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authorMattias Andrée <maandree@kth.se>2016-07-12 09:18:28 +0200
committerMattias Andrée <maandree@kth.se>2016-07-12 09:18:28 +0200
commit9401bbb93310a0a0eb3e366fd7be612cd72b5cad (patch)
treed881161408826a58852c321f2f77b0c24462df9f /src
parentConditionally store realpath(argv0) so we can reexecute even if argv0 is relative (diff)
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Implement marshal of the process
Signed-off-by: Mattias Andrée <maandree@kth.se>
Diffstat (limited to 'src')
-rw-r--r--src/gammad.c261
1 files changed, 196 insertions, 65 deletions
diff --git a/src/gammad.c b/src/gammad.c
index 6dcb31f..7dfebd9 100644
--- a/src/gammad.c
+++ b/src/gammad.c
@@ -38,6 +38,14 @@
/**
+ * Number put in front of the marshalled data
+ * so the program an detect incompatible updates
+ */
+#define MARSHAL_VERSION 0
+
+
+
+/**
* The name of the process
*/
char* argv0;
@@ -87,6 +95,16 @@ int gerror;
int init_stage = 0;
/**
+ * The adjustment method, -1 for automatic
+ */
+int method = -1;
+
+/**
+ * The site's name, may be `NULL`
+ */
+char* sitename = NULL;
+
+/**
* The libgamma site state
*/
libgamma_site_state_t site;
@@ -228,6 +246,17 @@ static inline char* get_pidfile_pathname(void)
/**
+ * Get the pathname of the state file
+ *
+ * @return The pathname of the state file, `NULL` on error
+ */
+static inline char* get_state_pathname(void)
+{
+ return get_pathname(".state");
+}
+
+
+/**
* Parse adjustment method name (or stringised number)
*
* @param arg The adjustment method name (or stringised number)
@@ -463,8 +492,8 @@ static int create_pidfile(char* pidfile)
/**
* Initialise the process
*
- * @param method The adjustment method, -1 for automatic
- * @param sitename The site's name, may be `NULL`
+ * @param full Perform a full initialisation, shall be done
+ * iff the state is not going to be unmarshalled
* @param preserve Preserve current gamma ramps at priority 0
* @param foreground Keep process in the foreground
* @param keep_stderr Keep stderr open
@@ -475,7 +504,7 @@ static int create_pidfile(char* pidfile)
* Otherwise: The negative of the exit value the
* process should have and shall exit immediately
*/
-static int initialise(int method, const char *sitename, int preserve, int foreground, int keep_stderr)
+static int initialise(int full, int preserve, int foreground, int keep_stderr)
{
struct sockaddr_un address;
struct rlimit rlimit;
@@ -487,22 +516,25 @@ static int initialise(int method, const char *sitename, int preserve, int foregr
/* Zero out some memory so it can be destoried safely. */
memset(&site, 0, sizeof(site));
- /* Close all file descriptors above stderr */
- if (getrlimit(RLIMIT_NOFILE, &rlimit) || (rlimit.rlim_cur == RLIM_INFINITY))
- n = 4 << 10;
- else
- n = (size_t)(rlimit.rlim_cur);
- for (i = STDERR_FILENO + 1; i < n; i++)
- close((int)i);
-
- /* Set umask, reset signal handlers, and reset signal mask */
- umask(0);
- for (r = 1; r < _NSIG; r++)
- signal(r, SIG_DFL);
- if (sigfillset(&mask))
- perror(argv0);
- else
- sigprocmask(SIG_UNBLOCK, &mask, NULL);
+ if (full)
+ {
+ /* Close all file descriptors above stderr */
+ if (getrlimit(RLIMIT_NOFILE, &rlimit) || (rlimit.rlim_cur == RLIM_INFINITY))
+ n = 4 << 10;
