[libvirt] PATCH: 19/25: Remove use of non-threadsafe POSIX apis
Jim Meyering
jim at meyering.net
Thu Jan 22 15:21:25 UTC 2009
"Daniel P. Berrange" <berrange at redhat.com> wrote:
> On Fri, Jan 16, 2009 at 12:25:02PM +0000, Daniel P. Berrange wrote:
>> On Fri, Jan 16, 2009 at 12:21:59PM +0000, Richard W.M. Jones wrote:
>> > 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.
>>
>> That's a good idea - in all the cases where we currently use getpwuid
>> all we actually want is the home directory path. So we could add a
>> simple func:
>>
>> char *virUserHomeDirectory(uid_t uid);
>>
>> and hide all the horrific code in there.
>
> Here's an update with that usage in it
One problem in virGetUserDirectory.
It always returns NULL.
And did you mean to include the TCP socket changes in this set?
> +char *virGetUserDirectory(virConnectPtr conn,
> + uid_t uid)
> +{
> + char *strbuf;
> + char *ret;
> + struct passwd pwbuf;
> + struct passwd *pw;
> + size_t strbuflen = sysconf(_SC_GETPW_R_SIZE_MAX);
> +
> + if (VIR_ALLOC_N(strbuf, strbuflen) < 0) {
> + virReportOOMError(conn);
> + return NULL;
> + }
> +
> + if (getpwuid_r(uid, &pwbuf, strbuf, strbuflen, &pw) != 0) {
> + virReportSystemError(conn, errno,
> + _("Failed to find user record for uid '%d'"),
> + uid);
> + VIR_FREE(strbuf);
> + return NULL;
> + }
> +
> + ret = strdup(pw->pw_dir);
> +
> + VIR_FREE(strbuf);
> + if (!ret)
> + virReportOOMError(conn);
> +
> + return NULL;
This fucntion alwasy returns NULL..
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