X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=findutils%2Fxargs.c;h=0d1bb43fc89a7e05ee06627342762f0149c1b0d2;hb=df9196d824ea9bca7590edade631362e89b5c6ce;hp=48adae90a2870dc590fb7a7514abd69baa68485b;hpb=6f3240abf946d99116a633d20d26ad2d681dbaed;p=oweals%2Fbusybox.git diff --git a/findutils/xargs.c b/findutils/xargs.c index 48adae90a..0d1bb43fc 100644 --- a/findutils/xargs.c +++ b/findutils/xargs.c @@ -1,105 +1,565 @@ +/* vi: set sw=4 ts=4: */ /* * Mini xargs implementation for busybox * - * Copyright (C) 1999,2000,2001 by Lineo, inc. - * Written by Erik Andersen , - * Remixed by Mark Whitley , - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. + * (C) 2002,2003 by Vladimir Oleynik * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * General Public License for more details. + * Special thanks + * - Mark Whitley and Glenn McGrath for stimulus to rewrite :) + * - Mike Rendell + * and David MacKenzie . * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * Licensed under GPLv2 or later, see file LICENSE in this source tree. * + * xargs is described in the Single Unix Specification v3 at + * http://www.opengroup.org/onlinepubs/007904975/utilities/xargs.html + */ + +//config:config XARGS +//config: bool "xargs" +//config: default y +//config: help +//config: xargs is used to execute a specified command for +//config: every item from standard input. +//config: +//config:config FEATURE_XARGS_SUPPORT_CONFIRMATION +//config: bool "Enable -p: prompt and confirmation" +//config: default y +//config: depends on XARGS +//config: help +//config: Support -p: prompt the user whether to run each command +//config: line and read a line from the terminal. +//config: +//config:config FEATURE_XARGS_SUPPORT_QUOTES +//config: bool "Enable single and double quotes and backslash" +//config: default y +//config: depends on XARGS +//config: help +//config: Support quoting in the input. +//config: +//config:config FEATURE_XARGS_SUPPORT_TERMOPT +//config: bool "Enable -x: exit if -s or -n is exceeded" +//config: default y +//config: depends on XARGS +//config: help +//config: Support -x: exit if the command size (see the -s or -n option) +//config: is exceeded. +//config: +//config:config FEATURE_XARGS_SUPPORT_ZERO_TERM +//config: bool "Enable -0: NUL-terminated input" +//config: default y +//config: depends on XARGS +//config: help +//config: Support -0: input items are terminated by a NUL character +//config: instead of whitespace, and the quotes and backslash +//config: are not special. + +//applet:IF_XARGS(APPLET_NOEXEC(xargs, xargs, BB_DIR_USR_BIN, BB_SUID_DROP, xargs)) + +//kbuild:lib-$(CONFIG_XARGS) += xargs.o + +#include "libbb.h" + +/* This is a NOEXEC applet. Be very careful! */ + + +//#define dbg_msg(...) bb_error_msg(__VA_ARGS__) +#define dbg_msg(...) ((void)0) + + +#ifdef TEST +# ifndef ENABLE_FEATURE_XARGS_SUPPORT_CONFIRMATION +# define ENABLE_FEATURE_XARGS_SUPPORT_CONFIRMATION 1 +# endif +# ifndef ENABLE_FEATURE_XARGS_SUPPORT_QUOTES +# define ENABLE_FEATURE_XARGS_SUPPORT_QUOTES 1 +# endif +# ifndef ENABLE_FEATURE_XARGS_SUPPORT_TERMOPT +# define ENABLE_FEATURE_XARGS_SUPPORT_TERMOPT 1 +# endif +# ifndef ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM +# define ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM 1 +# endif +#endif + + +struct globals { + char **args; + const char *eof_str; + int idx; +} FIX_ALIASING; +#define G (*(struct globals*)&bb_common_bufsiz1) +#define INIT_G() do { \ + G.eof_str = NULL; /* need to clear by hand because we are NOEXEC applet */ \ +} while (0) + + +/* + * This function has special algorithm. + * Don't use fork and include to main! + */ +static int xargs_exec(void) +{ + int status; + + status = spawn_and_wait(G.args); + if (status < 0) { + bb_simple_perror_msg(G.args[0]); + return errno == ENOENT ? 