Hello Ollie, Ollie Wild wrote: > Michael, > > Per our previous discussion, here are the updates to the execve(2) > manpage resulting from the variable length argument support patch in > linux-2.6.23-rc1. The execve API is unmodified. However, the > following should be noted in the "Notes" section. > > Prior to linux-2.6.23, the memory used to store the environment and > argument list strings was limited to 32 (MAX_ARG_PAGES) pages. On > most architectures, the page size is 4kB, leading to a maximum size of > 128kB. > > In linux-2.6.23 and later, most architectures support a size limit > derived from the current RLIMIT_STACK setting (see getrlimit(2)). For > these architectures, the total size is limited to 1/4 the allowed > stack size, the limit per string is 32 pages (MAX_ARG_STRLEN), and the > maximum number of strings is 0x7FFFFFFF. Architectures with no memory > management unit are excepted: they maintain the pre-2.6.23 limit.
Thanks. For man-pages-2.66 I have added the following text to execve.2: Limits on size of arguments + environment Most Unix implementations impose some limit on the total size of the command-line argument (argv) and environment (envp) strings that may be passed to a new program. POSIX.1 allows an implementation to advertise this limit using the ARG_MAX constant (either defined in <limits.h> or available at run time using the call sysconf(_SC_ARG_MAX)). On Linux prior to kernel 2.6.23, the memory used to store the environment and argument strings was limited to 32 pages (defined by the kernel constant MAX_ARG_PAGES). On architec- tures with a 4-kB page size, this yields a maximum size of 128 kB. On kernel 2.6.23 and later, most architectures support a size limit derived from the soft RLIMIT_STACK resource limit (see getrlimit(2)). For these architectures, the total size is limited to 1/4 of the allowed stack size, the limit per string is 32 pages (the kernel constant MAX_ARG_STRLEN), and the maximum number of strings is 0x7FFFFFFF. (This change allows programs to have a much larger argument and/or envi- ronment list. Imposing the 1/4-limit ensures that the new program always has some stack space.) Architectures with no memory management unit are excepted: they maintain the pre-2.6.23 limit. Cheers, Michael -- Michael Kerrisk maintainer of Linux man pages Sections 2, 3, 4, 5, and 7 Want to help with man page maintenance? Grab the latest tarball at http://www.kernel.org/pub/linux/docs/manpages/ read the HOWTOHELP file and grep the source files for 'FIXME'. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/