+ else
+ n = (size_t)(rlimit.rlim_cur);
+ for (i = STDERR_FILENO + 1; i < n; i++)
+ close((int)i);
+
+ /* Set umask, reset signal handlers, and reset signal mask */
+ umask(0);
+ for (r = 1; r < _NSIG; r++)
+ signal(r, SIG_DFL);
+ if (sigfillset(&mask))
+ perror(argv0);
+ else
+ sigprocmask(SIG_UNBLOCK, &mask, NULL);
+ }
/* Get method */
if ((method < 0) && (libgamma_list_methods(&method, 1, 0) < 1))
@@ -515,19 +547,22 @@ static int initialise(int method, const char *sitename, int preserve, int foregr
if ((gerror = libgamma_site_initialise(&site, method, sitename_dup)))
goto fail_libgamma;
- /* Get PID file and socket pathname */
- if (!(pidpath = get_pidfile_pathname()))
- goto fail;
- if (!(socketpath = get_socket_pathname()))
- goto fail;
-
- /* Create PID file */
- if ((r = create_pidfile(pidpath)) < 0)
+ if (full)
{
- free(pidpath), pidpath = NULL;
- if (r == -2)
- goto already_running;
- goto fail;
+ /* Get PID file and socket pathname */
+ if (!(pidpath = get_pidfile_pathname()))
+ goto fail;
+ if (!(socketpath = get_socket_pathname()))
+ goto fail;
+
+ /* Create PID file */
+ if ((r = create_pidfile(pidpath)) < 0)
+ {
+ free(pidpath), pidpath = NULL;
+ if (r == -2)
+ goto already_running;
+ goto fail;
+ }
}
/* Get partitions */
@@ -662,33 +697,36 @@ static int initialise(int method, const char *sitename, int preserve, int foregr
goto fail;
}
- /* Create socket and start listening */
- address.sun_family = AF_UNIX;
- if (strlen(socketpath) >= sizeof(address.sun_path))
+ if (full)
{
- errno = ENAMETOOLONG;
- goto fail;
+ /* Create socket and start listening */
+ address.sun_family = AF_UNIX;
+ if (strlen(socketpath) >= sizeof(address.sun_path))
+ {
+ errno = ENAMETOOLONG;
+ goto fail;
+ }
+ strcpy(address.sun_path, socketpath);
+ unlink(socketpath);
+ if ((socketfd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
+ goto fail;
+ if (fchmod(socketfd, S_IRWXU) < 0)
+ goto fail;
+ if (bind(socketfd, (struct sockaddr*)(&address), sizeof(address)) < 0)
+ goto fail;
+ if (listen(socketfd, SOMAXCONN) < 0)
+ goto fail;
+
+ /* Get the real pathname of the process's binary, in case
+ * it is relative, so we can re-execute without problem. */
+ if ((*argv0 != '/') && strchr(argv0, '/'))
+ if (!(argv0_real = realpath(argv0, NULL)))
+ goto fail;
+
+ /* Change directory to / to avoid blocking umounting */
+ if (chdir("/") < 0)
+ perror(argv0);
}
- strcpy(address.sun_path, socketpath);
- unlink(socketpath);
- if ((socketfd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
- goto fail;
- if (fchmod(socketfd, S_IRWXU) < 0)
- goto fail;
- if (bind(socketfd, (struct sockaddr*)(&address), sizeof(address)) < 0)
- goto fail;
- if (listen(socketfd, SOMAXCONN) < 0)
- goto fail;
-
- /* Get the real pathname of the process's binary, in case
- * it is relative, so we can re-execute without problem. */
- if ((*argv0 != '/') && strchr(argv0, '/'))
- if (!(argv0_real = realpath(argv0, NULL)))
- goto fail;
-
- /* Change directory to / to avoid blocking umounting */
- if (chdir("/") < 0)
- perror(argv0);
/* Set up signal handlers */
if (signal(SIGUSR1, sig_reexec) == SIG_ERR)
@@ -696,13 +734,16 @@ static int initialise(int method, const char *sitename, int preserve, int foregr
if (signal(SIGTERM, sig_terminate) == SIG_ERR)