127 : 126; + } + if (status == 255) { + bb_error_msg("%s: exited with status 255; aborting", G.args[0]); + return 124; + } + if (status >= 0x180) { + bb_error_msg("%s: terminated by signal %d", + G.args[0], status - 0x180); + return 125; + } + if (status) + return 123; + return 0; +} + +/* In POSIX/C locale isspace is only these chars: "\t\n\v\f\r" and space. + * "\t\n\v\f\r" happen to have ASCII codes 9,10,11,12,13. */ +#define ISSPACE(a) ({ unsigned char xargs__isspace = (a) - 9; xargs__isspace == (' ' - 9) || xargs__isspace <= (13 - 9); }) -#include -#include -#include -#include "busybox.h" +static void store_param(char *s) +{ + /* Grow by 256 elements at once */ + if (!(G.idx & 0xff)) { /* G.idx == N*256 */ + /* Enlarge, make G.args[(N+1)*256 - 1] last valid idx */ + G.args = xrealloc(G.args, sizeof(G.args[0]) * (G.idx + 0x100)); + } + G.args[G.idx++] = s; +} + +/* process[0]_stdin: + * Read characters into buf[n_max_chars+1], and when parameter delimiter + * is seen, store the address of a new parameter to args[]. + * If reading discovers that last chars do not form the complete + * parameter, the pointer to the first such "tail character" is returned. + * (buf has extra byte at the end to accomodate terminating NUL + * of "tail characters" string). + * Otherwise, the returned pointer points to NUL byte. + * On entry, buf[] may contain some "seed chars" which are to become + * the beginning of the first parameter. + */ + +#if ENABLE_FEATURE_XARGS_SUPPORT_QUOTES +static char* FAST_FUNC process_stdin(int n_max_chars, int n_max_arg, char *buf) +{ +#define NORM 0 +#define QUOTE 1 +#define BACKSLASH 2 +#define SPACE 4 + char q = '\0'; /* quote char */ + char state = NORM; + char *s = buf; /* start of the word */ + char *p = s + strlen(buf); /* end of the word */ + + buf += n_max_chars; /* past buffer's end */ + + /* "goto ret" is used instead of "break" to make control flow + * more obvious: */ + + while (1) { + int c = getchar(); + if (c == EOF) { + if (p != s) + goto close_word; + goto ret; + } + if (state == BACKSLASH) { + state = NORM; + goto set; + } + if (state == QUOTE) { + if (c != q) + goto set; + q = '\0'; + state = NORM; + } else { /* if (state == NORM) */ + if (ISSPACE(c)) { + if (p != s) { + close_word: + state = SPACE; + c = '\0'; + goto set; + } + } else { + if (c == '\\') { + state = BACKSLASH; + } else if (c == '\'' || c == '"') { + q = c; + state = QUOTE; + } else { + set: + *p++ = c; + } + } + } + if (state == SPACE) { /* word's delimiter or EOF detected */ + if (q) { + bb_error_msg_and_die("unmatched %s quote", + q == '\'' ? "single" : "double"); + } + /* A full word is loaded */ + if (G.eof_str) { + if (strcmp(s, G.eof_str) == 0) { + while (getchar() != EOF) + continue; + p = s; + goto ret; + } + } + store_param(s); + dbg_msg("args[]:'%s'", s); + s = p; + n_max_arg--; + if (n_max_arg == 0) { + goto ret; + } + state = NORM; + } + if (p == buf) { + goto ret; + } + } + ret: + *p = '\0'; + /* store_param(NULL) - caller will do it */ + dbg_msg("return:'%s'", s); + return s; +} +#else +/* The variant does not support single quotes, double quotes