[PATCH 1/1] prompt: Fix an off-by-one in the overf check in countpromt.

[warepire.ml@xxxxxxxxx]

From: Warepire <Warepire@xxxxxxxxxxxxxxxxxxxxxxxx>

This triggers overf when the prompt is exactly as wide as the
term, causes countprompt to count a 2-line prompt as 3 lines.
Which transmits an errorneus TCUP to the PTY. In some terminals
this causes the last line of the previous command to be erased.

Hexdumping the PTY in benign and trouble cases, for my term
TCUP is represented by "\x1b[A". The NOK dumps are when the
prompt is exactly as wide as the term.

OK chunk dump:
  0000  0d 1b 5b 30 6d 1b 5b 32 37 6d 1b 5b 32 34 6d 1b  ..[0m.[27m.[24m.
  0010  5b 4a 1b 5b 33 33 6d 7e 2f 76 74 65 2d 6e 67 2d  [J.[33m~/vte-ng-
  0020  30 2e 35 30 2e 32 2e 61 1b 5b 30 30 6d 20 0d 0a  0.50.2.a.[00m ..
  0030  1b 5b 33 37 6d 77 61 72 65 70 69 72 65 20 25 1b  .[37mwarepire %.
  0040  5b 30 30 6d 20 1b 5b 4b 1b 5b 36 34 43 1b 5b 30  [00m .[K.[64C.[0
  0050  31 3b 33 32 6d e2 9c 94 1b 5b 30 30 6d 20 49 4e  1;32m....[00m IN
  0060  53 1b 5b 36 39 44 0d 0d 1b 5b 41 1b 5b 3f 32 30  S.[69D...[A.[?20  <-- Correct number of TCUP
  0070  30 34 68 1b 5b 30 6d 1b 5b 32 37 6d 1b 5b 32 34  04h.[0m.[27m.[24
  0080  6d 1b 5b 4a 1b 5b 33 33 6d 7e 2f 76 74 65 2d 6e  m.[J.[33m~/vte-n
  0090  67 2d 30 2e 35 30 2e 32 2e 61 1b 5b 30 30 6d 20  g-0.50.2.a.[00m
  00a0  0d 0a 1b 5b 33 37 6d 77 61 72 65 70 69 72 65 20  ...[37mwarepire
  00b0  25 1b 5b 30 30 6d 20 1b 5b 4b 1b 5b 36 34 43 1b  %.[00m .[K.[64C.
  00c0  5b 30 31 3b 33 32 6d e2 9c 94 1b 5b 30 30 6d 20  [01;32m....[00m
  00d0  49 4e 53 1b 5b 36 39 44                          INS.[69D

NOK chunk dump:
  0000  0d 1b 5b 30 6d 1b 5b 32 37 6d 1b 5b 32 34 6d 1b  ..[0m.[27m.[24m.
  0010  5b 4a 1b 5b 33 33 6d 7e 2f 74 65 73 74 2d 64 69  [J.[33m~/test-di
  0020  72 2f 61 61 61 61 61 61 61 61 61 61 61 61 61 61  r/aaaaaaaaaaaaaa
  0030  61 61 61 61 61 61 61 61 61 61 61 61 61 61 61 61  aaaaaaaaaaaaaaaa
  0040  61 61 61 61 61 61 61 61 61 61 61 61 61 61 61 61  aaaaaaaaaaaaaaaa
  0050  61 61 61 61 61 2f 62 62 62 62 62 62 62 62 62 62  aaaaa/bbbbbbbbbb
  0060  62 62 62 2f 63 63 63 1b 5b 30 30 6d 20 0d 0a 1b  bbb/ccc.[00m ...
  0070  5b 33 37 6d 77 61 72 65 70 69 72 65 20 25 1b 5b  [37mwarepire %.[
  0080  30 30 6d 20 1b 5b 4b 1b 5b 36 34 43 1b 5b 30 31  00m .[K.[64C.[01
  0090  3b 33 32 6d e2 9c 94 1b 5b 30 30 6d 20 49 4e 53  ;32m....[00m INS
  00a0  1b 5b 36 39 44 0d 0d 1b 5b 41 1b 5b 41 1b 5b 3f  .[69D...[A.[A.[?  <--- Incorrect number of TCUP
  00b0  32 30 30 34 68 1b 5b 30 6d 1b 5b 32 37 6d 1b 5b  2004h.[0m.[27m.[
  00c0  32 34 6d 1b 5b 4a 1b 5b 33 33 6d 7e 2f 74 65 73  24m.[J.[33m~/tes
  00d0  74 2d 64 69 72 2f 61 61 61 61 61 61 61 61 61 61  t-dir/aaaaaaaaaa
  00e0  61 61 61 61 61 61 61 61 61 61 61 61 61 61 61 61  aaaaaaaaaaaaaaaa
  00f0  61 61 61 61 61 61 61 61 61 61 61 61 61 61 61 61  aaaaaaaaaaaaaaaa
  0100  61 61 61 61 61 61 61 61 61 2f 62 62 62 62 62 62  aaaaaaaaa/bbbbbb
  0110  62 62 62 62 62 62 62 2f 63 63 63 1b 5b 30 30 6d  bbbbbbb/ccc.[00m
  0120  20 0d 0a 1b 5b 33 37 6d 77 61 72 65 70 69 72 65   ...[37mwarepire
  0130  20 25 1b 5b 30 30 6d 20 1b 5b 4b 1b 5b 36 34 43   %.[00m .[K.[64C
  0140  1b 5b 30 31 3b 33 32 6d e2 9c 94 1b 5b 30 30 6d  .[01;32m....[00m
  0150  20 49 4e 53 1b 5b 36 39 44                        INS.[69D

