+/*
+ * rwbuffer.c
+ * common definitions for readbuffer/writebuffer
+ *
+ * readbuffer and writebuffer are:
+ * Copyright (C) 1997-1998,2000-2001 Ian Jackson <ian@chiark.greenend.org.uk>
+ *
+ * readbuffer is part of chiark backup, a system for backing up GNU/Linux and
+ * other UN*X-compatible machines, as used on chiark.greenend.org.uk.
+ * chiark backup is:
+ * Copyright (C) 1997-1998,2000-2001 Ian Jackson <ian@chiark.greenend.org.uk>
+ * Copyright (C) 1999 Peter Maydell <pmaydell@chiark.greenend.org.uk>
+ *
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2,
+ * or (at your option) any later version.
+ *
+ * This is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this file; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+#include <sys/time.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <assert.h>
+#include <ctype.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <sys/mman.h>
+
+#include "rwbuffer.h"
+
+#ifndef RWBUFFER_SIZE_MB_DEF
+#define RWBUFFER_SIZE_MB_DEF 16
+#endif
+
+#ifndef RWBUFFER_SIZE_MB_MAX
+#define RWBUFFER_SIZE_MB_MAX 512
+#endif
+
+unsigned char *buf, *wp, *rp;
+int used, seeneof;
+size_t buffersize;
+fd_set readfds;
+fd_set writefds;
+
+int min(int a, int b) { return a<=b ? a : b; }
+
+static void usage(FILE *f) {
+ if (fprintf(f,"usage: %s [--mlock] [<megabytes>]\n",progname) < 0)
+ { perror("print usage"); exit(16); }
+}
+
+static void usageerr(const char *what) {
+ fprintf(stderr,"%s: bad usage: %s\n",progname,what);
+ usage(stderr);
+ exit(12);
+}
+
+static void nonblock(int fd, int yesno) {
+ int r;
+ r= fcntl(fd,F_GETFL,0); if (r == -1) { perror("fcntl getfl"); exit(8); }
+ if (yesno) r |= O_NDELAY;
+ else r &= ~O_NDELAY;
+ if (fcntl(fd,F_SETFL,r) == -1) { perror("fcntl setfl"); exit(8); }
+}
+
+static void unnonblock(void) {
+ nonblock(0,0); nonblock(1,0);
+}
+
+void startup(const char *const *argv) {
+ const char *arg;
+ char *ep;
+ unsigned long opt_buffersize=RWBUFFER_SIZE_MB_DEF;
+ int opt_mlock=0;
+
+ assert(argv[0]);
+
+ while ((arg= *++argv)) {
+ if (!strcmp(arg,"--mlock")) {
+ opt_mlock= 1;
+ } else if (isdigit((unsigned char)arg[0])) {
+ opt_buffersize= strtoul(arg,&ep,0);
+ if (opt_buffersize > RWBUFFER_SIZE_MB_MAX)
+ usageerr("buffer size too big");
+ } else {
+ usageerr("invalid option");
+ }
+ }
+
+ buffersize= opt_buffersize*1024*1024;
+ buf= malloc(buffersize);
+ if (!buf) { perror("malloc buffer"); exit(6); }
+
+ if (opt_mlock) {
+ if (mlock(buf,buffersize)) { perror("mlock"); exit(2); }
+ }
+
+ used=0; wp=rp=buf; seeneof=0;
+ if (atexit(unnonblock)) { perror("atexit"); exit(16); }
+ nonblock(0,1); nonblock(1,1);
+}
+
+void callselect(void) {
+ int r;
+
+ for (;;) {
+ r= select(2,&readfds,&writefds,0,0);
+ if (r != -1) return;
+ if (errno != EINTR) {
+ perror("select"); exit(4);
+ }
+ }
+}