diff options
Diffstat (limited to 'mysys')
| -rw-r--r-- | mysys/my_vsnprintf.c | 26 |
1 files changed, 17 insertions, 9 deletions
diff --git a/mysys/my_vsnprintf.c b/mysys/my_vsnprintf.c index 0fe6eff24a6..7490ab4a9f2 100644 --- a/mysys/my_vsnprintf.c +++ b/mysys/my_vsnprintf.c @@ -19,6 +19,7 @@ #include <m_string.h> #include <stdarg.h> #include <m_ctype.h> +#include <assert.h> int my_snprintf(char* to, size_t n, const char* fmt, ...) { @@ -39,7 +40,7 @@ int my_vsnprintf(char *to, size_t n, const char* fmt, va_list ap) *to++= *fmt; /* Copy ordinary char */ continue; } - /* Skipp if max size is used (to be compatible with printf) */ + /* Skip if max size is used (to be compatible with printf) */ fmt++; while (isdigit(*fmt) || *fmt == '.' || *fmt == '-') fmt++; @@ -48,14 +49,13 @@ int my_vsnprintf(char *to, size_t n, const char* fmt, va_list ap) if (*fmt == 's') /* String parameter */ { reg2 char *par = va_arg(ap, char *); - uint plen; + uint plen,left_len = (uint)(end-to); if (!par) par = (char*)"(null)"; plen = (uint) strlen(par); - if ((uint) (end-to) > plen) /* Replace if possible */ - { - to=strmov(to,par); - continue; - } + if (left_len <= plen) + plen = left_len - 1; + to=strnmov(to,par,plen); + continue; } else if (*fmt == 'd' || *fmt == 'u') /* Integer parameter */ { @@ -74,20 +74,28 @@ int my_vsnprintf(char *to, size_t n, const char* fmt, va_list ap) break; *to++='%'; /* % used as % or unknown code */ } + DBUG_ASSERT(to <= end); *to='\0'; /* End of errmessage */ return (uint) (to - start); } #ifdef MAIN +#define OVERRUN_SENTRY 250 static void my_printf(const char * fmt, ...) { - char buf[32]; + char buf[33]; int n; va_list ar; va_start(ar, fmt); - n = my_vsnprintf(buf, sizeof(buf),fmt, ar); + buf[sizeof(buf)-1]=OVERRUN_SENTRY; + n = my_vsnprintf(buf, sizeof(buf)-1,fmt, ar); printf(buf); printf("n=%d, strlen=%d\n", n, strlen(buf)); + if (buf[sizeof(buf)-1] != OVERRUN_SENTRY) + { + fprintf(stderr, "Buffer overrun\n"); + abort(); + } va_end(ar); } |