lib/pthreadpool/pthreadpool_pipe.c

   1 /*
   2  * Unix SMB/CIFS implementation.
   3  * threadpool implementation based on pthreads
   4  * Copyright (C) Volker Lendecke 2009,2011
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 3 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include "replace.h"
  21 #include "system/filesys.h"
  22 #include "pthreadpool_pipe.h"
  23 #include "pthreadpool.h"
  24
  25 struct pthreadpool_pipe {
  26         struct pthreadpool *pool;
  27         int num_jobs;
  28         pid_t pid;
  29         int pipe_fds[2];
  30 };
  31
  32 static int pthreadpool_pipe_signal(int jobid,
  33                                    void (*job_fn)(void *private_data),
  34                                    void *job_private_data,
  35                                    void *private_data);
  36
  37 int pthreadpool_pipe_init(unsigned max_threads,
  38                           struct pthreadpool_pipe **presult)
  39 {
  40         struct pthreadpool_pipe *pool;
  41         int ret;
  42
  43         pool = calloc(1, sizeof(struct pthreadpool_pipe));
  44         if (pool == NULL) {
  45                 return ENOMEM;
  46         }
  47         pool->pid = getpid();
  48
  49         ret = pipe(pool->pipe_fds);
  50         if (ret == -1) {
  51                 int err = errno;
  52                 free(pool);
  53                 return err;
  54         }
  55
  56         ret = pthreadpool_init(max_threads, &pool->pool,
  57                                pthreadpool_pipe_signal, pool);
  58         if (ret != 0) {
  59                 close(pool->pipe_fds[0]);
  60                 close(pool->pipe_fds[1]);
  61                 free(pool);
  62                 return ret;
  63         }
  64
  65         *presult = pool;
  66         return 0;
  67 }
  68
  69 static int pthreadpool_pipe_signal(int jobid,
  70                                    void (*job_fn)(void *private_data),
  71                                    void *job_private_data,
  72                                    void *private_data)
  73 {
  74         struct pthreadpool_pipe *pool = private_data;
  75         ssize_t written;
  76
  77         do {
  78                 written = write(pool->pipe_fds[1], &jobid, sizeof(jobid));
  79         } while ((written == -1) && (errno == EINTR));
  80
  81         if (written != sizeof(jobid)) {
  82                 return errno;
  83         }
  84
  85         return 0;
  86 }
  87
  88 int pthreadpool_pipe_destroy(struct pthreadpool_pipe *pool)
  89 {
  90         int ret;
  91
  92         if (pool->num_jobs != 0) {
  93                 return EBUSY;
  94         }
  95
  96         ret = pthreadpool_destroy(pool->pool);
  97         if (ret != 0) {
  98                 return ret;
  99         }
 100
 101         close(pool->pipe_fds[0]);
 102         pool->pipe_fds[0] = -1;
 103
 104         close(pool->pipe_fds[1]);
 105         pool->pipe_fds[1] = -1;
 106
 107         free(pool);
 108         return 0;
 109 }
 110
 111 static int pthreadpool_pipe_reinit(struct pthreadpool_pipe *pool)
 112 {
 113         pid_t pid = getpid();
 114         int signal_fd;
 115         int ret;
 116
 117         if (pid == pool->pid) {
 118                 return 0;
 119         }
 120
 121         signal_fd = pool->pipe_fds[0];
 122
 123         close(pool->pipe_fds[0]);
 124         pool->pipe_fds[0] = -1;
 125
 126         close(pool->pipe_fds[1]);
 127         pool->pipe_fds[1] = -1;
 128
 129         ret = pipe(pool->pipe_fds);
 130         if (ret != 0) {
 131                 return errno;
 132         }
 133
 134         ret = dup2(pool->pipe_fds[0], signal_fd);
 135         if (ret != 0) {
 136                 return errno;
 137         }
 138
 139         pool->pipe_fds[0] = signal_fd;
 140         pool->num_jobs = 0;
 141
 142         return 0;
 143 }
 144
 145 int pthreadpool_pipe_add_job(struct pthreadpool_pipe *pool, int job_id,
 146                              void (*fn)(void *private_data),
 147                              void *private_data)
 148 {
 149         int ret;
 150
 151         ret = pthreadpool_pipe_reinit(pool);
 152         if (ret != 0) {
 153                 return ret;
 154         }
 155
 156         ret = pthreadpool_add_job(pool->pool, job_id, fn, private_data);
 157         if (ret != 0) {
 158                 return ret;
 159         }
 160
 161         pool->num_jobs += 1;
 162
 163         return 0;
 164 }
 165
 166 int pthreadpool_pipe_signal_fd(struct pthreadpool_pipe *pool)
 167 {
 168         return pool->pipe_fds[0];
 169 }
 170
 171 int pthreadpool_pipe_finished_jobs(struct pthreadpool_pipe *pool, int *jobids,
 172                                    unsigned num_jobids)
 173 {
 174         ssize_t to_read, nread, num_jobs;
 175         pid_t pid = getpid();
 176
 177         if (pool->pid != pid) {
 178                 return EINVAL;
 179         }
 180
 181         to_read = sizeof(int) * num_jobids;
 182
 183         do {
 184                 nread = read(pool->pipe_fds[0], jobids, to_read);
 185         } while ((nread == -1) && (errno == EINTR));
 186
 187         if (nread == -1) {
 188                 return -errno;
 189         }
 190         if ((nread % sizeof(int)) != 0) {
 191                 return -EINVAL;
 192         }
 193
 194         num_jobs = nread / sizeof(int);
 195
 196         if (num_jobs > pool->num_jobs) {
 197                 return -EINVAL;
 198         }
 199         pool->num_jobs -= num_jobs;
 200
 201         return num_jobs;
 202 }