aboutsummaryrefslogtreecommitdiff
path: root/toys/posix/xargs.c
blob: 0d51325335b080b6940c9e9158164f2122e52748 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
/* vi: set sw=4 ts=4:
 *
 * 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

USE_XARGS(NEWTOY(xargs, "^I:E:L#ptxrn#<1s#0", TOYFLAG_USR|TOYFLAG_BIN))

config XARGS
	bool "xargs"
	default y
	help
	  usage: xargs [-ptxr0] [-s NUM] [-n NUM] [-L 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.

	  -s	Size in bytes per command line
	  -n	Max number of arguments per command
	  -0	Each argument is NULL terminated, no whitespace or quote processing
	  #-p	Prompt for y/n from tty before running each command
	  #-t	Trace, print command line to stderr
	  #-x	Exit if can't fit everything in one command
	  #-r	Don't run command with empty input
	  #-L	Max number of lines of input per command
	  -E	stop at line matching string
*/

#include "toys.h"

DEFINE_GLOBALS(
	long max_bytes;
	long max_entries;
	long L;
	char *eofstr;
	char *I;

	long entries, bytes;
	char delim;
)

#define TT this.xargs

// 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 eofstr

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.max_entries && TT.entries >= TT.max_entries)
				return *s ? s : (char *)1;

			if (!*s) break;
			save = s;

			for (;;) {
				if (++TT.bytes >= TT.max_bytes && TT.max_bytes) return save;
				if (!*s || isspace(*s)) break;
				s++;
			}
			if (TT.eofstr) {
				int len = s-save;
				if (len == strlen(TT.eofstr) && !strncmp(save, TT.eofstr, len))
					return (char *)2;
			}
			if (entry) entry[TT.entries] = save;
			++TT.entries;
		}

	// -0 support
	} else {
		TT.bytes += strlen(data)+1;
		if (TT.max_bytes && TT.bytes >= TT.max_bytes) return data;
		if (TT.max_entries && TT.entries >= TT.max_entries)
			return (char *)1;
		if (entry) entry[TT.entries] = data;
		TT.entries++;
	}

	return NULL;
}

void xargs_main(void)
{
	struct double_list *dlist = NULL;
	int entries, bytes, done = 0, status;
	char *data = NULL;

	if (!(toys.optflags&1)) 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) {
		char **out;

		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 ((long)data <= 2) data = 0;
			else data = xstrdup(data);

			break;
		}

		// Accumulate cally thing

		if (data && !TT.entries) error_exit("argument too long");
		out = xzalloc((entries+TT.entries+1)*sizeof(char *));

		if (dlist) {
			struct double_list *dtemp;

			// Fill out command line to exec
			memcpy(out, toys.optargs, entries*sizeof(char *));
			TT.entries = 0;
			TT.bytes = bytes;
			dlist->prev->next = 0;
			for (dtemp = dlist; dtemp; dtemp = dtemp->next)
				handle_entries(dtemp->data, out+entries);
		}
		pid_t pid=fork();
		if (!pid) {
			xclose(0);
			open("/dev/null", O_RDONLY);
			xexec(out);
		}
		waitpid(pid, &status, 0);
		status = WEXITSTATUS(status);

		// 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);
	}
}