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/* xargs.c - Run command with arguments taken from stdin.
*
* Copyright 2011 Rob Landley <rob@landley.net>
*
* See http://opengroup.org/onlinepubs/9699919799/utilities/xargs.html
*
* TODO: Rich's whitespace objection, env size isn't fixed anymore.
* TODO: -I Insert mode
* TODO: -L Max number of lines of input per command
* TODO: -x Exit if can't fit everything in one command
* TODO: -P NUM Run up to NUM processes at once
USE_XARGS(NEWTOY(xargs, "^E:optrn#<1(max-args)s#0[!0E]", TOYFLAG_USR|TOYFLAG_BIN))
config XARGS
bool "xargs"
default y
help
usage: xargs [-0prt] [-s NUM] [-n NUM] [-E STR] COMMAND...
Run command line one or more times, appending arguments from stdin.
If command exits with 255, don't launch another even if arguments remain.
-0 Each argument is NULL terminated, no whitespace or quote processing
-E Stop at line matching string
-n Max number of arguments per command
-o Open tty for COMMAND's stdin (default /dev/null)
-p Prompt for y/n from tty before running each command
-r Don't run command with empty input
-s Size in bytes per command line
-t Trace, print command line to stderr
*/
#define FOR_xargs
#include "toys.h"
GLOBALS(
long s, n;
char *E;
long entries, bytes;
char delim;
FILE *tty;
)
// If out==NULL count TT.bytes and TT.entries, stopping at max.
// Otherwise, fill out out[]
// Returning NULL means need more data.
// Returning char * means hit data limits, start of data left over
// Returning 1 means hit data limits, but consumed all data
// Returning 2 means hit -E STR
static char *handle_entries(char *data, char **entry)
{
if (TT.delim) {
char *s = data;
// Chop up whitespace delimited string into args
while (*s) {
char *save;
while (isspace(*s)) {
if (entry) *s = 0;
s++;
}
if (TT.n && TT.entries >= TT.n)
return *s ? s : (char *)1;
if (!*s) break;
save = s;
// We ought to add sizeof(char *) to TT.bytes to be correct, but we don't
// for bug compatibility with busybox 1.30.1 and findutils 4.7.0.
for (;;) {
if (++TT.bytes >= TT.s && TT.s) return save;
if (!*s || isspace(*s)) break;
s++;
}
if (TT.E) {
int len = s-save;
if (len == strlen(TT.E) && !strncmp(save, TT.E, len))
return (char *)2;
}
if (entry) entry[TT.entries] = save;
++TT.entries;
}
// -0 support
} else {
TT.bytes += sizeof(char *)+strlen(data)+1;
if (TT.s && TT.bytes >= TT.s) return data;
if (TT.n && TT.entries >= TT.n) return data;
if (entry) entry[TT.entries] = data;
TT.entries++;
}
return NULL;
}
void xargs_main(void)
{
struct double_list *dlist = NULL, *dtemp;
int entries, bytes, done = 0, status;
char *data = NULL, **out;
pid_t pid;
long posix_max_bytes;
// POSIX requires that we never hit the ARG_MAX limit, even if we try to
// with -s. POSIX also says we have to reserve 2048 bytes "to guarantee
// that the invoked utility has room to modify its environment variables
// and command line arguments and still be able to invoke another utility",
// though obviously that's not really something you can guarantee.
posix_max_bytes = sysconf(_SC_ARG_MAX) - environ_bytes() - 2048;
if (!TT.s || TT.s > posix_max_bytes) TT.s = posix_max_bytes;
if (!FLAG(0)) TT.delim = '\n';
// If no optargs, call echo.
if (!toys.optc) {
free(toys.optargs);
*(toys.optargs = xzalloc(2*sizeof(char *)))="echo";
toys.optc = 1;
}
for (entries = 0, bytes = -1; entries < toys.optc; entries++, bytes++)
bytes += strlen(toys.optargs[entries]);
// Loop through exec chunks.
while (data || !done) {
int doit = 1;
TT.entries = 0;
TT.bytes = bytes;
// Loop reading input
for (;;) {
// Read line
if (!data) {
ssize_t l = 0;
l = getdelim(&data, (size_t *)&l, TT.delim, stdin);
if (l<0) {
data = 0;
done++;
break;
}
}
dlist_add(&dlist, data);
// Count data used
data = handle_entries(data, NULL);
if (!data) continue;
if (data == (char *)2) done++;
if ((unsigned long)data <= 2) data = 0;
else data = xstrdup(data);
break;
}
if (TT.entries == 0 && FLAG(r)) continue;
// Accumulate cally thing
if (data && !TT.entries) error_exit("argument too long");
out = xzalloc((entries+TT.entries+1)*sizeof(char *));
// Fill out command line to exec
memcpy(out, toys.optargs, entries*sizeof(char *));
TT.entries = 0;
TT.bytes = bytes;
if (dlist) dlist->prev->next = 0;
for (dtemp = dlist; dtemp; dtemp = dtemp->next)
handle_entries(dtemp->data, out+entries);
if (FLAG(p) || FLAG(t)) {
int i;
for (i = 0; out[i]; ++i) fprintf(stderr, "%s ", out[i]);
if (FLAG(p)) {
fprintf(stderr, "?");
if (!TT.tty) TT.tty = xfopen("/dev/tty", "re");
doit = fyesno(TT.tty, 0);
} else fprintf(stderr, "\n");
}
if (doit) {
if (!(pid = XVFORK())) {
xclose(0);
if (open(FLAG(o) ? "/dev/tty" : "/dev/null", O_RDONLY) != 0)
perror_exit("child stdin open");
xexec(out);
}
waitpid(pid, &status, 0);
status = WIFEXITED(status) ? WEXITSTATUS(status) : WTERMSIG(status)+127;
}
// Abritrary number of execs, can't just leak memory each time...
while (dlist) {
struct double_list *dtemp = dlist->next;
free(dlist->data);
free(dlist);
dlist = dtemp;
}
free(out);
}
if (TT.tty) fclose(TT.tty);
}
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