diff options
Diffstat (limited to 'src/lib/lockfile.c')
| -rw-r--r-- | src/lib/lockfile.c | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/src/lib/lockfile.c b/src/lib/lockfile.c new file mode 100644 index 00000000..a93d5f17 --- /dev/null +++ b/src/lib/lockfile.c @@ -0,0 +1,170 @@ +/* + * Ouroboros - Copyright (C) 2016 + * + * Lockfile for ouroboros system + * + * Dimitri Staessens <[email protected]> + * + * 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 2 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, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +#include <ouroboros/config.h> +#include <ouroboros/lockfile.h> + +#define OUROBOROS_PREFIX "lockfile" + +#include <ouroboros/logs.h> + +#include <stdlib.h> +#include <unistd.h> +#include <fcntl.h> +#include <string.h> +#include <signal.h> +#include <sys/mman.h> +#include <sys/stat.h> + +#define LF_SIZE (sizeof(pid_t)) + +struct lockfile { + pid_t * api; + int fd; +}; + +struct lockfile * lockfile_create() { + struct lockfile * lf = malloc(sizeof(*lf)); + if (lf == NULL) + return NULL; + + lf->fd = shm_open(LOCKFILE_NAME, O_CREAT | O_EXCL | O_RDWR, 0666); + if (lf->fd == -1) { + LOG_DBGF("Could not create lock file."); + free(lf); + return NULL; + } + + if (fchmod(lf->fd, 0666)) { + LOG_DBGF("Failed to chmod lockfile."); + free(lf); + return NULL; + } + + if (lseek(lf->fd, LF_SIZE - 1, SEEK_SET) < 0) { + LOG_DBGF("Failed to extend lockfile."); + free(lf); + return NULL; + } + + if (write(lf->fd, "", 1) != 1) { + LOG_DBGF("Failed to finalise lockfile."); + free(lf); + return NULL; + } + + lf->api = mmap(NULL, + LF_SIZE, PROT_READ | PROT_WRITE, + MAP_SHARED, + lf->fd, + 0); + + if (lf->api == MAP_FAILED) { + LOG_DBGF("Failed to map lockfile."); + + if (shm_unlink(LOCKFILE_NAME) == -1) + LOG_DBGF("Failed to remove invalid lockfile."); + + free(lf); + return NULL; + } + + *lf->api = getpid(); + + return lf; +} + +struct lockfile * lockfile_open() { + struct lockfile * lf = malloc(sizeof(*lf)); + if (lf == NULL) + return NULL; + + lf->fd = shm_open(LOCKFILE_NAME, O_RDWR, 0666); + if (lf->fd == -1) { + LOG_DBGF("Could not open lock file."); + free(lf); + return NULL; + } + + lf->api = mmap(NULL, + LF_SIZE, PROT_READ | PROT_WRITE, + MAP_SHARED, + lf->fd, + 0); + + if (lf->api == MAP_FAILED) { + LOG_DBGF("Failed to map lockfile."); + + if (shm_unlink(LOCKFILE_NAME) == -1) + LOG_DBGF("Failed to remove invalid lockfile."); + + free(lf); + return NULL; + } + + return lf; +} + +void lockfile_close(struct lockfile * lf) +{ + if (lf == NULL) { + LOG_DBGF("Bogus input. Bugging out."); + return; + } + + if (close(lf->fd) < 0) + LOG_DBGF("Couldn't close lockfile."); + + if (munmap(lf->api, LF_SIZE) == -1) + LOG_DBGF("Couldn't unmap lockfile."); + + free(lf); +} + +void lockfile_destroy(struct lockfile * lf) +{ + if (lf == NULL) { + LOG_DBGF("Bogus input. Bugging out."); + return; + } + + if (getpid() != *lf->api && kill(*lf->api, 0) == 0) { + LOG_DBGF("Only IRMd can destroy %s.", LOCKFILE_NAME); + return; + } + + if (close(lf->fd) < 0) + LOG_DBGF("Couldn't close lockfile."); + + if (munmap(lf->api, LF_SIZE) == -1) + LOG_DBGF("Couldn't unmap lockfile."); + + if (shm_unlink(LOCKFILE_NAME) == -1) + LOG_DBGF("Failed to remove lockfile."); + + free(lf); +} + +pid_t lockfile_owner(struct lockfile * lf) +{ + return *lf->api; +} |