sbase/xargs.c

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3.9 KiB
C
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/* See LICENSE file for copyright and license details. */
#include <errno.h>
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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/wait.h>
#include <unistd.h>
#include "text.h"
#include "util.h"
enum {
NARGS = 10000
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};
static int inputc(void);
static void deinputc(int);
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static void fillargbuf(int);
static int eatspace(void);
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static int parsequote(int);
static int parseescape(void);
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static char *poparg(void);
static void waitchld(void);
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static void spawn(void);
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static char *cmd[NARGS];
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static char *argb;
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static size_t argbsz;
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static size_t argbpos;
static int nerrors = 0;
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static char *eofstr;
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static int rflag = 0;
static void
usage(void)
{
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eprintf("usage: %s [-r] [-E eofstr] [cmd [arg...]]\n", argv0);
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}
int
main(int argc, char *argv[])
{
int leftover;
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long argsz, argmaxsz;
char *arg;
int i;
ARGBEGIN {
case 'r':
rflag = 1;
break;
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case 'E':
eofstr = EARGF(usage());
break;
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default:
usage();
} ARGEND;
argmaxsz = sysconf(_SC_ARG_MAX);
if (argmaxsz < 0)
eprintf("sysconf:");
/* Leave some room for environment variables */
argmaxsz -= 4 * 1024;
leftover = 0;
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do {
argsz = 0; i = 0;
if (argc > 0) {
for (; i < argc; i++) {
cmd[i] = strdup(argv[i]);
argsz += strlen(cmd[i]) + 1;
}
} else {
cmd[i] = strdup("/bin/echo");
argsz += strlen(cmd[i]) + 1;
i++;
}
while (leftover == 1 || (arg = poparg())) {
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if (argsz + strlen(arg) + 1 > argmaxsz ||
i >= NARGS - 1) {
if (strlen(arg) + 1 > argmaxsz)
enprintf(EXIT_FAILURE, "insufficient argument space\n");
leftover = 1;
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break;
}
cmd[i] = strdup(arg);
argsz += strlen(cmd[i]) + 1;
i++;
leftover = 0;
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}
cmd[i] = NULL;
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if (i == 1 && rflag == 1); else spawn();
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for (; i >= 0; i--)
free(cmd[i]);
} while (arg);
free(argb);
return nerrors > 0 ? 123 : 0;
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}
static int
inputc(void)
{
int ch;
ch = getc(stdin);
if (ch == EOF && ferror(stdin))
eprintf("stdin: read error:");
return ch;
}
static void
deinputc(int ch)
{
ungetc(ch, stdin);
}
static void
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fillargbuf(int ch)
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{
if (argbpos >= argbsz) {
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argbsz = argbpos == 0 ? 1 : argbsz * 2;
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argb = realloc(argb, argbsz);
if (!argb)
eprintf("realloc:");
}
argb[argbpos] = ch;
}
static int
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eatspace(void)
{
int ch;
while ((ch = inputc()) != EOF) {
switch (ch) {
case ' ': case '\t': case '\n':
break;
default:
deinputc(ch);
return ch;
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}
}
return -1;
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}
static int
parsequote(int q)
{
int ch;
while ((ch = inputc()) != EOF) {
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if (ch == q)
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return 0;
if (ch != '\n') {
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fillargbuf(ch);
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argbpos++;
}
}
return -1;
}
static int
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parseescape(void)
{
int ch;
if ((ch = inputc()) != EOF) {
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fillargbuf(ch);
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argbpos++;
return ch;
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}
return -1;
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}
static char *
poparg(void)
{
int ch;
argbpos = 0;
if (eatspace() == -1)
return NULL;
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while ((ch = inputc()) != EOF) {
switch (ch) {
case ' ': case '\t': case '\n':
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goto out;
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case '\'':
if (parsequote('\'') == -1)
enprintf(EXIT_FAILURE,
"unterminated single quote\n");
break;
case '\"':
if (parsequote('\"') == -1)
enprintf(EXIT_FAILURE,
"unterminated double quote\n");
break;
case '\\':
if (parseescape() == -1)
enprintf(EXIT_FAILURE, "backslash at EOF\n");
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break;
default:
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fillargbuf(ch);
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argbpos++;
break;
}
}
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out:
fillargbuf('\0');
if (eofstr && strcmp(argb, eofstr) == 0)
return NULL;
return argb;
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}
static void
waitchld(void)
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{
int status;
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wait(&status);
if (WIFEXITED(status)) {
if (WEXITSTATUS(status) == 255)
exit(124);
if (WEXITSTATUS(status) == 127 ||
WEXITSTATUS(status) == 126)
exit(WEXITSTATUS(status));
if (status != 0)
nerrors++;
}
if (WIFSIGNALED(status))
exit(125);
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}
static void
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spawn(void)
{
pid_t pid;
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int savederrno;
pid = fork();
if (pid < 0)
eprintf("fork:");
if (pid == 0) {
execvp(*cmd, cmd);
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savederrno = errno;
weprintf("execvp %s:", *cmd);
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_exit(savederrno == ENOENT ? 127 : 126);
}
waitchld();
}