busybox/findutils/xargs.c

/* vi: set sw=4 ts=4: */
/*
 * Mini xargs implementation for busybox
 * Options are supported: "-prtx -n max_arg -s max_chars -e[ouf_str]"
 *
 * (C) 2002,2003 by Vladimir Oleynik <dzo@simtreas.ru>
 *
 * Special thanks
 * - Mark Whitley and Glenn McGrath for stimulus to rewrite :)
 * - Mike Rendell <michael@cs.mun.ca>
 * and David MacKenzie <djm@gnu.ai.mit.edu>.
 *
 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
 *
 * xargs is described in the Single Unix Specification v3 at
 * http://www.opengroup.org/onlinepubs/007904975/utilities/xargs.html
 *
 */

#include "busybox.h"

/* COMPAT:  SYSV version defaults size (and has a max value of) to 470.
   We try to make it as large as possible. */
#if !defined(ARG_MAX) && defined(_SC_ARG_MAX)
#define ARG_MAX sysconf (_SC_ARG_MAX)
#endif
#ifndef ARG_MAX
#define ARG_MAX 470
#endif


#ifdef TEST
# ifndef CONFIG_FEATURE_XARGS_SUPPORT_CONFIRMATION
#  define CONFIG_FEATURE_XARGS_SUPPORT_CONFIRMATION
# endif
# ifndef CONFIG_FEATURE_XARGS_SUPPORT_QUOTES
#  define CONFIG_FEATURE_XARGS_SUPPORT_QUOTES
# endif
# ifndef CONFIG_FEATURE_XARGS_SUPPORT_TERMOPT
#  define CONFIG_FEATURE_XARGS_SUPPORT_TERMOPT
# endif
# ifndef CONFIG_FEATURE_XARGS_SUPPORT_ZERO_TERM
#  define CONFIG_FEATURE_XARGS_SUPPORT_ZERO_TERM
# endif
#endif

/*
   This function has special algorithm.
   Don't use fork and include to main!
*/
static int xargs_exec(char *const *args)
{
	pid_t p;
	volatile int exec_errno = 0;    /* shared vfork stack */
	int status;

	p = vfork();
	if (p < 0)
		bb_perror_msg_and_die("vfork");

	if (p == 0) {
		/* vfork -- child */
		execvp(args[0], args);
		exec_errno = errno;     /* set error to shared stack */
		_exit(1);
	}

	/* vfork -- parent */
	while (wait(&status) == (pid_t) -1)
		if (errno != EINTR)
			break;
	if (exec_errno) {
		errno = exec_errno;
		bb_perror_msg("%s", args[0]);
		return exec_errno == ENOENT ? 127 : 126;
	}
	if (WEXITSTATUS(status) == 255) {
		bb_error_msg("%s: exited with status 255; aborting", args[0]);
		return 124;
	}
	if (WIFSTOPPED(status)) {
		bb_error_msg("%s: stopped by signal %d",
			args[0], WSTOPSIG(status));
		return 125;
	}
	if (WIFSIGNALED(status)) {
		bb_error_msg("%s: terminated by signal %d",
			args[0], WTERMSIG(status));
		return 125;
	}
	if (WEXITSTATUS(status))
		return 123;
	return 0;
}


typedef struct xlist_s {
	char *data;
	size_t lenght;
	struct xlist_s *link;
} xlist_t;

static int eof_stdin_detected;

#define ISBLANK(c) ((c) == ' ' || (c) == '\t')
#define ISSPACE(c) (ISBLANK(c) || (c) == '\n' || (c) == '\r' \
		    || (c) == '\f' || (c) == '\v')

#ifdef CONFIG_FEATURE_XARGS_SUPPORT_QUOTES
static xlist_t *process_stdin(xlist_t * list_arg,
	const char *eof_str, size_t mc, char *buf)
{
#define NORM      0
#define QUOTE     1
#define BACKSLASH 2
#define SPACE     4

	char *s = NULL;         /* start word */
	char *p = NULL;         /* pointer to end word */
	char q = 0;             /* quote char */
	char state = NORM;
	char eof_str_detected = 0;
	size_t line_l = 0;      /* size loaded args line */
	int c;                  /* current char */
	xlist_t *cur;
	xlist_t *prev;

	for (prev = cur = list_arg; cur; cur = cur->link) {
		line_l += cur->lenght;  /* previous allocated */
		if (prev != cur)
			prev = prev->link;
	}