or backslash */ +static char* FAST_FUNC process_stdin(int n_max_chars, int n_max_arg, char *buf) +{ + char *s = buf; /* start of the word */ + char *p = s + strlen(buf); /* end of the word */ + + buf += n_max_chars; /* past buffer's end */ + + while (1) { + int c = getchar(); + if (c == EOF) { + if (p == s) + goto ret; + } + if (c == EOF || ISSPACE(c)) { + if (p == s) + continue; + c = EOF; + } + *p++ = (c == EOF ? '\0' : c); + if (c == EOF) { /* word's delimiter or EOF detected */ + /* A full word is loaded */ + if (G.eof_str) { + if (strcmp(s, G.eof_str) == 0) { + while (getchar() != EOF) + continue; + p = s; + goto ret; + } + } + store_param(s); + dbg_msg("args[]:'%s'", s); + s = p; + n_max_arg--; + if (n_max_arg == 0) { + goto ret; + } + } + if (p == buf) { + goto ret; + } + } + ret: + *p = '\0'; + /* store_param(NULL) - caller will do it */ + dbg_msg("return:'%s'", s); + return s; +} +#endif /* FEATURE_XARGS_SUPPORT_QUOTES */ +#if ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM +static char* FAST_FUNC process0_stdin(int n_max_chars, int n_max_arg, char *buf) +{ + char *s = buf; /* start of the word */ + char *p = s + strlen(buf); /* end of the word */ + + buf += n_max_chars; /* past buffer's end */ + + while (1) { + int c = getchar(); + if (c == EOF) { + if (p == s) + goto ret; + c = '\0'; + } + *p++ = c; + if (c == '\0') { /* word's delimiter or EOF detected */ + /* A full word is loaded */ + store_param(s); + dbg_msg("args[]:'%s'", s); + s = p; + n_max_arg--; + if (n_max_arg == 0) { + goto ret; + } + } + if (p == buf) { + goto ret; + } + } + ret: + *p = '\0'; + /* store_param(NULL) - caller will do it */ + dbg_msg("return:'%s'", s); + return s; +} +#endif /* FEATURE_XARGS_SUPPORT_ZERO_TERM */ + +#if ENABLE_FEATURE_XARGS_SUPPORT_CONFIRMATION +/* Prompt the user for a response, and + if the user responds affirmatively, return true; + otherwise, return false. Uses "/dev/tty", not stdin. */ +static int xargs_ask_confirmation(void) +{ + FILE *tty_stream; + int c, savec; + + tty_stream = xfopen_for_read(CURRENT_TTY); + fputs(" ?...", stderr); + fflush_all(); + c = savec = getc(tty_stream); + while (c != EOF && c != '\n') + c = getc(tty_stream); + fclose(tty_stream); + return (savec == 'y' || savec == 'Y'); +} +#else +# define xargs_ask_confirmation() 1 +#endif + +//usage:#define xargs_trivial_usage +//usage: "[OPTIONS] [PROG ARGS]" +//usage:#define xargs_full_usage "\n\n" +//usage: "Run PROG on every item given by stdin\n" +//usage: IF_FEATURE_XARGS_SUPPORT_CONFIRMATION( +//usage: "\n -p Ask user whether to run each command" +//usage: ) +//usage: "\n -r Don't run command if input is empty" +//usage: IF_FEATURE_XARGS_SUPPORT_ZERO_TERM( +//usage: "\n -0 Input is separated by NUL characters" +//usage: ) +//usage: "\n -t Print the command on stderr before execution" +//usage: "\n -e[STR] STR stops input processing" +//usage: "\n -n N Pass no more than N args to PROG" +//usage: "\n -s N Pass command line of no more than N bytes" +//usage: IF_FEATURE_XARGS_SUPPORT_TERMOPT( +//usage: "\n -x Exit if size is exceeded" +//usage: ) +//usage:#define xargs_example_usage +//usage: "$ ls | xargs gzip\n" +//usage: "$ find . -name '*.c' -print | xargs rm\n" + +/* Correct regardless of combination of CONFIG_xxx */ +enum { + OPTBIT_VERBOSE = 0, + OPTBIT_NO_EMPTY, + OPTBIT_UPTO_NUMBER, + OPTBIT_UPTO_SIZE, + OPTBIT_EOF_STRING, + OPTBIT_EOF_STRING1, + IF_FEATURE_XARGS_SUPPORT_CONFIRMATION(OPTBIT_INTERACTIVE,) + IF_FEATURE_XARGS_SUPPORT_TERMOPT( OPTBIT_TERMINATE ,) + IF_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 , /* GNU: -e[] */ + OPT_EOF_STRING1 = 1 << OPTBIT_EOF_STRING1, /* SUS: -E */ + OPT_INTERACTIVE = IF_FEATURE_XARGS_SUPPORT_CONFIRMATION((1 << OPTBIT_INTERACTIVE)) + 0, + OPT_TERMINATE = IF_FEATURE_XARGS_SUPPORT_TERMOPT( (1 << OPTBIT_TERMINATE )) + 0, + OPT_ZEROTERM = IF_FEATURE_XARGS_SUPPORT_ZERO_TERM( (1 << OPTBIT_ZEROTERM )) + 0, +}; +#define OPTION_STR "+trn:s:e::E:" \ + IF_FEATURE_XARGS_SUPPORT_CONFIRMATION("p") \ + IF_FEATURE_XARGS_SUPPORT_TERMOPT( "x") \ + IF_FEATURE_XARGS_SUPPORT_ZERO_TERM( "0") + +int xargs_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int xargs_main(int argc, char **argv) { - char *cmd_to_be_executed = NULL; - char *file_to_act_on = NULL; - - /* - * No options are supported in this version of xargs; no getopt. - * - * Re: The missing -t flag: Most programs that produce output also print - * the filename, so xargs doesn't really need to do it again. Supporting - * the -t flag =greatly= bloats up the size of this app and the memory it - * uses because you have to buffer all the input file strings in memory. If - * you really want to see the filenames that xargs will act on, just run it - * once with no args and xargs will echo the filename. Simple. - */ + int i; + int child_error = 0; + char *max_args; + char *max_chars; + char *buf; + unsigned opt; + int n_max_chars; + int n_max_arg; +#if ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM + char* FAST_FUNC (*read_args)(int, int, char*) = process_stdin; +#else +#define read_args process_stdin +#endif + + INIT_G(); - /* Store the command to be executed (taken from the command line) */ - if (argc == 1) { +#if ENABLE_DESKTOP && ENABLE_LONG_OPTS + /* For example, Fedora's build system uses --no-run-if-empty */ + applet_long_options = + "no-run-if-empty\0" No_argument "r" + ; +#endif + opt = getopt32(argv, OPTION_STR, &max_args, &max_chars, &G.eof_str, &G.eof_str); + + /* -E ""? You may wonder why not just omit -E? + * This is used for portability: + * old xargs was using "_" as default for -E / -e */ + if ((opt & OPT_EOF_STRING1) && G.eof_str[0] == '\0') + G.eof_str = NULL; + + if (opt & OPT_ZEROTERM) + IF_FEATURE_XARGS_SUPPORT_ZERO_TERM(read_args = process0_stdin); + + argv += optind; + argc -= optind; + if (!argv[0]) { /* default behavior is to echo all the filenames */ - cmd_to_be_executed = xstrdup("/bin/echo "); - } else { - /* concatenate all the arguments passed to xargs together */ - int i; - int len = 1; /* for the '\0' */ - for (i = 1; i < argc; i++) { - len += strlen(argv[i]); - len += 1; /* for the space between the args */ - cmd_to_be_executed = xrealloc(cmd_to_be_executed, len); - strcat(cmd_to_be_executed, argv[i]); - strcat(cmd_to_be_executed, " "); + *--argv = (char*)"echo"; + argc++; + } + + /* -s NUM default. fileutils-4.4.2 uses 128k, but I heasitate + * to use such a big value - first need to change code to use + * growable buffer instead of fixed one. + */ + n_max_chars = 32 * 1024; + /* Make smaller if system does not allow our default value. + * The Open Group Base Specifications Issue 6: + * "The xargs utility shall limit the command line length such that + * when the command line is invoked, the combined argument + * and environment lists (see the exec family of functions + * in the System Interfaces volume of IEEE Std 1003.1-2001) + * shall not exceed {ARG_MAX}-2048 bytes". + */ + { + long