diff options
| author | Alexander Sverdlin <alexander.sverdlin@siemens.com> | 2025-02-20 13:49:07 +0100 |
|---|---|---|
| committer | Tom Rini <trini@konsulko.com> | 2025-03-03 14:24:45 -0600 |
| commit | 1bc125becaa5e612923a9cfa1ec8e9f0b88ac28e (patch) | |
| tree | 375864c505446e6299520d66566d60eea514e423 /lib/tiny-printf.c | |
| parent | 0928e3cc719711d677083982de5dbb68da0a1470 (diff) | |
tiny-printf: emit \0 as %c
The current code has a problematic corner case with formar "%c" and
0 as parameter. The proper zero byte is being emitted into digit buffer
but the final copy into outstr expects null-terminated string and doesn't
copy the required \0 byte. This has lead to malformed TFTP packets, refer
to tftp_send() which relies on %c to generate multiple zero-terminated
strings in one buffer.
Introduce a variable to force the copy of one character in this case.
The new behaviour is consistent with non-tiny implementation.
Reported-by: Chintan Vankar <c-vankar@ti.com>
Signed-off-by: Alexander Sverdlin <alexander.sverdlin@siemens.com>
Diffstat (limited to 'lib/tiny-printf.c')
| -rw-r--r-- | lib/tiny-printf.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/lib/tiny-printf.c b/lib/tiny-printf.c index 0503c17341f..faf55d7f327 100644 --- a/lib/tiny-printf.c +++ b/lib/tiny-printf.c @@ -211,6 +211,7 @@ static int _vprintf(struct printf_info *info, const char *fmt, va_list va) bool lz = false; int width = 0; bool islong = false; + bool force_char = false; ch = *(fmt++); if (ch == '-') @@ -300,6 +301,8 @@ static int _vprintf(struct printf_info *info, const char *fmt, va_list va) break; case 'c': out(info, (char)(va_arg(va, int))); + /* For the case when it's \0 char */ + force_char = true; break; case 's': p = va_arg(va, char*); @@ -317,8 +320,10 @@ static int _vprintf(struct printf_info *info, const char *fmt, va_list va) while (width-- > 0) info->putc(info, lz ? '0' : ' '); if (p) { - while ((ch = *p++)) + while ((ch = *p++) || force_char) { info->putc(info, ch); + force_char = false; + } } } } |