	while (!eof_stdin_detected) {
		c = getchar();
		if (c == EOF) {
			eof_stdin_detected++;
			if (s)
				goto unexpected_eof;
			break;
		}
		if (eof_str_detected)
			continue;
		if (state == BACKSLASH) {
			state = NORM;
			goto set;
		} else if (state == QUOTE) {
			if (c == q) {
				q = 0;
				state = NORM;
			} else {
				goto set;
			}
		} else { /* if(state == NORM) */

			if (ISSPACE(c)) {
				if (s) {
unexpected_eof:
					state = SPACE;
					c = 0;
					goto set;
				}
			} else {
				if (s == NULL)
					s = p = buf;
				if (c == '\\') {
					state = BACKSLASH;
				} else if (c == '\'' || c == '"') {
					q = c;
					state = QUOTE;
				} else {
set:
					if ((size_t)(p - buf) >= mc)
						bb_error_msg_and_die("argument line too long");
					*p++ = c;
				}
			}
		}
		if (state == SPACE) {   /* word's delimiter or EOF detected */
			if (q) {
				bb_error_msg_and_die("unmatched %s quote",
					q == '\'' ? "single" : "double");
			}
			/* word loaded */
			if (eof_str) {
				eof_str_detected = strcmp(s, eof_str) == 0;
			}
			if (!eof_str_detected) {
				size_t lenght = (p - buf);

				cur = xmalloc(sizeof(xlist_t) + lenght);
				cur->data = memcpy(cur + 1, s, lenght);
				cur->lenght = lenght;
				cur->link = NULL;
				if (prev == NULL) {
					list_arg = cur;
				} else {
					prev->link = cur;
				}
				prev = cur;
				line_l += lenght;
				if (line_l > mc) {
					/* stop memory usage :-) */
					break;
				}
			}
			s = NULL;
			state = NORM;
		}
	}
	return list_arg;
}
#else
/* The variant does not support single quotes, double quotes or backslash */
static xlist_t *process_stdin(xlist_t * list_arg,
	const char *eof_str, size_t mc, char *buf)
{

	int c;                  /* current char */
	int eof_str_detected = 0;
	char *s = NULL;         /* start word */
	char *p = NULL;         /* pointer to end word */
	size_t line_l = 0;      /* size loaded args line */
	xlist_t *cur;
	xlist_t *prev;

	for (prev = cur = list_arg; cur; cur = cur->link) {
		line_l += cur->lenght;  /* previous allocated */
		if (prev != cur)
			prev = prev->link;
	}

	while (!eof_stdin_detected) {
		c = getchar();
		if (c == EOF) {
			eof_stdin_detected++;
		}
		if (eof_str_detected)
			continue;
		if (c == EOF || ISSPACE(c)) {
			if (s == NULL)
				continue;
			c = EOF;
		}
		if (s == NULL)
			s = p = buf;
		if ((p - buf) >= mc)
			bb_error_msg_and_die("argument line too long");
		*p++ = c == EOF ? 0 : c;
		if (c == EOF) { /* word's delimiter or EOF detected */
			/* word loaded */
			if (eof_str) {
				eof_str_detected = strcmp(s, eof_str) == 0;
			}
			if (!eof_str_detected) {
				size_t lenght = (p - buf);

				cur = xmalloc(sizeof(xlist_t) + lenght);
				cur->data = memcpy(cur + 1, s, lenght);
				cur->lenght = lenght;
				cur->link = NULL;
				if (prev == NULL) {
					list_arg = cur;
				} else {
					prev->link = cur;
				}
				prev = cur;
				line_l += lenght;
				if (line_l > mc) {
					/* stop memory usage :-) */
					break;
				}
				s = NULL;
			}
		}
	}
	return list_arg;
}
#endif /* CONFIG_FEATURE_XARGS_SUPPORT_QUOTES */


#ifdef CONFIG_FEATURE_XARGS_SUPPORT_CONFIRMATION
/* Prompt the user for a response, and
   if the user responds affirmatively, return true;
   otherwise, return false. Used "/dev/tty", not stdin. */
static int xargs_ask_confirmation(void)
{
	static FILE *tty_stream;
	int c, savec;

	if (!tty_stream) {
		tty_stream = xfopen(CURRENT_TTY, "r");
		/* pranoidal security by vodz */
		fcntl(fileno(tty_stream), F_SETFD, FD_CLOEXEC);
	}
	fputs(" ?...", stderr);
	fflush(stderr);
	c = savec = getc(tty_stream);
	while (c != EOF && c != '\n')
		c = getc(tty_stream);
	if (savec == 'y' || savec == 'Y')
		return 1;
	return 0;
}
#else
# define xargs_ask_confirmation() 1
#endif /* CONFIG_FEATURE_XARGS_SUPPORT_CONFIRMATION */

