[PATCH] rpcbind: add support for systemd socket activation

[Lennart Poettering <lennart@poettering.net>]

Heya!

(I sent this patch to Steve Dickson earlier, he asked me to post this
here.)

This patch allows us to spawn rpcbind automatically on first use in a
systemd environment, the same way it is done on MacOS X with launchd.

This makes use of socket-based activation as provided by systemd (in
case you are wondering, systemd is a Fedora 14 feature, described in all
detail here: http://0pointer.de/blog/projects/systemd.html). It uses the
reference implementation of the fd passing code, as supplied by systemd
upstream. I hope that's acceptable. It's liberally licensed, so I hope
this is OK. If not, it isn't difficult to reimplement this without the
reference implementation.

The algorithms implemented are described here:

    http://0pointer.de/public/systemd-man/sd_listen_fds.html
    http://0pointer.de/public/systemd-man/sd-daemon.html
    http://0pointer.de/public/systemd-man/daemon.html

Any comments welcome.

If this patch is OK then I can provide systemd unit files as well.

(This patch is generated with --ignore-space-change, to make it more
readable. A version generated without this switch you find here under
http://0pointer.de/public/0001-systemd-add-support-for-system-bus-activation.patch
That's actually the patch you might want to merge. This patch here in
the mail is the one you want to review. Since the rpcbind sources are a
bit chaotic when it comes to indenting and whitespace, this patch
ended up as messy as it is without the switch applied. Sorry for
that. I'd recommend adopting a stricter whitespace regime for the
package, following how they do it for the kernel. Would make it a lot
ncier to prepare patches, and all the git warning madness about weird
whitespace changes in your commits would go away. But anyway, this is
just me nitpicking.)

Lennart

Signed-off-by: Lennart Poettering <lennart@poettering.net>
---
 src/Makefile.am |    6 +-
 src/rpcbind.c   |   75 +++++++++-
 src/sd-daemon.c |  452 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/sd-daemon.h |  257 +++++++++++++++++++++++++++++++
 4 files changed, 783 insertions(+), 7 deletions(-)
 create mode 100644 src/sd-daemon.c
 create mode 100644 src/sd-daemon.h

diff --git a/src/Makefile.am b/src/Makefile.am
index cc0a85b..6340fe9 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -20,7 +20,8 @@ rpcbind_SOURCES =       check_bound.c rpcbind.c \
                         rpcb_svc_4.c rpcb_svc_com.c \
                         util.c pmap_svc.c rpcb_stat.c \
                         rpcb_svc.c security.c warmstart.c \
-                        rpcbind.h
+                        rpcbind.h \
+			sd-daemon.c sd-daemon.h
 
 rpcinfo_SOURCES =       rpcinfo.c
 rpcinfo_LDFLAGS =       -lpthread -ltirpc
@@ -32,3 +33,6 @@ rpcbind_LDADD = $(LIB_TIRPC)
 AM_CPPFLAGS = -I/usr/include/tirpc -DCHECK_LOCAL -DPORTMAP \
                        -DFACILITY=LOG_MAIL -DSEVERITY=LOG_INFO
      
+update-systemd:
+	curl http://cgit.freedesktop.org/systemd/plain/src/sd-daemon.c > sd-daemon.c
+	curl http://cgit.freedesktop.org/systemd/plain/src/sd-daemon.h > sd-daemon.h
diff --git a/src/rpcbind.c b/src/rpcbind.c
index 63023e1..0368eaf 100644
--- a/src/rpcbind.c
+++ b/src/rpcbind.c
@@ -70,6 +70,7 @@
 #include <nss.h>
 #include "config.h"
 #include "rpcbind.h"
+#include "sd-daemon.h"
 
 /*#define RPCBIND_DEBUG*/
 
@@ -282,6 +283,7 @@ init_transport(struct netconfig *nconf)
 	u_int32_t host_addr[4];  /* IPv4 or IPv6 */
 	struct sockaddr_un sun;
 	mode_t oldmask;
+	int n;
         res = NULL;
 
 	if ((nconf->nc_semantics != NC_TPI_CLTS) &&
@@ -301,6 +303,72 @@ init_transport(struct netconfig *nconf)
 	}
 #endif
 
