freebsd-dev/usr.bin/xargs/xargs.c
Warner Losh fbbd9655e5 Renumber copyright clause 4
Renumber cluase 4 to 3, per what everybody else did when BSD granted
them permission to remove clause 3. My insistance on keeping the same
numbering for legal reasons is too pedantic, so give up on that point.

Submitted by:	Jan Schaumann <jschauma@stevens.edu>
Pull Request:	https://github.com/freebsd/freebsd/pull/96
2017-02-28 23:42:47 +00:00

787 lines
17 KiB
C

/*-
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* John B. Roll Jr.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $xMach: xargs.c,v 1.6 2002/02/23 05:27:47 tim Exp $
*/
#if 0
#ifndef lint
static const char copyright[] =
"@(#) Copyright (c) 1990, 1993\n\
The Regents of the University of California. All rights reserved.\n";
#endif /* not lint */
#ifndef lint
static char sccsid[] = "@(#)xargs.c 8.1 (Berkeley) 6/6/93";
#endif /* not lint */
#endif
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/time.h>
#include <sys/limits.h>
#include <sys/resource.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <langinfo.h>
#include <locale.h>
#include <paths.h>
#include <regex.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "pathnames.h"
static void parse_input(int, char *[]);
static void prerun(int, char *[]);
static int prompt(void);
static void run(char **);
static void usage(void);
void strnsubst(char **, const char *, const char *, size_t);
static pid_t xwait(int block, int *status);
static void xexit(const char *, const int);
static void waitchildren(const char *, int);
static void pids_init(void);
static int pids_empty(void);
static int pids_full(void);
static void pids_add(pid_t pid);
static int pids_remove(pid_t pid);
static int findslot(pid_t pid);
static int findfreeslot(void);
static void clearslot(int slot);
static char echo[] = _PATH_ECHO;
static char **av, **bxp, **ep, **endxp, **xp;
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, Sflag, wasquoted, xflag;
static int curprocs, maxprocs;
static pid_t *childpids;
static volatile int childerr;
extern char **environ;
int
main(int argc, char *argv[])
{
long arg_max;
int ch, Jflag, nargs, nflag, nline;
size_t linelen;
struct rlimit rl;
char *endptr;
const char *errstr;
inpline = replstr = NULL;
ep = environ;
eofstr = "";
Jflag = nflag = 0;
(void)setlocale(LC_ALL, "");
/*
* POSIX.2 limits the exec line length to ARG_MAX - 2K. Running that
* caused some E2BIG errors, so it was changed to ARG_MAX - 4K. Given
* that the smallest argument is 2 bytes in length, this means that
* the number of arguments is limited to:
*
* (ARG_MAX - 4K - LENGTH(utility + arguments)) / 2.
*
* We arbitrarily limit the number of arguments to 5000. This is
* allowed by POSIX.2 as long as the resulting minimum exec line is
* at least LINE_MAX. Realloc'ing as necessary is possible, but
* probably not worthwhile.
*/
nargs = 5000;
if ((arg_max = sysconf(_SC_ARG_MAX)) == -1)
errx(1, "sysconf(_SC_ARG_MAX) failed");
nline = arg_max - 4 * 1024;
while (*ep != NULL) {
/* 1 byte for each '\0' */
nline -= strlen(*ep++) + 1 + sizeof(*ep);
}
maxprocs = 1;
while ((ch = getopt(argc, argv, "0E:I:J:L:n:oP:pR:S:s:rtx")) != -1)
switch (ch) {
case 'E':
eofstr = optarg;
break;
case 'I':
Jflag = 0;
Iflag = 1;
Lflag = 1;
replstr = optarg;
break;
case 'J':
Iflag = 0;
Jflag = 1;
replstr = optarg;
break;
case 'L':
Lflag = strtonum(optarg, 0, INT_MAX, &errstr);
if (errstr)
errx(1, "-L %s: %s", optarg, errstr);
break;
case 'n':
nflag = 1;
nargs = strtonum(optarg, 1, INT_MAX, &errstr);
if (errstr)
errx(1, "-n %s: %s", optarg, errstr);
break;
case 'o':
oflag = 1;
break;
case 'P':
maxprocs = strtonum(optarg, 0, INT_MAX, &errstr);
if (errstr)
errx(1, "-P %s: %s", optarg, errstr);
if (getrlimit(RLIMIT_NPROC, &rl) != 0)
errx(1, "getrlimit failed");
if (maxprocs == 0 || maxprocs > rl.rlim_cur)
maxprocs = rl.rlim_cur;
break;
case 'p':
pflag = 1;
break;
case 'R':
Rflag = strtol(optarg, &endptr, 10);
if (*endptr != '\0')
errx(1, "replacements must be a number");
break;
case 'r':
/* GNU compatibility */
break;
case 'S':
Sflag = strtoul(optarg, &endptr, 10);
if (*endptr != '\0')
errx(1, "replsize must be a number");
break;
case 's':
nline = strtonum(optarg, 0, INT_MAX, &errstr);
if (errstr)
errx(1, "-s %s: %s", optarg, errstr);
break;
case 't':
tflag = 1;
break;
case 'x':
xflag = 1;
break;
case '0':
zflag = 1;
break;
case '?':
default:
usage();
}
argc -= optind;
argv += optind;
if (!Iflag && Rflag)
usage();
if (!Iflag && Sflag)
usage();
if (Iflag && !Rflag)
Rflag = 5;
if (Iflag && !Sflag)
Sflag = 255;
if (xflag && !nflag)
usage();
if (Iflag || Lflag)
xflag = 1;
if (replstr != NULL && *replstr == '\0')
errx(1, "replstr may not be empty");
pids_init();
/*
* Allocate pointers for the utility name, the utility arguments,
* the maximum arguments to be read from stdin and the trailing
* NULL.
