d7b528920
Denys Vlasenko
2010-04-09
Subject
xargs: do not decrease orig_arg_max to negative values
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findutils/xargs.c+25 -20
| @@ -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; | |