Change license and style, reorganise file, make makefile portable, and fix bugs1.3

Signed-off-by: Mattias Andrée <maandree@kth.se>

1 files changed, 363 insertions, 0 deletions

diff --git a/servers-kernel.c b/servers-kernel.c
new file mode 100644
index 0000000..fd60aef
--- /dev/null
+++ b/servers-kernel.c
@@ -0,0 +1,363 @@
+/* See LICENSE file for copyright and license details. */
+#include "servers-kernel.h"
+#include "state.h"
+#include "util.h"
+
+#include <libgamma.h>
+
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/un.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <pwd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+
+/**
+ * Get the pathname of the runtime file
+ * 
+ * @param   suffix  The suffix for the file
+ * @return          The pathname of the file, `NULL` on error
+ */
+GCC_ONLY(__attribute__((__malloc__, __nonnull__)))
+static char *
+get_pathname(const char *restrict suffix)
+{
+	const char *restrict rundir = getenv("XDG_RUNTIME_DIR");
+	const char *restrict username = "";
+	char *name = NULL;
+	char *p;
+	char *restrict rc;
+	struct passwd *restrict pw;
+	size_t n;
+
+	if (sitename) {
+		name = memdup(sitename, strlen(sitename) + 1);
+		if (!name)
+			goto fail;
+	} else if ((name = libgamma_method_default_site(method))) {
+		name = memdup(name, strlen(name) + 1);
+		if (!name)
+			goto fail;
+	}
+
+	if (name) {
+		switch (method) {
+		case LIBGAMMA_METHOD_X_RANDR:
+		case LIBGAMMA_METHOD_X_VIDMODE:
+			if ((p = strrchr(name, ':')))
+				if ((p = strchr(p, '.')))
+					*p = '\0';
+			break;
+		default:
+			break;
+		}
+	}
+
+	if (!rundir || !*rundir)
+		rundir = "/tmp";
+
+	if ((pw = getpwuid(getuid())))
+		username = pw->pw_name ? pw->pw_name : "";
+
+	n = sizeof("/.coopgammad/~/.") + 3 * sizeof(int);
+	n += strlen(rundir) + strlen(username) + (name ? strlen(name) : 0) + strlen(suffix);
+	if (!(rc = malloc(n)))
+		goto fail;
+	sprintf(rc, "%s/.coopgammad/~%s/%i%s%s%s",
+	        rundir, username, method, name ? "." : "", name ? name : "", suffix);
+	free(name);
+	return rc;
+
+fail:
+	free(name);
+	return NULL;
+}
+
+
+/**
+ * Get the pathname of the socket
+ * 
+ * @return  The pathname of the socket, `NULL` on error
+ */
+char *
+get_socket_pathname(void)
+{
+	return get_pathname(".socket");
+}
+
+
+/**
+ * Get the pathname of the PID file
+ * 
+ * @return  The pathname of the PID file, `NULL` on error
+ */
+char *
+get_pidfile_pathname(void)
+{
+	return get_pathname(".pid");
+}
+
+
+/**
+ * Get the pathname of the state file
+ * 
+ * @return  The pathname of the state file, `NULL` on error
+ */
+char *
+get_state_pathname(void)
+{
+	return get_pathname(".state");
+}
+
+
+/**
+ * Check whether a PID file is outdated
+ * 
+ * @param   pidpath  The PID file
+ * @param   token    An environment variable (including both key and value)
+ *                   that must exist in the process if it is a coopgammad process
+ * @return           -1: An error occurred
+ *                    0: The service is already running
+ *                    1: The PID file is outdated
+ */
+GCC_ONLY(__attribute__((__nonnull__)))
+static int
+is_pidfile_reusable(const char *restrict pidpath, const char *restrict token)
+{
+	/* PORTERS: /proc/$PID/environ is Linux specific */
+
+	char temp[sizeof("/proc//environ") + 3 * sizeof(long long int)];
+	int fd = -1, saved_errno, tries = 0;
+	char *content = NULL;
+	char *p;
+	pid_t pid = 0;
+	size_t n;
+#if defined(__linux__) || defined(HAVE_LINUX_PROCFS)
+	char *end;
+#else
+	(void) token;
+#endif
+
+	/* Get PID */
+retry:
+	fd = open(pidpath, O_RDONLY);
+	if (fd < 0)
+		return -1;
+	content = nread(fd, &n);
+	if (!content)
+		goto fail;
+	close(fd);
+	fd = -1;
+
+	if (!n) {
+		if (++tries > 1)
+			goto bad;
+		msleep(100); /* 1 tenth of a second */
+		goto retry;
+	}
+
+	if ('0' > content[0] || content[0] > '9')
+		goto bad;
+	if (content[0] == '0' && '0' <= content[1] && content[1] <= '9')
+		goto bad;
+	for (p = content; *p; p++)
+		if ('0' <= *p && *p <= '9')
+			pid = pid * 10 + (*p & 15);
