4a9661709
Denys Vlasenko
2010-06-19
Subject
xargs: bump default -sNUM up to 32k. Use sysconf() to trim it down if necessary
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findutils/xargs.c+27 -25
| @@ -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 */ | |