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xargs: do not decrease orig_arg_max to negative values

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Based on patch by Nguyễn Thái Ngọc Duy <pclouds@gmail.com>

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2010-04-09 14:58:40 +02:00
parent 125d0154e6
commit d7b5289209
1 changed files with 25 additions and 20 deletions
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41
findutils/xargs.c
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@ -27,7 +27,7 @@
#if !defined(ARG_MAX) && defined(_SC_ARG_MAX) #if !defined(ARG_MAX) && defined(_SC_ARG_MAX)
# define ARG_MAX sysconf(_SC_ARG_MAX) # define ARG_MAX sysconf(_SC_ARG_MAX)
#endif #endif
#ifndef ARG_MAX #if !defined(ARG_MAX)
# define ARG_MAX 470 # define ARG_MAX 470
#endif #endif
@ -378,8 +378,6 @@ int xargs_main(int argc, char **argv)
int child_error = 0; int child_error = 0;
char *max_args, *max_chars; char *max_args, *max_chars;
int n_max_arg; int n_max_arg;
size_t n_chars = 0;
long orig_arg_max;
const char *eof_str = NULL; const char *eof_str = NULL;
unsigned opt; unsigned opt;
size_t n_max_chars; size_t n_max_chars;
@ -408,28 +406,35 @@ int xargs_main(int argc, char **argv)
argc++; argc++;
} }
orig_arg_max = ARG_MAX; n_max_chars = ARG_MAX; /* might be calling sysconf(_SC_ARG_MAX) */
if (orig_arg_max == -1) if (n_max_chars < 4*1024); /* paranoia */
orig_arg_max = LONG_MAX; n_max_chars = LONG_MAX;
orig_arg_max -= 2048; /* POSIX.2 requires subtracting 2048 */ /* 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) { 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++) { for (i = 0; i < argc; i++) {
n_chars += strlen(*argv) + 1; 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"); bb_error_msg_and_die("can't fit single argument within argument list size limit");
} }
n_max_chars -= n_chars; 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); 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 || while ((list = read_args(list, eof_str, n_max_chars, max_chars)) != NULL ||
!(opt & OPT_NO_EMPTY)) !(opt & OPT_NO_EMPTY))
{ {
size_t n_chars = 0;
opt |= OPT_NO_EMPTY; opt |= OPT_NO_EMPTY;
n = 0; n = 0;
n_chars = 0;
#if ENABLE_FEATURE_XARGS_SUPPORT_TERMOPT #if ENABLE_FEATURE_XARGS_SUPPORT_TERMOPT
for (cur = list; cur;) { for (cur = list; cur;) {
n_chars += cur->length; n_chars += cur->length;