NOK chunks from I/O channel:
0 chars and 0 bytes in 1 chunks left to process.
read/bp:
  0000  00 0d 1b 5b 30 6d 1b 5b 32 37 6d 1b 5b 32 34 6d  ...[0m.[27m.[24m
  0010  1b 5b 4a 1b 5b 33 33 6d 7e 2f 74 65 73 74 2d 64  .[J.[33m~/test-d
  0020  69 72 2f 61 61 61 61 61 61 61 61 61 61 61 61 61  ir/aaaaaaaaaaaaa
  0030  61 61 61 61 61 61 61 61 61 61 61 61 61 61 61 61  aaaaaaaaaaaaaaaa
  0040  61 61 61 61 61 61 61 61 61 61 61 61 61 61 61 61  aaaaaaaaaaaaaaaa
  0050  61 61 61 61 61 61 2f 62 62 62 62 62 62 62 62 62  aaaaaa/bbbbbbbbb
  0060  62 62 62 62 2f 63 63 63 1b 5b 30 30 6d 20 0d 0a  bbbb/ccc.[00m ..
  0070  1b 5b 33 37 6d 77 61 72 65 70 69 72 65 20 25 1b  .[37mwarepire %.
  0080  5b 30 30 6d 20                                   [00m
read 132/5355 bytes, again? yes, active? yes
read/bp:
  0000  00 1b 5b 4b 1b 5b 36 34 43 1b 5b 30 31 3b 33 32  ..[K.[64C.[01;32
  0010  6d e2 9c 94 1b 5b 30 30 6d 20 49 4e 53 1b 5b 36  m....[00m INS.[6
  0020  39 44                                            9D
read 165/5355 bytes, again? yes, active? yes
read/bp:
  0000  00 0d 0d 1b 5b 41 1b 5b 41 1b 5b 3f 32 30 30 34  ....[A.[A.[?2004  <--- Incorrect number of TCUP
  0010  68 1b 5b 30 6d 1b 5b 32 37 6d 1b 5b 32 34 6d 1b  h.[0m.[27m.[24m.
  0020  5b 4a 1b 5b 33 33 6d 7e 2f 74 65 73 74 2d 64 69  [J.[33m~/test-di
  0030  72 2f 61 61 61 61 61 61 61 61 61 61 61 61 61 61  r/aaaaaaaaaaaaaa
  0040  61 61 61 61 61 61 61 61 61 61 61 61 61 61 61 61  aaaaaaaaaaaaaaaa
  0050  61 61 61 61 61 61 61 61 61 61 61 61 61 61 61 61  aaaaaaaaaaaaaaaa
  0060  61 61 61 61 61 2f 62 62 62 62 62 62 62 62 62 62  aaaaa/bbbbbbbbbb
  0070  62 62 62 2f 63 63 63 1b 5b 30 30 6d 20 0d 0a 1b  bbb/ccc.[00m ...
  0080  5b 33 37 6d 77 61 72 65 70 69 72 65 20 25 1b 5b  [37mwarepire %.[
  0090  30 30 6d 20                                      00m
read 312/5355 bytes, again? yes, active? yes
read/bp:
  0000  00 1b 5b 4b 1b 5b 36 34 43 1b 5b 30 31 3b 33 32  ..[K.[64C.[01;32
  0010  6d e2 9c 94 1b 5b 30 30 6d 20 49 4e 53 1b 5b 36  m....[00m INS.[6
  0020  39 44                                            9D

Fixes: commit fa699be45debba815ea5e3ed5bfebde280d894a0
Signed-off-by: Warepire <Warepire@xxxxxxxxxxxxxxxxxxxxxxxx>
---
 Src/prompt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Src/prompt.c b/Src/prompt.c
index c478e69fb..9b9e33670 100644
--- a/Src/prompt.c
+++ b/Src/prompt.c
@@ -1087,7 +1087,7 @@ countprompt(char *str, int *wp, int *hp, int overf)
 #endif
 
     for (; *str; str++) {
-	if (w >= zterm_columns && overf >= 0) {
+	if (w > zterm_columns && overf >= 0) {
 	    w = 0;
 	    h++;
 	}
-- 
2.15.1