--- linux/fs/pipe.c 2018/04/24 18:08:38 1.1.1.7 +++ linux/fs/pipe.c 2018/04/24 18:12:09 1.1.1.9 @@ -1,18 +1,17 @@ /* * linux/fs/pipe.c * - * (C) 1991 Linus Torvalds + * Copyright (C) 1991, 1992 Linus Torvalds */ -#include -#include -#include -#include - #include #include #include +#include +#include +#include +#include static int pipe_read(struct inode * inode, struct file * filp, char * buf, int count) { @@ -21,7 +20,7 @@ static int pipe_read(struct inode * inod if (!(filp->f_flags & O_NONBLOCK)) while (!PIPE_SIZE(*inode)) { wake_up(& PIPE_WRITE_WAIT(*inode)); - if (inode->i_count != 2) /* are there any writers? */ + if (!PIPE_WRITERS(*inode)) /* are there any writers? */ return 0; if (current->signal & ~current->blocked) return -ERESTARTSYS; @@ -33,13 +32,12 @@ static int pipe_read(struct inode * inod chars = count; if (chars > size) chars = size; - count -= chars; + memcpy_tofs(buf, (char *)inode->i_size+PIPE_TAIL(*inode), chars ); read += chars; - size = PIPE_TAIL(*inode); PIPE_TAIL(*inode) += chars; PIPE_TAIL(*inode) &= (PAGE_SIZE-1); - while (chars-->0) - put_fs_byte(((char *)inode->i_size)[size++],buf++); + count -= chars; + buf += chars; } wake_up(& PIPE_WRITE_WAIT(*inode)); return read?read:-EAGAIN; @@ -49,35 +47,44 @@ static int pipe_write(struct inode * ino { int chars, size, written = 0; - if (inode->i_count != 2) { /* no readers */ + if (!PIPE_READERS(*inode)) { /* no readers */ send_sig(SIGPIPE,current,0); - return -EINTR; + 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 (!(size=(PAGE_SIZE-1)-PIPE_SIZE(*inode))) { - wake_up(& PIPE_READ_WAIT(*inode)); - if (inode->i_count != 2) { /* no readers */ + while (PIPE_SIZE(*inode) >= size) { + if (!PIPE_READERS(*inode)) { /* no readers */ send_sig(SIGPIPE,current,0); - return written?written:-EINTR; + return written?written:-EPIPE; } if (current->signal & ~current->blocked) - return written?written:-EINTR; - interruptible_sleep_on(&PIPE_WRITE_WAIT(*inode)); + return written?written:-ERESTARTSYS; + if (filp->f_flags & O_NONBLOCK) + return -EAGAIN; + else + interruptible_sleep_on(&PIPE_WRITE_WAIT(*inode)); } - chars = PAGE_SIZE-PIPE_HEAD(*inode); - if (chars > count) - chars = count; - if (chars > size) - chars = size; - count -= chars; - written += chars; - size = PIPE_HEAD(*inode); - PIPE_HEAD(*inode) += chars; - PIPE_HEAD(*inode) &= (PAGE_SIZE-1); - while (chars-->0) - ((char *)inode->i_size)[size++]=get_fs_byte(buf++); + 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((char *)inode->i_size+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; } - wake_up(& PIPE_READ_WAIT(*inode)); return written; } @@ -109,40 +116,89 @@ static int pipe_ioctl(struct inode *pino } } +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_WRITERS(*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 two routines should keep track of readers/writers, - * but it's currently done with the inode->i_count checking. + * 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)); } -static struct file_operations read_pipe_fops = { +/* + * The three 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 read_pipe_fops = { pipe_lseek, pipe_read, bad_pipe_rw, pipe_readdir, - NULL, /* pipe_select */ + pipe_select, pipe_ioctl, NULL, /* no special open code */ pipe_read_release }; -static struct file_operations write_pipe_fops = { +struct file_operations write_pipe_fops = { pipe_lseek, bad_pipe_rw, pipe_write, pipe_readdir, - NULL, /* pipe_select */ + pipe_select, pipe_ioctl, NULL, /* no special open code */ pipe_write_release }; +struct file_operations rdwr_pipe_fops = { + pipe_lseek, + pipe_read, + pipe_write, + pipe_readdir, + pipe_select, + pipe_ioctl, + NULL, /* no special open code */ + pipe_rdwr_release +}; + int sys_pipe(unsigned long * fildes) { struct inode * inode; @@ -151,14 +207,13 @@ int sys_pipe(unsigned long * fildes) int i,j; verify_area(fildes,8); - j=0; - for(i=0;j<2 && if_count++; + for(j=0 ; j<2 ; j++) + if (!(f[j] = get_empty_filp())) + break; if (j==1) - f[0]->f_count=0; + f[0]->f_count--; if (j<2) - return -1; + return -ENFILE; j=0; for(i=0;j<2 && ifilp[i]) { @@ -168,14 +223,16 @@ int sys_pipe(unsigned long * fildes) if (j==1) current->filp[fd[0]]=NULL; if (j<2) { - f[0]->f_count=f[1]->f_count=0; - return -1; + f[0]->f_count--; + f[1]->f_count--; + return -EMFILE; } if (!(inode=get_pipe_inode())) { - current->filp[fd[0]] = - current->filp[fd[1]] = NULL; - f[0]->f_count = f[1]->f_count = 0; - return -1; + 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;