*/
linelen = 1 + argc + nargs + 1;
if ((av = bxp = malloc(linelen * sizeof(char *))) == NULL)
errx(1, "malloc failed");
/*
* Use the user's name for the utility as argv[0], just like the
* shell. Echo is the default. Set up pointers for the user's
* arguments.
*/
if (*argv == NULL)
cnt = strlen(*bxp++ = echo);
else {
do {
if (Jflag && strcmp(*argv, replstr) == 0) {
char **avj;
jfound = 1;
argv++;
for (avj = argv; *avj; avj++)
cnt += strlen(*avj) + 1;
break;
}
cnt += strlen(*bxp++ = *argv) + 1;
} while (*++argv != NULL);
}
/*
* Set up begin/end/traversing pointers into the array. The -n
* count doesn't include the trailing NULL pointer, so the malloc
* added in an extra slot.
*/
endxp = (xp = bxp) + nargs;
/*
* Allocate buffer space for the arguments read from stdin and the
* trailing NULL. Buffer space is defined as the default or specified
* space, minus the length of the utility name and arguments. Set up
* begin/end/traversing pointers into the array. The -s count does
* include the trailing NULL, so the malloc didn't add in an extra
* slot.
*/
nline -= cnt;
if (nline <= 0)
errx(1, "insufficient space for command");
if ((bbp = malloc((size_t)(nline + 1))) == NULL)
errx(1, "malloc failed");
ebp = (argp = p = bbp) + nline - 1;
for (;;)
parse_input(argc, argv);
}
static void
parse_input(int argc, char *argv[])
{
int ch, foundeof;
char **avj;
foundeof = 0;
switch (ch = getchar()) {
case EOF:
/* No arguments since last exec. */
if (p == bbp)
xexit(*av, rval);
goto arg1;
case ' ':
case '\t':
/* Quotes escape tabs and spaces. */
if (insingle || indouble || zflag)
goto addch;
goto arg2;
case '\0':
if (zflag) {
/*
* Increment 'count', so that nulls will be treated
* as end-of-line, as well as end-of-argument. This
* is needed so -0 works properly with -I and -L.
*/
count++;
goto arg2;
}
goto addch;
case '\n':
if (zflag)
goto addch;
count++; /* Indicate end-of-line (used by -L) */
/* Quotes do not escape newlines. */
arg1: if (insingle || indouble) {
warnx("unterminated quote");
xexit(*av, 1);
}
arg2:
foundeof = *eofstr != '\0' &&
strncmp(argp, eofstr, p - argp) == 0;
/* Do not make empty args unless they are quoted */
if ((argp != p || wasquoted) && !foundeof) {
*p++ = '\0';
*xp++ = argp;
if (Iflag) {
size_t curlen;
if (inpline == NULL)
curlen = 0;
else {
/*
* If this string is not zero
* length, append a space for
* separation before the next
* argument.
*/
if ((curlen = strlen(inpline)))
strcat(inpline, " ");
}
curlen++;
/*
* Allocate enough to hold what we will
* be holding in a second, and to append
* a space next time through, if we have
* to.
*/
inpline = realloc(inpline, curlen + 2 +
strlen(argp));
if (inpline == NULL) {
warnx("realloc failed");
xexit(*av, 1);
}
if (curlen == 1)
strcpy(inpline, argp);
else
strcat(inpline, argp);
}
}
/*
* If max'd out on args or buffer, or reached EOF,
* run the command. If xflag and max'd out on buffer
* but not on args, object. Having reached the limit
* of input lines, as specified by -L is the same as
* maxing out on arguments.
