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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>
void usage() {
printf("parallel [OPTIONS] command -- arguments: for each argument, "
"run command with argument\n");
exit(1);
}
void exec_child(char **command, char *argument, int replace_cb) {
char **argv;
int argc = 0;
int i;
while (command[argc] != 0) {
argc++;
}
if (replace_cb == 0)
argc++;
argv = calloc(sizeof(char*), argc+1);
for (i = 0; i < argc; i++) {
argv[i] = command[i];
if (replace_cb && (strcmp(argv[i], "{}") == 0))
argv[i] = argument;
}
if (replace_cb == 0)
argv[i-1] = argument;
if (fork() == 0) {
/* Child */
execvp(argv[0], argv);
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;
int maxload = -1;
int opt;
char **command = calloc(sizeof(char*), argc);
char **arguments = NULL;
int argidx = 0;
int cidx = 0;
int returncode = 0;
int replace_cb = 0;
char *t;
while ((opt = getopt(argc, argv, "+hij:l:")) != -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 = strtoul(optarg, &t, 0);
if (errno != 0 || (t-optarg) != strlen(optarg)) {
fprintf(stderr, "option '%s' is not a number\n",
optarg);
exit(2);
}
break;
default: /* ’?’ */
usage();
break;
}
}
if (maxjobs < 0 && maxload < 0) {
maxjobs = 1; /* XXX: Maybe we should try to autodetect
number of CPUs? */
}
while (optind < argc) {
if (strcmp(argv[optind], "--") == 0) {
int i;
size_t mem = (sizeof (char*)) * (argc - optind);
arguments = malloc(mem);
if (! arguments) {
exit(1);
}
memset(arguments, 0, mem);
optind++; /* Skip the -- separator, skip after
* malloc so we have a trailing
* null */
for (i = 0; i < argc - optind; i++) {
arguments[i] = strdup(argv[optind + i]);
}
optind += i;
}
else {
command[cidx] = strdup(argv[optind]);
cidx++;
}
optind++;
}
while (arguments[argidx] != 0) {
double load;
getloadavg(&load, 1);
if ((maxjobs > 0 && curjobs < maxjobs) ||
(maxload > 0 && load < maxload)) {
exec_child(command, arguments[argidx], replace_cb);
argidx++;
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;
curjobs--;
}
}
}
while (curjobs > 0) {
returncode |= wait_for_child(0);
curjobs--;
}
return returncode;
}
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