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/*
* parallel.c - run commands in parallel until you run out of commands
*
* Copyright © 2008 Tollef Fog Heen <tfheen@err.no>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* version 2 as published by the Free Software Foundation.
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307
* USA
*
*/
#define _GNU_SOURCE
#include <unistd.h>
#include <string.h>
#include <stdio.h>
#include <sys/time.h>
#include <time.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/select.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#if defined(__FreeBSD_kernel__)
#define WEXITED 0
#endif
void usage() {
printf("parallel [OPTIONS] command -- arguments\n\tfor each argument, "
"run command with argument, in parallel\n");
printf("parallel [OPTIONS] -- commands\n\trun specified commands in parallel\n");
exit(1);
}
void exec_child(char **command, char **arguments, int replace_cb, int nargs) {
if (fork() != 0) {
return;
}
if (command[0]) {
char **argv;
int argc = 0;
int i;
char *s;
while (command[argc] != 0) {
argc++;
}
if (! replace_cb)
argc++;
argv = calloc(sizeof(char*), argc + nargs);
for (i = 0; i < argc; i++) {
while (replace_cb && (s=strstr(command[i], "{}"))) {
char *buf=malloc(strlen(command[i]) + strlen(arguments[0]));
s[0]='\0';
sprintf(buf, "%s%s%s", command[i], arguments[0], s+2);
command[i]=buf;
}
argv[i] = command[i];
}
if (! replace_cb)
memcpy(argv + i - 1, arguments, nargs * sizeof(char *));
execvp(argv[0], argv);
exit(1);
}
else {
int ret=system(arguments[0]);
if (WIFEXITED(ret)) {
exit(WEXITSTATUS(ret));
}
else {
exit(1);
}
}
return;
}
int wait_for_child(int options) {
id_t id_ignored = 0;
siginfo_t infop;
infop.si_pid = 0;
waitid(P_ALL, id_ignored, &infop, WEXITED | options);
if (infop.si_pid == 0) {
return -1; /* Nothing to wait for */
}
if (infop.si_code == CLD_EXITED) {
return infop.si_status;
}
return 1;
}
int main(int argc, char **argv) {
int maxjobs = -1;
int curjobs = 0;
double maxload = -1;
int argsatonce = 1;
int opt;
char **command = calloc(sizeof(char*), argc);
char **arguments = NULL;
int argidx = 0;
int arglen = 0;
int cidx = 0;
int returncode = 0;
int replace_cb = 0;
char *t;
while ((argv[optind] && strcmp(argv[optind], "--") != 0) &&
(opt = getopt(argc, argv, "+hij:l:n:")) != -1) {
switch (opt) {
case 'h':
usage();
break;
case 'i':
replace_cb = 1;
break;
case 'j':
errno = 0;
maxjobs = strtoul(optarg, &t, 0);
if (errno != 0 || (t-optarg) != strlen(optarg)) {
fprintf(stderr, "option '%s' is not a number\n",
optarg);
exit(2);
}
break;
case 'l':
errno = 0;
maxload = strtod(optarg, &t);
if (errno != 0 || (t-optarg) != strlen(optarg)) {
fprintf(stderr, "option '%s' is not a number\n",
optarg);
exit(2);
}
break;
case 'n':
errno = 0;
argsatonce = strtoul(optarg, &t, 0);
if (errno != 0 || argsatonce < 1 || (t-optarg) != strlen(optarg)) {
fprintf(stderr, "option '%s' is not a positive number\n",
optarg);
exit(2);
}
break;
default: /* ’?’ */
usage();
break;
}
}
if (replace_cb && argsatonce > 1) {
fprintf(stderr, "options -i and -n are incomaptible\n");
exit(2);
}
if (maxjobs < 0) {
#ifdef _SC_NPROCESSORS_ONLN
maxjobs = sysconf(_SC_NPROCESSORS_ONLN);
#else
#warning Cannot autodetect number of CPUS on this system: _SC_NPROCESSORS_ONLN not defined.
maxjobs = 1;
#endif
}
while (optind < argc) {
if (strcmp(argv[optind], "--") == 0) {
int i;
optind++;
arglen = argc - optind;
arguments = calloc(sizeof(char *), arglen);
if (! arguments) {
exit(1);
}
for (i = 0; i < arglen; i++) {
arguments[i] = strdup(argv[optind + i]);
}
optind += i;
}
else {
command[cidx] = strdup(argv[optind]);
cidx++;
}
optind++;
}
if (argsatonce > 1 && ! command[0]) {
fprintf(stderr, "option -n cannot be used without a command\n");
exit(2);
}
while (argidx < arglen) {
double load;
getloadavg(&load, 1);
if ((maxjobs == 0 || curjobs < maxjobs) &&
(maxload < 0 || load < maxload)) {
if (argsatonce > arglen - argidx)
argsatonce = arglen - argidx;
exec_child(command, arguments + argidx,
replace_cb, argsatonce);
argidx += argsatonce;
curjobs++;
}
if (maxjobs == 0 || curjobs == maxjobs) {
returncode |= wait_for_child(0);
curjobs--;
}
if (maxload > 0 && load >= maxload) {
int r;
sleep(1); /* XXX We should have a better
* heurestic than this */
r = wait_for_child(WNOHANG);
if (r > 0)
returncode |= r;
if (r != -1)
curjobs--;
}
}
while (curjobs > 0) {
returncode |= wait_for_child(0);
curjobs--;
}
return returncode;
}
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