Usermode/libc - Fix over-use of 64-bit divide in strtoull

[tpg/acess2.git] / Usermode / Libraries / libc.so_src / strtoi.c

diff --git a/Usermode/Libraries/libc.so_src/strtoi.c b/Usermode/Libraries/libc.so_src/strtoi.c
index de7f725..4fd2da5 100644 (file)
--- a/Usermode/Libraries/libc.so_src/strtoi.c
+++ b/Usermode/Libraries/libc.so_src/strtoi.c
@@ -27,7 +27,7 @@ unsigned long long strtoull(const char *str, char **end, int base)
        
        // Handle base detection for hex
        if( base == 0 || base == 16 ) {
-               if( *str == '0' && str[1] == 'x' ) {
+               if( *str == '0' && (str[1] == 'x' || str[1] == 'X') && isxdigit(str[2]) ) {
                        str += 2;
                        base = 16;
                }
@@ -43,6 +43,10 @@ unsigned long long strtoull(const char *str, char **end, int base)
        if( base == 0 )
                base = 10;
 
+       // Value before getting within 1 digit of ULLONG_MAX
+       // - Used to avoid overflow in more accurate check
+       unsigned long long      max_before_ullong_max = ULLONG_MAX / base;
+       unsigned int    space_above = ULLONG_MAX - max_before_ullong_max * base;
        while( *str )
        {
                 int    next = -1;
@@ -58,8 +62,31 @@ unsigned long long strtoull(const char *str, char **end, int base)
                        if( 'a' <= *str && *str <= 'a'+base-10-1 )
                                next = *str - 'a' + 10;
                }
+               //_SysDebug("strtoull - ret=0x%llx,next=%i,str='%s'", ret, next, str);
                if( next < 0 )
                        break;
+               
+               // If we're already out of range, keep eating
+               if( ret == ULLONG_MAX ) {
+                       errno = ERANGE;
+                       str ++;
+                       // Keep eating until first unrecognised character
+                       continue;
+               }
+       
+               // Rough then accurate check against max value
+               if( ret >= max_before_ullong_max )
+               {
+                       //_SysDebug("strtoull - 0x%llx>0x%llx", ret, max_before_ullong_max);
+                       if( (ret - max_before_ullong_max) * base + next > space_above ) {
+                               //_SysDebug("strtoull - %u*%u+%u (%u) > %u",
+                               //      (unsigned int)(ret - max_before_ullong_max), base, next, space_above);
+                               ret = ULLONG_MAX;
+                               errno = ERANGE;
+                               str ++;
+                               continue;
+                       }
+               }
                ret *= base;
                ret += next;
                str ++;
@@ -85,7 +112,6 @@ unsigned long strtoul(const char *ptr, char **end, int base)
 long long strtoll(const char *str, char **end, int base)
 {
         int    neg = 0;
-       unsigned long long      ret;
 
        if( !str ) {
                errno = EINVAL;
@@ -96,17 +122,36 @@ long long strtoll(const char *str, char **end, int base)
                str++;
        
        // Check for negative (or positive) sign
-       if(*str == '-' || *str == '+') {
+       if(*str == '-' || *str == '+')
+       {
+               //_SysDebug("strtoll - str[0:1] = '%.2s'", str);
+               if( !isdigit(str[1]) ) {
+                       // Non-digit, invalid string
+                       if(end) *end = (char*)str;
+                       return 0;
+               }
                neg = (*str == '-');
                str++;
        }
 
-       ret = strtoull(str, end, base); 
+       unsigned long long ret = strtoull(str, end, base);      
+       //_SysDebug("strtoll - neg=%i,ret=%llu", neg, ret);
 
-       if( neg )
+       if( neg ) {
+               if( -ret < LLONG_MIN ) {
+                       errno = ERANGE;
+                       return LLONG_MIN;
+               }
                return -ret;
+       }
        else
+       {
+               if( ret > LLONG_MAX ) {
+                       errno = ERANGE;
+                       return LLONG_MAX;
+               }
                return ret;
+       }
 }
 
 long strtol(const char *str, char **end, int base)