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Diffstat (limited to '')
| -rw-r--r-- | include/unistd.h | 151 |
1 files changed, 150 insertions, 1 deletions
diff --git a/include/unistd.h b/include/unistd.h index c1ab07b..a3f9f53 100644 --- a/include/unistd.h +++ b/include/unistd.h @@ -959,7 +959,156 @@ int daemon(int, int) #if defined(__SLIBC_SOURCE) -int daemonise(const char* int); /* TODO */ +/** + * Leave all opened files open. + */ +#define DAEMONISE_NO_CLOSE 1 + +/** + * Leave all signal handlers rather than + * appling default signal handlers. + */ +#define DAEMONISE_NO_SIG_DFL 2 + +/** + * Leave the signal block mask as-is. + */ +#define DAEMONISE_KEEP_SIGMASK 4 + +/** + * Do not remove malformatted environment entries. + */ +#define DAEMONISE_KEEP_ENVIRON 8 + +/** + * Do not set umask to zero. + */ +#define DAEMONISE_KEEP_UMASK 16 + +/** + * Do not create a PID file. + */ +#define DAEMONISE_NO_PID_FILE 32 + +/** + * Do not close stderr even if it is + * a terminal device. + * + * Cannot be combined with `DAEMONISE_KEEP_STDERR`. + */ +#define DAEMONISE_KEEP_STDERR 64 + +/** + * Close stderr even if it is + * not a terminal device. + * + * Cannot be combined with `DAEMONISE_KEEP_STDERR`. + */ +#define DAEMONISE_CLOSE_STDERR 128 + +/** + * Do not close stdin. + */ +#define DAEMONISE_KEEP_STDIN 256 + +/** + * Do not close stdout. + */ +#define DAEMONISE_KEEP_STDOUT 512 + +/** + * Daemonise the process. This means to: + * + * - close all file descritors except for those to + * stdin, stdout, and stderr, + * + * - remove all custom signal handlers, and apply + * the default handlers. + * + * - unblock all signals, + * + * - remove all malformatted entries in the + * environment (this not containing an '=',) + * + * - set the umask to zero, to be ensure that all + * file permissions are set as specified, + * + * - change directory to '/', to ensure that the + * process does not block any mountpoint from being + * unmounted, + * + * - fork to become a background process, + * + * - temporarily become a session leader to ensure + * that the process does not have a controlling + * terminal. + * + * - fork again to become a child of the daemon + * supervisor, (subreaper could however be in the + * say, so one should not merely rely on this when + * writing a daemon supervisor,) (the first child + * shall exit after this,) + * + * - create, exclusively, a PID file to stop the daemon + * to be being run twice concurrently, and to let + * the daemon supervicer know the process ID of the + * daemon, + * + * - redirect stdin and stdout to /dev/null, + * as well as stderr if it is currently directed + * to a terminal, and + * + * - exit in the original process to let the daemon + * supervisor know that the daemon has been + * initialised. + * + * Before calling this function, you should remove any + * environment variable that could negatively impact + * the runtime of the process. + * + * After calling this function, you should remove + * unnecessary privileges. + * + * Do not try do continue the process in failure unless + * you make sure to only do this in the original process. + * But not that things will not necessarily be as when + * you make the function call. The process can have become + * partially deamonised. + * + * @param name The name of the daemon. Use a hardcoded value, + * not the process name. Must not be `NULL`. + * @param flags Flags to modify the behaviour of the function. + * A bitwise OR combination of the constants: + * - `DAEMONISE_NO_CLOSE` + * - `DAEMONISE_NO_SIG_DFL` + * - `DAEMONISE_KEEP_SIGMASK` + * - `DAEMONISE_KEEP_ENVIRON` + * - `DAEMONISE_KEEP_UMASK` + * - `DAEMONISE_NO_PID_FILE` + * - `DAEMONISE_KEEP_STDERR` + * - `DAEMONISE_CLOSE_STDERR` + * - `DAEMONISE_KEEP_STDIN` + * - `DAEMONISE_KEEP_STDOUT` + * @return Zero on success, -1 on error. + * + * @throws EEXIST The PID file already exists on the system. + * Unless your daemon supervisor removs old + * PID files, this could mean that the daemon + * has exited without removing the PID file. + * @throws Any error specified for signal(3). + * @throws Any error specified for sigemptyset(3). + * @throws Any error specified for sigprocmask(3). + * @throws Any error specified for chdir(3). + * @throws Any error specified for pipe(3). + * @throws Any error specified for dup2(3). + * @throws Any error specified for fork(3). + * @throws Any error specified for setsid(3). + * @throws Any error specified for open(3). + * + * @since Always. + */ +int daemonise(const char* int) + __GCC_ONLY(__attributes__((__nonnull__))); #endif |