From: Andre Noll Date: Tue, 18 Mar 2008 17:59:25 +0000 (+0100) Subject: Implement the run command. X-Git-Tag: v0.0.3~7 X-Git-Url: http://git.tuebingen.mpg.de/?p=dss.git;a=commitdiff_plain;h=a0b87ba0529cc6ab075e1d7a11f8b4adc47948eb Implement the run command. --- diff --git a/Makefile b/Makefile index e0eeb48..b2d6fd1 100644 --- a/Makefile +++ b/Makefile @@ -1,4 +1,4 @@ -dss_objects := dss.o cmdline.o string.o fd.o exec.o signal.o daemon.o df.o +dss_objects := cmdline.o dss.o string.o fd.o exec.o signal.o daemon.o df.o time.o all: dss man: dss.1 @@ -22,7 +22,7 @@ include Makefile.deps dss: $(dss_objects) $(CC) $(CPPFLAGS) $(DEBUG_CPPFLAGS) -o $@ $(dss_objects) -%.o: %.c +%.o: %.c cmdline.h $(CC) -c $(CPPFLAGS) $(DEBUG_CPPFLAGS) $< %.ppm: %.sk diff --git a/dss.c b/dss.c index 1fa6d56..080b369 100644 --- a/dss.c +++ b/dss.c @@ -9,6 +9,7 @@ #include #include #include +#include #include #include #include @@ -25,6 +26,7 @@ #include "daemon.h" #include "signal.h" #include "df.h" +#include "time.h" struct gengetopt_args_info conf; @@ -32,6 +34,18 @@ char *dss_error_txt = NULL; static FILE *logfile; int signal_pipe; +/** Process id of current rsync process. */ +static pid_t rsync_pid; +/** Whether the rsync process is currently stopped */ +static int rsync_stopped; +/** Process id of current rm process. */ +static pid_t rm_pid; +/** When the next snapshot is due. */ +struct timeval next_snapshot_time; +/* Creation time of the snapshot currently being created. */ +int64_t current_snapshot_creation_time; + + DEFINE_DSS_ERRLIST; @@ -73,6 +87,19 @@ struct snapshot { unsigned interval; }; +/* + * An edge snapshot is either the oldest one or the newest one. + * + * We need to find either of them occasionally: The create code + * needs to know the newest snapshot because that is the one + * used as the link destination dir. The pruning code needs to + * find the oldest one in case disk space becomes low. + */ +struct edge_snapshot_data { + int64_t now; + struct snapshot snap; +}; + __printf_2_3 void dss_log(int ll, const char* fmt,...) { va_list argp; @@ -107,6 +134,21 @@ __printf_1_2 void dss_msg(const char* fmt,...) va_end(argp); } +/** + * Return the desired number of snapshots of an interval. + */ +unsigned num_snapshots(int interval) +{ + unsigned n; + + assert(interval >= 0); + + if (interval >= conf.num_intervals_arg) + return 0; + n = conf.num_intervals_arg - interval - 1; + return 1 << n; +} + int is_snapshot(const char *dirname, int64_t now, struct snapshot *s) { int i, ret; @@ -285,6 +327,22 @@ void get_snapshot_list(struct snapshot_list *sl) compare_snapshots); } +void stop_rsync_process(void) +{ + if (!rsync_pid || rsync_stopped) + return; + kill(SIGSTOP, rsync_pid); + rsync_stopped = 1; +} + +void restart_rsync_process(void) +{ + if (!rsync_pid || !rsync_stopped) + return; + kill (SIGCONT, rsync_pid); + rsync_stopped = 0; +} + void free_snapshot_list(struct snapshot_list *sl) { int i; @@ -343,9 +401,10 @@ int wait_for_process(pid_t pid, int *status) return ret; } -int remove_snapshot(struct snapshot *s, pid_t *pid) +int remove_snapshot(struct snapshot *s) { int fds[3] = {0, 0, 0}; + assert(!rm_pid); char *new_name = being_deleted_name(s); int ret = dss_rename(s->name, new_name); char *argv[] = {"rm", "-rf", new_name, NULL}; @@ -353,13 +412,16 @@ int remove_snapshot(struct snapshot *s, pid_t *pid) if (ret < 0) goto out; DSS_NOTICE_LOG("removing %s (interval = %i)\n", s->name, s->interval); - ret = dss_exec(pid, argv[0], argv, fds); + stop_rsync_process(); + ret = dss_exec(&rm_pid, argv[0], argv, fds); out: free(new_name); return ret; } - -int remove_redundant_snapshot(struct snapshot_list *sl, pid_t *pid) +/* + * return: 0: no redundant snapshots, 1: rm process started, negative: error + */ +int remove_redundant_snapshot(struct snapshot_list *sl) { int ret, i, interval; struct snapshot *s; @@ -367,7 +429,7 @@ int remove_redundant_snapshot(struct snapshot_list *sl, pid_t *pid) DSS_INFO_LOG("looking for intervals containing too many snapshots\n"); for (interval = conf.num_intervals_arg - 1; interval >= 0; interval--) { - unsigned keep = 1<<(conf.num_intervals_arg - interval - 1); + unsigned keep = num_snapshots(interval); unsigned num = sl->interval_count[interval]; struct snapshot *victim = NULL, *prev = NULL; int64_t score = LONG_MAX; @@ -411,13 +473,13 @@ int remove_redundant_snapshot(struct snapshot_list *sl, pid_t *pid) victim->name, victim->interval); continue; } - ret = remove_snapshot(victim, pid); + ret = remove_snapshot(victim); return ret < 0? ret : 1; } return 0; } -int remove_old_snapshot(struct snapshot_list *sl, pid_t *pid) +int remove_outdated_snapshot(struct snapshot_list *sl) { int i, ret; struct snapshot *s; @@ -432,7 +494,7 @@ int remove_old_snapshot(struct snapshot_list *sl, pid_t *pid) s->name, s->interval); continue; } - ret = remove_snapshot(s, pid); + ret = remove_snapshot(s); if (ret < 0) return ret; return 1; @@ -440,25 +502,278 @@ int remove_old_snapshot(struct snapshot_list *sl, pid_t *pid) return 0; } -int wait_for_rm_process(pid_t pid) +int handle_rm_exit(int status) { - int status, es, ret = wait_for_process(pid, &status); - if (ret < 0) - return ret; + int es, ret; + if (!WIFEXITED(status)) { - ret = E_INVOLUNTARY_EXIT; - make_err_msg("rm process %d died involuntary", (int)pid); - return ret; + make_err_msg("rm process %d died involuntary", (int)rm_pid); + ret = -E_INVOLUNTARY_EXIT; + goto out; } es = WEXITSTATUS(status); if (es) { + make_err_msg("rm process %d returned %d", (int)rm_pid, es); ret = -E_BAD_EXIT_CODE; - make_err_msg("rm process %d returned %d", (int)pid, es); + goto out; + } + ret = 1; + rm_pid = 0; +out: + return ret; +} + + +int wait_for_rm_process(void) +{ + int status, ret = wait_for_process(rm_pid, &status); + + if (ret < 0) + return ret; + return handle_rm_exit(status); +} + +void kill_process(pid_t pid) +{ + if (!pid) + return + DSS_WARNING_LOG("sending SIGTERM to pid %d\n", (int)pid); + kill(pid, SIGTERM); +} + +void handle_sighup() +{ + DSS_INFO_LOG("FIXME: no sighup handling yet\n"); +} + +int rename_incomplete_snapshot(int64_t start) +{ + char *old_name, *new_name; + int ret; + + ret = complete_name(start, get_current_time(), &new_name); + if (ret < 0) return ret; + old_name = incomplete_name(start); + ret = dss_rename(old_name, new_name); + if (ret >= 0) + DSS_NOTICE_LOG("%s -> %s\n", old_name, new_name); + free(old_name); + free(new_name); + return ret; +} + + +int handle_rsync_exit(int status) +{ + int es, ret; + + if (!WIFEXITED(status)) { + make_err_msg("rsync process %d died involuntary", (int)rsync_pid); + ret = -E_INVOLUNTARY_EXIT; + goto out; + } + es = WEXITSTATUS(status); + if (es != 0 && es != 23 && es != 24) { + make_err_msg("rsync process %d returned %d", (int)rsync_pid, es); + ret = -E_BAD_EXIT_CODE; + goto out; } + ret = rename_incomplete_snapshot(current_snapshot_creation_time); +out: + rsync_pid = 0; + current_snapshot_creation_time = 0; + rsync_stopped = 0; + return ret; +} + + +void compute_next_snapshot_time(struct snapshot_list *sl) +{ + struct timeval now, unit_interval = {.tv_sec = 24 * 3600 * conf.unit_interval_arg}, + tmp, diff; + int64_t x = 0; + unsigned wanted = num_snapshots(0), num_complete_snapshots = 0; + int i, ret; + struct snapshot *s; + + gettimeofday(&now, NULL); + FOR_EACH_SNAPSHOT(s, i, sl) { + if (!