#ifdef CONFIG_FEATURE_XARGS_SUPPORT_ZERO_TERM
static xlist_t *process0_stdin(xlist_t * list_arg, const char *eof_str ATTRIBUTE_UNUSED,
							   size_t mc, char *buf)
{
	int c;                  /* current char */
	char *s = NULL;         /* start word */
	char *p = NULL;         /* pointer to end word */
	size_t line_l = 0;      /* size loaded args line */
	xlist_t *cur;
	xlist_t *prev;

	for (prev = cur = list_arg; cur; cur = cur->link) {
		line_l += cur->lenght;  /* previous allocated */
		if (prev != cur)
			prev = prev->link;
	}

	while (!eof_stdin_detected) {
		c = getchar();
		if (c == EOF) {
			eof_stdin_detected++;
			if (s == NULL)
				break;
			c = 0;
		}
		if (s == NULL)
			s = p = buf;
		if ((size_t)(p - buf) >= mc)
			bb_error_msg_and_die("argument line too long");
		*p++ = c;
		if (c == 0) {   /* word's delimiter or EOF detected */
			/* word loaded */
			size_t lenght = (p - buf);

			cur = xmalloc(sizeof(xlist_t) + lenght);
			cur->data = memcpy(cur + 1, s, lenght);
			cur->lenght = lenght;
			cur->link = NULL;
			if (prev == NULL) {
				list_arg = cur;
			} else {
				prev->link = cur;
			}
			prev = cur;
			line_l += lenght;
			if (line_l > mc) {
				/* stop memory usage :-) */
				break;
			}
			s = NULL;
		}
	}
	return list_arg;
}
#endif /* CONFIG_FEATURE_XARGS_SUPPORT_ZERO_TERM */

/* Correct regardless of combination of CONFIG_xxx */
enum {
	OPTBIT_VERBOSE = 0,
	OPTBIT_NO_EMPTY,
	OPTBIT_UPTO_NUMBER,
	OPTBIT_UPTO_SIZE,
	OPTBIT_EOF_STRING,
	USE_FEATURE_XARGS_SUPPORT_CONFIRMATION(OPTBIT_INTERACTIVE,)
	USE_FEATURE_XARGS_SUPPORT_TERMOPT(     OPTBIT_TERMINATE  ,)
	USE_FEATURE_XARGS_SUPPORT_ZERO_TERM(   OPTBIT_ZEROTERM   ,)

	OPT_VERBOSE     = 1<<OPTBIT_VERBOSE    ,
	OPT_NO_EMPTY    = 1<<OPTBIT_NO_EMPTY   ,
	OPT_UPTO_NUMBER = 1<<OPTBIT_UPTO_NUMBER,
	OPT_UPTO_SIZE   = 1<<OPTBIT_UPTO_SIZE  ,
	OPT_EOF_STRING  = 1<<OPTBIT_EOF_STRING ,
	OPT_INTERACTIVE = USE_FEATURE_XARGS_SUPPORT_CONFIRMATION((1<<OPTBIT_INTERACTIVE)) + 0,
	OPT_TERMINATE   = USE_FEATURE_XARGS_SUPPORT_TERMOPT(     (1<<OPTBIT_TERMINATE  )) + 0,
	OPT_ZEROTERM    = USE_FEATURE_XARGS_SUPPORT_ZERO_TERM(   (1<<OPTBIT_ZEROTERM   )) + 0,
};
#define OPTION_STR "+trn:s:e::" \
	USE_FEATURE_XARGS_SUPPORT_CONFIRMATION("p") \
	USE_FEATURE_XARGS_SUPPORT_TERMOPT(     "x") \
	USE_FEATURE_XARGS_SUPPORT_ZERO_TERM(   "0")

int xargs_main(int argc, char **argv)
{
	char **args;
	int i, n;
	xlist_t *list = NULL;
	xlist_t *cur;
	int child_error = 0;
	char *max_args, *max_chars;
	int n_max_arg;
	size_t n_chars = 0;
	long orig_arg_max;
	const char *eof_str = "_";
	unsigned opt;
	size_t n_max_chars;
#if ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM
	xlist_t* (*read_args)(xlist_t*, const char*, size_t, char*) = process_stdin;
#else
#define read_args process_stdin
#endif

	opt = getopt32(argc, argv, OPTION_STR, &max_args, &max_chars, &eof_str);

	if (opt & OPT_ZEROTERM)
		USE_FEATURE_XARGS_SUPPORT_ZERO_TERM(read_args = process0_stdin);

	argc -= optind;
	argv += optind;
	if (!argc) {
		/* default behavior is to echo all the filenames */
		*argv = "echo";
		argc++;
	}