*/
if (xp == endxp || p > ebp || ch == EOF ||
(Lflag <= count && xflag) || foundeof) {
if (xflag && xp != endxp && p > ebp) {
warnx("insufficient space for arguments");
xexit(*av, 1);
}
if (jfound) {
for (avj = argv; *avj; avj++)
*xp++ = *avj;
}
prerun(argc, av);
if (ch == EOF || foundeof)
xexit(*av, rval);
p = bbp;
xp = bxp;
count = 0;
}
argp = p;
wasquoted = 0;
break;
case '\'':
if (indouble || zflag)
goto addch;
insingle = !insingle;
wasquoted = 1;
break;
case '"':
if (insingle || zflag)
goto addch;
indouble = !indouble;
wasquoted = 1;
break;
case '\\':
if (zflag)
goto addch;
/* Backslash escapes anything, is escaped by quotes. */
if (!insingle && !indouble && (ch = getchar()) == EOF) {
warnx("backslash at EOF");
xexit(*av, 1);
}
/* FALLTHROUGH */
default:
addch: if (p < ebp) {
*p++ = ch;
break;
}
/* If only one argument, not enough buffer space. */
if (bxp == xp) {
warnx("insufficient space for argument");
xexit(*av, 1);
}
/* Didn't hit argument limit, so if xflag object. */
if (xflag) {
warnx("insufficient space for arguments");
xexit(*av, 1);
}
if (jfound) {
for (avj = argv; *avj; avj++)
*xp++ = *avj;
}
prerun(argc, av);
xp = bxp;
cnt = ebp - argp;
memcpy(bbp, argp, (size_t)cnt);
p = (argp = bbp) + cnt;
*p++ = ch;
break;
}
}
/*
* Do things necessary before run()'ing, such as -I substitution,
* and then call run().
*/
static void
prerun(int argc, char *argv[])
{
char **tmp, **tmp2, **avj;
int repls;
repls = Rflag;
if (argc == 0 || repls == 0) {
*xp = NULL;
run(argv);
return;
}
avj = argv;
/*
* Allocate memory to hold the argument list, and
* a NULL at the tail.
*/
tmp = malloc((argc + 1) * sizeof(char *));
if (tmp == NULL) {
warnx("malloc failed");
xexit(*argv, 1);
}
tmp2 = tmp;
/*
* Save the first argument and iterate over it, we
* cannot do strnsubst() to it.
*/
if ((*tmp++ = strdup(*avj++)) == NULL) {
warnx("strdup failed");
xexit(*argv, 1);
}
/*
* For each argument to utility, if we have not used up
* the number of replacements we are allowed to do, and
* if the argument contains at least one occurrence of
* replstr, call strnsubst(), else just save the string.
* Iterations over elements of avj and tmp are done
* where appropriate.
*/
while (--argc) {
*tmp = *avj++;
if (repls && strstr(*tmp, replstr) != NULL) {
strnsubst(tmp++, replstr, inpline, (size_t)Sflag);
if (repls > 0)
repls--;
} else {
if ((*tmp = strdup(*tmp)) == NULL) {
warnx("strdup failed");
xexit(*argv, 1);
}
tmp++;
}
}
/*
* Run it.
*/
*tmp = NULL;
run(tmp2);
/*
* Walk from the tail to the head, free along the way.
*/
for (; tmp2 != tmp; tmp--)
free(*tmp);
/*
* Now free the list itself.
*/
free(tmp2);
/*
* Free the input line buffer, if we have one.
*/
if (inpline != NULL) {
free(inpline);
inpline = NULL;
}
}
static void
run(char **argv)
{
pid_t pid;
int fd;
char **avec;
/*
* If the user wants to be notified of each command before it is
* executed, notify them. If they want the notification to be
* followed by a prompt, then prompt them.
*/
if (tflag || pflag) {
(void)fprintf(stderr, "%s", *argv);
for (avec = argv + 1; *avec != NULL; ++avec)
(void)fprintf(stderr, " %s", *avec);
/*
* If the user has asked to be prompted, do so.
*/
if (pflag)
/*
* If they asked not to exec, return without execution
* but if they asked to, go to the execution. If we
* could not open their tty, break the switch and drop
* back to -t behaviour.
