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sscanf(): NuttX libc tried to guess how many characters to parse, extracted them into a buffer, then ran strtol() on that buffer. That guess is often wrong. A better approach would be to call strtol() directly on the input data, using the endptr return value to determine how many characters to skip after parsing. From Kosma Moczek

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This commit is contained in:
Gregory Nutt 2014-08-18 07:33:17 -06:00
parent a8d7772ad6
commit a325cb9f0d
1 changed files with 27 additions and 26 deletions
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53
libc/stdio/lib_sscanf.c
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@ -405,6 +405,10 @@ int vsscanf(FAR const char *buf, FAR const char *fmt, va_list ap)
if (*buf) if (*buf)
{ {
FAR char *endptr;
int errsave;
long tmplong;
/* Skip over any white space before the integer string */ /* Skip over any white space before the integer string */
while (isspace(*buf)) while (isspace(*buf))
@ -459,35 +463,32 @@ int vsscanf(FAR const char *buf, FAR const char *fmt, va_list ap)
lvdbg("vsscanf: tmp[]=\"%s\"\n", tmp); lvdbg("vsscanf: tmp[]=\"%s\"\n", tmp);
/* Perform the integer conversion */ /* Perform the integer conversion */
/* Preserve the errno value */
buf += width; errsave = get_errno();
set_errno(0);
if (sign)
{
tmplong = strtol(tmp, &endptr, base);
}
else
{
tmplong = strtoul(tmp, &endptr, base);
}
/* Check if the number was successfully converted */
if (tmp == endptr || get_errno() == ERANGE)
{
return count;
}
/* Move by the actual number of characters converted */
buf += (endptr - tmp);
set_errno(errsave);
if (!noassign) if (!noassign)
{ {
FAR char *endptr;
int errsave;
long tmplong;
/* Preserve the errno value */
errsave = get_errno();
set_errno(0);
if (sign)
{
tmplong = strtol(tmp, &endptr, base);
}
else
{
tmplong = strtoul(tmp, &endptr, base);
}
/* Check if the number was successfully converted */
if (tmp == endptr || get_errno() == ERANGE)
{
return count;
}
set_errno(errsave);
/* We have to check whether we need to return a long /* We have to check whether we need to return a long
* or an int. * or an int.