(s->flags & SS_COMPLETE)) + continue; + num_complete_snapshots++; + x += s->completion_time - s->creation_time; + } + assert(x >= 0); + if (num_complete_snapshots) + x /= num_complete_snapshots; /* avg time to create one snapshot */ + x *= wanted; /* time to create all snapshots in interval 0 */ + tmp.tv_sec = x; + tmp.tv_usec = 0; + ret = tv_diff(&unit_interval, &tmp, &diff); /* time between creation */ + if (ret < 0) { + next_snapshot_time = now; + return; + } + tv_divide(wanted, &diff, &tmp); + tv_add(&now, &tmp, &next_snapshot_time); +} + +void handle_signal(struct snapshot_list *sl) +{ + int sig, ret = next_signal(); + + if (ret <= 0) + goto out; + sig = ret; + switch (sig) { + int status; + pid_t pid; + case SIGINT: + case SIGTERM: + restart_rsync_process(); + kill_process(rsync_pid); + kill_process(rm_pid); + exit(EXIT_FAILURE); + case SIGHUP: + handle_sighup(); + break; + case SIGCHLD: + ret = reap_child(&pid, &status); + if (ret <= 0) + break; + assert(pid == rsync_pid || pid == rm_pid); + if (pid == rsync_pid) + ret = handle_rsync_exit(status); + else + ret = handle_rm_exit(status); + free_snapshot_list(sl); + get_snapshot_list(sl); + compute_next_snapshot_time(sl); + } +out: + if (ret < 0) + log_err_msg(ERROR, -ret); +} + +int get_oldest(const char *dirname, void *private) +{ + struct edge_snapshot_data *esd = private; + struct snapshot s; + int ret = is_snapshot(dirname, esd->now, &s); + + if (ret <= 0) + return 1; + if (s.creation_time > esd->snap.creation_time) + return 1; + free(esd->snap.name); + esd->snap = s; return 1; } +int remove_oldest_snapshot() +{ + int ret; + struct edge_snapshot_data esd = { + .now = get_current_time(), + .snap = {.creation_time = LLONG_MAX} + }; + for_each_subdir(get_oldest, &esd); + if (!esd.snap.name) /* no snapshot found */ + return 0; + DSS_INFO_LOG("oldest snapshot: %s\n", esd.snap.name); + ret = 0; + if (esd.snap.creation_time == current_snapshot_creation_time) + goto out; /* do not remove the snapshot currently being created */ + ret = remove_snapshot(&esd.snap); +out: + free(esd.snap.name); + return ret; +} + +/* TODO: Also consider number of inodes. */ +int disk_space_low(void) +{ + struct disk_space ds; + int ret = get_disk_space(".", &ds); + + if (ret < 0) + return ret; + if (conf.min_free_mb_arg) + if (ds.free_mb < conf.min_free_mb_arg) + return 1; + if (conf.min_free_percent_arg) + if (ds.percent_free < conf.min_free_percent_arg) + return 1; + return 0; +} + +int try_to_free_disk_space(int low_disk_space, struct snapshot_list *sl) +{ + int ret; + + ret = remove_outdated_snapshot(sl); + if (ret) /* error, or we are removing something */ + return ret; + /* no outdated snapshot */ + ret = remove_redundant_snapshot(sl); + if (ret) + return ret; + if (!low_disk_space) + return 0; + DSS_WARNING_LOG("disk space low and nothing obvious to remove\n"); + ret = remove_oldest_snapshot(); + if (ret) + return ret; + make_err_msg("uhuhu: not enough disk space for a single snapshot"); + return -ENOSPC; +} + +int