goto fail;
- /* Initialise the server */
- if (server_initialise() < 0)
- goto fail;
- init_stage++;
+ if (full)
+ {
+ /* Initialise the server */
+ if (server_initialise() < 0)
+ goto fail;
+ init_stage++;
+ }
/* Place in the background unless -f */
- if (foreground == 0)
+ if (full && (foreground == 0))
{
pid_t pid;
int fd = -1, saved_errno;
@@ -783,7 +824,7 @@ static int initialise(int method, const char *sitename, int preserve, int foregr
errno = saved_errno;
done_background:;
}
- else
+ else if (full)
{
/* Signal the spawner that the service is ready */
close(STDOUT_FILENO);
@@ -873,6 +914,84 @@ static void destroy(void)
unlink(pidpath);
free(pidpath);
free(argv0_real);
+ free(sitename);
+}
+
+
+/**
+ * Marshal the state of the process
+ *
+ * @param buf Output buffer for the marshalled data,
+ * `NULL` to only measure how large the
+ * buffer needs to be
+ * @return The number of marshalled news
+ */
+static size_t marshal(void* buf)
+{
+ size_t off = 0, i, n;
+ char* bs = buf;
+
+ if (bs != NULL)
+ *(int*)(bs + off) = MARSHAL_VERSION;
+ off += sizeof(int);
+
+ if (argv0_real == NULL)
+ {
+ if (bs != NULL)
+ *(bs + off) = '\0';
+ off += 1;
+ }
+ else
+ {
+ n = strlen(argv0_real) + 1;
+ if (bs != NULL)
+ memcpy(bs + off, argv0_real, n);
+ off += n;
+ }
+
+ if (bs != NULL)
+ *(size_t*)(bs + off) = outputs_n;
+ off += sizeof(size_t);
+
+ for (i = 0; i < outputs_n; i++)
+ off += output_marshal(outputs + i , bs ? bs + off : NULL);
+
+ if (bs != NULL)
+ *(int*)(bs + off) = socketfd;
+ off += sizeof(int);
+
+ n = strlen(pidpath) + 1;
+ if (bs != NULL)
+ memcpy(bs + off, pidpath, n);
+ off += n;
+
+ n = strlen(socketpath) + 1;
+ if (bs != NULL)
+ memcpy(bs + off, socketpath, n);
+ off += n;
+
+ off += server_marshal(bs ? bs + off : NULL);
+
+ if (bs != NULL)
+ *(int*)(bs + off) = init_stage;
+ off += sizeof(int);
+
+ if (bs != NULL)
+ *(int*)(bs + off) = method;
+ off += sizeof(int);
+
+ if (bs != NULL)
+ *(int*)(bs + off) = sitename != NULL;
+ off += sizeof(int);
+ if (sitename != NULL)
+ {
+ n = strlen(sitename) + 1;
+ if (bs != NULL)
+ memcpy(bs + off, sitename, n);
+ off += n;
+ }
+
+ return off;
}
@@ -915,13 +1034,17 @@ static void usage(void)
*/
int main(int argc, char** argv)
{
- int method = -1, rc = 1, preserve = 0, foreground = 0, keep_stderr = 0, r;
- char* sitename = NULL;
+ int rc = 1, preserve = 0, foreground = 0, keep_stderr = 0, r;
+ char* statefile = NULL;
ARGBEGIN
{
case 's':
sitename = EARGF(usage());
+ /* To simplify re-exec: */
+ sitename = memdup(sitename, strlen(sitename) + 1);
+ if (sitename == NULL)
+ goto fail;
break;
case 'm':
method = get_method(EARGF(usage()));
@@ -937,6 +1060,9 @@ int main(int argc, char** argv)
case 'k':
keep_stderr = 1;
break;
+ case '#': /* Internal, do not document */
+ statefile = EARGF(usage());
+ break;
default:
usage();
}
@@ -944,7 +1070,7 @@ int main(int argc, char** argv)
if (argc > 0)
usage();
- switch ((r = initialise(method, sitename, preserve, foreground, keep_stderr)))
+ switch ((r = initialise(statefile == NULL, preserve, foreground, keep_stderr)))
{
case 1:
break;
@@ -959,6 +1085,11 @@ int main(int argc, char** argv)
return -r;
}
+ if (statefile != NULL)
+ {
+ /* TODO unmarshal */
+ }
+
rc = 0;
done:
destroy();