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Diffstat (limited to 'shm/shmmodule.c')
| -rw-r--r-- | shm/shmmodule.c | 1386 |
1 files changed, 1386 insertions, 0 deletions
diff --git a/shm/shmmodule.c b/shm/shmmodule.c new file mode 100644 index 0000000..cee6d7a --- /dev/null +++ b/shm/shmmodule.c @@ -0,0 +1,1386 @@ +/**************************************************************************** + * + * « shmmodule.c © 1997, 1998 by INRIA. All rights reserved. + * + * Permission is hereby granted, free of charge, to any person obtaining + * a copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY WARRANTIES, EXPRESS OR IMPLIED, + * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY + * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * + * IN NO EVENT SHALL THE INRIA OR THE AUTHORS BE LIABLE FOR ANY DIRECT, + * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES, + * INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, + * LOSS OF USE, DATA, OR PROFITS OR BUSINESS INTERRUPTION, HOWEVER CAUSED AND + * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT, + * INCLUDING NEGLIGENCE OR OTHERWISE, ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. » + * + ***************************************************************************/ + +/* Python Shared Memory module by Vladimir Marangozov */ + +/* + This module provides an interface to System V shared memory IPC. + + Version history: + - 1.0 - Released by Mr. Marangozov in the 1990s. + - 1.1 - Released by me. Fixes a few bugs (including some memory leaks) and adds the ability + to read the blocking flag on semaphores. + - 1.1.1 - Updated setup.py to handle compile options for Linux users. + + See http://NikitaTheSpider.com/python/shm/ for more thorough documentation, updates, contact + info, setup.py, a more Pythonic wrapper, etc. + + Philip Semanchuk, Feb. 2007 + + + Module interface: + + - shm.create_memory(int Key, int Size [,int Perm=0666]) --> object + - shm.create_semaphore(int Key [,int Value=1 [,int Perm=0666]]) --> object + - shm.error + - shm.ftok(string Path, int ProjId) --> int + - shm.getsemid(int Key) --> int + - shm.getshmid(int Key) --> int + - shm.memory(int Shmid) --> object + - shm.memory_haskey(int Key) --> int + - shm.remove_memory(int Shmid) --> None + - shm.remove_semaphore(int Semid) --> None + - shm.semaphore(int Semid) --> object + - shm.semaphore_haskey(int Key) --> int + + Memory Objects: + + + Members: + + - m.addr - attachment address in the process address space + - m.attached - 0|1 + - m.cgid - gid of creator + - m.cpid - pid of creator + - m.cuid - uid of creator + - m.gid - gid of owner + - m.key - segment key or IPC_PRIVATE (=0) + - m.lpid - pid of last shmop + - m.nattch - current # of attached processes + - m.perm - operation permission + - m.shmid - shared memory segment id + - m.size - segment size + - m.uid - uid of owner + + + Methods: + + - m.attach([int Addr=0 [,int How=0]]) --> None + - m.detach() --> None + - m.read(int Nbytes [,int Offset=0]) --> string + - m.setgid(int Gid) --> None + - m.setperm(int Perm) --> None + - m.setuid(int Uid) --> None + - m.write(string Data [,int Offset=0]) --> None + + Semaphore Objects: + + + Members: + + - s.cgid - gid of creator + - s.cuid - uid of creator + - s.gid - gid of owner + - s.key - semaphore key or IPC_PRIVATE (=0) + - s.lpid - pid of last semop + - s.ncnt - current # of processes waiting for s.val > 0 + - s.perm - operation permission + - s.semid - semaphore id + - s.uid - uid of owner + - s.val - value of the semaphore counter + - s.zcnt - current # of processes waiting for s.val == 0 + - s.blocking - whether or not the semaphore is in blocking mode + + + Methods: + + - s.P() --> None - blocks if s.val == 0; decrements s.val + - s.V() --> None - increments s.val + - s.Z() --> None - blocks until s.val == 0 + - s.setblocking(0|1) --> None + - s.setgid(int Gid) --> None + - s.setperm(int Perm) --> None + - s.setuid(int Uid) --> None + - s.setundo(0|1) --> None + - s.setval(int Value) --> None + +*/ + +/* ------------------------------------------------------------------------- */ +#include "Python.h" +#include "structmember.h" + +/* v1.1 - added */ +//#ifdef __FreeBSD__ +//#include <machine/param.h> /* for system definition of PAGE_SIZE */ +//#endif + +#include <sys/types.h> +#include <sys/ipc.h> /* for system's IPC_xxx definitions */ +#include <sys/shm.h> /* for shmget, shmat, shmdt, shmctl */ +#include <sys/sem.h> /* for semget, semctl, semop */ + +#if defined(__GLIBC__) +#define key __key +#endif /* __GLIBC__ */ + +/* +-- Exception type for errors detected by this module. +*/ + +static PyObject *PyShm_Error; + +/* +-- Convenience function to raise an error according to errno. +*/ + +static PyObject * +PyShm_Err(void) +{ + return PyErr_SetFromErrno(PyShm_Error); +} + +/* +-- The object holding a shared memory segment +*/ + +typedef struct { + PyObject_HEAD + int shmid; /* shared memory id */ + int mode; /* attachment mode */ + void *addr; /* shmseg start address */ + struct shmid_ds ds; /* data structure */ +} PyShmMemoryObject; + +staticforward PyTypeObject PyShmMemory_Type; + +#define PyShmObj PyShmMemoryObject +#define PyShmMemory_Check(op) ((op)->ob_type == &PyShmMemory_Type) + +/* +-- The object holding a semaphore +*/ + +typedef struct { + PyObject_HEAD + int semid; /* semaphore id */ + short opflag; /* IPC_NOWAIT, SEM_UNDO */ + struct semid_ds ds; /* data structure */ +} PyShmSemaphoreObject; + +#ifndef HAVE_UNION_SEMUN +union semun { + int val; /* used for SETVAL only */ + struct semid_ds *buf; /* for IPC_STAT and IPC_SET */ + unsigned short *array; /* used for GETALL and SETALL */ +}; +#endif + +typedef union semun semctl_arg; + +staticforward PyTypeObject PyShmSemaphore_Type; + +#define PyShmSemObj PyShmSemaphoreObject +#define PyShmSemaphore_Check(op) ((op)->ob_type == &PyShmSemaphore_Type) + +/* +-- Internal dictionaries for Python memory and semaphore objects +*/ + +static PyObject *shm_dict = NULL; +static PyObject *sem_dict = NULL; + +/************************************************************/ +/* Memory Objects */ +/************************************************************/ + +/* This is to check the validity of a Python memory object + (and to refresh its data status structure). Notably, we + have to check that the real memory segment it points to + is still in memory and hasn't changed (test its id and + size). It could be that the segment has been removed and + created again by someone else with the same key. This is + fine as far as the segment (1) has the same id and size, + and (2) is accessible via shmctl. If you have a better + test, you're welcome :-) */ + +static int +check_memory_identity(PyShmObj *o) +{ + int new_shmid; + int old_shmid = o->shmid; + int old_size = o->ds.shm_segsz; + key_t old_key = o->ds.shm_perm.key; + + /* + -- 1. Try to get the segment identified by the old key (if not IPC_PRIVATE) + -- 2. On failure or on mismatch of the new and the old id -> fail. + -- 3. Try to refresh the object's status using the new id. + -- 4. On failure (the segment cannot be accessed) -> fail. + -- 5. Finaly, compare the old size and the one we got via the new id. + */ + if (old_key != IPC_PRIVATE) { + new_shmid = shmget(old_key, 0, 0); + if (new_shmid != old_shmid) + return 0; + } + else + new_shmid = old_shmid; + if ((shmctl(new_shmid, IPC_STAT, &(o->ds)) != -1) && + (old_size == o->ds.shm_segsz) && + (old_key == o->ds.shm_perm.key)) + return 1; + return 0; +} + +/* Convenience macro for updating the shared memory data status structure */ + +#define refresh_memory_status(o) \ + if (!check_memory_identity(o)) { \ + PyErr_SetString(PyShm_Error, "can't