arg_max = 0; +#if defined _SC_ARG_MAX + arg_max = sysconf(_SC_ARG_MAX) - 2048; +#elif defined ARG_MAX + arg_max = ARG_MAX - 2048; +#endif + if (arg_max > 0 && n_max_chars > arg_max) + n_max_chars = arg_max; + } + if (opt & OPT_UPTO_SIZE) { + n_max_chars = xatou_range(max_chars, 1, INT_MAX); + } + /* Account for prepended fixed arguments */ + { + size_t n_chars = 0; + for (i = 0; argv[i]; i++) { + n_chars += strlen(argv[i]) + 1; } + n_max_chars -= n_chars; + } + /* Sanity check */ + if (n_max_chars <= 0) { + bb_error_msg_and_die("can't fit single argument within argument list size limit"); } - /* Now, read in one line at a time from stdin, and store this - * line to be used later as an argument to the command */ - while ((file_to_act_on = get_line_from_file(stdin)) !=NULL) { + buf = xzalloc(n_max_chars + 1); - FILE *cmd_output = NULL; - char *output_line = NULL; - char *execstr = NULL; + n_max_arg = n_max_chars; + if (opt & OPT_UPTO_NUMBER) { + n_max_arg = xatou_range(max_args, 1, INT_MAX); + /* Not necessary, we use growable args[]: */ + /* if (n_max_arg > n_max_chars) n_max_arg = n_max_chars */ + } - /* eat the newline off the filename. */ - chomp(file_to_act_on); + /* Allocate pointers for execvp */ + /* We can statically allocate (argc + n_max_arg + 1) elements + * and do not bother with resizing args[], but on 64-bit machines + * this results in args[] vector which is ~8 times bigger + * than n_max_chars! That is, with n_max_chars == 20k, + * args[] will take 160k (!), which will most likely be + * almost entirely unused. + */ + /* See store_param() for matching 256-step growth logic */ + G.args = xmalloc(sizeof(G.args[0]) * ((argc + 0xff) & ~0xff)); + + /* Store the command to be executed, part 1 */ + for (i = 0; argv[i]; i++) + G.args[i] = argv[i]; + + while (1) { + char *rem; + + G.idx = argc; + rem = read_args(n_max_chars, n_max_arg, buf); + store_param(NULL); + + if (!G.args[argc]) { + if (*rem != '\0') + bb_error_msg_and_die("argument line too long"); + if (opt & OPT_NO_EMPTY) + break; + } + opt |= OPT_NO_EMPTY; - /* eat blank lines */ - if (strlen(file_to_act_on) == 0) - continue; + if (opt & (OPT_INTERACTIVE | OPT_VERBOSE)) { + const char *fmt = " %s" + 1; + char **args = G.args; + for (i = 0; args[i]; i++) { + fprintf(stderr, fmt, args[i]); + fmt = " %s"; + } + if (!(opt & OPT_INTERACTIVE)) + bb_putchar_stderr('\n'); + } - /* assemble the command and execute it */ - execstr = xcalloc(strlen(cmd_to_be_executed) + - strlen(file_to_act_on) + 1, sizeof(char)); - strcat(execstr, cmd_to_be_executed); - strcat(execstr, file_to_act_on); - cmd_output = popen(execstr, "r"); - if (cmd_output == NULL) - perror_msg_and_die("popen"); + if (!(opt & OPT_INTERACTIVE) || xargs_ask_confirmation()) { + child_error = xargs_exec(); + } - /* harvest the output */ - while ((output_line = get_line_from_file(cmd_output)) != NULL) { - fputs(output_line, stdout); - free(output_line); + if (child_error > 0 && child_error != 123) { + break; } - /* clean up */ - pclose(cmd_output); - free(execstr); - free(file_to_act_on); + overlapping_strcpy(buf, rem); + } /* while */ + + if (ENABLE_FEATURE_CLEAN_UP) { + free(G.args); + free(buf); } -#ifdef BB_FEATURE_CLEAN_UP - free(cmd_to_be_executed); -#endif + return child_error; +} - return 0; + +#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(EXIT_FAILURE); } -/* vi: set sw=4 ts=4: */ +int main(int argc, char **argv) +{ + return xargs_main(argc, argv); +} +#endif /* TEST */