Hi,
This is adds -P to xargs, taken from freebsd. Example usage:
find . -type f -name \*.iso -print0 | xargs -0n1 -P4 bzip2
- Axel Scheepers
diff --git a/usr.bin/xargs/xargs.1 b/usr.bin/xargs/xargs.1
index 045e235..4d76b98 100644
--- a/usr.bin/xargs/xargs.1
+++ b/usr.bin/xargs/xargs.1
@@ -58,6 +58,7 @@
.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
@@ -192,6 +193,12 @@ 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 o
Reopen stdin as
.Pa /dev/tty
@@ -285,7 +292,7 @@ utility is expected to be
.St -p1003.2
compliant.
The
-.Fl J , o
+.Fl J , o , P
and
.Fl R
options are non-standard
diff --git a/usr.bin/xargs/xargs.c b/usr.bin/xargs/xargs.c
index f48b975..cc0a59c 100644
--- a/usr.bin/xargs/xargs.c
+++ b/usr.bin/xargs/xargs.c
@@ -66,6 +66,7 @@ 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, **expx, **xp;
@@ -73,6 +74,8 @@ static char *argp, *bbp, *ebp, *inpline, *p, *replstr;
static const char *eofstr;
static int count, insingle, indouble, oflag, pflag, tflag, Rflag, rval, zflag;
static int cnt, Iflag, jfound, Lflag, wasquoted, xflag;
+static int curprocs, maxprocs;
+static volatile int childerr;
extern char **environ;
@@ -112,7 +115,9 @@ 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:opR:s:tx")) != -1)
+
+ maxprocs = 1;
+ while ((ch = getopt(argc, argv, "0E:I:J:L:n:P:opR:s:tx")) != -1)
switch(ch) {
case 'E':
eofstr = optarg;
@@ -144,6 +149,10 @@ main(int argc, char *argv[])
case 'p':
pflag = 1;
break;
+ case 'P':
+ if ((maxprocs = atoi(optarg)) <= 0)
+ errx(1, "max.processes must be >0");
+ break;
case 'R':
if ((Rflag = atoi(optarg)) <= 0)
errx(1, "illegal number of replacements");
@@ -245,8 +254,10 @@ 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':
@@ -323,8 +334,10 @@ 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;
@@ -463,10 +476,8 @@ prerun(int argc, char *argv[])
static void
run(char **argv)
{
- volatile int childerr;
char **avec;
pid_t pid;
- int status;
/*
* If the user wants to be notified of each command before it is
@@ -516,17 +527,40 @@ 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);
+}
+
+/*
+ * Handle child processes.
+ */
+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");
}
/*
@@ -567,6 +601,7 @@ usage(void)
{
fprintf(stderr,
"usage: xargs [-0opt] [-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);
}