access shared memory segment"); \ + return NULL; \ + } + +/* +-- attach([,address=0 [,how=0]]) +*/ + +/* Attach the shared memory segment to the process address space */ + +static PyObject * +PyShmMemory_attach(PyShmObj *self, PyObject *args) +{ + unsigned long address = 0; + int mode = 0; + void *addr, *old_addr; + + if (!PyArg_ParseTuple(args, "|li", &address, &mode)) + return NULL; + refresh_memory_status(self); + /* return if already attached with the same mode to the same address */ + if ((self->addr != NULL) && (self->mode == mode) && + ((address == 0) || (self->addr == (void *)address))) { + Py_INCREF(Py_None); + return Py_None; + } + /* perform the attach */ + addr = (void *)shmat(self->shmid, (void *)address, mode); + if (addr == (void *)-1) + return PyShm_Err(); + old_addr = self->addr; + self->addr = addr; + self->mode = mode; + /* XXX - multiple attachments of the same shared memory segment + to different locations of the process address space is + not supported. */ + shmdt(old_addr); + Py_INCREF(Py_None); + return Py_None; +} + +/* +-- detach() +*/ + +/* Detach the memory object from the process address space */ + +static PyObject * +PyShmMemory_detach(PyShmObj *self, PyObject *args) +{ + if (!PyArg_NoArgs(args)) + return NULL; + if (self->addr != NULL) { + refresh_memory_status(self); + if (shmdt(self->addr) != 0) + return PyShm_Err(); + self->addr = NULL; /* mark as detached */ + } + Py_INCREF(Py_None); + return Py_None; +} + +/* +-- read(int Nbytes [,int Offset=0]) --> string +*/ + +/* Return a string of n bytes peeked from the shared memory segment */ + +static PyObject * +PyShmMemory_read(PyShmObj *self, PyObject *args) +{ + unsigned long n, offset = 0; + char buf[128]; + char *addr; + + if (!PyArg_ParseTuple(args, "l|l", &n, &offset)) + return NULL; + refresh_memory_status(self); + if (self->addr == NULL) { + PyErr_SetString(PyShm_Error, "R/W operation on detached memory"); + return NULL; + } + if ((unsigned long)self->ds.shm_segsz < (n + offset)) { + sprintf(buf, "read() argument%s exceed%s upper memory limit", + offset ? "s" : "", offset ? "" : "s"); + PyErr_SetString(PyShm_Error, buf); + return NULL; + } + addr = (char *)((unsigned long)self->addr + offset); + return PyString_FromStringAndSize(addr, n); +} + +/* +-- setgid(int Gid) +*/ + +static PyObject * +PyShmMemory_setgid(PyShmObj *self, PyObject *args) +{ + long newgid, oldgid; + + if (!PyArg_ParseTuple(args, "l", &newgid)) + return NULL; + refresh_memory_status(self); + oldgid = (long)self->ds.shm_perm.gid; + self->ds.shm_perm.gid = (gid_t)newgid; + if (shmctl(self->shmid, IPC_SET, &(self->ds)) == -1) { + self->ds.shm_perm.gid = (gid_t)oldgid; + return PyShm_Err(); + } + Py_INCREF(Py_None); + return Py_None; +} + +/* +-- setperm(int Perm) +*/ + +static PyObject * +PyShmMemory_setperm(PyShmObj *self, PyObject *args) +{ + long newmode, oldmode; + + if (!PyArg_ParseTuple(args, "l", &newmode)) + return NULL; + refresh_memory_status(self); + newmode &= 0777; /* permission bits only */ + oldmode = (mode_t)self->ds.shm_perm.mode; + self->ds.shm_perm.mode ^= 0777; + self->ds.shm_perm.mode |= (mode_t)newmode; + if (shmctl(self->shmid, IPC_SET, &(self->ds)) == -1) { + self->ds.shm_perm.mode = (mode_t)oldmode; + return PyShm_Err(); + } + Py_INCREF(Py_None); + return Py_None; +} + +/* +-- setuid(int Uid) +*/ + +static PyObject * +PyShmMemory_setuid(PyShmObj *self, PyObject *args) +{ + long newuid, olduid; + + if (!PyArg_ParseTuple(args, "l", &newuid)) + return NULL; + refresh_memory_status(self); + olduid = (long)self->ds.shm_perm.uid; + /* v1.1 - fixed typo that set the group id rather than the user id */ + self->ds.shm_perm.uid = (uid_t)newuid; + if (shmctl(self->shmid, IPC_SET, &(self->ds)) == -1) { + self->ds.shm_perm.uid = (uid_t)olduid; + return PyShm_Err(); + } + Py_INCREF(Py_None); + return