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Diffstat (limited to 'man/man2/personality.2')
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diff --git a/man/man2/personality.2 b/man/man2/personality.2 new file mode 100644 index 000000000..976f27c6d --- /dev/null +++ b/man/man2/personality.2 @@ -0,0 +1,296 @@ +.\" Copyright (C) 1995, Thomas K. Dyas <tdyas@eden.rutgers.edu> +.\" and Copyright (C) 2016, Michael Kerrisk <mtk.manpages@gmail.com> +.\" +.\" SPDX-License-Identifier: Linux-man-pages-copyleft +.\" +.\" Created Sat Aug 21 1995 Thomas K. Dyas <tdyas@eden.rutgers.edu> +.\" +.\" typo corrected, aeb, 950825 +.\" added layout change from joey, 960722 +.\" changed prototype, documented 0xffffffff, aeb, 030101 +.\" Modified 2004-11-03 patch from Martin Schulze <joey@infodrom.org> +.\" +.TH personality 2 (date) "Linux man-pages (unreleased)" +.SH NAME +personality \- set the process execution domain +.SH LIBRARY +Standard C library +.RI ( libc ", " \-lc ) +.SH SYNOPSIS +.nf +.B #include <sys/personality.h> +.P +.BI "int personality(unsigned long " persona ); +.fi +.SH DESCRIPTION +Linux supports different execution domains, or personalities, for each +process. +Among other things, execution domains tell Linux how to map +signal numbers into signal actions. +The execution domain system allows +Linux to provide limited support for binaries compiled under other +UNIX-like operating systems. +.P +If +.I persona +is not +0xffffffff, then +.BR personality () +sets the caller's execution domain to the value specified by +.IR persona . +Specifying +.I persona +as 0xffffffff provides a way of retrieving +the current persona without changing it. +.P +A list of the available execution domains can be found in +.IR <sys/personality.h> . +The execution domain is a 32-bit value in which the top three +bytes are set aside for flags that cause the kernel to modify the +behavior of certain system calls so as to emulate historical or +architectural quirks. +The least significant byte is a value defining the personality +the kernel should assume. +The flag values are as follows: +.TP +.BR ADDR_COMPAT_LAYOUT " (since Linux 2.6.9)" +With this flag set, provide legacy virtual address space layout. +.TP +.BR ADDR_NO_RANDOMIZE " (since Linux 2.6.12)" +With this flag set, disable address-space-layout randomization. +.TP +.BR ADDR_LIMIT_32BIT " (since Linux 2.2)" +Limit the address space to 32 bits. +.TP +.BR ADDR_LIMIT_3GB " (since Linux 2.4.0)" +With this flag set, use 0xc0000000 as the offset at which to search +a virtual memory chunk on +.BR mmap (2); +otherwise use 0xffffe000. +Applies to 32-bit x86 processes only. +.TP +.BR FDPIC_FUNCPTRS " (since Linux 2.6.11)" +User-space function pointers to signal handlers point +to descriptors. +Applies only to ARM if BINFMT_ELF_FDPIC and SuperH. +.TP +.BR MMAP_PAGE_ZERO " (since Linux 2.4.0)" +Map page 0 as read-only +(to support binaries that depend on this SVr4 behavior). +.TP +.BR READ_IMPLIES_EXEC " (since Linux 2.6.8)" +With this flag set, +.B PROT_READ +implies +.B PROT_EXEC +for +.BR mmap (2). +.TP +.BR SHORT_INODE " (since Linux 2.4.0)" +No effect. +.TP +.BR STICKY_TIMEOUTS " (since Linux 1.2.0)" +With this flag set, +.BR select (2), +.BR pselect (2), +and +.BR ppoll (2) +do not modify the returned timeout argument when +interrupted by a signal handler. +.TP +.BR UNAME26 " (since Linux 3.1)" +Have +.BR uname (2) +report a 2.6.