+	if (!__rpc_nconf2sockinfo(nconf, &si)) {
+		syslog(LOG_ERR, "cannot get information for %s",
+		    nconf->nc_netid);
+		return (1);
+	}
+
+	n = sd_listen_fds(0);
+	if (n < 0) {
+		syslog(LOG_ERR, "failed to acquire systemd scokets: %s", strerror(-n));
+		return 1;
+	}
+
+	if (n > 0) {
+		int fd;
+
+		/* We have systemd sockets, now find those that match
+		 * our netconfig structure. */
+
+		for (fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + n; fd++) {
+			struct __rpc_sockinfo si_other;
+			union {
+				struct sockaddr sa;
+				struct sockaddr_un un;
+				struct sockaddr_in in4;
+				struct sockaddr_in6 in6;
+				struct sockaddr_storage storage;
+			} sa;
+			socklen_t addrlen = sizeof(sa);
+
+			if (!__rpc_fd2sockinfo(fd, &si_other)) {
+				syslog(LOG_ERR, "cannog get information for fd %i", fd);
+				return 1;
+			}
+
+			if (si.si_af != si_other.si_af ||
+			    si.si_socktype != si_other.si_socktype ||
+			    si.si_proto != si_other.si_proto)
+				continue;
+
+			if (getsockname(fd, &sa.sa, &addrlen) < 0) {
+				syslog(LOG_ERR, "failed to query socket name: %s",
+				       strerror(errno));
+				goto error;
+			}
+
+			/* Copy the address */
+			taddr.addr.maxlen = taddr.addr.len = addrlen;
+			taddr.addr.buf = malloc(addrlen);
+			if (taddr.addr.buf == NULL) {
+				syslog(LOG_ERR,
+				       "cannot allocate memory for %s address",
+				       nconf->nc_netid);
+				goto error;
+			}
+			memcpy(taddr.addr.buf, &sa, addrlen);
+
+			my_xprt = (SVCXPRT *)svc_tli_create(fd, nconf, &taddr,
+                                RPC_MAXDATASIZE, RPC_MAXDATASIZE);
+			if (my_xprt == (SVCXPRT *)NULL) {
+				syslog(LOG_ERR, "%s: could not create service",
+                                        nconf->nc_netid);
+				goto error;
+			}
+		}
+	} else {
+
 	/*
 	 * XXX - using RPC library internal functions. For NC_TPI_CLTS
 	 * we call this later, for each socket we like to bind.
@@ -313,12 +381,6 @@ init_transport(struct netconfig *nconf)
 		}
 	}
 
-	if (!__rpc_nconf2sockinfo(nconf, &si)) {
-		syslog(LOG_ERR, "cannot get information for %s",
-		    nconf->nc_netid);
-		return (1);
-	}
-
 	if ((strcmp(nconf->nc_netid, "local") == 0) ||
 	    (strcmp(nconf->nc_netid, "unix") == 0)) {
 		memset(&sun, 0, sizeof sun);
@@ -555,6 +617,7 @@ init_transport(struct netconfig *nconf)
 			goto error;
 		}
 	}
+	}
 
