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1.1.1.2 root 1: /*
2: * linux/fs/pipe.c
3: *
4: * (C) 1991 Linus Torvalds
5: */
6:
1.1 root 7: #include <signal.h>
1.1.1.3 root 8: #include <errno.h>
9: #include <termios.h>
1.1.1.4 root 10: #include <fcntl.h>
1.1 root 11:
12: #include <linux/sched.h>
13: #include <asm/segment.h>
1.1.1.3 root 14: #include <linux/kernel.h>
1.1 root 15:
1.1.1.4 root 16: int pipe_read(struct inode * inode, struct file * filp, char * buf, int count)
1.1 root 17: {
1.1.1.2 root 18: int chars, size, read = 0;
1.1 root 19:
1.1.1.4 root 20: if (!(filp->f_flags & O_NONBLOCK))
21: while (!PIPE_SIZE(*inode)) {
1.1.1.3 root 22: wake_up(& PIPE_WRITE_WAIT(*inode));
1.1.1.2 root 23: if (inode->i_count != 2) /* are there any writers? */
1.1.1.4 root 24: return 0;
1.1.1.3 root 25: if (current->signal & ~current->blocked)
1.1.1.4 root 26: return -ERESTARTSYS;
1.1.1.3 root 27: interruptible_sleep_on(& PIPE_READ_WAIT(*inode));
1.1.1.2 root 28: }
1.1.1.4 root 29: while (count>0 && (size = PIPE_SIZE(*inode))) {
1.1.1.2 root 30: chars = PAGE_SIZE-PIPE_TAIL(*inode);
31: if (chars > count)
32: chars = count;
33: if (chars > size)
34: chars = size;
35: count -= chars;
36: read += chars;
37: size = PIPE_TAIL(*inode);
38: PIPE_TAIL(*inode) += chars;
39: PIPE_TAIL(*inode) &= (PAGE_SIZE-1);
40: while (chars-->0)
41: put_fs_byte(((char *)inode->i_size)[size++],buf++);
1.1 root 42: }
1.1.1.3 root 43: wake_up(& PIPE_WRITE_WAIT(*inode));
1.1.1.5 ! root 44: return read?read:-EAGAIN;
1.1 root 45: }
46:
1.1.1.4 root 47: int pipe_write(struct inode * inode, struct file * filp, char * buf, int count)
1.1 root 48: {
1.1.1.2 root 49: int chars, size, written = 0;
1.1 root 50:
1.1.1.2 root 51: while (count>0) {
52: while (!(size=(PAGE_SIZE-1)-PIPE_SIZE(*inode))) {
1.1.1.3 root 53: wake_up(& PIPE_READ_WAIT(*inode));
1.1.1.2 root 54: if (inode->i_count != 2) { /* no readers */
1.1 root 55: current->signal |= (1<<(SIGPIPE-1));
1.1.1.4 root 56: return written?written:-EINTR;
1.1 root 57: }
1.1.1.4 root 58: if (current->signal & ~current->blocked)
59: return written?written:-EINTR;
60: interruptible_sleep_on(&PIPE_WRITE_WAIT(*inode));
1.1 root 61: }
1.1.1.2 root 62: chars = PAGE_SIZE-PIPE_HEAD(*inode);
63: if (chars > count)
64: chars = count;
65: if (chars > size)
66: chars = size;
67: count -= chars;
68: written += chars;
69: size = PIPE_HEAD(*inode);
70: PIPE_HEAD(*inode) += chars;
71: PIPE_HEAD(*inode) &= (PAGE_SIZE-1);
72: while (chars-->0)
73: ((char *)inode->i_size)[size++]=get_fs_byte(buf++);
1.1 root 74: }
1.1.1.3 root 75: wake_up(& PIPE_READ_WAIT(*inode));
1.1.1.2 root 76: return written;
1.1 root 77: }
78:
79: int sys_pipe(unsigned long * fildes)
80: {
1.1.1.4 root 81: struct inode * inode;
1.1 root 82: struct file * f[2];
83: int fd[2];
84: int i,j;
85:
86: j=0;
87: for(i=0;j<2 && i<NR_FILE;i++)
88: if (!file_table[i].f_count)
89: (f[j++]=i+file_table)->f_count++;
90: if (j==1)
91: f[0]->f_count=0;
92: if (j<2)
93: return -1;
94: j=0;
95: for(i=0;j<2 && i<NR_OPEN;i++)
96: if (!current->filp[i]) {
97: current->filp[ fd[j]=i ] = f[j];
98: j++;
99: }
100: if (j==1)
101: current->filp[fd[0]]=NULL;
102: if (j<2) {
103: f[0]->f_count=f[1]->f_count=0;
104: return -1;
105: }
106: if (!(inode=get_pipe_inode())) {
107: current->filp[fd[0]] =
108: current->filp[fd[1]] = NULL;
109: f[0]->f_count = f[1]->f_count = 0;
110: return -1;
111: }
112: f[0]->f_inode = f[1]->f_inode = inode;
113: f[0]->f_pos = f[1]->f_pos = 0;
114: f[0]->f_mode = 1; /* read */
115: f[1]->f_mode = 2; /* write */
116: put_fs_long(fd[0],0+fildes);
117: put_fs_long(fd[1],1+fildes);
118: return 0;
119: }
1.1.1.3 root 120:
1.1.1.4 root 121: int pipe_ioctl(struct inode *pino, int cmd, int arg)
1.1.1.3 root 122: {
123: switch (cmd) {
124: case FIONREAD:
125: verify_area((void *) arg,4);
126: put_fs_long(PIPE_SIZE(*pino),(unsigned long *) arg);
127: return 0;
128: default:
129: return -EINVAL;
130: }
131: }
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