Rewrite of xargs by Vladimir N. Oleynik

1 files changed, 84 insertions, 62 deletions

diff --git a/findutils/xargs.c b/findutils/xargs.c
index 471bae45b..677618dc0 100644
--- a/findutils/xargs.c
+++ b/findutils/xargs.c
@@ -1,9 +1,10 @@
 /*
  * Mini xargs implementation for busybox
+ * Only "-prt" options are supported in this version of xargs.
  *
- * Copyright (C) 1999,2000 by Lineo, inc. and Erik Andersen
- * Copyright (C) 1999,2000,2001 by Erik Andersen <andersee@debian.org>
- * Remixed by Mark Whitley <markw@codepoet.org>
+ * (C) 2002 by Vladimir Oleynik <dzo@simtreas.ru>
+ *
+ * Special thanks Mark Whitley for stimul to rewrote :)
  *
  * 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
@@ -23,84 +24,105 @@
 
 #include <stdio.h>
 #include <stdlib.h>
-#include <string.h>
+#include <unistd.h>
+#include <getopt.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/wait.h>
 #include "busybox.h"
 
+
+/*
+   This function have special algorithm.
+   Don`t use fork and include to main!
+*/
+static void xargs_exec(char * const * args)
+{
+        int p;
+        int common[4];  /* shared vfork stack */
+
+        common[0] = 0;
+        if ((p = vfork()) >= 0) {
+                if (p == 0) {
+                        /* vfork -- child */
+                        execvp(args[0], args);
+                        common[0] = errno; /* set error to shared stack */
+                        _exit(1);
+                } else {
+                        /* vfork -- parent */
+                        wait(NULL);
+                        if(common[0]) {
+                                errno = common[0];
+                                perror_msg_and_die("%s", args[0]);
+                        }
+                }
+        } else {
+                perror_msg_and_die("vfork");
+        }
+}
+
 int xargs_main(int argc, char **argv)
 {
-        char *cmd_to_be_executed;
         char *file_to_act_on;
-        int i;
-        int len;
+        char **args;
+        int  i, a;
+        char flg_vi       = 0;    /* verbose |& interactive */
+        char flg_no_empty = 0;
 
-        /*
-         * 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.
-         */
+        while ((a = getopt(argc, argv, "prt")) > 0) {
+                switch(a) {
+                        case 'p':
+                                flg_vi |= 3;
+                                break;
+                        case 't':
+                                flg_vi |= 1;
+                                break;
+                        case 'r':
+                                flg_no_empty = 1;
+                                break;
+                        default:
+                                show_usage();
+                }
+        }
 
-        argv++;
-        len = argc;     /* arg = count for ' ' + trailing '\0' */
-        /* Store the command to be executed (taken from the command line) */
-        if (argc == 1) {
+        a = argc - optind;
+        argv += optind;
+        if(a==0) {
                 /* default behavior is to echo all the filenames */
-                argv[0] = "/bin/echo";
-                len++;  /* space for trailing '\0' */
-        } else {
-                argc--;
-                }
-        /* concatenate all the arguments passed to xargs together */
-        for (i = 0; i < argc; i++)
-                len += strlen(argv[i]);
-        cmd_to_be_executed = xmalloc (len);
-        for (i = len = 0; i < argc; i++) {
-                len = sprintf(cmd_to_be_executed + len, "%s ", argv[i]);
+                *argv = "/bin/echo";
+                a++;
         }
+        /* allocating pointers for execvp: a*arg, arg from stdin, NULL */
+        args = xcalloc(a + 3, sizeof(char *));
+
+        /* Store the command to be executed (taken from the command line) */
+        for (i = 0; i < a; i++)
+                args[i] = *argv++;
 
         /* 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) {
-
-                FILE *cmd_output;
-                char *output_line;
-                char *execstr;
-
+        while ((file_to_act_on = get_line_from_file(stdin)) != NULL) {
                 /* eat the newline off the filename. */
                 chomp(file_to_act_on);
-
-                /* eat blank lines */
-                if (file_to_act_on[0] == 0)
-                        continue;
-
-                /* assemble the command and execute it */
-                bb_asprintf(&execstr, "%s%s", cmd_to_be_executed, file_to_act_on);
-                
-                cmd_output = popen(execstr, "r");
-                if (cmd_output == NULL)
-                        perror_msg_and_die("popen");
-
-                /* harvest the output */
-                while ((output_line = get_line_from_file(cmd_output)) != NULL) {
-                        fputs(output_line, stdout);
-                        free(output_line);
+                if(file_to_act_on[0] != 0 || flg_no_empty == 0) {
+                        args[a] = file_to_act_on[0] ? file_to_act_on : NULL;
+                        if(flg_vi) {
+                                for(i=0; args[i]; i++) {
+                                        if(i)
+                                                fputc(' ', stderr);
+                                        fputs(args[i], stderr);
+                                }
+                                fprintf(stderr, "%s", ((flg_vi & 2) ? " ?..." : "\n"));
+                        }
+                        if((flg_vi & 2) == 0 || ask_confirmation() != 0 ) {
+                                xargs_exec(args);
+                        }
                 }
-
                 /* clean up */
-                pclose(cmd_output);
-                free(execstr);
                 free(file_to_act_on);
         }
-
 #ifdef CONFIG_FEATURE_CLEAN_UP
-        free(cmd_to_be_executed);
+        free(args);
 #endif
-
         return 0;
 }
-
-/* vi: set sw=4 ts=4: */