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Re: [libvirt] PATCH: 19/25: Remove use of non-threadsafe POSIX apis



On Tue, Jan 13, 2009 at 05:46:37PM +0000, Daniel P. Berrange wrote:
> +        char buf[1024];

sysconf (_SC_GETPW_R_SIZE_MAX)?

Looking at glibc's implementation of getpwuid (which uses getpwuid_r),
I see that glibc dynamically reallocates the buffer as necessary to
the correct size for the return value.  The logic of this is fairly
simple so maybe we should do the same?

>From glibc:

  buffer = malloc (/*some_initial_size*/);

  while (buffer != NULL
         && (getpwuid_r (const char *name, &resbuf, buffer,
                         buffer_size, &result)
             == ERANGE))
    {
      char *new_buf;
      buffer_size *= 2;
      new_buf = (char *) realloc (buffer, buffer_size);
      if (new_buf == NULL)
        {
          free (buffer);
          errno = ENOMEM;
        }
      buffer = new_buf;
    }


Anyhow, +1 but I'd be happier if these functions were centralized in
somewhere like src/utils.c.

Rich.

-- 
Richard Jones, Emerging Technologies, Red Hat  http://et.redhat.com/~rjones
virt-top is 'top' for virtual machines.  Tiny program with many
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http://et.redhat.com/~rjones/virt-top


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