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Add the -P option which executes multiple copies of the specified utility

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in parallel. Idea from GNU xargs.
This commit is contained in:
Tim J. Robbins 2002-12-21 10:17:13 +00:00
parent fabf7ce58c
commit 330d23f50e
2 changed files with 57 additions and 19 deletions
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10
usr.bin/xargs/xargs.1
View File

@ -57,6 +57,7 @@
.Fl n Ar number
.Op Fl x
.Oc
.Op Fl P Ar maxjobs
.Op Fl s Ar size
.Op Ar utility Op Ar argument ...
.Sh DESCRIPTION
@ -191,6 +192,12 @@ arguments remaining for the last invocation of
The current default value for
.Ar number
is 5000.
.It Fl P Ar maxprocs
Parallel mode: run at most
.Ar maxprocs
invocations of
.Ar utility
at once.
.It Fl p
Echo each command to be executed and ask the user whether it should be
executed.
@ -273,7 +280,8 @@ utility is expected to be
.St -p1003.2
compliant.
The
.Fl J
.Fl J ,
.Fl P
and
.Fl R
options are non-standard

66
usr.bin/xargs/xargs.c
View File

@ -76,6 +76,7 @@ static int prompt(void);
static void run(char **);
static void usage(void);
void strnsubst(char **, const char *, const char *, size_t);
static void waitchildren(const char *, int);
static char echo[] = _PATH_ECHO;
static char **av, **bxp, **ep, **exp, **xp;
@ -83,6 +84,9 @@ static char *argp, *bbp, *ebp, *inpline, *p, *replstr;
static const char *eofstr;
static int count, insingle, indouble, pflag, tflag, Rflag, rval, zflag;
static int cnt, Iflag, jfound, Lflag, wasquoted, xflag;
static int curprocs, maxprocs;
static volatile int childerr;
extern char **environ;
@ -121,7 +125,8 @@ main(int argc, char *argv[])
/* 1 byte for each '\0' */
nline -= strlen(*ep++) + 1 + sizeof(*ep);
}
while ((ch = getopt(argc, argv, "0E:I:J:L:n:pR:s:tx")) != -1)
maxprocs = 1;
while ((ch = getopt(argc, argv, "0E:I:J:L:n:P:pR:s:tx")) != -1)
switch(ch) {
case 'E':
eofstr = optarg;
@ -145,6 +150,10 @@ main(int argc, char *argv[])
if ((nargs = atoi(optarg)) <= 0)
errx(1, "illegal argument count");
break;
case 'P':
if ((maxprocs = atoi(optarg)) <= 0)
errx(1, "max. processes must be >0");
break;
case 'p':
pflag = 1;
break;
@ -249,8 +258,10 @@ parse_input(int argc, char *argv[])
switch(ch = getchar()) {
case EOF:
/* No arguments since last exec. */
if (p == bbp)
if (p == bbp) {
waitchildren(*argv, 1);
exit(rval);
}
goto arg1;
case ' ':
case '\t':
@ -327,8 +338,10 @@ arg2:
*xp++ = *avj;
}
prerun(argc, av);
if (ch == EOF || foundeof)
if (ch == EOF || foundeof) {
waitchildren(*argv, 1);
exit(rval);
}
p = bbp;
xp = bxp;
count = 0;
@ -467,10 +480,8 @@ prerun(int argc, char *argv[])
static void
run(char **argv)
{
volatile int childerr;
char **avec;
pid_t pid;
int status;
char **avec;
/*
* If the user wants to be notified of each command before it is
@ -512,17 +523,35 @@ exec:
childerr = errno;
_exit(1);
}
pid = waitpid(pid, &status, 0);
if (pid == -1)
err(1, "waitpid");
/* If we couldn't invoke the utility, exit. */
if (childerr != 0)
err(childerr == ENOENT ? 127 : 126, "%s", *argv);
/* If utility signaled or exited with a value of 255, exit 1-125. */
if (WIFSIGNALED(status) || WEXITSTATUS(status) == 255)
exit(1);
if (WEXITSTATUS(status))
rval = 1;
curprocs++;
waitchildren(*argv, 0);
}
static void
waitchildren(const char *name, int waitall)
{
pid_t pid;
int status;
while ((pid = wait3(&status, !waitall && curprocs < maxprocs ?
WNOHANG : 0, NULL)) > 0) {
curprocs--;
/* If we couldn't invoke the utility, exit. */
if (childerr != 0) {
errno = childerr;
err(errno == ENOENT ? 127 : 126, "%s", name);
}
/*
* If utility signaled or exited with a value of 255,
* exit 1-125.
*/
if (WIFSIGNALED(status) || WEXITSTATUS(status) == 255)
exit(1);
if (WEXITSTATUS(status))
rval = 1;
}
if (pid == -1 && errno != ECHILD)
err(1, "wait3");
}
/*
@ -564,6 +593,7 @@ usage(void)
{
fprintf(stderr,
"usage: xargs [-0pt] [-E eofstr] [-I replstr [-R replacements]] [-J replstr]\n"
" [-L number] [-n number [-x] [-s size] [utility [argument ...]]\n");
" [-L number] [-n number [-x] [-P maxprocs] [-s size]\n"
" [utility [argument ...]]\n");
exit(1);
}