diff options
| author | Heinrich Schuchardt <xypron.glpk@gmx.de> | 2019-09-04 21:13:45 +0200 |
|---|---|---|
| committer | Heinrich Schuchardt <xypron.glpk@gmx.de> | 2019-09-05 23:18:51 +0200 |
| commit | 97ea0690f4ea8b30f66fab7dc3bd439714647989 (patch) | |
| tree | 539ea3b0ca2d7cc8181a5260170850aed638026d | |
| parent | d41f99e17976e7a6c72fdba0025eb26d2c628494 (diff) | |
efi_loader: cursor positioning
When backspacing in column 0 do no set the column index to ULONG_MAX.
Ensure that the row number is not set to ULONG_MAX even if the row count is
advertised as 0.
Ignore control characters other the 0x08, 0x0a, 0x0d when updating the
column.
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
| -rw-r--r-- | lib/efi_loader/efi_console.c | 18 |
1 files changed, 13 insertions, 5 deletions
diff --git a/lib/efi_loader/efi_console.c b/lib/efi_loader/efi_console.c index d4765afb98..5560fc8dea 100644 --- a/lib/efi_loader/efi_console.c +++ b/lib/efi_loader/efi_console.c @@ -156,13 +156,14 @@ static efi_status_t EFIAPI efi_cout_output_string( * Update the cursor position. * * The UEFI spec provides advance rules for U+0000, U+0008, U+000A, - * and U000D. All other characters, including control characters - * U+0007 (BEL) and U+0009 (TAB), have to increase the column by one. + * and U000D. All other control characters are ignored. Any non-control + * character increase the column by one. */ for (p = string; *p; ++p) { switch (*p) { case '\b': /* U+0008, backspace */ - con->cursor_column = max(0, con->cursor_column - 1); + if (con->cursor_column) + con->cursor_column--; break; case '\n': /* U+000A, newline */ con->cursor_column = 0; @@ -178,14 +179,21 @@ static efi_status_t EFIAPI efi_cout_output_string( */ break; default: - con->cursor_column++; + /* Exclude control codes */ + if (*p > 0x1f) + con->cursor_column++; break; } if (con->cursor_column >= mode->columns) { con->cursor_column = 0; con->cursor_row++; } - con->cursor_row = min(con->cursor_row, (s32)mode->rows - 1); + /* + * When we exceed the row count the terminal will scroll up one + * line. We have to adjust the cursor position. + */ + if (con->cursor_row >= mode->rows && con->cursor_row) + con->cursor_row--; } out: |