 #ifdef PORTMAP
 	/*
diff --git a/src/sd-daemon.c b/src/sd-daemon.c
new file mode 100644
index 0000000..3bb258d
--- /dev/null
+++ b/src/sd-daemon.c
@@ -0,0 +1,452 @@
+/*-*- Mode: C; c-basic-offset: 8 -*-*/
+
+/***
+  Copyright 2010 Lennart Poettering
+
+  Permission is hereby granted, free of charge, to any person
+  obtaining a copy of this software and associated documentation files
+  (the "Software"), to deal in the Software without restriction,
+  including without limitation the rights to use, copy, modify, merge,
+  publish, distribute, sublicense, and/or sell copies of the Software,
+  and to permit persons to whom the Software is furnished to do so,
+  subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be
+  included in all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+  BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+  ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+***/
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <sys/fcntl.h>
+#include <netinet/in.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdarg.h>
+#include <stdio.h>
+
+#include "sd-daemon.h"
+
+int sd_listen_fds(int unset_environment) {
+
+#if defined(DISABLE_SYSTEMD) || !defined(__linux__)
+        return 0;
+#else
+        int r, fd;
+        const char *e;
+        char *p = NULL;
+        unsigned long l;
+
+        if (!(e = getenv("LISTEN_PID"))) {
+                r = 0;
+                goto finish;
+        }
+
+        errno = 0;
+        l = strtoul(e, &p, 10);
+
+        if (errno != 0) {
+                r = -errno;
+                goto finish;
+        }
+
+        if (!p || *p || l <= 0) {
+                r = -EINVAL;
+                goto finish;
+        }
+
+        /* Is this for us? */
+        if (getpid() != (pid_t) l) {
+                r = 0;
+                goto finish;
+        }
+
+        if (!(e = getenv("LISTEN_FDS"))) {
+                r = 0;
+                goto finish;
+        }
+
+        errno = 0;
+        l = strtoul(e, &p, 10);
+
+        if (errno != 0) {
+                r = -errno;
+                goto finish;
+        }
+
+        if (!p || *p) {
+                r = -EINVAL;
+                goto finish;
+        }
+
+        for (fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + (int) l; fd ++) {
+                int flags;
+
+                if ((flags = fcntl(fd, F_GETFD)) < 0) {
+                        r = -errno;
+                        goto finish;
+                }
+
+                if (flags & FD_CLOEXEC)
+                        continue;
+
+                if (fcntl(fd, F_SETFD, flags | FD_CLOEXEC) < 0) {
+                        r = -errno;
+                        goto finish;
+                }
+        }
+
+        r = (int) l;
+
+finish:
+        if (unset_environment) {
+                unsetenv("LISTEN_PID");
+                unsetenv("LISTEN_FDS");
+        }
+
+        return r;
+#endif
+}
+
+int sd_is_fifo(int fd, const char *path) {
+        struct stat st_fd;
+
+        if (fd < 0)
+                return -EINVAL;
+
+        memset(&st_fd, 0, sizeof(st_fd));
+        if (fstat(fd, &st_fd) < 0)
+                return -errno;
+
+        if (!S_ISFIFO(st_fd.st_mode))
+                return 0;
+
+        if (path) {
+                struct stat st_path;
+
+                memset(&st_path, 0, sizeof(st_path));
+                if (stat(path, &st_path) < 0) {
+
+                        if (errno == ENOENT || errno == ENOTDIR)
+                                return 0;
+
+                        return -errno;
+                }
+
+                return
+                        st_path.st_dev == st_fd.st_dev &&
+                        st_path.st_ino == st_fd.st_ino;
+        }
+
+        return 1;
+}
+
+static int sd_is_socket_internal(int fd, int type, int listening) {
+        struct stat st_fd;
+
+        if (fd < 0 || type < 0)
+                return -EINVAL;
+
+        if (fstat(fd, &st_fd) < 0)
+                return -errno;
+
+        if (!S_ISSOCK(st_fd.st_mode))
+                return 0;
+
+        if (type != 0) {
+                int other_type = 0;
+                socklen_t l = sizeof(other_type);
+
+                if (getsockopt(fd, SOL_SOCKET, SO_TYPE, &other_type, &l) < 0)
+                        return -errno;
+
+                if (l != sizeof(other_type))
+                        return -EINVAL;
+
+                if (other_type != type)
+                        return 0;
