diff options
Diffstat (limited to 'do/shmio')
| -rw-r--r-- | do/shmio | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/do/shmio b/do/shmio new file mode 100644 index 0000000000..b7107684ac --- /dev/null +++ b/do/shmio @@ -0,0 +1,55 @@ +int +do_shmio(optype, arglast) +int optype; +int *arglast; +{ +#ifdef HAS_SHM + register STR **st = stack->ary_array; + register int sp = arglast[0]; + STR *mstr; + char *mbuf, *shm; + int id, mpos, msize; + struct shmid_ds shmds; +#ifndef VOIDSHMAT + extern char *shmat(); +#endif + + id = (int)str_gnum(st[++sp]); + mstr = st[++sp]; + mpos = (int)str_gnum(st[++sp]); + msize = (int)str_gnum(st[++sp]); + errno = 0; + if (shmctl(id, IPC_STAT, &shmds) == -1) + return -1; + if (mpos < 0 || msize < 0 || mpos + msize > shmds.shm_segsz) { + errno = EFAULT; /* can't do as caller requested */ + return -1; + } + shm = (char*)shmat(id, (char*)NULL, (optype == O_SHMREAD) ? SHM_RDONLY : 0); + if (shm == (char *)-1) /* I hate System V IPC, I really do */ + return -1; + mbuf = str_get(mstr); + if (optype == O_SHMREAD) { + if (mstr->str_cur < msize) { + STR_GROW(mstr, msize+1); + mbuf = str_get(mstr); + } + Copy(shm + mpos, mbuf, msize, char); + mstr->str_cur = msize; + mstr->str_ptr[msize] = '\0'; + } + else { + int n; + + if ((n = mstr->str_cur) > msize) + n = msize; + Copy(mbuf, shm + mpos, n, char); + if (n < msize) + memzero(shm + mpos + n, msize - n); + } + return shmdt(shm); +#else + fatal("shm I/O not implemented"); +#endif +} + |