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	xargs.c - sbase - suckless unix tools
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	---
	xargs.c (4934B)
	---
	1 /* See LICENSE file for copyright and license details. */
	2 #include <sys/wait.h>
	3
	4 #include <errno.h>
	5 #include <limits.h>
	6 #include <stdint.h>
	7 #include <stdio.h>
	8 #include <stdlib.h>
	9 #include <string.h>
	10 #include <unistd.h>
	11
	12 #include "util.h"
	13
	14 #define NARGS 10000
	15
	16 static int inputc(void);
	17 static void fillargbuf(int);
	18 static int eatspace(void);
	19 static int parsequote(int);
	20 static int parseescape(void);
	21 static char *poparg(void);
	22 static void waitchld(void);
	23 static void spawn(void);
	24
	25 static size_t argbsz;
	26 static size_t argbpos;
	27 static size_t maxargs = 0;
	28 static int nerrors = 0;
	29 static int rflag = 0, nflag = 0, tflag = 0, xflag = 0, Iflag = 0;
	30 static char *argb;
	31 static char *cmd[NARGS];
	32 static char *eofstr;
	33
	34 static int
	35 inputc(void)
	36 {
	37 int ch;
	38
	39 ch = getc(stdin);
	40 if (ch == EOF && ferror(stdin))
	41 eprintf("getc <stdin>:");
	42
	43 return ch;
	44 }
	45
	46 static void
	47 fillargbuf(int ch)
	48 {
	49 if (argbpos >= argbsz) {
	50 argbsz = argbpos == 0 ? 1 : argbsz * 2;
	51 argb = erealloc(argb, argbsz);
	52 }
	53 argb[argbpos] = ch;
	54 }
	55
	56 static int
	57 eatspace(void)
	58 {
	59 int ch;
	60
	61 while ((ch = inputc()) != EOF) {
	62 switch (ch) {
	63 case ' ': case '\t': case '\n':
	64 break;
	65 default:
	66 ungetc(ch, stdin);
	67 return ch;
	68 }
	69 }
	70 return -1;
	71 }
	72
	73 static int
	74 parsequote(int q)
	75 {
	76 int ch;
	77
	78 while ((ch = inputc()) != EOF) {
	79 if (ch == q)
	80 return 0;
	81 if (ch != '\n') {
	82 fillargbuf(ch);
	83 argbpos++;
	84 }
	85 }
	86
	87 return -1;
	88 }
	89
	90 static int
	91 parseescape(void)
	92 {
	93 int ch;
	94
	95 if ((ch = inputc()) != EOF) {
	96 fillargbuf(ch);
	97 argbpos++;
	98 return ch;
	99 }
	100
	101 return -1;
	102 }
	103
	104 static char *
	105 poparg(void)
	106 {
	107 int ch;
	108
	109 argbpos = 0;
	110 if (eatspace() < 0)
	111 return NULL;
	112 while ((ch = inputc()) != EOF) {
	113 switch (ch) {
	114 case ' ':
	115 case '\t':
	116 if (Iflag)
	117 goto fill;
	118 case '\n':
	119 goto out;
	120 case '\'':
	121 if (parsequote('\'') < 0)
	122 eprintf("unterminated single quote\n");
	123 break;
	124 case '\"':
	125 if (parsequote('\"') < 0)
	126 eprintf("unterminated double quote\n");
	127 break;
	128 case '\\':
	129 if (parseescape() < 0)
	130 eprintf("backslash at EOF\n");
	131 break;
	132 default:
	133 fill:
	134 fillargbuf(ch);
	135 argbpos++;
	136 break;
	137 }
	138 }
	139 out:
	140 fillargbuf('\0');
	141
	142 return (eofstr && !strcmp(argb, eofstr)) ? NULL : argb;
	143 }
	144
	145 static void
	146 waitchld(void)
	147 {
	148 int status;
	149
	150 wait(&status);
	151 if (WIFEXITED(status)) {
	152 if (WEXITSTATUS(status) == 255)
	153 exit(124);
	154 if (WEXITSTATUS(status) == 127 \|\|
