[Minios-devel] [UNIKRAFT PATCH] lib/nolibc: Fix vsnprintf when size is zero

[Razvan Rotaru <razvanrtr@xxxxxxxxxxx>]

Modified PCHAR macro so that it evaluates its parameter and updates
their values every time. Without this, when size is zero, vsnprintf
blocks in an infinite loop whenever the format string contains '%d'.

Signed-off-by: Razvan Rotaru <razvanrtr@xxxxxxxxxxx>
---
 lib/nolibc/stdio.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/nolibc/stdio.c b/lib/nolibc/stdio.c
index 7e3d368..c2e9f59 100644
--- a/lib/nolibc/stdio.c
+++ b/lib/nolibc/stdio.c
@@ -101,8 +101,9 @@ int vsnprintf(char *str, size_t size, const char *fmt, 
va_list ap)
 {
 #define PCHAR(c)                                                               
\
        {                                                                      \
+               int cc = c;                                                    \
                if (size >= 2) {                                               \
-                       *str++ = c;                                            \
+                       *str++ = cc;                                           \
                        size--;                                                \
                }                                                              \
                retval++;                                                      \
-- 
2.11.0


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