diff options
Diffstat (limited to 'gnuradio-runtime/lib/gr_vmcircbuf_sysv_shm.cc')
| -rw-r--r-- | gnuradio-runtime/lib/gr_vmcircbuf_sysv_shm.cc | 194 |
1 files changed, 194 insertions, 0 deletions
diff --git a/gnuradio-runtime/lib/gr_vmcircbuf_sysv_shm.cc b/gnuradio-runtime/lib/gr_vmcircbuf_sysv_shm.cc new file mode 100644 index 0000000000..d9cf75e70f --- /dev/null +++ b/gnuradio-runtime/lib/gr_vmcircbuf_sysv_shm.cc @@ -0,0 +1,194 @@ +/* -*- c++ -*- */ +/* + * Copyright 2003 Free Software Foundation, Inc. + * + * This file is part of GNU Radio + * + * GNU Radio is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 3, or (at your option) + * any later version. + * + * GNU Radio is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with GNU Radio; see the file COPYING. If not, write to + * the Free Software Foundation, Inc., 51 Franklin Street, + * Boston, MA 02110-1301, USA. + */ + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif +#include <gr_vmcircbuf_sysv_shm.h> +#include <stdexcept> +#include <assert.h> +#include <unistd.h> +#include <stdlib.h> +#include <fcntl.h> +#ifdef HAVE_SYS_IPC_H +#include <sys/ipc.h> +#endif +#ifdef HAVE_SYS_SHM_H +#include <sys/shm.h> +#endif +#include <errno.h> +#include <stdio.h> +#include <gr_pagesize.h> + + +gr_vmcircbuf_sysv_shm::gr_vmcircbuf_sysv_shm (int size) + : gr_vmcircbuf (size) +{ +#if !defined(HAVE_SYS_SHM_H) + fprintf (stderr, "gr_vmcircbuf_sysv_shm: sysv shared memory is not available\n"); + throw std::runtime_error ("gr_vmcircbuf_sysv_shm"); +#else + + int pagesize = gr_pagesize(); + + if (size <= 0 || (size % pagesize) != 0){ + fprintf (stderr, "gr_vmcircbuf_sysv_shm: invalid size = %d\n", size); + throw std::runtime_error ("gr_vmcircbuf_sysv_shm"); + } + + int shmid_guard = -1; + int shmid1 = -1; + int shmid2 = -1; + + // We use this as a guard page. We'll map it read-only on both ends of the buffer. + // Ideally we'd map it no access, but I don't think that's possible with SysV + if ((shmid_guard = shmget (IPC_PRIVATE, pagesize, IPC_CREAT | 0400)) == -1){ + perror ("gr_vmcircbuf_sysv_shm: shmget (0)"); + throw std::runtime_error ("gr_vmcircbuf_sysv_shm"); + } + + if ((shmid2 = shmget (IPC_PRIVATE, 2 * size + 2 * pagesize, IPC_CREAT | 0700)) == -1){ + perror ("gr_vmcircbuf_sysv_shm: shmget (1)"); + shmctl (shmid_guard, IPC_RMID, 0); + throw std::runtime_error ("gr_vmcircbuf_sysv_shm"); + } + + if ((shmid1 = shmget (IPC_PRIVATE, size, IPC_CREAT | 0700)) == -1){ + perror ("gr_vmcircbuf_sysv_shm: shmget (2)"); + shmctl (shmid_guard, IPC_RMID, 0); + shmctl (shmid2, IPC_RMID, 0); + throw std::runtime_error ("gr_vmcircbuf_sysv_shm"); + } + + void *first_copy = shmat (shmid2, 0, 0); + if (first_copy == (void *) -1){ + perror ("gr_vmcircbuf_sysv_shm: shmat (1)"); + shmctl (shmid_guard, IPC_RMID, 0); + shmctl (shmid2, IPC_RMID, 0); + shmctl (shmid1, IPC_RMID, 0); + throw std::runtime_error ("gr_vmcircbuf_sysv_shm"); + } + + shmctl (shmid2, IPC_RMID, 0); + + // There may be a race between our detach and attach. + // + // If the system allocates all shared memory segments at the same + // virtual addresses in all processes and if the system allocates + // some other segment to first_copy or first_copoy + size between + // our detach and attach, the attaches below could fail [I've never + // seen it fail for this reason]. + + shmdt (first_copy); + + // first read-only guard page + if (shmat (shmid_guard, first_copy, SHM_RDONLY) == (void *) -1){ + perror ("gr_vmcircbuf_sysv_shm: shmat (2)"); + shmctl (shmid_guard, IPC_RMID, 0); + shmctl (shmid1, IPC_RMID, 0); + throw std::runtime_error ("gr_vmcircbuf_sysv_shm"); + } + + // first copy + if (shmat (shmid1, (char *) first_copy + pagesize, 0) == (void *) -1){ + perror ("gr_vmcircbuf_sysv_shm: shmat (3)"); + shmctl (shmid_guard, IPC_RMID, 0); + shmctl (shmid1, IPC_RMID, 0); + shmdt (first_copy); + throw std::runtime_error ("gr_vmcircbuf_sysv_shm"); + } + + // second copy + if (shmat (shmid1, (char *) first_copy + pagesize + size, 0) == (void *) -1){ + perror ("gr_vmcircbuf_sysv_shm: shmat (4)"); + shmctl (shmid_guard, IPC_RMID, 0); + shmctl (shmid1, IPC_RMID, 0); + shmdt ((char *)first_copy + pagesize); + throw std::runtime_error ("gr_vmcircbuf_sysv_shm"); + } + + // second read-only guard page + if (shmat (shmid_guard, (char *) first_copy + pagesize + 2 * size, SHM_RDONLY) == (void *) -1){ + perror ("gr_vmcircbuf_sysv_shm: shmat (5)"); + shmctl (shmid_guard, IPC_RMID, 0); + shmctl (shmid1, IPC_RMID, 0); + shmdt (first_copy); + shmdt ((char *)first_copy + pagesize); + shmdt ((char *)first_copy + pagesize + size); + throw std::runtime_error ("gr_vmcircbuf_sysv_shm"); + } + + shmctl (shmid1, IPC_RMID, 0); + shmctl (shmid_guard, IPC_RMID, 0); + + // Now remember the important stuff + + d_base = (char *) first_copy + pagesize; + d_size = size; +#endif +} + +gr_vmcircbuf_sysv_shm::~gr_vmcircbuf_sysv_shm () +{ +#if defined(HAVE_SYS_SHM_H) + if (shmdt (d_base - gr_pagesize()) == -1 + || shmdt (d_base) == -1 + || shmdt (d_base + d_size) == -1 + || shmdt (d_base + 2 * d_size) == -1){ + perror ("gr_vmcircbuf_sysv_shm: shmdt (2)"); + } +#endif +} + +// ---------------------------------------------------------------- +// The factory interface +// ---------------------------------------------------------------- + + +gr_vmcircbuf_factory *gr_vmcircbuf_sysv_shm_factory::s_the_factory = 0; + +gr_vmcircbuf_factory * +gr_vmcircbuf_sysv_shm_factory::singleton () +{ + if (s_the_factory) + return s_the_factory; + + s_the_factory = new gr_vmcircbuf_sysv_shm_factory (); + return s_the_factory; +} + +int +gr_vmcircbuf_sysv_shm_factory::granularity () +{ + return gr_pagesize (); +} + +gr_vmcircbuf * +gr_vmcircbuf_sysv_shm_factory::make (int size) +{ + try { + return new gr_vmcircbuf_sysv_shm (size); + } + catch (...){ + return 0; + } +} |