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SubjectRe: [PATCH 19/22] perf tools: Add filename__read_str util function
On Sat, Nov 23, 2013 at 12:43:59AM +0900, Namhyung Kim wrote:
> 2013-11-21 (목), 12:01 +0100, Jiri Olsa:
> > Adding filename__read_str util function to read
> > text file and return it in the char array.
> >
> > The interface is:
> > int filename__read_str(const char *filename, char **buf, size_t *sizep)
> >
> > Returns 0/-1 if the read suceeded/fail respectively.
> >
> > buf - place to store the data pointer
> > size - place to store data size
>
> [SNIP]
> > +int filename__read_str(const char *filename, char **buf, size_t *sizep)
> > +{
> > + size_t size = 0, alloc_size = 0;
> > + void *bf = NULL, *nbf;
> > + int fd, n, err = 0;
> > +
> > + fd = open(filename, O_RDONLY);
> > + if (fd < 0)
> > + return -errno;
> > +
> > + do {
> > + if (size == alloc_size) {
> > + alloc_size += BUFSIZ;
> > + nbf = realloc(bf, alloc_size);
> > + if (!nbf) {
> > + err = -ENOMEM;
> > + break;
> > + }
> > +
> > + bf = nbf;
> > + }
> > +
> > + n = read(fd, bf + size, BUFSIZ);
>
> Shouldn't it be "read(fd, bf + size, alloc_size - size)"?
> Otherwise there might be a problem if read() returned early for some
> reason with small size and then retry with a full BUFSIZ..
>
>
> > + if (n < 0) {
> > + err = 0;
>
> I think it needs to check the size also since read() might fail at the
> first invocation. What about this?
>
> if (n < 0) {
> if (size)
> err = 0;
> else
> err = -errno;
>

ok, added.. plus warning in the 'if (size)' leg,
because we're returning data even if we failed.

thanks,
jirka
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