| /* |
| * Copyright (C) 2011-2013 Red Hat, Inc. |
| * |
| * This file is part of LVM2. |
| * |
| * This copyrighted material is made available to anyone wishing to use, |
| * modify, copy, or redistribute it subject to the terms and conditions |
| * of the GNU Lesser General Public License v.2.1. |
| * |
| * You should have received a copy of the GNU Lesser General Public License |
| * along with this program; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| #define _REENTRANT |
| |
| #include "tool.h" |
| |
| #include "daemon-io.h" |
| |
| #include <errno.h> |
| |
| /* |
| * Read a single message from a (socket) filedescriptor. Messages are delimited |
| * by blank lines. This call will block until all of a message is received. The |
| * memory will be allocated from heap. Upon error, all memory is freed and the |
| * buffer pointer is set to NULL. |
| * |
| * See also write_buffer about blocking (read_buffer has identical behaviour). |
| */ |
| int buffer_read(int fd, struct buffer *buffer) { |
| int result; |
| |
| if (!buffer_realloc(buffer, 32)) /* ensure we have some space */ |
| return 0; |
| |
| while (1) { |
| result = read(fd, buffer->mem + buffer->used, buffer->allocated - buffer->used); |
| if (result > 0) { |
| buffer->used += result; |
| if (buffer->used >= 4 && !strncmp((buffer->mem) + buffer->used - 4, "\n##\n", 4)) { |
| buffer->used -= 4; |
| buffer->mem[buffer->used] = 0; |
| break; /* success, we have the full message now */ |
| } |
| if ((buffer->allocated - buffer->used < 32) && |
| !buffer_realloc(buffer, 1024)) |
| return 0; |
| } else if (result == 0) { |
| errno = ECONNRESET; |
| return 0; /* we should never encounter EOF here */ |
| } else if (result < 0 && (errno == EAGAIN || |
| (EWOULDBLOCK != EAGAIN && errno == EWOULDBLOCK) || |
| errno == EINTR || errno == EIO)) { |
| fd_set in; |
| FD_ZERO(&in); |
| FD_SET(fd, &in); |
| /* ignore the result, this is just a glorified sleep */ |
| select(FD_SETSIZE, &in, NULL, NULL, NULL); |
| } else if (result < 0) |
| return 0; |
| } |
| |
| return 1; |
| } |
| |
| /* |
| * Write a buffer to a filedescriptor. Keep trying. Blocks (even on |
| * SOCK_NONBLOCK) until all of the write went through. |
| */ |
| int buffer_write(int fd, const struct buffer *buffer) { |
| static const struct buffer _terminate = { .mem = (char *) "\n##\n", .used = 4 }; |
| const struct buffer *use; |
| int done, written, result; |
| |
| for (done = 0; done < 2; ++done) { |
| use = (done == 0) ? buffer : &_terminate; |
| for (written = 0; written < use->used;) { |
| result = write(fd, use->mem + written, use->used - written); |
| if (result > 0) |
| written += result; |
| else if (result < 0 && (errno == EAGAIN || |
| (EWOULDBLOCK != EAGAIN && errno == EWOULDBLOCK) || |
| errno == EINTR || errno == EIO)) { |
| fd_set out; |
| FD_ZERO(&out); |
| FD_SET(fd, &out); |
| /* ignore the result, this is just a glorified sleep */ |
| select(FD_SETSIZE, NULL, &out, NULL, NULL); |
| } else if (result < 0) |
| return 0; /* too bad */ |
| } |
| } |
| |
| return 1; |
| } |