One very small nit...
On 05/03/2016 10:46 AM, Olga Kornievskaia wrote:
> This patch moves reading of the upcall information from the child thread
> into the main thread. It removes the need to synchronize between the
> parent and child thread before processing upcall. Also it creates the thread
> in a detached state.
>
> Signed-off-by: Olga Kornievskaia <kolga@xxxxxxxxxx>
> ---
> utils/gssd/gssd.c | 95 +++++++++++++++++++++++++++++++++++---------------
> utils/gssd/gssd.h | 13 +++++--
> utils/gssd/gssd_proc.c | 73 +++++++++++---------------------------
> 3 files changed, 98 insertions(+), 83 deletions(-)
>
> diff --git a/utils/gssd/gssd.c b/utils/gssd/gssd.c
> index 9bf7917..95b6715 100644
> --- a/utils/gssd/gssd.c
> +++ b/utils/gssd/gssd.c
> @@ -363,54 +363,93 @@ gssd_destroy_client(struct clnt_info *clp)
>
> static void gssd_scan(void);
>
> -static inline void
> -wait_for_child_and_detach(pthread_t th)
> +static void
> +start_upcall_thread(void (*func)(struct clnt_upcall_info *), void *info)
> +{
> + pthread_attr_t attr;
> + pthread_t th;
> + int ret;
> +
> + ret = pthread_attr_init(&attr);
> + if (ret != 0) {
> + printerr(0, "ERROR: failed to init pthread attr: ret %d: %s\n",
> + ret, strerror(errno));
> + goto err;
> + }
> + ret = pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
> + if (ret != 0) {
> + printerr(0, "ERROR: failed to create pthread attr: ret %d: "
> + "%s\n", ret, strerror(errno));
> + goto err;
> + }
> +
> + ret = pthread_create(&th, &attr, (void *)func, (void *)info);
> + if (ret != 0) {
> + printerr(0, "ERROR: pthread_create failed: ret %d: %s\n",
> + ret, strerror(errno));
> + goto err;
> + }
> + return;
> +err:
> + free(info);
> +}
> +
> +static struct clnt_upcall_info *alloc_upcall_info(struct clnt_info *clp)
> {
> - pthread_mutex_lock(&pmutex);
> - while (!thread_started)
> - pthread_cond_wait(&pcond, &pmutex);
> - thread_started = false;
> - pthread_mutex_unlock(&pmutex);
> - pthread_detach(th);
> + struct clnt_upcall_info *info;
> +
> + info = malloc(sizeof(struct clnt_upcall_info));
> + if (info == NULL)
> + return NULL;
> + info->clp = clp;
> +
> + return info;
> }
>
> -/* For each upcall create a thread, detach from the main process so that
> - * resources are released back into the system without the need for a join.
> - * We need to wait for the child thread to start and consume the event from
> - * the file descriptor.
> +/* For each upcall read the upcall info into the buffer, then create a
> + * thread in a detached state so that resources are released back into
> + * the system without the need for a join.
> */
> static void
> gssd_clnt_gssd_cb(int UNUSED(fd), short UNUSED(which), void *data)
> {
> struct clnt_info *clp = data;
> - pthread_t th;
> - int ret;
> + struct clnt_upcall_info *info;
>
> - ret = pthread_create(&th, NULL, (void *)handle_gssd_upcall,
> - (void *)clp);
> - if (ret != 0) {
> - printerr(0, "ERROR: pthread_create failed: ret %d: %s\n",
> - ret, strerror(errno));
> + info = alloc_upcall_info(clp);
> + if (info == NULL)
> + return;
> +
> + info->lbuflen = read(clp->gssd_fd, info->lbuf, sizeof(info->lbuf));
> + if (info->lbuflen <= 0 || info->lbuf[info->lbuflen-1] != '\n') {
> + printerr(0, "WARNING: %s: failed reading request\n", __func__);
> + free(info);
> return;
> }
> - wait_for_child_and_detach(th);
> + info->lbuf[info->lbuflen-1] = 0;
> +
> + start_upcall_thread(handle_gssd_upcall, info);
Instead of having start_upcall_thread() free the info pointer
I think it makes it more readable if gssd_clnt_gssd_cb() does the
free... So the routine would allocate the pointer, populate the
pointer and free the point all in one routine.
