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Diffstat (limited to 'lib/libc/gen/dl_iterate_phdr.3')
| -rw-r--r-- | lib/libc/gen/dl_iterate_phdr.3 | 117 |
1 files changed, 117 insertions, 0 deletions
diff --git a/lib/libc/gen/dl_iterate_phdr.3 b/lib/libc/gen/dl_iterate_phdr.3 new file mode 100644 index 000000000000..448d6fbb2fc5 --- /dev/null +++ b/lib/libc/gen/dl_iterate_phdr.3 @@ -0,0 +1,117 @@ +.\" Copyright (c) 2005 Mark Kettenis +.\" Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org> +.\" +.\" Permission to use, copy, modify, and distribute this software for any +.\" purpose with or without fee is hereby granted, provided that the above +.\" copyright notice and this permission notice appear in all copies. +.\" +.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES +.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF +.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR +.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES +.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN +.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF +.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. +.\" +.\" $OpenBSD: dl_iterate_phdr.3,v 1.3 2007/05/31 19:19:48 jmc Exp $ +.Dd April 5, 2021 +.Dt DL_ITERATE_PHDR 3 +.Os +.Sh NAME +.Nm dl_iterate_phdr +.Nd iterate over program headers +.Sh LIBRARY +For the dynamically linked binaries, the service is provided by +.Xr ld-elf.so.1 1 +dynamic linker. +Statically linked programs use an implementation of +.Fn dl_iterate_phdr +from libc. +.Sh SYNOPSIS +.In link.h +.Ft int +.Fn dl_iterate_phdr "int (*callback)(struct dl_phdr_info *, size_t, void *)" "void *data" +.Sh DESCRIPTION +The +.Fn dl_iterate_phdr +function iterates over all ELF objects loaded into a process's +address space, calling +.Fa callback +for each object, passing it information about the object's +program headers and the +.Fa data +argument. +The iteration is aborted when all objects are passed, or when the next +.Fa callback +call returns non-zero value. +The information about the program headers is passed in a structure +that is defined as: +.Bd -literal +struct dl_phdr_info { + Elf_Addr dlpi_addr; + const char *dlpi_name; + const Elf_Phdr *dlpi_phdr; + Elf_Half dlpi_phnum; + unsigned long long int dlpi_adds; + unsigned long long int dlpi_subs; + size_t dlpi_tls_modid; + void *dlpi_tls_data; +}; +.Ed +.Pp +The members of +.Li struct dl_phdr_info +have the following meaning: +.Bl -tag -width dlpi_tls_modid +.It Fa dlpi_addr +The base address at which the object is mapped into the address +space of the calling process. +.It Fa dlpi_name +The pathname of the ELF object. +.It Fa dlpi_phdr +A pointer to the object's program headers. +.It Fa dlpi_phnum +The number of program headers in the object. +.It Fa dlpi_adds +The counter of the object loads performed by the dynamic linker. +.It Fa dlpi_subs +The counter of the object unloads performed by the dynamic linker. +.It Fa dlpi_tls_modid +The TLS index of the object. +.It Fa dlpi_tls_data +A pointer to the calling thread' TLS data segment for this module, +if it was allocated, +.Dv NULL +otherwise. +.El +.Pp +Future versions of +.Fx +might add more members to this structure. +To make it possible for programs to check whether any new members have +been added, the size of the structure is passed as an second argument to +.Fa callback . +.Pp +The third argument to callback is the +.Fa data +value passed to the call to +.Fn dl_iterate_phdr , +allowing the +.Fa callback +to have a context. +.Sh RETURN VALUES +The +.Fn dl_iterate_phdr +returns the value returned by the last +.Fa callback +call executed. +.Sh SEE ALSO +.Xr ld 1 , +.Xr ld-elf.so.1 1 , +.Xr dlopen 3 , +.Xr elf 5 +.Sh HISTORY +The +.Nm +function first appeared in +.Fx 7.0 . |