ss: use compact output for undetected screen width

This change fixes calculation of width in case user pipes the output.

SS output output works correctly when stdout is a terminal. When one
pipes the output, it tries to use 80 or 160 columns. That adds a
line-break if user has terminal width of 100 chars and output is of
the similar width. No width is assumed here.

To reproduce the issue, call
ss | less
and see every other line empty if your screen is between 80 and 160
columns wide.

This second version of the patch fixes screen_width being set to arbitrary
value.

Signed-off-by: Peter Junos <petoju@gmail.com>
Signed-off-by: David Ahern <dsahern@gmail.com>

diff --git a/misc/ss.c b/misc/ss.c
index 95f1d37a4cf37f5d8f208b18f05e1660d0acbe27..378b985c61ebb51bb8372958ddc3f6cd29c36274 100644 (file)
--- a/misc/ss.c
+++ b/misc/ss.c
@@ -1135,10 +1135,10 @@ static void buf_free_all(void)
        buffer.chunks = 0;
 }
 
-/* Get current screen width, default to 80 columns if TIOCGWINSZ fails */
+/* Get current screen width, returns -1 if TIOCGWINSZ fails */
 static int render_screen_width(void)
 {
-       int width = 80;
+       int width = -1;
 
        if (isatty(STDOUT_FILENO)) {
                struct winsize w;
@@ -1159,9 +1159,15 @@ static int render_screen_width(void)
  */
 static void render_calc_width(void)
 {
-       int screen_width = render_screen_width();
+       int screen_width, first, len = 0, linecols = 0;
        struct column *c, *eol = columns - 1;
-       int first, len = 0, linecols = 0;
+       bool compact_output = false;
+
+       screen_width = render_screen_width();
+       if (screen_width == -1) {
+               screen_width = INT_MAX;
+               compact_output = true;
+       }
 
        /* First pass: set width for each column to measured content length */
        for (first = 1, c = columns; c - columns < COL_MAX; c++) {
@@ -1183,6 +1189,11 @@ static void render_calc_width(void)
                        first = 0;
        }
 
+       if (compact_output) {
+               /* Compact output, skip extending columns. */
+               return;
+       }
+
        /* Second pass: find out newlines and distribute available spacing */
        for (c = columns; c - columns < COL_MAX; c++) {
                int pad, spacing, rem, last;