	orig_arg_max = ARG_MAX;
	if (orig_arg_max == -1)
		orig_arg_max = LONG_MAX;
	orig_arg_max -= 2048;   /* POSIX.2 requires subtracting 2048 */

	if (opt & OPT_UPTO_SIZE) {
		n_max_chars = xatoul_range(max_chars, 1, orig_arg_max);
		for (i = 0; i < argc; i++) {
			n_chars += strlen(*argv) + 1;
		}
		if (n_max_chars < n_chars) {
			bb_error_msg_and_die("cannot fit single argument within argument list size limit");
		}
		n_max_chars -= n_chars;
	} else {
		/* Sanity check for systems with huge ARG_MAX defines (e.g., Suns which
		   have it at 1 meg).  Things will work fine with a large ARG_MAX but it
		   will probably hurt the system more than it needs to; an array of this
		   size is allocated.  */
		if (orig_arg_max > 20 * 1024)
			orig_arg_max = 20 * 1024;
		n_max_chars = orig_arg_max;
	}
	max_chars = xmalloc(n_max_chars);

	if (opt & OPT_UPTO_NUMBER) {
		n_max_arg = xatoul_range(max_args, 1, INT_MAX);
	} else {
		n_max_arg = n_max_chars;
	}

	while ((list = read_args(list, eof_str, n_max_chars, max_chars)) != NULL ||
		!(opt & OPT_NO_EMPTY))
	{
		opt |= OPT_NO_EMPTY;
		n = 0;
		n_chars = 0;
#ifdef CONFIG_FEATURE_XARGS_SUPPORT_TERMOPT
		for (cur = list; cur;) {
			n_chars += cur->lenght;
			n++;
			cur = cur->link;
			if (n_chars > n_max_chars || (n == n_max_arg && cur)) {
				if (opt & OPT_TERMINATE)
					bb_error_msg_and_die("argument list too long");
				break;
			}
		}
#else
		for (cur = list; cur; cur = cur->link) {
			n_chars += cur->lenght;
			n++;
			if (n_chars > n_max_chars || n == n_max_arg) {
				break;
			}
		}
#endif /* CONFIG_FEATURE_XARGS_SUPPORT_TERMOPT */

		/* allocate pointers for execvp:
		   argc*arg, n*arg from stdin, NULL */
		args = xzalloc((n + argc + 1) * sizeof(char *));

		/* store the command to be executed
		   (taken from the command line) */
		for (i = 0; i < argc; i++)
			args[i] = argv[i];
		/* (taken from stdin) */
		for (cur = list; n; cur = cur->link) {
			args[i++] = cur->data;
			n--;
		}

		if (opt & (OPT_INTERACTIVE | OPT_VERBOSE)) {
			for (i = 0; args[i]; i++) {
				if (i)
					fputc(' ', stderr);
				fputs(args[i], stderr);
			}
			if (!(opt & OPT_INTERACTIVE))
				fputc('\n', stderr);
		}
		if (!(opt & OPT_INTERACTIVE) || xargs_ask_confirmation()) {
			child_error = xargs_exec(args);
		}

		/* clean up */
		for (i = argc; args[i]; i++) {
			cur = list;
			list = list->link;
			free(cur);
		}
		free(args);
		if (child_error > 0 && child_error != 123) {
			break;
		}
	}
	if (ENABLE_FEATURE_CLEAN_UP) free(max_chars);
	return child_error;
}


#ifdef TEST

const char *applet_name = "debug stuff usage";

void bb_show_usage(void)
{
	fprintf(stderr, "Usage: %s [-p] [-r] [-t] -[x] [-n max_arg] [-s max_chars]\n",
		applet_name);
	exit(1);
}

