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authorDenys Vlasenko <vda.linux@googlemail.com>2010-06-19 19:44:01 (GMT)
committer Denys Vlasenko <vda.linux@googlemail.com>2010-06-19 19:44:01 (GMT)
commit4a96617095f40e3cfcf148a8a7d5d83f71079aa1 (patch)
tree15f72e679e30da4d36c75c18795da848bd960207
parente15a6c82dff9f85cfb2ee5ff32b00cbd722c7d92 (diff)
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xargs: bump default -sNUM up to 32k. Use sysconf() to trim it down if necessary
function old new delta xargs_main 819 830 +11 Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--findutils/xargs.c52
1 files changed, 27 insertions, 25 deletions
diff --git a/findutils/xargs.c b/findutils/xargs.c
index 46a62cb..7b9f1fb 100644
--- a/findutils/xargs.c
+++ b/findutils/xargs.c
@@ -59,14 +59,6 @@
//config: are not special.
#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! */
@@ -440,35 +432,43 @@ 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 +476,8 @@ 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 */