select_loop(void) +{ + int ret; + struct timeval tv = {.tv_sec = 60, .tv_usec = 0}; + struct snapshot_list sl = {.num_snapshots = 0}; + + get_snapshot_list(&sl); + compute_next_snapshot_time(&sl); + for (;;) { + struct timeval now; + fd_set rfds; + int low_disk_space; + + FD_ZERO(&rfds); + ret = dss_select(signal_pipe + 1, &rfds, NULL, &tv); + if (ret < 0) + return ret; + if (FD_ISSET(signal_pipe, &rfds)) + handle_signal(&sl); + if (rm_pid) + continue; + ret = disk_space_low(); + if (ret < 0) + break; + low_disk_space = ret; + if (low_disk_space) + stop_rsync_process(); + ret = try_to_free_disk_space(low_disk_space, &sl); + if (ret < 0) + break; + if (rm_pid) + continue; + if (rsync_pid) { + restart_rsync_process(); + continue; + } + /* neither rsync nor rm are running. Start rsync? */ + gettimeofday(&now, NULL); + if (tv_diff(&now, &next_snapshot_time, NULL) < 0) + continue; + } + free_snapshot_list(&sl); + return ret; +} + int com_run(void) { int ret; @@ -470,7 +785,7 @@ int com_run(void) ret = install_sighandler(SIGHUP); if (ret < 0) return ret; - return 42; + return select_loop(); } void log_disk_space(struct disk_space *ds) @@ -484,7 +799,6 @@ int com_prune(void) { int ret; struct snapshot_list sl; - pid_t pid; struct disk_space ds; ret = get_disk_space(".", &ds); @@ -493,25 +807,25 @@ int com_prune(void) log_disk_space(&ds); for (;;) { get_snapshot_list(&sl); - ret = remove_old_snapshot(&sl, &pid); + ret = remove_outdated_snapshot(&sl); free_snapshot_list(&sl); if (ret < 0) return ret; if (!ret) break; - ret = wait_for_rm_process(pid); + ret = wait_for_rm_process(); if (ret < 0) goto out; } for (;;) { get_snapshot_list(&sl); - ret = remove_redundant_snapshot(&sl, &pid); + ret = remove_redundant_snapshot(&sl); free_snapshot_list(&sl); if (ret < 0) return ret; if (!ret) break; - ret = wait_for_rm_process(pid); + ret = wait_for_rm_process(); if (ret < 0) goto out; } @@ -520,36 +834,31 @@ out: return ret; } -struct newest_snapshot_data { - char * newest_name; - int64_t newest_creation_time; - int64_t now; -}; - int get_newest_complete(const char *dirname, void *private) { - struct newest_snapshot_data *nsd = private; + struct edge_snapshot_data *esd = private; struct snapshot s; - int ret = is_snapshot(dirname, nsd->now, &s); + int ret = is_snapshot(dirname, esd->now, &s); if (ret <= 0) return 1; - if (s.creation_time < nsd->newest_creation_time) + if (s.flags != SS_COMPLETE) /* incomplete or being deleted */ + return 1; + if (s.creation_time < esd->snap.creation_time) return 1; - nsd->newest_creation_time = s.creation_time; - free(nsd->newest_name); - nsd->newest_name = s.name; + free(esd->snap.name); + esd->snap = s; return 1; } __malloc char *name_of_newest_complete_snapshot(void) { - struct newest_snapshot_data nsd = { + struct edge_snapshot_data esd = { .now = get_current_time(), - .newest_creation_time = -1 + .snap = {.creation_time = -1} }; - for_each_subdir(get_newest_complete, &nsd); - return nsd.newest_name; + for_each_subdir(get_newest_complete, &esd); + return esd.snap.name; } void create_rsync_argv(char ***argv, int64_t *num) @@ -597,38 +906,19 @@ void free_rsync_argv(char **argv) free(argv); } -int create_snapshot(char **argv, pid_t *pid) +int create_snapshot(char **argv) { int fds[3] = {0, 0, 0}; - return dss_exec(pid, argv[0], argv, fds); -} - -int rename_incomplete_snapshot(int64_t start) -{ - char *old_name, *new_name; - int ret; - - ret = complete_name(start, get_current_time(), &new_name); - if (ret < 0) - return ret; - old_name = incomplete_name(start); - ret = dss_rename(old_name, new_name); - if (ret >= 0) - DSS_NOTICE_LOG("%s -> %s\n", old_name, new_name); - free(old_name); - free(new_name); - return ret; + return dss_exec(&rsync_pid, argv[0], argv, fds); } int com_create(void) { - int ret, status, es; + int ret, status; char **rsync_argv; - int64_t snapshot_num; - pid_t pid; - create_rsync_argv(&rsync_argv, &snapshot_num); + create_rsync_argv(&rsync_argv, ¤t_snapshot_creation_time); if (conf.dry_run_given) { int i; char *msg = NULL; @@ -642,25 +932,15 @@ int com_create(void) free(msg); return 1; } - DSS_NOTICE_LOG("creating snapshot %lli\n", (long long)snapshot_num); - ret = create_snapshot(rsync_argv, &pid); + DSS_NOTICE_LOG("creating snapshot %lli\n", + (long long)current_snapshot_creation_time); + ret = create_snapshot(rsync_argv); if (ret < 0) goto out; - ret = wait_for_process(pid, &status); + ret = wait_for_process(rsync_pid, &status); if (ret < 0) goto out; - if (!WIFEXITED(status)) { - ret = E_INVOLUNTARY_EXIT; - make_err_msg("rsync process %d died involuntary", (int)pid); - goto out; - } - es = WEXITSTATUS(status); - if (es != 0 && es != 23 && es != 24) { - ret = -E_BAD_EXIT_CODE; - make_err_msg("rsync process %d returned %d", (int)pid, es); - goto out; - } - ret = rename_incomplete_snapshot(snapshot_num); + ret = handle_rsync_exit(status); out: free_rsync_argv(rsync_argv); return ret; diff --git a/dss.ggo b/dss.ggo index ec861c0..8cd79ae 100644 --- a/dss.ggo +++ b/dss.ggo @@ -245,19 +245,33 @@ details=" The daemon will, in an endlees loop, create a snapshot and then sleep that many minutes. " +option "min_free_mb" m +#~~~~~~~~~~~~~~~~~~~~~ - -option "min_free" m -#~~~~~~~~~~~~~~~~~~ - -"minimal amount of free space" +"minimal amount of free disk space" int typestr="gigabytes" - default="50" + default="100" optional details=" - If less that this many gigabytes of space is available, - dss will start to remove snapshots (starting from the oldest - snapshot) until the free disk space exeecds this value. + If less that this many megabytes of space is available, \"dss + --run\" dss will start to remove snapshots (starting from the + oldest snapshot) until the free disk space exeecds this value. + See also the --min_free_percent option. + + A value of zero deactivates this check. + +" + +option "min_free_percent" - +#~~~~~~~~~~~~~~~~~~~~~~~~~~ +"minimal percent of free disk space" +int typestr="percent" +default="2" +optional +details=" + See --min_free. Note that it is not recommended to set both + --min_fre_mb and --min_free_percent to zero as this will + cause your file system to fill up quickly. " diff --git a/fd.c b/fd.c index db0433f..4ac6170 100644 --- a/fd.c +++ b/fd.c @@ -102,3 +102,33 @@ __must_check int mark_fd_nonblocking(int fd) return 1; } +/** + * dss' wrapper for select(2). + * + * It calls select(2) (with no exceptfds) and starts over if select() was + * interrupted by a signal. + * + * \param n The highest-numbered descriptor in any of the two sets, plus 1. + * \param readfds fds that should be checked for readability. + * \param writefds fds that should be checked for writablility. + * \param timeout_tv upper bound on the amount of time elapsed before select() + * returns. + * + * \return The return value of the underlying select() call on success, the + * negative system error code on errors. + * + * All