I think it would make start_upcall_thread() simpler since
it would not need all those goto...
steved.
> }
>
> static void
> gssd_clnt_krb5_cb(int UNUSED(fd), short UNUSED(which), void *data)
> {
> struct clnt_info *clp = data;
> - pthread_t th;
> - int ret;
> + struct clnt_upcall_info *info;
>
> - ret = pthread_create(&th, NULL, (void *)handle_krb5_upcall,
> - (void *)clp);
> - if (ret != 0) {
> - printerr(0, "ERROR: pthread_create failed: ret %d: %s\n",
> - ret, strerror(errno));
> + info = alloc_upcall_info(clp);
> + if (info == NULL)
> + return;
> +
> + if (read(clp->krb5_fd, &info->uid,
> + sizeof(info->uid)) < (ssize_t)sizeof(info->uid)) {
> + printerr(0, "WARNING: %s: failed reading uid from krb5 "
> + "upcall pipe: %s\n", __func__, strerror(errno));
> + free(info);
> return;
> }
> - wait_for_child_and_detach(th);
> +
> + start_upcall_thread(handle_krb5_upcall, info);
> }
>
> static struct clnt_info *
> diff --git a/utils/gssd/gssd.h b/utils/gssd/gssd.h
> index 565bce3..f4f5975 100644
> --- a/utils/gssd/gssd.h
> +++ b/utils/gssd/gssd.h
> @@ -49,7 +49,7 @@
> #define GSSD_DEFAULT_MACHINE_CRED_SUFFIX "machine"
> #define GSSD_DEFAULT_KEYTAB_FILE "/etc/krb5.keytab"
> #define GSSD_SERVICE_NAME "nfs"
> -
> +#define RPC_CHAN_BUF_SIZE 32768
> /*
> * The gss mechanisms that we can handle
> */
> @@ -85,8 +85,15 @@ struct clnt_info {
> struct sockaddr_storage addr;
> };
>
> -void handle_krb5_upcall(struct clnt_info *clp);
> -void handle_gssd_upcall(struct clnt_info *clp);
> +struct clnt_upcall_info {
> + struct clnt_info *clp;
> + char lbuf[RPC_CHAN_BUF_SIZE];
> + int lbuflen;
> + uid_t uid;
> +};
> +
> +void handle_krb5_upcall(struct clnt_upcall_info *clp);
> +void handle_gssd_upcall(struct clnt_upcall_info *clp);
>
>
> #endif /* _RPC_GSSD_H_ */
> diff --git a/utils/gssd/gssd_proc.c b/utils/gssd/gssd_proc.c
> index afaaf9e..d74d372 100644
> --- a/utils/gssd/gssd_proc.c
> +++ b/utils/gssd/gssd_proc.c
> @@ -79,7 +79,6 @@
> #include "nfsrpc.h"
> #include "nfslib.h"
> #include "gss_names.h"
> -#include "misc.h"
>
> /* Encryption types supported by the kernel rpcsec_gss code */
> int num_krb5_enctypes = 0;
> @@ -708,45 +707,22 @@ out_return_error:
> goto out;
> }
>
> -/* signal to the parent thread that we have read from the file descriptor.
> - * it should allow the parent to proceed to poll on the descriptor for
> - * the next upcall from the kernel.