+		else
+			break;
+	if (*p++ != '\n')
+		goto bad;
+	if (*p)
+		goto bad;
+	if ((size_t)(p - content) != n)
+		goto bad;
+	sprintf(temp, "%llu\n", (unsigned long long)pid);
+	if (strcmp(content, temp))
+		goto bad;
+	free(content);
+
+	/* Validate PID */
+#if defined(__linux__) || defined(HAVE_LINUX_PROCFS)
+	sprintf(temp, "/proc/%llu/environ", (unsigned long long int)pid);
+	fd = open(temp, O_RDONLY);
+	if (fd < 0)
+		return (errno == ENOENT || errno == EACCES) ? 1 : -1;
+	content = nread(fd, &n);
+	if (!content)
+		goto fail;
+	close(fd), fd = -1;
+
+	for (end = &(p = content)[n]; p != end; p = &strchr(p, '\0')[1])
+		if (!strcmp(p, token))
+			return free(content), 0;
+	free(content);
+#else
+	if (!kill(pid, 0) || errno == EINVAL)
+		return 0;
+#endif
+
+	return 1;
+
+bad:
+	fprintf(stderr, "%s: pid file contains invalid content: %s\n", argv0, pidpath);
+	errno = 0;
+	return -1;
+
+fail:
+	saved_errno = errno;
+	free(content);
+	if (fd >= 0)
+		close(fd);
+	errno = saved_errno;
+	return -1;
+}
+
+
+/**
+ * Create PID file
+ * 
+ * @param   pidpath  The pathname of the PID file
+ * @return           Zero on success, -1 on error,
+ *                   -2 if the service is already running
+ */
+int
+create_pidfile(char *pidpath)
+{
+	int fd = -1, r, saved_errno;
+	char *p;
+	char *restrict token = NULL;
+
+	/* Create token used to validate the service. */
+	token = malloc(sizeof("COOPGAMMAD_PIDFILE_TOKEN=") + strlen(pidpath));
+	if (!token)
+		return -1;
+	sprintf(token, "COOPGAMMAD_PIDFILE_TOKEN=%s", pidpath);
+#if !defined(USE_VALGRIND)
+	if (putenv(token))
+		goto putenv_fail;
+	/* `token` must not be free! */
+#else
+	{
+		static char static_token[sizeof("COOPGAMMAD_PIDFILE_TOKEN=") + PATH_MAX];
+		if (strlen(pidpath) > PATH_MAX)
+			abort();
+		strcpy(static_token, token);
+		if (putenv(static_token))
+			goto fail;
+	}
+#endif
+
+	/* Create PID file's directory. */
+	for (p = pidpath; *p == '/'; p++);
+	while ((p = strchr(p, '/'))) {
+		*p = '\0';
+		if (mkdir(pidpath, 0755) < 0) {
+			if (errno != EEXIST) {
+				*p = '/';
+				goto fail;
+			}
+		}
+		*p++ = '/';
+	}
+
+	/* Create PID file. */
+retry:
+	fd = open(pidpath, O_CREAT | O_EXCL | O_WRONLY, 0644);
+	if (fd < 0) {
+		if (errno == EINTR)
+			goto retry;
+		if (errno != EEXIST)
+			return -1;
+		r = is_pidfile_reusable(pidpath, token);
+		if (r > 0) {
+			unlink(pidpath);
+			goto retry;
+		} else if (r < 0) {
+			goto fail;
+		}
+		fprintf(stderr, "%s: service is already running\n", argv0);
+		errno = 0;
+		return -2;
+	}
+
+	/* Write PID to PID file. */
+	if (dprintf(fd, "%llu\n", (unsigned long long)getpid()) < 0)
+		goto fail;
+
+	/* Done */
+#if defined(USE_VALGRIND)
+	free(token);
+#endif
+	if (close(fd) < 0)
+		if (errno != EINTR)
+			return -1;
+	return 0;
+#if !defined(USE_VALGRIND)
+putenv_fail:
+	free(token);
+#endif
+fail:
+#if defined(USE_VALGRIND)
+	free(token);
+#endif
+	if (fd >= 0) {
+		saved_errno = errno;
+		close(fd);
+		unlink(pidpath);
+		errno = saved_errno;
+	}
+	return -1;
+}
+
+
+/**
+ * Create socket and start listening
+ * 
+ * @param   socketpath  The pathname of the socket
+ * @return              Zero on success, -1 on error
+ */
+int
+create_socket(const char *socketpath)
+{
+	struct sockaddr_un address;
+
+	address.sun_family = AF_UNIX;
+	if (strlen(socketpath) >= sizeof(address.sun_path)) {
+		errno = ENAMETOOLONG;
+		return -1;
+	}
+	strcpy(address.sun_path, socketpath);
+	unlink(socketpath);
+	socketfd = socket(PF_UNIX, SOCK_STREAM, 0);
+	if (socketfd < 0)
+		return -1;
+	if (fchmod(socketfd, S_IRWXU) < 0)
+		return -1;
+	if (bind(socketfd, (struct sockaddr *)&address, (socklen_t)sizeof(address)) < 0)
+		return -1;
+	if (listen(socketfd, SOMAXCONN) < 0)
+		return -1;
+
+	return 0;
+}
+
+
+/**
+ * Close and unlink the socket
+ * 
+ * @param  socketpath  The pathname of the socket
+ */
+void
+close_socket(const char *socketpath)
+{
+	if (socketfd >= 0) {
+		shutdown(socketfd, SHUT_RDWR);
+		close(socketfd);
+		unlink(socketpath);
+	}
+}