[libvirt] PATCH: 19/25: Remove use of non-threadsafe POSIX apis
Daniel P. Berrange
berrange at redhat.com
Thu Jan 22 15:17:43 UTC 2009
On Thu, Jan 22, 2009 at 10:48:59AM +0000, Daniel P. Berrange 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
>
> diff --git a/src/util.c b/src/util.c
> --- a/src/util.c
> +++ b/src/util.c
> @@ -49,6 +49,9 @@
> #include <paths.h>
> #endif
> #include <netdb.h>
> +#ifdef HAVE_GETPWUID_R
> +#include <pwd.h>
> +#endif
>
> #include "virterror_internal.h"
> #include "logging.h"
> @@ -1431,3 +1434,37 @@ int virKillProcess(pid_t pid, int sig)
> return kill(pid, sig);
> #endif
> }
> +
> +
> +#ifdef HAVE_GETPWUID_R
> +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;
> +}
> +#endif
Delibrate mistake here :-)
s/return NULL/return ret/
Otherwise it always returns NULL :-)
Daniel
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