* Nils Carlson ([email protected]) wrote:
> Changes since v1:
> * Use list length, not the size in bytes
> * Fix a possible bug for pid_t in a sscanf
> * Use list length in the dir scanning function
>
> Restructure the command to separate the pid gathering.
> This will allow a root user to gather pid from multiple user
> directories.
>
> Signed-off-by: Nils Carlson <[email protected]>
> ---
> libustctl/libustctl.c | 81
> +++++++++++++++++++++++++++++++------------------
> 1 files changed, 51 insertions(+), 30 deletions(-)
>
> diff --git a/libustctl/libustctl.c b/libustctl/libustctl.c
> index d57e645..5625f43 100644
> --- a/libustctl/libustctl.c
> +++ b/libustctl/libustctl.c
> @@ -88,53 +88,74 @@ int ustctl_connect_pid(pid_t pid)
> return sock;
> }
>
> -pid_t *ustctl_get_online_pids(void)
> +static void get_pids_in_dir(DIR *dir, pid_t **pid_list,
> + unsigned int *pid_list_size)
> {
> struct dirent *dirent;
> - DIR *dir;
> - unsigned int ret_size = 1 * sizeof(pid_t), i = 0;
> -
> - dir = opendir(SOCK_DIR);
> - if (!dir) {
> - return NULL;
> - }
> -
> - pid_t *ret = (pid_t *) malloc(ret_size);
> + unsigned int read_pid;
>
> while ((dirent = readdir(dir))) {
> if (!strcmp(dirent->d_name, ".") ||
> - !strcmp(dirent->d_name, "..")) {
> + !strcmp(dirent->d_name, "..") ||
> + !strcmp(dirent->d_name, "ust-consumer") ||
> + dirent->d_type == DT_DIR) {
>
> continue;
> }
>
> - if (dirent->d_type != DT_DIR &&
> - !!strcmp(dirent->d_name, "ust-consumer")) {
> -
> - sscanf(dirent->d_name, "%u", (unsigned int *) &ret[i]);
> - /* FIXME: Here we previously called pid_is_online, which
> - * always returned 1, now I replaced it with just 1.
> - * We need to figure out an intelligent way of solving
> - * this, maybe connect-disconnect.
> - */
> - if (1) {
> - ret_size += sizeof(pid_t);
> - ret = (pid_t *) realloc(ret, ret_size);
> - ++i;
> - }
> + sscanf(dirent->d_name, "%u", &read_pid);
> +
> + (*pid_list)[*pid_list_size - 1] = read_pid;
> + /* FIXME: Here we previously called pid_is_online, which
> + * always returned 1, now I replaced it with just 1.
> + * We need to figure out an intelligent way of solving
> + * this, maybe connect-disconnect.
> + */
> + if (1) {
> + (*pid_list_size)++;
> + *pid_list = realloc(*pid_list,
> + *pid_list_size * sizeof(pid_t));
Rather than reallocating the memory space each time we add a single
entry, I would recommend to double the size each time we need to grow
the allocated space. We use a "0" entry at the end to denote the end of
the list anyway, so allocating an area larger than needed should not
hurt, and it will turn this O(nb items) * mem allocation runtime cost
into a O(log(nb items)) * mem allocation runtime cost.
Thanks,
Mathieu
> }
> }
>
> - ret[i] = 0; /* Array end */
> + (*pid_list)[*pid_list_size - 1] = 0; /* Array end */
> +}
>
> - if (ret[0] == 0) {
> - /* No PID at all */
> - free(ret);
> +pid_t *ustctl_get_online_pids(void)
> +{
> + char *dir_name;
> + DIR *dir;
> + unsigned int pid_list_size = 1;
> + pid_t *pid_list = NULL;
> +
> + dir_name = ustcomm_user_sock_dir();
> + if (!dir_name) {
> return NULL;
> }
>
> + dir = opendir(dir_name);
> + if (!dir) {
> + goto free_dir_name;
> + }
> +
> + pid_list = malloc(pid_list_size * sizeof(pid_t));
> +
> + get_pids_in_dir(dir, &pid_list, &pid_list_size);
> +
> + if (pid_list[0] == 0) {
> + /* No PID at all */
> + free(pid_list);
> + pid_list = NULL;
> + goto close_dir;
> + }
> +
> +close_dir:
> closedir(dir);
> - return ret;
> +
> +free_dir_name:
> + free(dir_name);
> +
> + return pid_list;
> }
>
> /**
> --
> 1.7.1
>
>
> _______________________________________________
> ltt-dev mailing list
> [email protected]
> http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
>
--
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com
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