+        }
+
+        if (listening >= 0) {
+                int accepting = 0;
+                socklen_t l = sizeof(accepting);
+
+                if (getsockopt(fd, SOL_SOCKET, SO_ACCEPTCONN, &accepting, &l) < 0)
+                        return -errno;
+
+                if (l != sizeof(accepting))
+                        return -EINVAL;
+
+                if (!accepting != !listening)
+                        return 0;
+        }
+
+        return 1;
+}
+
+union sockaddr_union {
+        struct sockaddr sa;
+        struct sockaddr_in in4;
+        struct sockaddr_in6 in6;
+        struct sockaddr_un un;
+        struct sockaddr_storage storage;
+};
+
+int sd_is_socket(int fd, int family, int type, int listening) {
+        int r;
+
+        if (family < 0)
+                return -EINVAL;
+
+        if ((r = sd_is_socket_internal(fd, type, listening)) <= 0)
+                return r;
+
+        if (family > 0) {
+                union sockaddr_union sockaddr;
+                socklen_t l;
+
+                memset(&sockaddr, 0, sizeof(sockaddr));
+                l = sizeof(sockaddr);
+
+                if (getsockname(fd, &sockaddr.sa, &l) < 0)
+                        return -errno;
+
+                if (l < sizeof(sa_family_t))
+                        return -EINVAL;
+
+                return sockaddr.sa.sa_family == family;
+        }
+
+        return 1;
+}
+
+int sd_is_socket_inet(int fd, int family, int type, int listening, uint16_t port) {
+        union sockaddr_union sockaddr;
+        socklen_t l;
+        int r;
+
+        if (family != 0 && family != AF_INET && family != AF_INET6)
+                return -EINVAL;
+
+        if ((r = sd_is_socket_internal(fd, type, listening)) <= 0)
+                return r;
+
+        memset(&sockaddr, 0, sizeof(sockaddr));
+        l = sizeof(sockaddr);
+
+        if (getsockname(fd, &sockaddr.sa, &l) < 0)
+                return -errno;
+
+        if (l < sizeof(sa_family_t))
+                return -EINVAL;
+
+        if (sockaddr.sa.sa_family != AF_INET &&
+            sockaddr.sa.sa_family != AF_INET6)
+                return 0;
+
+        if (family > 0)
+                if (sockaddr.sa.sa_family != family)
+                        return 0;
+
+        if (port > 0) {
+                if (sockaddr.sa.sa_family == AF_INET) {
+                        if (l < sizeof(struct sockaddr_in))
+                                return -EINVAL;
+
+                        return htons(port) == sockaddr.in4.sin_port;
+                } else {
+                        if (l < sizeof(struct sockaddr_in6))
+                                return -EINVAL;
+
+                        return htons(port) == sockaddr.in6.sin6_port;
+                }
+        }
+
+        return 1;
+}
+
+int sd_is_socket_unix(int fd, int type, int listening, const char *path, size_t length) {
+        union sockaddr_union sockaddr;
+        socklen_t l;
+        int r;
+
+        if ((r = sd_is_socket_internal(fd, type, listening)) <= 0)
+                return r;
+
+        memset(&sockaddr, 0, sizeof(sockaddr));
+        l = sizeof(sockaddr);
+
+        if (getsockname(fd, &sockaddr.sa, &l) < 0)
+                return -errno;
+
+        if (l < sizeof(sa_family_t))
+                return -EINVAL;
+
+        if (sockaddr.sa.sa_family != AF_UNIX)
+                return 0;
+
+        if (path) {
+                if (length <= 0)
+                        length = strlen(path);
+
+                if (length <= 0)
+                        /* Unnamed socket */
+                        return l == sizeof(sa_family_t);
+
+                if (path[0])
+                        /* Normal path socket */
+                        return
+                                (l >= sizeof(sa_family_t) + length + 1) &&
+                                memcmp(path, sockaddr.un.sun_path, length+1) == 0;
+                else
+                        /* Abstract namespace socket */
+                        return
+                                (l == sizeof(sa_family_t) + length) &&
+                                memcmp(path, sockaddr.un.sun_path, length) == 0;
+        }
+
+        return 1;
+}
+
+int sd_notify(int unset_environment, const char *state) {
+#if defined(DISABLE_SYSTEMD) || !defined(__linux__)
+        return 0;
+#else
+        int fd = -1, r;
+        struct msghdr msghdr;
+        struct iovec iovec;
+        union sockaddr_union sockaddr;
