/**
* coopgammad -- Cooperative gamma server
* Copyright (C) 2016 Mattias Andrée (maandree@kth.se)
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "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;
int saved_errno;
if (site.site)
{
name = memdup(site.site, strlen(site.site) + 1);
if (name == NULL)
goto fail;
}
else if ((name = libgamma_method_default_site(site.method)))
{
name = memdup(name, strlen(name) + 1);
if (name == NULL)
goto fail;
}
if (name != NULL)
switch (site.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) + strlen(name) + strlen(suffix);
if (!(rc = malloc(n)))
goto fail;
sprintf(rc, "%s/.coopgammad/~%s/%i%s%s%s",
rundir, username, site.method, name ? "." : "", name ? name : "", suffix);
return rc;
fail:
saved_errno = errno;
free(name);
errno = saved_errno;
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(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 == NULL)
goto fail;
close(fd), fd = -1;
if (n == 0)
{
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;
/* Validate PID */
#if defined(HAVE_LINUX_PROCFS)
sprintf(temp, "/proc/%llu/environ", (unsigned long long)pid);
fd = open(temp, O_RDONLY);
if (fd < 0)
return ((errno == ENOENT) || (errno == EACCES)) ? 1 : -1;
content = nread(fd, &n);
if (content == NULL)
goto fail;
close(fd), fd = -1;
for (end = (p = content) + n; p != end; p = strchr(p, '\0') + 1)
if (!strcmp(p, token))
return 0;
#else
if ((kill(pid, 0) == 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, r, saved_errno;
char* p;
char* restrict token;
/* Create token used to validate the service. */
token = malloc(sizeof("COOPGAMMAD_PIDFILE_TOKEN=") + strlen(pidpath));
if (token == NULL)
return -1;
sprintf(token, "COOPGAMMAD_PIDFILE_TOKEN=%s", pidpath);
if (putenv(token))
return -1;
/* Create PID file's directory. */
for (p = pidpath; *p == '/'; p++);
while ((p = strchr(p, '/')))
{
*p = '\0';
if (mkdir(pidpath, 0755) < 0)
if (errno != EEXIST)
return -1;
*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 (close(fd) < 0)
if (errno != EINTR)
return -1;
return 0;
fail:
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);
if ((socketfd = socket(PF_UNIX, SOCK_STREAM, 0)) < 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);
}
}