arguments are passed verbatim to select(2). + * \sa select(2) select_tut(2). + */ +int dss_select(int n, fd_set *readfds, fd_set *writefds, + struct timeval *timeout_tv) +{ + int ret, err; + do { + ret = select(n, readfds, writefds, NULL, timeout_tv); + err = errno; + } while (ret < 0 && err == EINTR); + if (ret < 0) + return -ERRNO_TO_DSS_ERROR(errno); + return ret; +} diff --git a/fd.h b/fd.h index fa14ad2..e24d446 100644 --- a/fd.h +++ b/fd.h @@ -21,3 +21,6 @@ _static_inline_ int dss_rename(const char *old_path, const char *new_path) make_err_msg("rename %s -> %s failed", old_path, new_path); return ret; } + +int dss_select(int n, fd_set *readfds, fd_set *writefds, + struct timeval *timeout_tv); diff --git a/signal.c b/signal.c index c82e58b..03926a4 100644 --- a/signal.c +++ b/signal.c @@ -86,21 +86,20 @@ static void generic_signal_handler(int s) * * \sa waitpid(2) */ -int reap_child(pid_t *pid) +int reap_child(pid_t *pid, int *status) { - int status; - *pid = waitpid(-1, &status, WNOHANG); + *pid = waitpid(-1, status, WNOHANG); if (!*pid) return 0; if (*pid < 0) return -ERRNO_TO_DSS_ERROR(errno); - if (WIFEXITED(status)) + if (WIFEXITED(*status)) DSS_DEBUG_LOG("child %i exited. Exit status: %i\n", (int)*pid, - WEXITSTATUS(status)); - else if (WIFSIGNALED(status)) + WEXITSTATUS(*status)); + else if (WIFSIGNALED(*status)) DSS_DEBUG_LOG("child %i was killed by signal %i\n", (int)*pid, - WTERMSIG(status)); + WTERMSIG(*status)); else DSS_WARNING_LOG("child %i terminated abormally\n", (int)*pid); return 1; diff --git a/signal.h b/signal.h index 93fa8a8..1f7bf08 100644 --- a/signal.h +++ b/signal.h @@ -8,6 +8,6 @@ int signal_init(void); int install_sighandler(int); -int reap_child(pid_t *pid); int next_signal(void); void signal_shutdown(void); +int reap_child(pid_t *pid, int *status); diff --git a/string.c b/string.c index cf6d0b1..ac9c336 100644 --- a/string.c +++ b/string.c @@ -13,6 +13,7 @@ #include "gcc-compat.h" #include "log.h" #include "error.h" +#include "string.h" __noreturn void clean_exit(int status); @@ -183,15 +184,6 @@ __must_check __malloc char *get_homedir(void) return dss_strdup(pw? pw->pw_dir : "/tmp"); } -/** \cond LLONG_MAX and LLONG_LIN might not be defined. */ -#ifndef LLONG_MAX -#define LLONG_MAX (1 << (sizeof(long) - 1)) -#endif -#ifndef LLONG_MIN -#define LLONG_MIN (-LLONG_MAX - 1LL) -#endif -/** \endcond */ - /** * Convert a string to a 64-bit signed integer value. * diff --git a/string.h b/string.h index 41afe8f..187f1f4 100644 --- a/string.h +++ b/string.h @@ -7,3 +7,13 @@ __printf_1_2 void make_err_msg(const char* fmt,...); __must_check __malloc char *get_homedir(void); int dss_atoi64(const char *str, int64_t *value); __must_check __malloc char *dss_logname(void); + +/** \cond LLONG_MAX and LLONG_LIN might not be defined. */ +#ifndef LLONG_MAX +#define LLONG_MAX (1 << (sizeof(long) - 1)) +#endif +#ifndef LLONG_MIN +#define LLONG_MIN (-LLONG_MAX - 1LL) +#endif +/** \endcond */ + diff --git a/time.c b/time.c new file mode 100644 index 0000000..18366cd --- /dev/null +++ b/time.c @@ -0,0 +1,131 @@ +#include +#include +#include + +/* + * Copyright (C) 2005-2008 Andre Noll + * + * Licensed under the GPL v2. For licencing details see COPYING. + */ + +/** \file time.c Helper functions for dealing with time values. */ + +/** + * Convert struct timeval to milliseconds. + * + * \param tv The time value value to convert. + * + * \return The number off milliseconds