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authorDenys Vlasenko <vda.linux@googlemail.com>2010-04-09 12:58:40 (GMT)
committer Denys Vlasenko <vda.linux@googlemail.com>2010-04-09 12:58:40 (GMT)
commitd7b5289209131ae94b540b35f0f147d2302ec0c9 (patch)
tree99f42a344c1216060dc7fe8347c5e1773d1e0d52
parent125d0154e6c591addbaf1fae7c9ffdf5b7e7ed7b (diff)
downloadbusybox-d7b5289209131ae94b540b35f0f147d2302ec0c9.tar.gz
busybox-d7b5289209131ae94b540b35f0f147d2302ec0c9.tar.bz2
xargs: do not decrease orig_arg_max to negative values
Based on patch by Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--findutils/xargs.c45
1 files changed, 25 insertions, 20 deletions
diff --git a/findutils/xargs.c b/findutils/xargs.c
index f5dbc78..3785f1e 100644
--- a/findutils/xargs.c
+++ b/findutils/xargs.c
@@ -25,10 +25,10 @@
/* 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)
+# define ARG_MAX sysconf(_SC_ARG_MAX)
#endif
-#ifndef ARG_MAX
-#define ARG_MAX 470
+#if !defined(ARG_MAX)
+# define ARG_MAX 470
#endif
@@ -378,8 +378,6 @@ int xargs_main(int argc, char **argv)
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 = NULL;
unsigned opt;
size_t n_max_chars;
@@ -408,28 +406,35 @@ int xargs_main(int argc, char **argv)
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 */
+ n_max_chars = ARG_MAX; /* might be calling sysconf(_SC_ARG_MAX) */
+ if (n_max_chars < 4*1024); /* paranoia */
+ n_max_chars = LONG_MAX;
+ /* 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 -= 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;
if (opt & OPT_UPTO_SIZE) {
- n_max_chars = xatoul_range(max_chars, 1, orig_arg_max);
+ size_t n_chars = 0;
+ n_max_chars = xatoul_range(max_chars, 1, n_max_chars);
for (i = 0; i < argc; i++) {
n_chars += strlen(*argv) + 1;
}
- if (n_max_chars < n_chars) {
+ if (n_max_chars <= n_chars) {
bb_error_msg_and_die("can't 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);
@@ -442,9 +447,9 @@ int xargs_main(int argc, char **argv)
while ((list = read_args(list, eof_str, n_max_chars, max_chars)) != NULL ||
!(opt & OPT_NO_EMPTY))
{
+ size_t n_chars = 0;
opt |= OPT_NO_EMPTY;
n = 0;
- n_chars = 0;
#if ENABLE_FEATURE_XARGS_SUPPORT_TERMOPT
for (cur = list; cur;) {
n_chars += cur->length;