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SubjectRe: [PATCH 19/22] perf tools: Add filename__read_str util function
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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;

Thanks,
Namhyung

> + break;
> + }
> +
> + size += n;
> + } while (n > 0);
> +
> + if (!err) {
> + *sizep = size;
> + *buf = bf;
> + } else
> + free(bf);
> +
> + close(fd);
> + return err;
> +}



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