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Diffstat (limited to 'port/pidfile.c')
| -rw-r--r-- | port/pidfile.c | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/port/pidfile.c b/port/pidfile.c new file mode 100644 index 000000000000..4deb2349d20a --- /dev/null +++ b/port/pidfile.c @@ -0,0 +1,183 @@ +/* $NetBSD: pidfile.c,v 1.2 2016/04/05 12:28:57 christos Exp $ */ + +/*- + * Copyright (c) 1999 The NetBSD Foundation, Inc. + * All rights reserved. + * + * This code is derived from software contributed to The NetBSD Foundation + * by Jason R. Thorpe, Matthias Scheler and Julio Merino. + * + * 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. + * + * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS + * ``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 FOUNDATION 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. + */ +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + +#include <sys/cdefs.h> +#if defined(LIBC_SCCS) && !defined(lint) +__RCSID("$NetBSD: pidfile.c,v 1.2 2016/04/05 12:28:57 christos Exp $"); +#endif + +#include <sys/param.h> + +#include <paths.h> +#include <stdbool.h> +#include <stdlib.h> +#include <stdio.h> +#include <string.h> +#include <unistd.h> +#ifdef HAVE_LIBUTIL_H +#include <libutil.h> +#endif +#ifdef HAVE_UTIL_H +#include <util.h> +#endif + +static pid_t pidfile_pid; +static char *pidfile_path; + +/* Deletes an existent pidfile iff it was created by this process. */ +static void +pidfile_cleanup(void) +{ + + if ((pidfile_path != NULL) && (pidfile_pid == getpid())) + (void) unlink(pidfile_path); +} + +/* Registers an atexit(3) handler to delete the pidfile we have generated. + * We only register the handler when we create a pidfile, so we can assume + * that the pidfile exists. + * + * Returns 0 on success or -1 if the handler could not be registered. */ +static int +register_atexit_handler(void) +{ + static bool done = false; + + if (!done) { + if (atexit(pidfile_cleanup) < 0) + return -1; + done = true; + } + + return 0; +} + +/* Given a new pidfile name in 'path', deletes any previously-created pidfile + * if the previous file differs to the new one. + * + * If a previous file is deleted, returns 1, which means that a new pidfile + * must be created. Otherwise, this returns 0, which means that the existing + * file does not need to be touched. */ +static int +cleanup_old_pidfile(const char* path) +{ + if (pidfile_path != NULL) { + if (strcmp(pidfile_path, path) != 0) { + pidfile_cleanup(); + + free(pidfile_path); + pidfile_path = NULL; + + return 1; + } else + return 0; + } else + return 1; +} + +/* Constructs a name for a pidfile in the default location (/var/run). If + * 'basename' is NULL, uses the name of the current program for the name of + * the pidfile. + * + * Returns a pointer to a dynamically-allocatd string containing the absolute + * path to the pidfile; NULL on failure. */ +static char * +generate_varrun_path(const char *bname) +{ + char *path; + + if (bname == NULL) + bname = getprogname(); + + /* _PATH_VARRUN includes trailing / */ + if (asprintf(&path, "%s%s.pid", _PATH_VARRUN, bname) == -1) + return NULL; + return path; +} + +/* Creates a pidfile with the provided name. The new pidfile is "registered" + * in the global variables pidfile_path and pidfile_pid so that any further + * call to pidfile(3) can check if we are recreating the same file or a new + * one. + * + * Returns 0 on success or -1 if there is any error. */ +static int +create_pidfile(const char* path) +{ + FILE *f; + + if (register_atexit_handler() == -1) + return -1; + + if (cleanup_old_pidfile(path) == 0) + return 0; + + pidfile_path = strdup(path); + if (pidfile_path == NULL) + return -1; + + if ((f = fopen(path, "w")) == NULL) { + free(pidfile_path); + pidfile_path = NULL; + return -1; + } + + pidfile_pid = getpid(); + + (void) fprintf(f, "%d\n", pidfile_pid); + (void) fclose(f); + + return 0; +} + +int +pidfile(const char *path) +{ + + if (path == NULL || strchr(path, '/') == NULL) { + char *default_path; + + if ((default_path = generate_varrun_path(path)) == NULL) + return -1; + + if (create_pidfile(default_path) == -1) { + free(default_path); + return -1; + } + + free(default_path); + return 0; + } else + return create_pidfile(path); +} |