int main(int argc, char **argv)
{
	return xargs_main(argc, argv);
}
#endif /* TEST */
1	niro	532	/* vi: set sw=4 ts=4: */
2			/*
3			* Mini xargs implementation for busybox
4			* Options are supported: "-prtx -n max_arg -s max_chars -e[ouf_str]"
5			*
6			* (C) 2002,2003 by Vladimir Oleynik <dzo@simtreas.ru>
7			*
8			* Special thanks
9			* - Mark Whitley and Glenn McGrath for stimulus to rewrite :)
10			* - Mike Rendell <michael@cs.mun.ca>
11			* and David MacKenzie <djm@gnu.ai.mit.edu>.
12			*
13			* Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
14			*
15			* xargs is described in the Single Unix Specification v3 at
16			* http://www.opengroup.org/onlinepubs/007904975/utilities/xargs.html
17			*
18			*/
19
20			#include "busybox.h"
21
22			/* COMPAT: SYSV version defaults size (and has a max value of) to 470.
23			We try to make it as large as possible. */
24			#if !defined(ARG_MAX) && defined(_SC_ARG_MAX)
25			#define ARG_MAX sysconf (_SC_ARG_MAX)
26			#endif
27			#ifndef ARG_MAX
28			#define ARG_MAX 470
29			#endif
30
31
32			#ifdef TEST
33			# ifndef CONFIG_FEATURE_XARGS_SUPPORT_CONFIRMATION
34			# define CONFIG_FEATURE_XARGS_SUPPORT_CONFIRMATION
35			# endif
36			# ifndef CONFIG_FEATURE_XARGS_SUPPORT_QUOTES
37			# define CONFIG_FEATURE_XARGS_SUPPORT_QUOTES
38			# endif
39			# ifndef CONFIG_FEATURE_XARGS_SUPPORT_TERMOPT
40			# define CONFIG_FEATURE_XARGS_SUPPORT_TERMOPT
41			# endif
42			# ifndef CONFIG_FEATURE_XARGS_SUPPORT_ZERO_TERM
43			# define CONFIG_FEATURE_XARGS_SUPPORT_ZERO_TERM
44			# endif
45			#endif
46
47			/*
48			This function has special algorithm.
49			Don't use fork and include to main!
50			*/
51			static int xargs_exec(char const args)
52			{
53			pid_t p;
54			volatile int exec_errno = 0; /* shared vfork stack */
55			int status;
56
57			p = vfork();
58			if (p < 0)
59			bb_perror_msg_and_die("vfork");
60
61			if (p == 0) {
62			/* vfork -- child */
63			execvp(args[0], args);
64			exec_errno = errno; /* set error to shared stack */
65			_exit(1);
66			}
67
68			/* vfork -- parent */
69			while (wait(&status) == (pid_t) -1)
70			if (errno != EINTR)
71			break;
72			if (exec_errno) {
73			errno = exec_errno;
74			bb_perror_msg("%s", args[0]);
75			return exec_errno == ENOENT ? 127 : 126;
76			}
77			if (WEXITSTATUS(status) == 255) {
78			bb_error_msg("%s: exited with status 255; aborting", args[0]);
79			return 124;
80			}
81			if (WIFSTOPPED(status)) {
82			bb_error_msg("%s: stopped by signal %d",
83			args[0], WSTOPSIG(status));
84			return 125;
85			}
86			if (WIFSIGNALED(status)) {
87			bb_error_msg("%s: terminated by signal %d",
88			args[0], WTERMSIG(status));
89			return 125;
90			}
91			if (WEXITSTATUS(status))
92			return 123;
93			return 0;
94			}
95
96
97			typedef struct xlist_s {
98			char *data;
99			size_t lenght;
100			struct xlist_s *link;
101			} xlist_t;
102
103			static int eof_stdin_detected;
104
105			#define ISBLANK(c) ((c) == ' ' \|\| (c) == '\t')
106			#define ISSPACE(c) (ISBLANK(c) \|\| (c) == '\n' \|\| (c) == '\r' \
107			\|\| (c) == '\f' \|\| (c) == '\v')
108
109			#ifdef CONFIG_FEATURE_XARGS_SUPPORT_QUOTES
110			static xlist_t process_stdin(xlist_t list_arg,
111			const char eof_str, size_t mc, char buf)
112			{
113			#define NORM 0
114			#define QUOTE 1
115			#define BACKSLASH 2
116			#define SPACE 4
117
118			char s = NULL; / start word */
119			char p = NULL; / pointer to end word */
120			char q = 0; /* quote char */
121			char state = NORM;
122			char eof_str_detected = 0;
123			size_t line_l = 0; /* size loaded args line */
124			int c; /* current char */
125			xlist_t *cur;
126			xlist_t *prev;
127
128			for (prev = cur = list_arg; cur; cur = cur->link) {
