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Diffstat (limited to 'support/nfs/mydaemon.c')
| -rw-r--r-- | support/nfs/mydaemon.c | 153 |
1 files changed, 153 insertions, 0 deletions
diff --git a/support/nfs/mydaemon.c b/support/nfs/mydaemon.c new file mode 100644 index 0000000..d1cf08d --- /dev/null +++ b/support/nfs/mydaemon.c @@ -0,0 +1,153 @@ +/* + mydaemon.c + + Copyright (c) 2000 The Regents of the University of Michigan. + All rights reserved. + + Copyright (c) 2000 Dug Song <dugsong@UMICH.EDU>. + Copyright (c) 2002 Andy Adamson <andros@UMICH.EDU>. + Copyright (c) 2002 Marius Aamodt Eriksen <marius@UMICH.EDU>. + Copyright (c) 2002 J. Bruce Fields <bfields@UMICH.EDU>. + Copyright (c) 2013 Jeff Layton <jlayton@redhat.com> + + All rights reserved, all wrongs reversed. + + Redistribution and use in source and binary forms, with or without + modification, are permitted provided that the following conditions + are met: + + 1. Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + 2. Redistributions in binary form must reproduce the above copyright + notice, this list of conditions and the following disclaimer in the + documentation and/or other materials provided with the distribution. + 3. Neither the name of the University nor the names of its + contributors may be used to endorse or promote products derived + from this software without specific prior written permission. + + THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED + WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF + MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE + DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR + BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF + LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING + NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +*/ + +#include <sys/param.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <errno.h> +#include <unistd.h> +#include <stdio.h> +#include <stdbool.h> +#include <stdlib.h> +#include <string.h> +#include <syslog.h> +#include <xlog.h> + +#include "nfslib.h" + +static int pipefds[2] = { -1, -1}; + +/** + * daemon_init - initial daemon setup + * @fg: whether to run in the foreground + * + * This function is like daemon(), but with our own special sauce to delay + * the exit of the parent until the child is set up properly. A pipe is created + * between parent and child. The parent process will wait to exit until the + * child dies or writes an int on the pipe signaling its status. + */ +void +daemon_init(bool fg) +{ + int pid, status, tempfd; + + if (fg) + return; + + if (pipe(pipefds) < 0) { + xlog_err("mydaemon: pipe() failed: errno %d (%s)\n", + errno, strerror(errno)); + exit(EXIT_FAILURE); + } + + pid = fork(); + if (pid < 0) { + xlog_err("mydaemon: fork() failed: errno %d (%s)\n", + errno, strerror(errno)); + exit(EXIT_FAILURE); + } + + if (pid > 0) { + /* Parent */ + close(pipefds[1]); + if (read(pipefds[0], &status, sizeof(status)) != sizeof(status)) + exit(EXIT_FAILURE); + exit(status); + } + + /* Child */ + close(pipefds[0]); + setsid (); + + if (chdir ("/")) { + xlog_err("mydaemon: chdir() failed: errno %d (%s)\n", + errno, strerror(errno)); + exit(EXIT_FAILURE); + } + + while (pipefds[1] <= 2) { + pipefds[1] = dup(pipefds[1]); + if (pipefds[1] < 0) { + xlog_err("mydaemon: dup() failed: errno %d (%s)\n", + errno, strerror(errno)); + exit(EXIT_FAILURE); + } + } + + tempfd = open("/dev/null", O_RDWR); + if (tempfd < 0) { + xlog_err("mydaemon: can't open /dev/null: errno %d " + "(%s)\n", errno, strerror(errno)); + exit(EXIT_FAILURE); + } + + dup2(tempfd, 0); + dup2(tempfd, 1); + dup2(tempfd, 2); + close(tempfd); + closelog(); + dup2(pipefds[1], 3); + pipefds[1] = 3; + closeall(4); +} + +/** + * daemon_ready - tell interested parties that the daemon is ready + * + * This function tells e.g. the parent process that the daemon is up + * and running. + */ +void +daemon_ready(void) +{ + int status = 0; + + if (pipefds[1] > 0) { + if (write(pipefds[1], &status, sizeof(status)) != sizeof(status)) { + xlog_err("WARN: writing to parent pipe failed: errno " + "%d (%s)\n", errno, strerror(errno)); + } + close(pipefds[1]); + pipefds[1] = -1; + } +} + |