Py_None; +} + +/* +-- write(string Data [, int Offset=0]) +*/ + +/* Write a string to the shared memory segment. */ + +static PyObject * +PyShmMemory_write(PyShmObj *self, PyObject *args) +{ + char *data; + unsigned long n, offset = 0; + char buf[128]; + char *addr; + + if (!PyArg_ParseTuple(args, "s#|l", &data, &n, &offset)) + return NULL; + refresh_memory_status(self); + if (self->addr == NULL) { + PyErr_SetString(PyShm_Error, "R/W operation on detached memory"); + return NULL; + } + if (self->mode & SHM_RDONLY) { + PyErr_SetString(PyShm_Error, + "can't write on read-only attached memory"); + return NULL; + } + if ((unsigned long)self->ds.shm_segsz < (n + offset)) { + sprintf(buf, "write() argument%s exceed%s upper memory limit", + offset ? "s" : "", offset ? "" : "s"); + PyErr_SetString(PyShm_Error, buf); + return NULL; + } + addr = (void *)((unsigned long)self->addr + offset); + memcpy(addr, data, n); + Py_INCREF(Py_None); + return Py_None; +} + +/* List of methods for shared memory objects */ + +static PyMethodDef memory_methods[] = { + {"attach", (PyCFunction)PyShmMemory_attach, 1, + "attach([int Addr=0 [,int How=0]]) --> None | except shm.error"}, + {"detach", (PyCFunction)PyShmMemory_detach, 0, + "detach() --> None | except shm.error"}, + {"read", (PyCFunction)PyShmMemory_read, 1, + "read(int Nbytes [,int Offset=0]) --> string | except shm.error"}, + {"setgid", (PyCFunction)PyShmMemory_setgid, 1, + "setgid(int Gid) --> None | except shm.error"}, + {"setperm", (PyCFunction)PyShmMemory_setperm, 1, + "setperm(int Perm) --> None | except shm.error"}, + {"setuid", (PyCFunction)PyShmMemory_setuid, 1, + "setuid(int Uid) --> None | except shm.error"}, + {"write", (PyCFunction)PyShmMemory_write, 1, + "write(string Data [,int Offset=0]) --> None | except shm.error"}, + {NULL, NULL} /* sentinel */ +}; + +#define OFF(x) offsetof(PyShmMemoryObject, x) +#define OFF1(x) OFF(ds) + offsetof(struct shmid_ds, x) +#define OFF2(x) OFF1(shm_perm) + offsetof(struct ipc_perm, x) + +/* List of members for shared memory objects */ + +/* Note: member types are set in the initshm function. + Members which need separate processing are: + - addr --> it is not part of the shmid_ds structure + - attached --> function depending on addr + - nattch --> system dependent declaration in shmid_ds (unknown type) + - perm --> return permission (lower 9) bits only of ds.shm_perm.mode +*/ + +static struct memberlist memory_memberlist[] = { + {"cgid", T_INT, OFF2(cgid), RO}, /* 0 (gid_t) */ + {"cpid", T_INT, OFF1(shm_cpid), RO}, /* 1 (pid_t) */ + {"cuid", T_INT, OFF2(cuid), RO}, /* 2 (uid_t) */ + {"key", T_INT, OFF2(key), RO}, /* 3 (key_t) */ + {"lpid", T_INT, OFF1(shm_lpid), RO}, /* 4 (pid_t) */ + {"shmid", T_INT, OFF(shmid), RO}, /* 5 (int) */ + {"size", T_INT, OFF1(shm_segsz), RO}, /* 6 (int) */ + {"gid", T_INT, OFF2(gid), RO}, /* 7 (gid_t) */ + {"uid", T_INT, OFF2(uid), RO}, /* 8 (uid_t) */ + /* The following members are implemented without this table */ + {"addr", T_INT, 0, RO}, /* 9 (void *) */ + {"attached",T_INT, 0, RO}, /* 10 (int) */ + {"nattch", T_INT, 0, RO}, /* 11 sys.dep. */ + {"perm", T_INT, 0, RO}, /* 12 (mode_t) */ + {NULL} /* sentinel */ +}; + +#undef OFF +#undef OFF1 +#undef OFF2 + +static void +PyShmMemory_dealloc(PyShmObj *self) +{ + /* del shm_dict[key], ignore if it fails */ + if (PyDict_DelItem(shm_dict, PyInt_FromLong(self->shmid)) == -1) + PyErr_Clear(); + /* all references in the current process to the shared + memory segment are lost, so if attached, detach it. + XXX: This is not true when Python is embedded. + + if (self->addr != NULL) { + shmdt(self->addr); + } + */ + /* v1.1 - changed the reference below from PyMem_DEL to PyObject_Del. */ + PyObject_Del(self); +} + +static PyObject * +PyShmMemory_getattr(PyShmObj *self, char *name) +{ + PyObject *res; + + res = Py_FindMethod(memory_methods, (PyObject *)self, name); + if (res != NULL) + return res; + PyErr_Clear(); + refresh_memory_status(self); + if (strcmp(name, "attached") == 0) + return PyInt_FromLong((self->addr == NULL) ? 