(40+x) version number rather than a MAJOR.x version number. +Added as a stopgap measure to support broken applications that +could not handle the +kernel version-numbering switch from Linux 2.6.x to Linux 3.x. +.TP +.BR WHOLE_SECONDS " (since Linux 1.2.0)" +No effect. +.P +The available execution domains are: +.TP +.BR PER_BSD " (since Linux 1.2.0)" +BSD. (No effects.) +.TP +.BR PER_HPUX " (since Linux 2.4)" +Support for 32-bit HP/UX. +This support was never complete, and was dropped so that since Linux 4.0, +this value has no effect. +.TP +.BR PER_IRIX32 " (since Linux 2.2)" +IRIX 5 32-bit. +Never fully functional; support dropped in Linux 2.6.27. +Implies +.BR STICKY_TIMEOUTS . +.TP +.BR PER_IRIX64 " (since Linux 2.2)" +IRIX 6 64-bit. +Implies +.BR STICKY_TIMEOUTS ; +otherwise no effect. +.TP +.BR PER_IRIXN32 " (since Linux 2.2)" +IRIX 6 new 32-bit. +Implies +.BR STICKY_TIMEOUTS ; +otherwise no effect. +.TP +.BR PER_ISCR4 " (since Linux 1.2.0)" +Implies +.BR STICKY_TIMEOUTS ; +otherwise no effect. +.TP +.BR PER_LINUX " (since Linux 1.2.0)" +Linux. +.TP +.BR PER_LINUX32 " (since Linux 2.2)" +.BR uname (2) +returns the name of the 32-bit architecture in the +.I machine +field ("i686" instead of "x86_64", &c.). +.IP +Under ia64 (Itanium), processes with this personality don't have the +O_LARGEFILE +.BR open (2) +flag forced. +.IP +Under 64-bit ARM, setting this personality is forbidden if +.BR execve (2)ing +a 32-bit process would also be forbidden +(cf. the allow_mismatched_32bit_el0 kernel parameter and +.IR Documentation/arm64/asymmetric-32bit.rst ). +.TP +.BR PER_LINUX32_3GB " (since Linux 2.4)" +Same as +.BR PER_LINUX32 , +but implies +.BR ADDR_LIMIT_3GB . +.TP +.BR PER_LINUX_32BIT " (since Linux 2.0)" +Same as +.BR PER_LINUX , +but implies +.BR ADDR_LIMIT_32BIT . +.TP +.BR PER_LINUX_FDPIC " (since Linux 2.6.11)" +Same as +.BR PER_LINUX , +but implies +.BR FDPIC_FUNCPTRS . +.TP +.BR PER_OSF4 " (since Linux 2.4)" +OSF/1 v4. +.\" commit 987f20a9dcce3989e48d87cff3952c095c994445 +No effect since Linux 6.1, which removed a.out binary support. +Before, on alpha, +.\" Following is from a comment in arch/alpha/kernel/osf_sys.c +would clear top 32 bits of iov_len in the user's buffer for +compatibility with old versions of OSF/1 where iov_len +was defined as. +.IR int . +.TP +.BR PER_OSR5 " (since Linux 2.4)" +SCO OpenServer 5. +Implies +.B STICKY_TIMEOUTS +and +.BR WHOLE_SECONDS ; +otherwise no effect. +.TP +.BR PER_RISCOS " (since Linux 2.3.7; macro since Linux 2.3.13)" +Acorn RISC OS/Arthur (MIPS). +No effect. +.\" commit 125ec7b4e90cbae4eed5a7ff1ee479cc331dcf3c +Up to Linux v4.0, would set the emulation altroot to +.I /usr/gnemul/riscos +(cf.\& +.BR PER_SUNOS , +below). +Before then, up to Linux 2.6.3, just Arthur emulation. +.TP +.BR PER_SCOSVR3 " (since Linux 1.2.0)" +SCO UNIX System V Release 3. +Same as +.BR PER_OSR5 , +but also implies +.BR SHORT_INODE . +.TP +.BR PER_SOLARIS " (since Linux 2.4)" +Solaris. +Implies +.BR STICKY_TIMEOUTS ; +otherwise no effect. +.TP +.BR PER_SUNOS " (since Linux 2.4.0)" +Sun OS. +Same as +.BR PER_BSD , +but implies +.BR STICKY_TIMEOUTS . +Prior to Linux 2.6.26, +diverted library and dynamic linker searches to +.IR /usr/gnemul . +Buggy, largely unmaintained, and almost entirely unused. +.TP +.BR PER_SVR3 " (since Linux 1.2.0)" +AT&T UNIX System V Release 3. +Implies +.B STICKY_TIMEOUTS +and +.BR SHORT_INODE ; +otherwise no effect. +.TP +.BR PER_SVR4 " (since Linux 1.2.0)" +AT&T UNIX System V Release 4. +Implies +.B STICKY_TIMEOUTS +and +.BR MMAP_PAGE_ZERO ; +otherwise no effect. +.TP +.BR PER_UW7 " (since Linux 2.4)" +UnixWare 7. +Implies +.B STICKY_TIMEOUTS +and +.BR MMAP_PAGE_ZERO ; +otherwise no effect. +.TP +.BR PER_WYSEV386 " (since Linux 1.2.0)" +WYSE UNIX System V/386. +Implies +.B STICKY_TIMEOUTS +and +.BR SHORT_INODE ; +otherwise no effect. +.TP +.BR PER_XENIX " (since Linux 1.2.0)" +XENIX. +Implies +.B STICKY_TIMEOUTS +and +.BR SHORT_INODE ; +otherwise no effect. +.SH RETURN VALUE +On success, the previous +.I persona +is returned. +On error, \-1 is returned, and +.I errno +is set to indicate the error. +.SH ERRORS +.TP +.B EINVAL +The kernel was unable to change the personality. +.SH STANDARDS +Linux. +.SH HISTORY +Linux 1.1.20, +.\" (and thus first in a stable kernel release with Linux 1.2.0) +glibc 2.3. +.\" personality wrapper first appeared in glibc 1.90, +.\" <sys/personality.h> was added later in glibc 2.2.91. +.SH SEE ALSO +.BR setarch (8) |