+        struct ucred *ucred;
+        union {
+                struct cmsghdr cmsghdr;
+                uint8_t buf[CMSG_SPACE(sizeof(struct ucred))];
+        } control;
+        const char *e;
+
+        if (!state) {
+                r = -EINVAL;
+                goto finish;
+        }
+
+        if (!(e = getenv("NOTIFY_SOCKET")))
+                return 0;
+
+        /* Must be an abstract socket, or an absolute path */
+        if ((e[0] != '@' && e[0] != '/') || e[1] == 0) {
+                r = -EINVAL;
+                goto finish;
+        }
+
+        if ((fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0)) < 0) {
+                r = -errno;
+                goto finish;
+        }
+
+        memset(&sockaddr, 0, sizeof(sockaddr));
+        sockaddr.sa.sa_family = AF_UNIX;
+        strncpy(sockaddr.un.sun_path, e, sizeof(sockaddr.un.sun_path));
+
+        if (sockaddr.un.sun_path[0] == '@')
+                sockaddr.un.sun_path[0] = 0;
+
+        memset(&iovec, 0, sizeof(iovec));
+        iovec.iov_base = (char*) state;
+        iovec.iov_len = strlen(state);
+
+        memset(&control, 0, sizeof(control));
+        control.cmsghdr.cmsg_level = SOL_SOCKET;
+        control.cmsghdr.cmsg_type = SCM_CREDENTIALS;
+        control.cmsghdr.cmsg_len = CMSG_LEN(sizeof(struct ucred));
+
+        ucred = (struct ucred*) CMSG_DATA(&control.cmsghdr);
+        ucred->pid = getpid();
+        ucred->uid = getuid();
+        ucred->gid = getgid();
+
+        memset(&msghdr, 0, sizeof(msghdr));
+        msghdr.msg_name = &sockaddr;
+        msghdr.msg_namelen = sizeof(sa_family_t) + strlen(e);
+
+        if (msghdr.msg_namelen > sizeof(struct sockaddr_un))
+                msghdr.msg_namelen = sizeof(struct sockaddr_un);
+
+        msghdr.msg_iov = &iovec;
+        msghdr.msg_iovlen = 1;
+        msghdr.msg_control = &control;
+        msghdr.msg_controllen = control.cmsghdr.cmsg_len;
+
+        if (sendmsg(fd, &msghdr, MSG_NOSIGNAL) < 0) {
+                r = -errno;
+                goto finish;
+        }
+
+        r = 1;
+
+finish:
+        if (unset_environment)
+                unsetenv("NOTIFY_SOCKET");
+
+        if (fd >= 0)
+                close(fd);
+
+        return r;
+#endif
+}
+
+int sd_notifyf(int unset_environment, const char *format, ...) {
+#if defined(DISABLE_SYSTEMD) || !defined(__linux__)
+        return 0;
+#else
+        va_list ap;
+        char *p = NULL;
+        int r;
+
+        va_start(ap, format);
+        r = vasprintf(&p, format, ap);
+        va_end(ap);
+
+        if (r < 0 || !p)
+                return -ENOMEM;
+
+        r = sd_notify(unset_environment, p);
+        free(p);
+
+        return r;
+#endif
+}
+
+int sd_booted(void) {
+#if defined(DISABLE_SYSTEMD) || !defined(__linux__)
+        return 0;
+#else
+
+        struct stat a, b;
+
+        /* We simply test whether the systemd cgroup hierarchy is
+         * mounted */
+
+        if (lstat("/cgroup", &a) < 0)
+                return 0;
+
+        if (lstat("/cgroup/systemd", &b) < 0)
+                return 0;
+
+        return a.st_dev != b.st_dev;
+#endif
+}
diff --git a/src/sd-daemon.h b/src/sd-daemon.h
new file mode 100644
index 0000000..fd6221f
--- /dev/null
+++ b/src/sd-daemon.h
@@ -0,0 +1,257 @@
+/*-*- Mode: C; c-basic-offset: 8 -*-*/
+
+#ifndef foosddaemonhfoo
+#define foosddaemonhfoo
+
+/***
+  Copyright 2010 Lennart Poettering
+
+  Permission is hereby granted, free of charge, to any person
+  obtaining a copy of this software and associated documentation files
+  (the "Software"), to deal in the Software without restriction,
+  including without limitation the rights to use, copy, modify, merge,
+  publish, distribute, sublicense, and/or sell copies of the Software,
+  and to permit persons to whom the Software is furnished to do so,
+  subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be
+  included in all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+  BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+  ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+***/
+
+#include <sys/types.h>
+#include <inttypes.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+  Reference implementation of a few systemd related interfaces for
+  writing daemons. These interfaces are trivial to implement. To
+  simplify porting we provide this reference implementation.
+  Applications are welcome to reimplement the algorithms described