in \a tv. + */ +long unsigned tv2ms(const struct timeval *tv) +{ + return tv->tv_sec * 1000 + (tv->tv_usec + 500)/ 1000; +} + +/** + * Convert milliseconds to a struct timeval. + * + * \param n The number of milliseconds. + * \param tv Result pointer. + */ +void ms2tv(long unsigned n, struct timeval *tv) +{ + tv->tv_sec = n / 1000; + tv->tv_usec = (n % 1000) * 1000; +} + +/** + * Convert a double to a struct timeval. + * + * \param x The value to convert. + * \param tv Result pointer. + */ +void d2tv(double x, struct timeval *tv) +{ + tv->tv_sec = x; + tv->tv_usec = (x - (double)tv->tv_sec) * 1000.0 * 1000.0 + 0.5; +} + +/** + * Compute the difference of two time values. + * + * \param b Minuend. + * \param a Subtrahend. + * \param diff Result pointer. + * + * If \a diff is not \p NULL, it contains the absolute value |\a b - \a a| on + * return. + * + * \return If \a b < \a a, this function returns -1, otherwise it returns 1. + */ +int tv_diff(const struct timeval *b, const struct timeval *a, struct timeval *diff) +{ + int ret = 1; + + if ((b->tv_sec < a->tv_sec) || + ((b->tv_sec == a->tv_sec) && (b->tv_usec < a->tv_usec))) { + const struct timeval *tmp = a; + a = b; + b = tmp; + ret = -1; + } + if (!diff) + return ret; + diff->tv_sec = b->tv_sec - a->tv_sec; + if (b->tv_usec < a->tv_usec) { + diff->tv_sec--; + diff->tv_usec = 1000 * 1000 - a->tv_usec + b->tv_usec; + } else + diff->tv_usec = b->tv_usec - a->tv_usec; + return ret; +} + +/** + * Add two time values. + * + * \param a First addend. + * \param b Second addend. + * \param sum Contains the sum \a + \a b on return. + */ +void tv_add(const struct timeval *a, const struct timeval *b, + struct timeval *sum) +{ + sum->tv_sec = a->tv_sec + b->tv_sec; + if (a->tv_usec + b->tv_usec >= 1000 * 1000) { + sum->tv_sec++; + sum->tv_usec = a->tv_usec + b->tv_usec - 1000 * 1000; + } else + sum->tv_usec = a->tv_usec + b->tv_usec; +} + +/** + * Compute integer multiple of given struct timeval. + * + * \param mult The integer value to multiply with. + * \param tv The timevalue to multiply. + * + * \param result Contains \a mult * \a tv on return. + */ +void tv_scale(const unsigned long mult, const struct timeval *tv, + struct timeval *result) +{ + result->tv_sec = mult * tv->tv_sec; + result->tv_sec += tv->tv_usec * mult / 1000 / 1000; + result->tv_usec = tv->tv_usec * mult % (1000 * 1000); +} + +/** + * Compute a fraction of given struct timeval. + * + * \param divisor The integer value to divide by. + * \param tv The timevalue to divide. + * \param result Contains (1 / mult) * tv on return. + */ +void tv_divide(const unsigned long divisor, const struct timeval *tv, + struct timeval *result) +{ + uint64_t x = ((uint64_t)tv->tv_sec * 1000 * 1000 + tv->tv_usec) / divisor; + + result->tv_sec = x / 1000 / 1000; + result->tv_usec = x % (1000 * 1000); +} diff --git a/time.h b/time.h new file mode 100644 index 0000000..97b3065 --- /dev/null +++ b/time.h @@ -0,0 +1,8 @@ +int tv_diff(const struct timeval *b, const struct timeval *a, struct timeval *diff); +long unsigned tv2ms(const struct timeval*); +void d2tv(double, struct timeval*); +void tv_add(const struct timeval*, const struct timeval *, struct timeval *); +void tv_scale(const unsigned long, const struct timeval *, struct timeval *); +void tv_divide(const unsigned long divisor, const struct timeval *tv, + struct timeval *result); +void ms2tv(const long unsigned n, struct timeval *tv);