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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
- USE_XARGS(NEWTOY(xargs, "^E:P#<0=1optrn#<1(max-args)s#0[!0E]", TOYFLAG_USR|TOYFLAG_BIN))
- config XARGS
- bool "xargs"
- default y
- help
- usage: xargs [-0prt] [-snE 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
- -P Parallel processes (default 1)
- -r Don't run with empty input (otherwise always run command once)
- -s Size in bytes per command line
- -t Trace, print command line to stderr
- */
- #define FOR_xargs
- #include "toys.h"
- GLOBALS(
- long s, n, P;
- char *E;
- long entries, bytes, np;
- char delim;
- FILE *tty;
- )
- // If !entry count TT.bytes and TT.entries, stopping at max.
- // Otherwise, fill out entry[].
- // 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 *save, *ss, *s;
- // Chop up whitespace delimited string into args
- for (s = data; *s; TT.entries++) {
- while (isspace(*s)) s++;
- if (TT.n && TT.entries >= TT.n) return *s ? s : (char *)1;
- if (!*s) break;
- save = ss = s;
- // Specifying -s can cause "argument too long" errors.
- if (!FLAG(s)) TT.bytes += sizeof(void *)+1;
- for (;;) {
- if (++TT.bytes >= TT.s) return save;
- if (!*s || isspace(*s)) break;
- s++;
- }
- if (TT.E && strstart(&ss, TT.E) && ss == s) return (char *)2;
- if (entry) {
- entry[TT.entries] = save;
- if (*s) *s++ = 0;
- }
- }
- // -0 support
- } else {
- long bytes = TT.bytes+sizeof(char *)+strlen(data)+1;
- if (bytes >= TT.s || (TT.n && TT.entries >= TT.n)) return data;
- TT.bytes = bytes;
- if (entry) entry[TT.entries] = data;
- TT.entries++;
- }
- return 0;
- }
- // Handle SIGUSR1 and SIGUSR2 for -P
- static void signal_P(int sig)
- {
- if (sig == SIGUSR2 && TT.P>1) TT.P--;
- else TT.P++;
- }
- void xargs_main(void)
- {
- struct double_list *dlist = 0, *dtemp;
- int entries, bytes, done = 0, status;
- char *data = 0, **out = 0;
- pid_t pid = 0;
- xsignal_flags(SIGUSR1, signal_P, SA_RESTART);
- xsignal_flags(SIGUSR2, signal_P, SA_RESTART);
- // 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.
- if (!FLAG(s)) TT.s = sysconf(_SC_ARG_MAX) - environ_bytes() - 4096;
- TT.delim = '\n'*!FLAG(0);
- // If no optargs, call echo.
- if (!toys.optc) {
- free(toys.optargs);
- *(toys.optargs = xzalloc(2*sizeof(char *)))="echo";
- toys.optc = 1;
- }
- // count entries
- for (entries = 0, bytes = -1; entries < toys.optc; entries++)
- bytes += strlen(toys.optargs[entries])+1+sizeof(char *)*!FLAG(s);
- if (bytes >= TT.s) error_exit("command too long");
- // Loop through exec chunks.
- while (data || !done) {
- TT.entries = 0;
- TT.bytes = bytes;
- // Loop reading input
- for (;;) {
- // Read line
- if (!data) {
- size_t l = 0;
- if (getdelim(&data, &l, TT.delim, stdin)<0) {
- data = 0;
- done++;
- break;
- }
- }
- dlist_add(&dlist, data);
- // Count data used
- if (!(data = handle_entries(data, 0))) continue;
- if (data == (char *)2) done++;
- if ((unsigned long)data <= 2) data = 0;
- else data = xstrdup(data);
- break;
- }
- if (!TT.entries) {
- if (data) error_exit("argument too long");
- if (pid || FLAG(r)) goto reap_children;
- }
- // Fill out command line to exec
- out = xzalloc((entries+TT.entries+1)*sizeof(char *));
- 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");
- if (!fyesno(TT.tty, 0)) goto reap_children;
- } else fprintf(stderr, "\n");
- }
- if (!(pid = XVFORK())) {
- close(0);
- xopen_stdio(FLAG(o) ? "/dev/tty" : "/dev/null", O_RDONLY);
- xexec(out);
- }
- TT.np++;
- reap_children:
- while (TT.np) {
- int xv = (TT.np == TT.P) || (!data && done);
- if (1>(xv = waitpid(-1, &status, WNOHANG*!xv))) break;
- TT.np--;
- xv = WIFEXITED(status) ? WEXITSTATUS(status) : WTERMSIG(status)+128;
- if (xv == 255) {
- error_msg("%s: exited with status 255; aborting", *out);
- toys.exitval = 124;
- break;
- } else if ((xv|1)==127) toys.exitval = xv;
- else if (xv>127) xv = 125;
- else if (xv) toys.exitval = 123;
- }
- // Abritrary number of execs, can't just leak memory each time...
- llist_traverse(dlist, llist_free_double);
- dlist = 0;
- free(out);
- out = 0;
- }
- while (TT.np && -1 != wait(&status)) TT.np--;
- if (TT.tty) fclose(TT.tty);
- }
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