> - */
> -static inline void
> -signal_parent_event_consumed(void)
> -{
> - pthread_mutex_lock(&pmutex);
> - thread_started = true;
> - pthread_cond_signal(&pcond);
> - pthread_mutex_unlock(&pmutex);
> -}
> -
> void
> -handle_krb5_upcall(struct clnt_info *clp)
> +handle_krb5_upcall(struct clnt_upcall_info *info)
> {
> - uid_t uid;
> - int status;
> + struct clnt_info *clp = info->clp;
>
> - status = read(clp->krb5_fd, &uid, sizeof(uid)) < (ssize_t)sizeof(uid);
> - signal_parent_event_consumed();
> + printerr(2, "\n%s: uid %d (%s)\n", __func__, info->uid, clp->relpath);
>
> - if (status) {
> - printerr(0, "WARNING: failed reading uid from krb5 "
> - "upcall pipe: %s\n", strerror(errno));
> - return;
> - }
> -
> - printerr(2, "\n%s: uid %d (%s)\n", __func__, uid, clp->relpath);
> -
> - process_krb5_upcall(clp, uid, clp->krb5_fd, NULL, NULL);
> + process_krb5_upcall(clp, info->uid, clp->krb5_fd, NULL, NULL);
> + free(info);
> }
>
> void
> -handle_gssd_upcall(struct clnt_info *clp)
> +handle_gssd_upcall(struct clnt_upcall_info *info)
> {
> + struct clnt_info *clp = info->clp;
> uid_t uid;
> - char lbuf[RPC_CHAN_BUF_SIZE];
> - int lbuflen = 0;
> char *p;
> char *mech = NULL;
> char *uidstr = NULL;
> @@ -754,19 +730,9 @@ handle_gssd_upcall(struct clnt_info *clp)
> char *service = NULL;
> char *enctypes = NULL;
>
> - lbuflen = read(clp->gssd_fd, lbuf, sizeof(lbuf));
> - signal_parent_event_consumed();
> + printerr(2, "\n%s: '%s' (%s)\n", __func__, info->lbuf, clp->relpath);
>
> - if (lbuflen <= 0 || lbuf[lbuflen-1] != '\n') {
> - printerr(0, "WARNING: handle_gssd_upcall: "
> - "failed reading request\n");
> - return;
> - }
> - lbuf[lbuflen-1] = 0;
> -
> - printerr(2, "\n%s: '%s' (%s)\n", __func__, lbuf, clp->relpath);
> -
> - for (p = strtok(lbuf, " "); p; p = strtok(NULL, " ")) {
> + for (p = strtok(info->lbuf, " "); p; p = strtok(NULL, " ")) {
> if (!strncmp(p, "mech=", strlen("mech=")))
> mech = p + strlen("mech=");
> else if (!strncmp(p, "uid=", strlen("uid=")))
> @@ -782,8 +748,8 @@ handle_gssd_upcall(struct clnt_info *clp)
> if (!mech || strlen(mech) < 1) {
> printerr(0, "WARNING: handle_gssd_upcall: "
> "failed to find gss mechanism name "
> - "in upcall string '%s'\n", lbuf);
> - return;
> + "in upcall string '%s'\n", info->lbuf);
> + goto out;
> }
>
> if (uidstr) {
> @@ -795,21 +761,21 @@ handle_gssd_upcall(struct clnt_info *clp)
> if (!uidstr) {
> printerr(0, "WARNING: handle_gssd_upcall: "
> "failed to find uid "
> - "in upcall string '%s'\n", lbuf);
> - return;
> + "in upcall string '%s'\n", info->lbuf);
> + goto out;
> }
>
> if (enctypes && parse_enctypes(enctypes) != 0) {
> printerr(0, "WARNING: handle_gssd_upcall: "
> "parsing encryption types failed: errno %d\n", errno);
> - return;
> + goto out;
> }
>
> if (target && strlen(target) < 1) {
> printerr(0, "WARNING: handle_gssd_upcall: "
> "failed to parse target name "
> - "in upcall string '%s'\n", lbuf);
> - return;
> + "in upcall string '%s'\n", info->lbuf);
> + goto out;
> }
>
> /*
> @@ -823,8 +789,8 @@ handle_gssd_upcall(struct clnt_info *clp)
> if (service && strlen(service) < 1) {
> printerr(0, "WARNING: handle_gssd_upcall: "
> "failed to parse service type "
> - "in upcall string '%s'\n", lbuf);
> - return;
> + "in upcall string '%s'\n", info->lbuf);
> + goto out;
> }
>
> if (strcmp(mech, "krb5") == 0 && clp->servername)
> @@ -835,5 +801,8 @@ handle_gssd_upcall(struct clnt_info *clp)
> "received unknown gss mech '%s'\n", mech);
> do_error_downcall(clp->gssd_fd, uid, -EACCES);
> }
> +out:
> + free(info);
> + return;
> }
>
>
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