sbase/xargs.c

261 lines
4.1 KiB
C

/* See LICENSE file for copyright and license details. */
#include <errno.h>
#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
};
static int inputc(void);
static void deinputc(int);
static void fillargbuf(int);
static int eatspace(void);
static int parsequote(int);
static int parseescape(void);
static char *poparg(void);
static void waitchld(void);
static void spawn(void);
static char *cmd[NARGS];
static char *argb;
static size_t argbsz;
static size_t argbpos;
static long maxargs = 0;
static int nerrors = 0;
static char *eofstr;
static int rflag = 0, nflag = 0;
static void
usage(void)
{
eprintf("usage: %s [-n maxargs] [-r] [-E eofstr] [cmd [arg...]]\n", argv0);
}
int
main(int argc, char *argv[])
{
int leftover = 0;
long argsz, argmaxsz;
char *arg = "";
int i, a;
ARGBEGIN {
case 'n':
nflag = 1;
if ((maxargs = strtol(EARGF(usage()), NULL, 10)) <= 0)
eprintf("%s: value for -n option should be >= 1\n", argv0);
break;
case 'r':
rflag = 1;
break;
case 'E':
eofstr = EARGF(usage());
break;
default:
usage();
} ARGEND;
argmaxsz = sysconf(_SC_ARG_MAX);
if (argmaxsz < 0)
eprintf("sysconf:");
/* Leave some room for environment variables */
argmaxsz -= 4 * 1024;
do {
argsz = 0; i = 0; a = 0;
if (argc > 0) {
for (; i < argc; i++) {
cmd[i] = estrdup(argv[i]);
argsz += strlen(cmd[i]) + 1;
}
} else {
cmd[i] = estrdup("/bin/echo");
argsz += strlen(cmd[i]) + 1;
i++;
}
while (leftover == 1 || (arg = poparg())) {
if (argsz + strlen(arg) + 1 > argmaxsz ||
i >= NARGS - 1) {
if (strlen(arg) + 1 > argmaxsz)
eprintf("insufficient argument space\n");
leftover = 1;
break;
}
cmd[i] = estrdup(arg);
argsz += strlen(cmd[i]) + 1;
i++;
a++;
leftover = 0;
if (nflag == 1 && a >= maxargs)
break;
}
cmd[i] = NULL;
if (a >= maxargs && nflag == 1)
spawn();
else if (!a || (i == 1 && rflag == 1))
;
else
spawn();
for (; i >= 0; i--)
free(cmd[i]);
} while (arg);
free(argb);
return nerrors > 0 ? 123 : 0;
}
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
fillargbuf(int ch)
{
if (argbpos >= argbsz) {
argbsz = argbpos == 0 ? 1 : argbsz * 2;
argb = erealloc(argb, argbsz);
}
argb[argbpos] = ch;
}
static int
eatspace(void)
{
int ch;
while ((ch = inputc()) != EOF) {
switch (ch) {
case ' ': case '\t': case '\n':
break;
default:
deinputc(ch);
return ch;
}
}
return -1;
}
static int
parsequote(int q)
{
int ch;
while ((ch = inputc()) != EOF) {
if (ch == q)
return 0;
if (ch != '\n') {
fillargbuf(ch);
argbpos++;
}
}
return -1;
}
static int
parseescape(void)
{
int ch;
if ((ch = inputc()) != EOF) {
fillargbuf(ch);
argbpos++;
return ch;
}
return -1;
}
static char *
poparg(void)
{
int ch;
argbpos = 0;
if (eatspace() < 0)
return NULL;
while ((ch = inputc()) != EOF) {
switch (ch) {
case ' ': case '\t': case '\n':
goto out;
case '\'':
if (parsequote('\'') < 0)
eprintf("unterminated single quote\n");
break;
case '\"':
if (parsequote('\"') < 0)
eprintf("unterminated double quote\n");
break;
case '\\':
if (parseescape() < 0)
eprintf("backslash at EOF\n");
break;
default:
fillargbuf(ch);
argbpos++;
break;
}
}
out:
fillargbuf('\0');
if (eofstr && strcmp(argb, eofstr) == 0)
return NULL;
return argb;
}
static void
waitchld(void)
{
int status;
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);
}
static void
spawn(void)
{
pid_t pid;
int savederrno;
pid = fork();
if (pid < 0)
eprintf("fork:");
if (pid == 0) {
execvp(*cmd, cmd);
savederrno = errno;
weprintf("execvp %s:", *cmd);
_exit(savederrno == ENOENT ? 127 : 126);
}
waitchld();
}