0 : 1); + if (strcmp(name, "addr") == 0) { + if (self->addr != NULL) + return PyInt_FromLong((unsigned long)self->addr); + else { + Py_INCREF(Py_None); + return Py_None; + } + } + if (strcmp(name, "nattch") == 0) + return PyInt_FromLong(self->ds.shm_nattch); + if (strcmp(name, "perm") == 0) + return PyInt_FromLong(self->ds.shm_perm.mode & 0777); + return PyMember_Get((char *)self, memory_memberlist, name); +} + +static PyObject * +PyShmMemory_repr(PyShmObj *self, char *name) +{ + char buf[100]; + char buf2[20]; + + refresh_memory_status(self); + if (self->addr == NULL) + sprintf(buf2, "None"); + else + /* v 1.1 - changed format from %lx to %p. */ + sprintf(buf2, "0x%p", self->addr); + sprintf(buf, "<%s shared memory object, id=%d, size=%u, addr=%s>", + (self->addr == NULL) ? "detached" : (self->mode & SHM_RDONLY) ? + "attached RO" : "attached R/W", + self->shmid, + self->ds.shm_segsz, + buf2); + return PyString_FromString(buf); +} + +/* Type object for shared memory objects */ + +static PyTypeObject PyShmMemory_Type = { + PyObject_HEAD_INIT(&PyType_Type) + 0, /*ob_size*/ + "shared memory", /*tp_name*/ + sizeof(PyShmObj), /*tp_size*/ + 0, /*tp_itemsize*/ + /* methods */ + (destructor)PyShmMemory_dealloc, /*tp_dealloc*/ + 0, /*tp_print*/ + (getattrfunc)PyShmMemory_getattr, /*tp_getattr*/ + 0, /*tp_setattr*/ + 0, /*tp_compare*/ + (reprfunc)PyShmMemory_repr, /*tp_repr*/ + 0, /*tp_as_number*/ + 0, /*tp_as_sequence*/ + 0, /*tp_as_mapping*/ +}; + +/************************************************************/ +/* Semaphore Objects */ +/************************************************************/ + +/* This is to check the validity of a Python semaphore object */ + +static int +check_semaphore_identity(PyShmSemObj *o) +{ + int new_semid; + int old_semid = o->semid; + unsigned short old_nsems = o->ds.sem_nsems; + key_t old_key = o->ds.sem_perm.key; + semctl_arg arg; + + if (old_key != IPC_PRIVATE) { + new_semid = semget(old_key, 0, 0); + if (new_semid != old_semid) + return 0; + } + else + new_semid = old_semid; + arg.buf = &(o->ds); + if ((semctl(new_semid, 0, IPC_STAT, arg) != -1) && + (old_nsems == o->ds.sem_nsems) && + (old_key == o->ds.sem_perm.key)) + return 1; + return 0; +} + +/* Convenience macro for updating the semaphore data status structure */ + +#define refresh_semaphore_status(o) \ + if (!check_semaphore_identity(o)) { \ + PyErr_SetString(PyShm_Error, \ + "can't access semaphore"); \ + return NULL; \ + } + +/* +-- P() +*/ + +static PyObject * +PyShmSemaphore_P(PyShmSemObj *self, PyObject *args) +{ + struct sembuf op[1]; + int res; + + op[0].sem_num = 0; + op[0].sem_op = -1; + op[0].sem_flg = self->opflag; + + if (!PyArg_NoArgs(args)) + return NULL; + refresh_semaphore_status(self); + res = semop(self->semid, op, (size_t)1); + if (res == -1) + return PyShm_Err(); + Py_INCREF(Py_None); + return Py_None; +} + +/* +-- V() +*/ + +static PyObject * +PyShmSemaphore_V(PyShmSemObj *self, PyObject *args) +{ + struct sembuf op[1]; + int res; + + op[0].sem_num = 0; + op[0].sem_op = 1; + op[0].sem_flg = self->opflag; + + if (!PyArg_NoArgs(args)) + return NULL; + refresh_semaphore_status(self); + res = semop(self->semid, op, (size_t)1); + if (res == -1) + return PyShm_Err(); + Py_INCREF(Py_None); + return Py_None; +} + +/* +-- Z() +*/ + +static PyObject * +PyShmSemaphore_Z(PyShmSemObj *self, PyObject *args) +{ + struct sembuf op[1]; + int res; + + op[0].sem_num = 0; + op[0].sem_op = 0; + op[0].sem_flg = self->opflag; + + if (!PyArg_NoArgs(args)) + return NULL; + refresh_semaphore_status(self); + res = semop(self->semid, op, (size_t)1); + if (res == -1) + return PyShm_Err(); + Py_INCREF(Py_None); + return Py_None; +} + +/* +-- setblocking(0|1) +*/ + +static PyObject * +PyShmSemaphore_setblocking(PyShmSemObj *self, PyObject *args) +{ + int block; + + if (!PyArg_ParseTuple(args, "i", &block)) + return NULL; + refresh_semaphore_status(self); + if (block) + self->opflag &= ~IPC_NOWAIT; + else + self->opflag |= IPC_NOWAIT; + Py_INCREF(Py_None); + return Py_None; +} + +/* +-- setgid(int Gid) +*/ + +static PyObject * +PyShmSemaphore_setgid(PyShmSemObj *self, PyObject *args) +{ + long newgid, oldgid; + semctl_arg arg; + + if (!PyArg_ParseTuple(args, "l", &newgid)) + return NULL; + refresh_semaphore_status(self); + oldgid = (long)self->ds.sem_perm.gid; + self->ds.sem_perm.gid = (gid_t)newgid; + arg.buf = &(self->ds); + if (semctl(self->semid, 0, IPC_SET, arg) == -1) { + self->ds.sem_perm.gid = (gid_t)oldgid; + return PyShm_Err(); + } + Py_INCREF(Py_None); + return Py_None; +} + +/* +-- setperm(int Perm) +*/ + +static PyObject * +PyShmSemaphore_setperm(PyShmSemObj *self, PyObject *args) +{ + long newmode, oldmode; + semctl_arg arg; + + if (!PyArg_ParseTuple(args, "l", &newmode)) + return NULL; + refresh_semaphore_status(self); + newmode &= 0777; /* permission bits only */ + oldmode = (mode_t)self->ds.sem_perm.mode; + self->ds.sem_perm.mode ^= 0777; + self->ds.sem_perm.mode |= (mode_t)newmode; + arg.buf = &(self->ds); + if (semctl(self->semid, 0, IPC_SET, arg) == -1) { + self->ds.sem_perm.mode = (mode_t)oldmode; + return PyShm_Err(); + } + Py_INCREF(Py_None); + return Py_None; +} + +/* +-- setuid(int Uid) +*/ + +static PyObject * +PyShmSemaphore_setuid(PyShmSemObj *self, PyObject *args) +{ + long newuid, olduid; + semctl_arg arg; + + if (!PyArg_ParseTuple(args, "l", &newuid)) + return NULL; + refresh_semaphore_status(self); + olduid = (long)self->ds.sem_perm.uid; + /* v1.1 - fixed typo that set the group id rather than the user id */ + self->ds.sem_perm.uid = (uid_t)newuid; + arg.buf = &(self->ds); + if (semctl(self->semid, 0, IPC_SET, arg) == -1) { + self->ds.sem_perm.uid = (uid_t)olduid; + return PyShm_Err(); + } + Py_INCREF(Py_None); + return Py_None; +} + +/* +-- setundo(0|1) +*/ + +static PyObject * +PyShmSemaphore_setundo(PyShmSemObj *self, PyObject *args) +{ + int undo; + + if (!PyArg_ParseTuple(args, "i", &undo)) + return NULL; + refresh_semaphore_status(self); + if (undo) + self->opflag |= SEM_UNDO; + else + self->opflag &= ~SEM_UNDO; + Py_INCREF(Py_None); + return Py_None; +} + +/* +-- setval(int Value) +*/ + +static PyObject * +PyShmSemaphore_setval(PyShmSemObj *self, PyObject *args) +{ + int value; + semctl_arg arg; + + if (!PyArg_ParseTuple(args, "i", &value)) + return NULL; + refresh_semaphore_status(self); + arg.val = value; + if (semctl(self->semid, 0, SETVAL, arg) == -1) + return PyShm_Err(); + Py_INCREF(Py_None); + return Py_None; +} + +/* List of methods for semaphore objects */ + +static PyMethodDef semaphore_methods[] = { + {"P", (PyCFunction)PyShmSemaphore_P, 0, + "P() --> None | except shm.error"}, + {"V", (PyCFunction)PyShmSemaphore_V, 0, + "V() --> None | except shm.error"}, + {"Z", (PyCFunction)PyShmSemaphore_Z, 0, + "Z() --> None | except shm.error"}, + {"setblocking", (PyCFunction)PyShmSemaphore_setblocking, 1, + "setblocking(0|1) --> None"}, + {"setgid", (PyCFunction)PyShmSemaphore_setgid, 1, + "setgid(int Gid) --> None | except shm.error"}, + {"setperm", (PyCFunction)PyShmSemaphore_setperm, 1, + "setperm(int Perm) --> None | except shm.error"}, + {"setuid", (PyCFunction)PyShmSemaphore_setuid, 1, + "setuid(int Uid) --> None | except shm.error"}, + {"setundo", (PyCFunction)PyShmSemaphore_setundo, 1, + "setundo(0|1) --> None"}, + {"setval", (PyCFunction)PyShmSemaphore_setval, 1, + "setval(int Value) --> None | except shm.error"}, + {NULL, NULL} /* sentinel */ +}; + +#define