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busybox/findutils/xargs.c

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/* 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 */
BB_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);
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 = (char*)"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 */
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