129			line_l += cur->lenght; /* previous allocated */
130			if (prev != cur)
131			prev = prev->link;
132			}
133
134			while (!eof_stdin_detected) {
135			c = getchar();
136			if (c == EOF) {
137			eof_stdin_detected++;
138			if (s)
139			goto unexpected_eof;
140			break;
141			}
142			if (eof_str_detected)
143			continue;
144			if (state == BACKSLASH) {
145			state = NORM;
146			goto set;
147			} else if (state == QUOTE) {
148			if (c == q) {
149			q = 0;
150			state = NORM;
151			} else {
152			goto set;
153			}
154			} else { /* if(state == NORM) */
155
156			if (ISSPACE(c)) {
157			if (s) {
158			unexpected_eof:
159			state = SPACE;
160			c = 0;
161			goto set;
162			}
163			} else {
164			if (s == NULL)
165			s = p = buf;
166			if (c == '\\') {
167			state = BACKSLASH;
168			} else if (c == '\'' \|\| c == '"') {
169			q = c;
170			state = QUOTE;
171			} else {
172			set:
173			if ((size_t)(p - buf) >= mc)
174			bb_error_msg_and_die("argument line too long");
175			*p++ = c;
176			}
177			}
178			}
179			if (state == SPACE) { /* word's delimiter or EOF detected */
180			if (q) {
181			bb_error_msg_and_die("unmatched %s quote",
182			q == '\'' ? "single" : "double");
183			}
184			/* word loaded */
185			if (eof_str) {
186			eof_str_detected = strcmp(s, eof_str) == 0;
187			}
188			if (!eof_str_detected) {
189			size_t lenght = (p - buf);
190
191			cur = xmalloc(sizeof(xlist_t) + lenght);
192			cur->data = memcpy(cur + 1, s, lenght);
193			cur->lenght = lenght;
194			cur->link = NULL;
195			if (prev == NULL) {
196			list_arg = cur;
197			} else {
198			prev->link = cur;
199			}
200			prev = cur;
201			line_l += lenght;
202			if (line_l > mc) {
203			/* stop memory usage :-) */
204			break;
205			}
206			}
207			s = NULL;
208			state = NORM;
209			}
210			}
211			return list_arg;
212			}
213			#else
214			/* The variant does not support single quotes, double quotes or backslash */
215			static xlist_t process_stdin(xlist_t list_arg,
216			const char eof_str, size_t mc, char buf)
217			{
218
219			int c; /* current char */
220			int eof_str_detected = 0;
221			char s = NULL; / start word */
222			char p = NULL; / pointer to end word */
223			size_t line_l = 0; /* size loaded args line */
224			xlist_t *cur;
225			xlist_t *prev;
226
227			for (prev = cur = list_arg; cur; cur = cur->link) {
228			line_l += cur->lenght; /* previous allocated */
229			if (prev != cur)
230			prev = prev->link;
231			}
232
233			while (!eof_stdin_detected) {
234			c = getchar();
235			if (c == EOF) {
236			eof_stdin_detected++;
237			}
238			if (eof_str_detected)
239			continue;
240			if (c == EOF \|\| ISSPACE(c)) {
241			if (s == NULL)
242			continue;
243			c = EOF;
244			}
245			if (s == NULL)
246			s = p = buf;
247			if ((p - buf) >= mc)
248			bb_error_msg_and_die("argument line too long");
249			*p++ = c == EOF ? 0 : c;
250			if (c == EOF) { /* word's delimiter or EOF detected */
251			/* word loaded */
252			if (eof_str) {
253			eof_str_detected = strcmp(s, eof_str) == 0;
254			}
255			if (!eof_str_detected) {
256			size_t lenght = (p - buf);
257
258			cur = xmalloc(sizeof(xlist_t) + lenght);
259			cur->data = memcpy(cur + 1, s, lenght);
260			cur->lenght = lenght;
261			cur->link = NULL;
262			if (prev == NULL) {
263			list_arg = cur;
264			} else {
265			prev->link = cur;
266			}
267			prev = cur;
268			line_l += lenght;
269			if (line_l > mc) {
270			/* stop memory usage :-) */
271			break;
272			}
273			s = NULL;
274			}
275			}
276			}
277			return list_arg;
278			}
279			#endif /* CONFIG_FEATURE_XARGS_SUPPORT_QUOTES */
280
281
282			#ifdef CONFIG_FEATURE_XARGS_SUPPORT_CONFIRMATION
283			/* Prompt the user for a response, and
284			if the user responds affirmatively, return true;
