ip: code shrink

[oweals/busybox.git] / findutils / xargs.c

diff --git a/findutils/xargs.c b/findutils/xargs.c
index 46a62cbf1d0b3f93305d4765122b178512fe16fc..0d1bb43fc89a7e05ee06627342762f0149c1b0d2 100644 (file)
--- a/findutils/xargs.c
+++ b/findutils/xargs.c
@@ -9,16 +9,12 @@
  * - 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.
+ * 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
  */
 
-//applet:IF_XARGS(APPLET_NOEXEC(xargs, xargs, _BB_DIR_USR_BIN, _BB_SUID_DROP, xargs))
-
-//kbuild:lib-$(CONFIG_XARGS) += xargs.o
-
 //config:config XARGS
 //config:      bool "xargs"
 //config:      default y
@@ -58,15 +54,11 @@
 //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"
-/* 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
-#if !defined(ARG_MAX)
-# define ARG_MAX 470
-#endif
 
 /* This is a NOEXEC applet. Be very careful! */
 
@@ -97,7 +89,9 @@ struct globals {
        int idx;
 } FIX_ALIASING;
 #define G (*(struct globals*)&bb_common_bufsiz1)
-#define INIT_G() do { } while (0)
+#define INIT_G() do { \
+       G.eof_str = NULL; /* need to clear by hand because we are NOEXEC applet */ \
+} while (0)
 
 
 /*
@@ -355,7 +349,6 @@ static int xargs_ask_confirmation(void)
 //usage:       "[OPTIONS] [PROG ARGS]"
 //usage:#define xargs_full_usage "\n\n"
 //usage:       "Run PROG on every item given by stdin\n"
-//usage:     "\nOptions:"
 //usage:       IF_FEATURE_XARGS_SUPPORT_CONFIRMATION(
 //usage:     "\n       -p      Ask user whether to run each command"
 //usage:       )
@@ -420,7 +413,12 @@ int xargs_main(int argc, char **argv)
 
        INIT_G();
 
-       G.eof_str = NULL;
+#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?
@@ -440,35 +438,43 @@ int xargs_main(int argc, char **argv)
                argc++;
        }
 
-       /* The Open Group Base Specifications Issue 6:
+       /* -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".
         */
-       n_max_chars = ARG_MAX; /* might be calling sysconf(_SC_ARG_MAX) */
-       if (n_max_chars < 4*1024); /* paranoia */
-               n_max_chars = 4*1024;
-       n_max_chars -= 2048;
-       /* 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 (n_max_chars > 20 * 1024)
-               n_max_chars = 20 * 1024;
-
+       {
+               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) {
-               size_t n_chars = 0;
                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;
-               if (n_max_chars <= 0) {
-                       bb_error_msg_and_die("can't fit single argument within argument list size limit");
-               }
+       }
+       /* Sanity check */
+       if (n_max_chars <= 0) {
+               bb_error_msg_and_die("can't fit single argument within argument list size limit");
        }
 
        buf = xzalloc(n_max_chars + 1);
@@ -476,6 +482,8 @@ int xargs_main(int argc, char **argv)
        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 */
        }
 
        /* Allocate pointers for execvp */