*/
switch (prompt()) {
case 0:
return;
case 1:
goto exec;
case 2:
break;
}
(void)fprintf(stderr, "\n");
(void)fflush(stderr);
}
exec:
childerr = 0;
switch (pid = vfork()) {
case -1:
warn("vfork");
xexit(*argv, 1);
case 0:
if (oflag) {
if ((fd = open(_PATH_TTY, O_RDONLY)) == -1)
err(1, "can't open /dev/tty");
} else {
fd = open(_PATH_DEVNULL, O_RDONLY);
}
if (fd > STDIN_FILENO) {
if (dup2(fd, STDIN_FILENO) != 0)
err(1, "can't dup2 to stdin");
close(fd);
}
execvp(argv[0], argv);
childerr = errno;
_exit(1);
}
pids_add(pid);
waitchildren(*argv, 0);
}
/*
* Wait for a tracked child to exit and return its pid and exit status.
*
* Ignores (discards) all untracked child processes.
* Returns -1 and sets errno to ECHILD if no tracked children exist.
* If block is set, waits indefinitely for a child process to exit.
* If block is not set and no children have exited, returns 0 immediately.
*/
static pid_t
xwait(int block, int *status) {
pid_t pid;
if (pids_empty()) {
errno = ECHILD;
return (-1);
}
while ((pid = waitpid(-1, status, block ? 0 : WNOHANG)) > 0)
if (pids_remove(pid))
break;
return (pid);
}
static void
xexit(const char *name, const int exit_code) {
waitchildren(name, 1);
exit(exit_code);
}
static void
waitchildren(const char *name, int waitall)
{
pid_t pid;
int status;
int cause_exit = 0;
while ((pid = xwait(waitall || pids_full(), &status)) > 0) {
/*
* If we couldn't invoke the utility or if utility exited
* because of a signal or with a value of 255, warn (per
* POSIX), and then wait until all other children have
* exited before exiting 1-125. POSIX requires us to stop
* reading if child exits because of a signal or with 255,
* but it does not require us to exit immediately; waiting
* is preferable to orphaning.
*/
if (childerr != 0 && cause_exit == 0) {
errno = childerr;
waitall = 1;
cause_exit = ENOENT ? 127 : 126;
warn("%s", name);
} else if (WIFSIGNALED(status)) {
waitall = cause_exit = 1;
warnx("%s: terminated with signal %d; aborting",
name, WTERMSIG(status));
} else if (WEXITSTATUS(status) == 255) {
waitall = cause_exit = 1;
warnx("%s: exited with status 255; aborting", name);
} else if (WEXITSTATUS(status))
rval = 1;
}
if (cause_exit)
exit(cause_exit);
if (pid == -1 && errno != ECHILD)
err(1, "waitpid");
}
#define NOPID (0)
static void
pids_init(void)
{
int i;
if ((childpids = malloc(maxprocs * sizeof(*childpids))) == NULL)
errx(1, "malloc failed");
for (i = 0; i < maxprocs; i++)
clearslot(i);
}
static int
pids_empty(void)
{
return (curprocs == 0);
}
static int
pids_full(void)
{
return (curprocs >= maxprocs);
}
static void
pids_add(pid_t pid)
{
int slot;
slot = findfreeslot();
childpids[slot] = pid;
curprocs++;
}
static int
pids_remove(pid_t pid)
{
int slot;
if ((slot = findslot(pid)) < 0)
return (0);
clearslot(slot);
curprocs--;
return (1);
}
static int
findfreeslot(void)
{
int slot;
if ((slot = findslot(NOPID)) < 0)
errx(1, "internal error: no free pid slot");
return (slot);
}
static int
findslot(pid_t pid)
{
int slot;
for (slot = 0; slot < maxprocs; slot++)
if (childpids[slot] == pid)
return (slot);
return (-1);
}
static void
clearslot(int slot)
{
childpids[slot] = NOPID;
}
/*
* Prompt the user about running a command.
*/
static int
prompt(void)
{
regex_t cre;
size_t rsize;
int match;
char *response;
FILE *ttyfp;
if ((ttyfp = fopen(_PATH_TTY, "r")) == NULL)
return (2); /* Indicate that the TTY failed to open. */
(void)fprintf(stderr, "?...");
(void)fflush(stderr);
if ((response = fgetln(ttyfp, &rsize)) == NULL ||
regcomp(&cre, nl_langinfo(YESEXPR), REG_BASIC) != 0) {
(void)fclose(ttyfp);
return (0);
}
response[rsize - 1] = '\0';
match = regexec(&cre, response, 0, NULL, 0);
(void)fclose(ttyfp);
regfree(&cre);
return (match == 0);
}
static void
usage(void)
{
fprintf(stderr,
"usage: xargs [-0opt] [-E eofstr] [-I replstr [-R replacements] [-S replsize]]\n"
" [-J replstr] [-L number] [-n number [-x]] [-P maxprocs]\n"
" [-s size] [utility [argument ...]]\n");
exit(1);
}