285			otherwise, return false. Used "/dev/tty", not stdin. */
286			static int xargs_ask_confirmation(void)
287			{
288			static FILE *tty_stream;
289			int c, savec;
290
291			if (!tty_stream) {
292			tty_stream = xfopen(CURRENT_TTY, "r");
293			/* pranoidal security by vodz */
294			fcntl(fileno(tty_stream), F_SETFD, FD_CLOEXEC);
295			}
296			fputs(" ?...", stderr);
297			fflush(stderr);
298			c = savec = getc(tty_stream);
299			while (c != EOF && c != '\n')
300			c = getc(tty_stream);
301			if (savec == 'y' \|\| savec == 'Y')
302			return 1;
303			return 0;
304			}
305			#else
306			# define xargs_ask_confirmation() 1
307			#endif /* CONFIG_FEATURE_XARGS_SUPPORT_CONFIRMATION */
308
309			#ifdef CONFIG_FEATURE_XARGS_SUPPORT_ZERO_TERM
310			static xlist_t process0_stdin(xlist_t list_arg, const char *eof_str ATTRIBUTE_UNUSED,
311			size_t mc, char *buf)
312			{
313			int c; /* current char */
314			char s = NULL; / start word */
315			char p = NULL; / pointer to end word */
316			size_t line_l = 0; /* size loaded args line */
317			xlist_t *cur;
318			xlist_t *prev;
319
320			for (prev = cur = list_arg; cur; cur = cur->link) {
321			line_l += cur->lenght; /* previous allocated */
322			if (prev != cur)
323			prev = prev->link;
324			}
325
326			while (!eof_stdin_detected) {
327			c = getchar();
328			if (c == EOF) {
329			eof_stdin_detected++;
330			if (s == NULL)
331			break;
332			c = 0;
333			}
334			if (s == NULL)
335			s = p = buf;
336			if ((size_t)(p - buf) >= mc)
337			bb_error_msg_and_die("argument line too long");
338			*p++ = c;
339			if (c == 0) { /* word's delimiter or EOF detected */
340			/* word loaded */
341			size_t lenght = (p - buf);
342
343			cur = xmalloc(sizeof(xlist_t) + lenght);
344			cur->data = memcpy(cur + 1, s, lenght);
345			cur->lenght = lenght;
346			cur->link = NULL;
347			if (prev == NULL) {
348			list_arg = cur;
349			} else {
350			prev->link = cur;
351			}
352			prev = cur;
353			line_l += lenght;
354			if (line_l > mc) {
355			/* stop memory usage :-) */
356			break;
357			}
358			s = NULL;
359			}
360			}
361			return list_arg;
362			}
363			#endif /* CONFIG_FEATURE_XARGS_SUPPORT_ZERO_TERM */
364
365			/* Correct regardless of combination of CONFIG_xxx */
366			enum {
367			OPTBIT_VERBOSE = 0,
368			OPTBIT_NO_EMPTY,
369			OPTBIT_UPTO_NUMBER,
370			OPTBIT_UPTO_SIZE,
371			OPTBIT_EOF_STRING,
372			USE_FEATURE_XARGS_SUPPORT_CONFIRMATION(OPTBIT_INTERACTIVE,)
373			USE_FEATURE_XARGS_SUPPORT_TERMOPT( OPTBIT_TERMINATE ,)
374			USE_FEATURE_XARGS_SUPPORT_ZERO_TERM( OPTBIT_ZEROTERM ,)
375
376			OPT_VERBOSE = 1<<OPTBIT_VERBOSE ,
377			OPT_NO_EMPTY = 1<<OPTBIT_NO_EMPTY ,
378			OPT_UPTO_NUMBER = 1<<OPTBIT_UPTO_NUMBER,
379			OPT_UPTO_SIZE = 1<<OPTBIT_UPTO_SIZE ,
380			OPT_EOF_STRING = 1<<OPTBIT_EOF_STRING ,
381			OPT_INTERACTIVE = USE_FEATURE_XARGS_SUPPORT_CONFIRMATION((1<<OPTBIT_INTERACTIVE)) + 0,
382			OPT_TERMINATE = USE_FEATURE_XARGS_SUPPORT_TERMOPT( (1<<OPTBIT_TERMINATE )) + 0,
383			OPT_ZEROTERM = USE_FEATURE_XARGS_SUPPORT_ZERO_TERM( (1<<OPTBIT_ZEROTERM )) + 0,
384			};
385			#define OPTION_STR "+trn:s:e::" \
386			USE_FEATURE_XARGS_SUPPORT_CONFIRMATION("p") \
387			USE_FEATURE_XARGS_SUPPORT_TERMOPT( "x") \
388			USE_FEATURE_XARGS_SUPPORT_ZERO_TERM( "0")
389
390			int xargs_main(int argc, char **argv)
391			{
392			char **args;
393			int i, n;
394			xlist_t *list = NULL;
395			xlist_t *cur;
396			int child_error = 0;
397			char max_args, max_chars;
398			int n_max_arg;
399			size_t n_chars = 0;
400			long orig_arg_max;
401			const char *eof_str = "_";
402			unsigned opt;
403			size_t n_max_chars;
404			#if ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM
405			xlist_t* (read_args)(xlist_t, const char, size_t, char) = process_stdin;