+  here if they do not want to include these two source files.
+
+  The following functionality is provided:
+
+  - Support for logging with log levels on stderr
+  - File descriptor passing for socket-based activation
+  - Daemon startup and status notification
+  - Detection of systemd boots
+
+  You may compile this with -DDISABLE_SYSTEMD to disable systemd
+  support. This makes all those calls NOPs that are directly related to
+  systemd (i.e. only sd_is_xxx() will stay useful).
+
+  Since this is drop-in code we don't want any of our symbols to be
+  exported in any case. Hence we declare hidden visibility for all of
+  them.
+
+  You may find an up-to-date version of these source files online:
+
+  http://cgit.freedesktop.org/systemd/plain/src/sd-daemon.h
+  http://cgit.freedesktop.org/systemd/plain/src/sd-daemon.c
+
+  This should compile on non-Linux systems, too, but with the
+  exception of the sd_is_xxx() calls all functions will become NOPs.
+
+  See sd-daemon(7) for more information.
+*/
+
+#if __GNUC__ >= 4
+#define _sd_printf_attr_(a,b) __attribute__ ((format (printf, a, b)))
+#define _sd_hidden_ __attribute__ ((visibility("hidden")))
+#else
+#define _sd_printf_attr_(a,b)
+#define _sd_hidden_
+#endif
+
+/*
+  Log levels for usage on stderr:
+
+          fprintf(stderr, SD_NOTICE "Hello World!\n");
+
+  This is similar to printk() usage in the kernel.
+*/
+#define SD_EMERG   "<0>"  /* system is unusable */
+#define SD_ALERT   "<1>"  /* action must be taken immediately */
+#define SD_CRIT    "<2>"  /* critical conditions */
+#define SD_ERR     "<3>"  /* error conditions */
+#define SD_WARNING "<4>"  /* warning conditions */
+#define SD_NOTICE  "<5>"  /* normal but significant condition */
+#define SD_INFO    "<6>"  /* informational */
+#define SD_DEBUG   "<7>"  /* debug-level messages */
+
+/* The first passed file descriptor is fd 3 */
+#define SD_LISTEN_FDS_START 3
+
+/*
+  Returns how many file descriptors have been passed, or a negative
+  errno code on failure. Optionally, removes the $LISTEN_FDS and
+  $LISTEN_PID file descriptors from the environment (recommended, but
+  problematic in threaded environments). If r is the return value of
+  this function you'll find the file descriptors passed as fds
+  SD_LISTEN_FDS_START to SD_LISTEN_FDS_START+r-1. Returns a negative
+  errno style error code on failure. This function call ensures that
+  the FD_CLOEXEC flag is set for the passed file descriptors, to make
+  sure they are not passed on to child processes. If FD_CLOEXEC shall
+  not be set, the caller needs to unset it after this call for all file
+  descriptors that are used.
+
+  See sd_listen_fds(3) for more information.
+*/
+int sd_listen_fds(int unset_environment) _sd_hidden_;
+
+/*
+  Helper call for identifying a passed file descriptor. Returns 1 if
+  the file descriptor is a FIFO in the file system stored under the
+  specified path, 0 otherwise. If path is NULL a path name check will
+  not be done and the call only verifies if the file descriptor
+  refers to a FIFO. Returns a negative errno style error code on
+  failure.
+
+  See sd_is_fifo(3) for more information.
+*/
+int sd_is_fifo(int fd, const char *path) _sd_hidden_;
+
+/*
+  Helper call for identifying a passed file descriptor. Returns 1 if
+  the file descriptor is a socket of the specified family (AF_INET,
+  ...) and type (SOCK_DGRAM, SOCK_STREAM, ...), 0 otherwise. If
+  family is 0 a socket family check will not be done. If type is 0 a
+  socket type check will not be done and the call only verifies if
+  the file descriptor refers to a socket. If listening is > 0 it is
+  verified that the socket is in listening mode. (i.e. listen() has
+  been called) If listening is == 0 it is verified that the socket is
+  not in listening mode. If listening is < 0 no listening mode check
+  is done. Returns a negative errno style error code on failure.
+
+  See sd_is_socket(3) for more information.
+*/
+int sd_is_socket(int fd, int family, int type, int listening) _sd_hidden_;
+
+/*
+  Helper call for identifying a passed file descriptor. Returns 1 if
+  the file descriptor is an Internet socket, of the specified family
+  (either AF_INET or AF_INET6) and the specified type (SOCK_DGRAM,
+  SOCK_STREAM, ...), 0 otherwise. If version is 0 a protocol version
+  check is not done. If type is 0 a socket type check will not be
+  done. If port is 0 a socket port check will not be done. The