OFF(x) offsetof(PyShmSemaphoreObject, x) +#define OFF1(x) OFF(ds) + offsetof(struct semid_ds, x) +#define OFF2(x) OFF1(sem_perm) + offsetof(struct ipc_perm, x) + +/* List of members for semaphore objects */ + +/* Note: member types are set in the initshm function. + Members which need separate processing are: + - val, lpid, ncnt, zcnt --> in kernel memory, not accessible from a process + - perm --> return permission (lower 9) bits only of ds.sem_perm.mode + - blocking --> in opflags +*/ + +static struct memberlist semaphore_memberlist[] = { + {"cgid", T_INT, OFF2(cgid), RO}, /* 0 (gid_t) */ + {"cuid", T_INT, OFF2(cuid), RO}, /* 1 (uid_t) */ + {"key", T_INT, OFF2(key), RO}, /* 2 (key_t) */ + {"semid", T_INT, OFF(semid), RO}, /* 3 (int) */ + {"gid", T_INT, OFF2(gid), RO}, /* 4 (gid_t) */ + {"uid", T_INT, OFF2(uid), RO}, /* 5 (uid_t) */ + /* The following members are implemented without this table */ + {"lpid", T_INT, 0, RO}, /* 6 (ushort) */ + {"ncnt", T_INT, 0, RO}, /* 7 (ushort) */ + {"perm", T_INT, 0, RO}, /* 8 (mode_t) */ + {"val", T_INT, 0, RO}, /* 9 (ushort) */ + {"zcnt", T_INT, 0, RO}, /* 10 (ushort) */ + {"blocking",T_INT, 0, RO}, /* 11 (ushort) */ + {NULL} /* sentinel */ +}; + +#undef OFF +#undef OFF1 +#undef OFF2 + +static void +PyShmSemaphore_dealloc(PyShmSemObj *self) +{ + /* del sem_dict[key], ignore if it fails */ + if (PyDict_DelItem(sem_dict, PyInt_FromLong(self->semid)) == -1) + PyErr_Clear(); + /* v1.1 - changed the reference below from PyMem_DEL to PyObject_Del. */ + PyObject_Del(self); +} + +static PyObject * +PyShmSemaphore_getattr(PyShmSemObj *self, char *name) +{ + PyObject *res; + + res = Py_FindMethod(semaphore_methods, (PyObject *)self, name); + if (res != NULL) + return res; + PyErr_Clear(); + refresh_semaphore_status(self); + if (strcmp(name, "val") == 0) + return PyInt_FromLong(semctl(self->semid, 0, GETVAL, 0)); + if (strcmp(name, "lpid") == 0) + return PyInt_FromLong(semctl(self->semid, 0, GETPID, 0)); + if (strcmp(name, "ncnt") == 0) + return PyInt_FromLong(semctl(self->semid, 0, GETNCNT, 0)); + if (strcmp(name, "zcnt") == 0) + return PyInt_FromLong(semctl(self->semid, 0, GETZCNT, 0)); + if (strcmp(name, "perm") == 0) + return PyInt_FromLong(self->ds.sem_perm.mode & 0777); + /* v1.1 - added blocking */ + if (strcmp(name, "blocking") == 0) + return PyInt_FromLong(self->opflag & IPC_NOWAIT ? 0 : 1); + return PyMember_Get((char *)self, semaphore_memberlist, name); +} + +static PyObject * +PyShmSemaphore_repr(PyShmSemObj *self, char *name) +{ + /* v1.1 - added blocking */ + char buf[200]; + + refresh_semaphore_status(self); + sprintf(buf, "<semaphore object, id=%d, val=%d, ncnt=%d, zcnt=%d, blocking=%d>", + self->semid, + semctl(self->semid, 0, GETVAL, 0), + semctl(self->semid, 0, GETNCNT, 0), + semctl(self->semid, 0, GETZCNT, 0), + self->opflag & IPC_NOWAIT ? 0 : 1); + return PyString_FromString(buf); +} + +/* Type object for semaphore objects */ + +static PyTypeObject PyShmSemaphore_Type = { + PyObject_HEAD_INIT(&PyType_Type) + 0, /*ob_size*/ + "semaphore", /*tp_name*/ + sizeof(PyShmSemObj), /*tp_size*/ + 0, /*tp_itemsize*/ + /* methods */ + (destructor)PyShmSemaphore_dealloc, /*tp_dealloc*/ + 0, /*tp_print*/ + (getattrfunc)PyShmSemaphore_getattr,/*tp_getattr*/ + 0, /*tp_setattr*/ + 0, /*tp_compare*/ + (reprfunc)PyShmSemaphore_repr, /*tp_repr*/ + 0, /*tp_as_number*/ + 0, /*tp_as_sequence*/ + 0, /*tp_as_mapping*/ +}; + +/************************************************************/ +/* Module Interface */ +/************************************************************/ + +/* +-- ftok(string Path, int ProjId) -> int +*/ + +/* Compute a key by using the system's ftok algorithm */ + +static PyObject * +PyShm_ftok(PyObject *self, PyObject *args) +{ + char *path; + char id; + key_t key; + + if (!PyArg_ParseTuple(args, "sb", &path, &id)) + return NULL; + key = ftok(path, id); + return PyInt_FromLong((long)key); +} + +/* +-- getshmid(int Key) --> int | except KeyError +*/ + +/* Return a shared memory segment id from a given key */ + +static PyObject * +PyShm_getshmid(PyObject *self, PyObject *args) +{ + long key; + int shmid; + + if (!PyArg_ParseTuple(args, "l", &key)) + return NULL; + shmid = shmget((key_t)key, 0, 0); + if (shmid == -1) { + PyErr_SetObject(PyExc_KeyError, PyInt_FromLong(key)); + return NULL; + } + return PyInt_FromLong(shmid); +} + +/* +-- memory_haskey(int Key) --> int +*/ + +/* Check whether there is a shared memory segment with the given key */ + +static PyObject * +PyShm_memory_haskey(PyObject *self, PyObject *args) +{ + long key; + int shmid; + + if (!PyArg_ParseTuple(args, "l", &key)) + return NULL; + shmid = shmget((key_t)key, 0, 0); + return PyInt_FromLong((shmid == -1) ? 0 : 1); +} + +/* +-- memory(int Shmid) --> object | except shm.error +*/ + +/* Get an existing shared memory segment and return it as a python object. */ + +static PyObject * +PyShm_memory(PyObject *self, PyObject *args) +{ + int shmid; + PyShmObj *o; + PyObject *keyo; + + if (!PyArg_ParseTuple(args, "i", &shmid)) + return NULL; + keyo = PyInt_FromLong(shmid); + /* get the object from the dictionary */ + if (PyMapping_HasKey(shm_dict, keyo)) { + o = (PyShmObj *)PyDict_GetItem(shm_dict, keyo); + Py_INCREF(o); + } + else { + /* not found, create it */ + if ((o = PyObject_NEW(PyShmObj, &PyShmMemory_Type)) == NULL) + return NULL; + o->shmid = shmid; + o->addr = NULL; + o->mode = 0; + /* shm_dict[shmid] = o */ + if (PyDict_SetItem(shm_dict, keyo, (PyObject *)o) == -1) { + Py_DECREF(o); + PyErr_SetString(PyShm_Error, "can't initialize shared memory object"); + return NULL; + } + Py_DECREF(o); /* the owned reference in shm_dict doesn't count! */ + } + /* v1.1 - plugged memory leak */ + Py_DECREF(keyo); + /* set up the status data */ + if (shmctl(o->shmid, IPC_STAT, &(o->ds)) == -1) { + Py_DECREF(o); + PyErr_SetString(PyShm_Error, "can't access shared memory segment"); + return NULL; + } + return (PyObject *)o; +} + +/* +-- create_memory(int Key, int Size [,int Perm=0666]) --> object +*/ + +/* Create a new shared memory segment. */ + +static PyObject * +PyShm_create_memory(PyObject *self, PyObject *args) +{ + long key; + int size, shmid; + int perm = 0666; /* Default permission is -rw-rw-rw- */ + PyObject *py_shmid; + PyObject *memory; + + if (!PyArg_ParseTuple(args, "li|i", &key, &size, &perm)) + return NULL; + shmid = shmget((key_t)key, size, perm | IPC_CREAT | IPC_EXCL); + if (shmid == -1) + return PyShm_Err(); + /* v1.1 - fixed memory leak resulting from inlining Py_BuildValue */ + py_shmid = Py_BuildValue("(i)", shmid); + memory = PyShm_memory(self, py_shmid); + Py_DECREF(py_shmid); + + return memory; +} + +/* +-- remove_memory(int Shmid) --> None | except shm.error +*/ + +/* Remove an existing shared memory segment. */ + +static PyObject * +PyShm_remove_memory(PyObject *self, PyObject *args) +{ + int shmid, res; + + if (!PyArg_ParseTuple(args, "i", &shmid)) + return NULL; + res = shmctl(shmid, IPC_RMID, 0); /* remove it */ + if (res == -1) + return PyShm_Err(); + Py_INCREF(Py_None); + return Py_None; +} + +/* +-- getsemid(int Key) --> int | except KeyError +*/ + +/* Return a semaphore id from a given key */ + +static PyObject * +PyShm_getsemid(PyObject *self, PyObject *args) +{ + long key; + int semid; + + if (!PyArg_ParseTuple(args, "l", &key)) + return NULL; + semid = semget((key_t)key, 0, 0); + if (semid == -1) { + PyErr_SetObject(PyExc_KeyError, PyInt_FromLong(key)); + return NULL; + } + return PyInt_FromLong(semid); +} + +/* +-- semaphore_haskey(int Key) --> int +*/ + +/* Check whether there is a semaphore with the given key */ + +static PyObject * +PyShm_semaphore_haskey(PyObject *self, PyObject *args) +{ + long key; + int semid; + |