406			#else
407			#define read_args process_stdin
408			#endif
409
410			opt = getopt32(argc, argv, OPTION_STR, &max_args, &max_chars, &eof_str);
411
412			if (opt & OPT_ZEROTERM)
413			USE_FEATURE_XARGS_SUPPORT_ZERO_TERM(read_args = process0_stdin);
414
415			argc -= optind;
416			argv += optind;
417			if (!argc) {
418			/* default behavior is to echo all the filenames */
419			*argv = "echo";
420			argc++;
421			}
422
423			orig_arg_max = ARG_MAX;
424			if (orig_arg_max == -1)
425			orig_arg_max = LONG_MAX;
426			orig_arg_max -= 2048; /* POSIX.2 requires subtracting 2048 */
427
428			if (opt & OPT_UPTO_SIZE) {
429			n_max_chars = xatoul_range(max_chars, 1, orig_arg_max);
430			for (i = 0; i < argc; i++) {
431			n_chars += strlen(*argv) + 1;
432			}
433			if (n_max_chars < n_chars) {
434			bb_error_msg_and_die("cannot fit single argument within argument list size limit");
435			}
436			n_max_chars -= n_chars;
437			} else {
438			/* Sanity check for systems with huge ARG_MAX defines (e.g., Suns which
439			have it at 1 meg). Things will work fine with a large ARG_MAX but it
440			will probably hurt the system more than it needs to; an array of this
441			size is allocated. */
442			if (orig_arg_max > 20 * 1024)
443			orig_arg_max = 20 * 1024;
444			n_max_chars = orig_arg_max;
445			}
446			max_chars = xmalloc(n_max_chars);
447
448			if (opt & OPT_UPTO_NUMBER) {
449			n_max_arg = xatoul_range(max_args, 1, INT_MAX);
450			} else {
451			n_max_arg = n_max_chars;
452			}
453
454			while ((list = read_args(list, eof_str, n_max_chars, max_chars)) != NULL \|\|
455			!(opt & OPT_NO_EMPTY))
456			{
457			opt \|= OPT_NO_EMPTY;
458			n = 0;
459			n_chars = 0;
460			#ifdef CONFIG_FEATURE_XARGS_SUPPORT_TERMOPT
461			for (cur = list; cur;) {
462			n_chars += cur->lenght;
463			n++;
464			cur = cur->link;
465			if (n_chars > n_max_chars \|\| (n == n_max_arg && cur)) {
466			if (opt & OPT_TERMINATE)
467			bb_error_msg_and_die("argument list too long");
468			break;
469			}
470			}
471			#else
472			for (cur = list; cur; cur = cur->link) {
473			n_chars += cur->lenght;
474			n++;
475			if (n_chars > n_max_chars \|\| n == n_max_arg) {
476			break;
477			}
478			}
479			#endif /* CONFIG_FEATURE_XARGS_SUPPORT_TERMOPT */
480
481			/* allocate pointers for execvp:
482			argcarg, narg from stdin, NULL */
483			args = xzalloc((n + argc + 1) * sizeof(char *));
484
485			/* store the command to be executed
486			(taken from the command line) */
487			for (i = 0; i < argc; i++)
488			args[i] = argv[i];
489			/* (taken from stdin) */
490			for (cur = list; n; cur = cur->link) {
491			args[i++] = cur->data;
492			n--;
493			}
494
495			if (opt & (OPT_INTERACTIVE \| OPT_VERBOSE)) {
496			for (i = 0; args[i]; i++) {
497			if (i)
498			fputc(' ', stderr);
499			fputs(args[i], stderr);
500			}
501			if (!(opt & OPT_INTERACTIVE))
502			fputc('\n', stderr);
503			}
504			if (!(opt & OPT_INTERACTIVE) \|\| xargs_ask_confirmation()) {
505			child_error = xargs_exec(args);
506			}
507
508			/* clean up */
509			for (i = argc; args[i]; i++) {
510			cur = list;
511			list = list->link;
512			free(cur);
513			}
514			free(args);
515			if (child_error > 0 && child_error != 123) {
516			break;
517			}
518			}
519			if (ENABLE_FEATURE_CLEAN_UP) free(max_chars);
520			return child_error;
521			}
522
523
524			#ifdef TEST
525
526			const char *applet_name = "debug stuff usage";
527
528			void bb_show_usage(void)
529			{
530			fprintf(stderr, "Usage: %s [-p] [-r] [-t] -[x] [-n max_arg] [-s max_chars]\n",
531			applet_name);
532			exit(1);
533			}
534
535			int main(int argc, char **argv)
536			{
537			return xargs_main(argc, argv);
538			}
539			#endif /* TEST */