Re: [Libvir] [PATCH] Enhanced stats for fullvirt domains

Hi Rich, I know this patch just moved the code below, and the probability of data corruption and file I/O errors here is low, but... "Richard W.M. Jones" <rjones(a)redhat.com&gt; wrote: Since all of fread, strtoll, and fclose can fail, and since the 64 bytes from fread might be a valid prefix, but not terminated (i.e., strtoll could overrun the STR buffer -- yeah, it's far-fetched, but still) the above should probably be rewritten something like e.g., WARNING: the following may not even compile /* Convert NUL-or-NL-terminated string to int64_t, detecting overflow, invalid string (i.e., non-digit), or a long long value that doesn't fit in int64_t (probably only theoretical). */ static int xstrtoint64 (char const *s, int base, int64_t *result) { long long int lli; char *p; errno = 0; lli = strtoll (s, &p, base); if (errno || !(*p == 0 || *p == '\n') || p == s || (int64_t) lli != lli) return -1; *result = lli; return 0; } static int64_t read_stat (const char *path) { char str[64]; int64_t r; int i; FILE *fp; fp = fopen (path, "r"); if (!fp) return -1; /* read, but don't bail out before closing */ i = fread (str, sizeof str, 1, fp); if (fclose (fp) != 0 || i < 2 /* ensure we read at least two bytes */ || str[i - 1] != 0 /* the last byte must be zero */ || xstrtoint64 (str, 10, &r) != 0) return -1; return r; }