+  listening flag is used the same way as in sd_is_socket(). Returns a
+  negative errno style error code on failure.
+
+  See sd_is_socket_inet(3) for more information.
+*/
+int sd_is_socket_inet(int fd, int family, int type, int listening, uint16_t port) _sd_hidden_;
+
+/*
+  Helper call for identifying a passed file descriptor. Returns 1 if
+  the file descriptor is an AF_UNIX socket of the specified type
+  (SOCK_DGRAM, SOCK_STREAM, ...) and path, 0 otherwise. If type is 0
+  a socket type check will not be done. If path is NULL a socket path
+  check will not be done. For normal AF_UNIX sockets set length to
+  0. For abstract namespace sockets set length to the length of the
+  socket name (including the initial 0 byte), and pass the full
+  socket path in path (including the initial 0 byte). The listening
+  flag is used the same way as in sd_is_socket(). Returns a negative
+  errno style error code on failure.
+
+  See sd_is_socket_unix(3) for more information.
+*/
+int sd_is_socket_unix(int fd, int type, int listening, const char *path, size_t length) _sd_hidden_;
+
+/*
+  Informs systemd about changed daemon state. This takes a number of
+  newline seperated environment-style variable assignments in a
+  string. The following variables are known:
+
+     READY=1      Tells systemd that daemon startup is finished (only
+                  relevant for services of Type=notify). The passed
+                  argument is a boolean "1" or "0". Since there is
+                  little value in signalling non-readiness the only
+                  value daemons should send is "READY=1".
+
+     STATUS=...   Passes a single-line status string back to systemd
+                  that describes the daemon state. This is free-from
+                  and can be used for various purposes: general state
+                  feedback, fsck-like programs could pass completion
+                  percentages and failing programs could pass a human
+                  readable error message. Example: "STATUS=Completed
+                  66% of file system check..."
+
+     ERRNO=...    If a daemon fails, the errno-style error code,
+                  formatted as string. Example: "ERRNO=2" for ENOENT.
+
+     BUSERROR=... If a daemon fails, the D-Bus error-style error
+                  code. Example: "BUSERROR=org.freedesktop.DBus.Error.TimedOut"
+
+     MAINPID=...  The main pid of a daemon, in case systemd did not
+                  fork off the process itself. Example: "MAINPID=4711"
+
+  Daemons can choose to send additional variables. However, it is
+  recommened to prefix variable names not listed above with X_.
+
+  Returns a negative errno-style error code on failure. Returns > 0
+  if systemd could be notified, 0 if it couldn't possibly because
+  systemd is not running.
+
+  Example: When a daemon finished starting up, it could issue this
+  call to notify systemd about it:
+
+     sd_notify(0, "READY=1");
+
+  See sd_notifyf() for more complete examples.
+
+  See sd_notify(3) for more information.
+*/
+int sd_notify(int unset_environment, const char *state) _sd_hidden_;
+
+/*
+  Similar to sd_notify() but takes a format string.
+
+  Example 1: A daemon could send the following after initialization:
+
+     sd_notifyf(0, "READY=1\n"
+                   "STATUS=Processing requests...\n"
+                   "MAINPID=%lu",
+                   (unsigned long) getpid());
+
+  Example 2: A daemon could send the following shortly before
+  exiting, on failure:
+
+     sd_notifyf(0, "STATUS=Failed to start up: %s\n"
+                   "ERRNO=%i",
+                   strerror(errno),
+                   errno);
+
+  See sd_notifyf(3) for more information.
+*/
+int sd_notifyf(int unset_environment, const char *format, ...) _sd_printf_attr_(2,3) _sd_hidden_;
+
+/*
+  Returns > 0 if the system was booted with systemd. Returns < 0 on
+  error. Returns 0 if the system was not booted with systemd. Note
+  that all of the functions above handle non-systemd boots just
+  fine. You should NOT protect them with a call to this function. Also
+  note that this function checks whether the system, not the user
+  session is controlled by systemd. However the functions above work
+  for both session and system services.
+
+  See sd_booted(3) for more information.
+*/
+int sd_booted(void) _sd_hidden_;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
-- 
1.7.0.1



Lennart

-- 
Lennart Poettering - Red Hat, Inc.