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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 | /* * linux/fs/pipe.c * * Copyright (C) 1991, 1992 Linus Torvalds */ #include <asm/segment.h> #include <linux/sched.h> #include <linux/kernel.h> #include <linux/errno.h> #include <linux/signal.h> #include <linux/fcntl.h> #include <linux/termios.h> static int pipe_read(struct inode * inode, struct file * filp, char * buf, int count) { int chars, size, read = 0; if (!(filp->f_flags & O_NONBLOCK)) while (!PIPE_SIZE(*inode)) { wake_up(& PIPE_WRITE_WAIT(*inode)); if (!PIPE_WRITERS(*inode)) /* are there any writers? */ return 0; if (current->signal & ~current->blocked) return -ERESTARTSYS; interruptible_sleep_on(& PIPE_READ_WAIT(*inode)); } while (count>0 && (size = PIPE_SIZE(*inode))) { chars = PAGE_SIZE-PIPE_TAIL(*inode); if (chars > count) chars = count; if (chars > size) chars = size; memcpy_tofs(buf, PIPE_BASE(*inode)+PIPE_TAIL(*inode), chars ); read += chars; PIPE_TAIL(*inode) += chars; PIPE_TAIL(*inode) &= (PAGE_SIZE-1); count -= chars; buf += chars; } wake_up(& PIPE_WRITE_WAIT(*inode)); if (read) return read; if (PIPE_WRITERS(*inode)) return -EAGAIN; return 0; } static int pipe_write(struct inode * inode, struct file * filp, char * buf, int count) { int chars, size, written = 0; if (!PIPE_READERS(*inode)) { /* no readers */ send_sig(SIGPIPE,current,0); return -EPIPE; } /* if count < PAGE_SIZE, we have to make it atomic */ if (count < PAGE_SIZE) size = PAGE_SIZE-count; else size = PAGE_SIZE-1; while (count>0) { while (PIPE_SIZE(*inode) >= size) { if (!PIPE_READERS(*inode)) { /* no readers */ send_sig(SIGPIPE,current,0); return written?written:-EPIPE; } if (current->signal & ~current->blocked) return written?written:-ERESTARTSYS; if (filp->f_flags & O_NONBLOCK) return written?written:-EAGAIN; else interruptible_sleep_on(&PIPE_WRITE_WAIT(*inode)); } while (count>0 && (size = (PAGE_SIZE-1)-PIPE_SIZE(*inode))) { chars = PAGE_SIZE-PIPE_HEAD(*inode); if (chars > count) chars = count; if (chars > size) chars = size; memcpy_fromfs(PIPE_BASE(*inode)+PIPE_HEAD(*inode), buf, chars ); written += chars; PIPE_HEAD(*inode) += chars; PIPE_HEAD(*inode) &= (PAGE_SIZE-1); count -= chars; buf += chars; } wake_up(& PIPE_READ_WAIT(*inode)); size = PAGE_SIZE-1; } return written; } static int pipe_lseek(struct inode * inode, struct file * file, off_t offset, int orig) { return -ESPIPE; } static int pipe_readdir(struct inode * inode, struct file * file, struct dirent * de, int count) { return -ENOTDIR; } static int bad_pipe_rw(struct inode * inode, struct file * filp, char * buf, int count) { return -EBADF; } static int pipe_ioctl(struct inode *pino, struct file * filp, unsigned int cmd, unsigned long arg) { int error; switch (cmd) { case FIONREAD: error = verify_area(VERIFY_WRITE, (void *) arg,4); if (!error) put_fs_long(PIPE_SIZE(*pino),(unsigned long *) arg); return error; default: return -EINVAL; } } static int pipe_select(struct inode * inode, struct file * filp, int sel_type, select_table * wait) { switch (sel_type) { case SEL_IN: if (!PIPE_EMPTY(*inode) || !PIPE_WRITERS(*inode)) return 1; select_wait(&PIPE_READ_WAIT(*inode), wait); return 0; case SEL_OUT: if (!PIPE_FULL(*inode) || !PIPE_READERS(*inode)) return 1; select_wait(&PIPE_WRITE_WAIT(*inode), wait); return 0; case SEL_EX: if (!PIPE_READERS(*inode) || !PIPE_WRITERS(*inode)) return 1; select_wait(&inode->i_wait,wait); return 0; } return 0; } /* * Arggh. Why does SunOS have to have different select() behaviour * for pipes and fifos? Hate-Hate-Hate. See difference in SEL_IN.. */ static int fifo_select(struct inode * inode, struct file * filp, int sel_type, select_table * wait) { switch (sel_type) { case SEL_IN: if (!PIPE_EMPTY(*inode)) return 1; select_wait(&PIPE_READ_WAIT(*inode), wait); return 0; case SEL_OUT: if (!PIPE_FULL(*inode) || !PIPE_READERS(*inode)) return 1; select_wait(&PIPE_WRITE_WAIT(*inode), wait); return 0; case SEL_EX: if (!PIPE_READERS(*inode) || !PIPE_WRITERS(*inode)) return 1; select_wait(&inode->i_wait,wait); return 0; } return 0; } /* * The 'connect_xxx()' functions are needed for named pipes when * the open() code hasn't guaranteed a connection (O_NONBLOCK), * and we need to act differently until we do get a writer.. */ static int connect_read(struct inode * inode, struct file * filp, char * buf, int count) { while (!PIPE_SIZE(*inode)) { if (PIPE_WRITERS(*inode)) break; if (filp->f_flags & O_NONBLOCK) return -EAGAIN; wake_up(& PIPE_WRITE_WAIT(*inode)); if (current->signal & ~current->blocked) return -ERESTARTSYS; interruptible_sleep_on(& PIPE_READ_WAIT(*inode)); } filp->f_op = &read_fifo_fops; return pipe_read(inode,filp,buf,count); } static int connect_select(struct inode * inode, struct file * filp, int sel_type, select_table * wait) { switch (sel_type) { case SEL_IN: if (!PIPE_EMPTY(*inode)) { filp->f_op = &read_fifo_fops; return 1; } select_wait(&PIPE_READ_WAIT(*inode), wait); return 0; case SEL_OUT: if (!PIPE_FULL(*inode)) return 1; select_wait(&PIPE_WRITE_WAIT(*inode), wait); return 0; case SEL_EX: if (!PIPE_READERS(*inode) || !PIPE_WRITERS(*inode)) return 1; select_wait(&inode->i_wait,wait); return 0; } return 0; } /* * Ok, these three routines NOW keep track of readers/writers, * Linus previously did it with inode->i_count checking. */ static void pipe_read_release(struct inode * inode, struct file * filp) { PIPE_READERS(*inode)--; wake_up(&PIPE_WRITE_WAIT(*inode)); } static void pipe_write_release(struct inode * inode, struct file * filp) { PIPE_WRITERS(*inode)--; wake_up(&PIPE_READ_WAIT(*inode)); } static void pipe_rdwr_release(struct inode * inode, struct file * filp) { PIPE_READERS(*inode)--; PIPE_WRITERS(*inode)--; wake_up(&PIPE_READ_WAIT(*inode)); wake_up(&PIPE_WRITE_WAIT(*inode)); } /* * The file_operations structs are not static because they * are also used in linux/fs/fifo.c to do operations on fifo's. */ struct file_operations connecting_fifo_fops = { pipe_lseek, connect_read, bad_pipe_rw, pipe_readdir, connect_select, pipe_ioctl, NULL, /* no mmap on pipes.. surprise */ NULL, /* no special open code */ pipe_read_release, NULL }; struct file_operations read_fifo_fops = { pipe_lseek, pipe_read, bad_pipe_rw, pipe_readdir, fifo_select, pipe_ioctl, NULL, /* no mmap on pipes.. surprise */ NULL, /* no special open code */ pipe_read_release, NULL }; struct file_operations write_fifo_fops = { pipe_lseek, bad_pipe_rw, pipe_write, pipe_readdir, fifo_select, pipe_ioctl, NULL, /* mmap */ NULL, /* no special open code */ pipe_write_release, NULL }; struct file_operations rdwr_fifo_fops = { pipe_lseek, pipe_read, pipe_write, pipe_readdir, fifo_select, pipe_ioctl, NULL, /* mmap */ NULL, /* no special open code */ pipe_rdwr_release, NULL }; struct file_operations read_pipe_fops = { pipe_lseek, pipe_read, bad_pipe_rw, pipe_readdir, pipe_select, pipe_ioctl, NULL, /* no mmap on pipes.. surprise */ NULL, /* no special open code */ pipe_read_release, NULL }; struct file_operations write_pipe_fops = { pipe_lseek, bad_pipe_rw, pipe_write, pipe_readdir, pipe_select, pipe_ioctl, NULL, /* mmap */ NULL, /* no special open code */ pipe_write_release, NULL }; struct file_operations rdwr_pipe_fops = { pipe_lseek, pipe_read, pipe_write, pipe_readdir, pipe_select, pipe_ioctl, NULL, /* mmap */ NULL, /* no special open code */ pipe_rdwr_release, NULL }; struct inode_operations pipe_inode_operations = { &rdwr_pipe_fops, NULL, /* create */ NULL, /* lookup */ NULL, /* link */ NULL, /* unlink */ NULL, /* symlink */ NULL, /* mkdir */ NULL, /* rmdir */ NULL, /* mknod */ NULL, /* rename */ NULL, /* readlink */ NULL, /* follow_link */ NULL, /* bmap */ NULL, /* truncate */ NULL /* permission */ }; asmlinkage int sys_pipe(unsigned long * fildes) { struct inode * inode; struct file * f[2]; int fd[2]; int i,j; j = verify_area(VERIFY_WRITE,fildes,8); if (j) return j; for(j=0 ; j<2 ; j++) if (!(f[j] = get_empty_filp())) break; if (j==1) f[0]->f_count--; if (j<2) return -ENFILE; j=0; for(i=0;j<2 && i<NR_OPEN;i++) if (!current->filp[i]) { current->filp[ fd[j]=i ] = f[j]; j++; } if (j==1) current->filp[fd[0]]=NULL; if (j<2) { f[0]->f_count--; f[1]->f_count--; return -EMFILE; } if (!(inode=get_pipe_inode())) { current->filp[fd[0]] = NULL; current->filp[fd[1]] = NULL; f[0]->f_count--; f[1]->f_count--; return -ENFILE; } f[0]->f_inode = f[1]->f_inode = inode; f[0]->f_pos = f[1]->f_pos = 0; f[0]->f_flags = O_RDONLY; f[0]->f_op = &read_pipe_fops; f[0]->f_mode = 1; /* read */ f[1]->f_flags = O_WRONLY; f[1]->f_op = &write_pipe_fops; f[1]->f_mode = 2; /* write */ put_fs_long(fd[0],0+fildes); put_fs_long(fd[1],1+fildes); return 0; } |