	155 WEXITSTATUS(status) == 126)
	156 exit(WEXITSTATUS(status));
	157 if (status)
	158 nerrors++;
	159 }
	160 if (WIFSIGNALED(status))
	161 exit(125);
	162 }
	163
	164 static void
	165 spawn(void)
	166 {
	167 int savederrno;
	168 int first = 1;
	169 char **p;
	170
	171 if (tflag) {
	172 for (p = cmd; *p; p++) {
	173 if (!first)
	174 fputc(' ', stderr);
	175 fputs(*p, stderr);
	176 first = 0;
	177 }
	178 fputc('\n', stderr);
	179 }
	180
	181 switch (fork()) {
	182 case -1:
	183 eprintf("fork:");
	184 case 0:
	185 execvp(*cmd, cmd);
	186 savederrno = errno;
	187 weprintf("execvp %s:", *cmd);
	188 _exit(126 + (savederrno == ENOENT));
	189 }
	190 waitchld();
	191 }
	192
	193 static void
	194 usage(void)
	195 {
	196 eprintf("usage: %s [-rtx] [-E eofstr] [-n num] [-s num] "
	197 "[cmd [arg ...]]\n", argv0);
	198 }
	199
	200 int
	201 main(int argc, char *argv[])
	202 {
	203 int ret = 0, leftover = 0, i, j;
	204 size_t argsz, argmaxsz;
	205 size_t arglen, a;
	206 char *arg = "";
	207 char *replstr;
	208
	209 if ((argmaxsz = sysconf(_SC_ARG_MAX)) == (size_t)-1)
	210 argmaxsz = _POSIX_ARG_MAX;
	211 /* Leave some room for environment variables */
	212 argmaxsz -= 4096;
	213
	214 ARGBEGIN {
	215 case 'n':
	216 nflag = 1;
	217 maxargs = estrtonum(EARGF(usage()), 1, MIN(SIZE_MAX, LLO…
	218 break;
	219 case 'r':
	220 rflag = 1;
	221 break;
	222 case 's':
	223 argmaxsz = estrtonum(EARGF(usage()), 1, MIN(SIZE_MAX, LL…
	224 break;
	225 case 't':
	226 tflag = 1;
	227 break;
	228 case 'x':
	229 xflag = 1;
	230 break;
	231 case 'E':
	232 eofstr = EARGF(usage());
	233 break;
	234 case 'I':
	235 Iflag = 1;
	236 xflag = 1;
	237 nflag = 1;
	238 maxargs = 1;
	239 replstr = EARGF(usage());
	240 break;
	241 default:
	242 usage();
	243 } ARGEND
	244
	245 do {
	246 argsz = 0; i = 0; a = 0;
	247 if (argc) {
	248 for (; i < argc; i++) {
	249 cmd[i] = estrdup(argv[i]);
	250 argsz += strlen(cmd[i]) + 1;
	251 }
	252 } else {
	253 cmd[i] = estrdup("/bin/echo");
	254 argsz += strlen("/bin/echo") + 1;
	255 i++;
	256 }
	257 while (leftover \|\| (arg = poparg())) {
	258 arglen = strlen(arg);
	259 if (argsz + arglen >= argmaxsz \|\| i >= NARGS - 1…
	260 if (arglen >= argmaxsz) {
	261 weprintf("insufficient argument …
	262 if (xflag)
	263 exit(1);
	264 }
	265 leftover = 1;
	266 break;
	267 }
	268
	269 if (!Iflag) {
	270 cmd[i] = estrdup(arg);
	271 argsz += arglen + 1;
	272 } else {
	273 for (j = 1; j < i; j++) {
	274 char *p = cmd[j];
	275 argsz -= strlen(cmd[j]);
	276 strnsubst(&cmd[j], replstr, arg,…
	277 argsz += strlen(cmd[j]);
	278 free(p);
	279 }
	280 }
	281
	282 i++;
	283 a++;
	284 leftover = 0;
	285 if (nflag && a >= maxargs)
	286 break;
	287 }
	288 cmd[i] = NULL;
	289 if (a >= maxargs && nflag)
	290 spawn();
	291 else if (!a \|\| (i == 1 && rflag))
	292 ;
	293 else
	294 spawn();
	295 for (; i >= 0; i--)
	296 free(cmd[i]);
	297 } while (arg);
	298
	299 free(argb);
	300
	301 if (nerrors \|\| (fshut(stdin, "<stdin>") \| fshut(stdout, "<stdout…
	302 ret = 123;
	303
	304 return ret;
	305 }