIO || ++ioerror_count > 4)
+                                G.ioerror_count = 0;
+                        else if (errno != EIO || ++G.ioerror_count > 4)
                                 cleanup(1);
                 }
         }