static int hadoop_group_info_fetch_nonreentrant(
struct hadoop_group_info *ginfo, gid_t gid)
{
struct group *group;
int i, num_users = 0;
char **g;
do {
errno = 0;
group = getgrgid(gid);
} while ((!group) && (errno == EINTR));
if (!group) {
return getgrgid_error_translate(errno);
}
ginfo->group.gr_name = strdup(group->gr_name);
if (!ginfo->group.gr_name) {
hadoop_group_info_clear(ginfo);
return ENOMEM;
}
ginfo->group.gr_passwd = strdup(group->gr_passwd);
if (!ginfo->group.gr_passwd) {
hadoop_group_info_clear(ginfo);
return ENOMEM;
}
ginfo->group.gr_gid = group->gr_gid;
if (group->gr_mem) {
for (g = group->gr_mem, num_users = 0;
*g; g++) {
num_users++;
}
}
ginfo->group.gr_mem = calloc(num_users + 1, sizeof(char *));
if (!ginfo->group.gr_mem) {
hadoop_group_info_clear(ginfo);
return ENOMEM;
}
for (i = 0; i < num_users; i++) {
ginfo->group.gr_mem[i] = strdup(group->gr_mem[i]);
if (!ginfo->group.gr_mem[i]) {
hadoop_group_info_clear(ginfo);
return ENOMEM;
}
}
return 0;
}
void hadoop_group_info_free(struct hadoop_group_info *ginfo)
{
if (!ginfo->buf_sz) {
hadoop_group_info_clear(ginfo);
} else {
free(ginfo->buf);
}
free(ginfo);
}
int hadoop_group_info_fetch(struct hadoop_group_info *ginfo, gid_t gid)
{
int ret;
hadoop_group_info_clear(ginfo);
if (!ginfo->buf_sz) {
static pthread_mutex_t g_getgrnam_lock = PTHREAD_MUTEX_INITIALIZER;
pthread_mutex_lock(&g_getgrnam_lock);
ret = hadoop_group_info_fetch_nonreentrant(ginfo, gid);
pthread_mutex_unlock(&g_getgrnam_lock);
return ret;
} else {
return hadoop_group_info_fetch_reentrant(ginfo, gid);
}
}
int hadoop_group_info_fetch(struct hadoop_group_info *ginfo, gid_t gid)
{
struct group *group;
int ret;
size_t buf_sz;
char *nbuf;
hadoop_group_info_clear(ginfo);
for (;;) {
// On success, the following call returns 0 and group is set to non-NULL.
group = NULL;
ret = getgrgid_r(gid, &ginfo->group, ginfo->buf,
ginfo->buf_sz, &group);
switch(ret) {
case 0:
if (!group) {
// Not found.
return ENOENT;
}
// Found.
return 0;
case EINTR:
// EINTR: a signal was handled and this thread was allowed to continue.
break;
case ERANGE:
// ERANGE: the buffer was not big enough.
if (ginfo->buf_sz == MAX_GROUP_BUFFER_SIZE) {
// Already tried with the max size.
return ENOMEM;
}
buf_sz = ginfo->buf_sz * 2;
if (buf_sz > MAX_GROUP_BUFFER_SIZE) {
buf_sz = MAX_GROUP_BUFFER_SIZE;
}
nbuf = realloc(ginfo->buf, buf_sz);
if (!nbuf) {
return ENOMEM;
}
ginfo->buf = nbuf;
ginfo->buf_sz = buf_sz;
break;
default:
// Lookup failed.
return getgrgid_error_translate(ret);
}
}
}
