| link.5 (13511) | link.5 (13744) |
|---|---|
| 1.\" Copyright (c) 1993 Paul Kranenburg 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. --- 12 unchanged lines hidden (view full) --- 21.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 22.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 27.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28.\" | 1.\" Copyright (c) 1993 Paul Kranenburg 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. --- 12 unchanged lines hidden (view full) --- 21.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 22.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 27.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28.\" |
| 29.\" $Id: link.5,v 1.2 1995/04/16 12:35:13 ats Exp $ | 29.\" $Id: link.5,v 1.3 1996/01/20 07:29:06 mpp Exp $ |
| 30.\" 31.Dd October 23, 1993 32.Dt LINK 5 33.Os 34.Sh NAME 35.Nm link 36.Nd dynamic loader and link editor interface 37.Sh SYNOPSIS --- 9 unchanged lines hidden (view full) --- 47as it serves such similar functions as symbol definitions (including the 48accompanying string table) and relocation records needed to resolve 49references to external entities. It also records a number of data structures 50unique to the dynamic loading and linking process. These include references 51to other objects that are required to complete the link-editing process and 52indirection tables to facilitate 53.Em Position Independent Code 54(PIC for short) to improve sharing of code pages among different processes. | 30.\" 31.Dd October 23, 1993 32.Dt LINK 5 33.Os 34.Sh NAME 35.Nm link 36.Nd dynamic loader and link editor interface 37.Sh SYNOPSIS --- 9 unchanged lines hidden (view full) --- 47as it serves such similar functions as symbol definitions (including the 48accompanying string table) and relocation records needed to resolve 49references to external entities. It also records a number of data structures 50unique to the dynamic loading and linking process. These include references 51to other objects that are required to complete the link-editing process and 52indirection tables to facilitate 53.Em Position Independent Code 54(PIC for short) to improve sharing of code pages among different processes. |
| 55The collection of data structures described here will be refered to as the | 55The collection of data structures described here will be referred to as the |
| 56.Em Run-time Relocation Section (RRS) 57and is embedded in the standard text and data segments of the dynamically 58linked program or shared object image as the existing 59.Xr a.out 60format offers no room for it elsewhere. 61.Pp 62Several utilities cooperate to ensure that the task of getting a program 63ready to run can complete successfully in a way that optimizes the use 64of system resources. The compiler emits PIC code from which shared libraries 65can be built by 66.Xr ld 1 . 67The compiler also includes size information of any initialized data items 68through the .size assembler directive. PIC code differs from conventional code 69in that it accesses data variables through an indirection table, the | 56.Em Run-time Relocation Section (RRS) 57and is embedded in the standard text and data segments of the dynamically 58linked program or shared object image as the existing 59.Xr a.out 60format offers no room for it elsewhere. 61.Pp 62Several utilities cooperate to ensure that the task of getting a program 63ready to run can complete successfully in a way that optimizes the use 64of system resources. The compiler emits PIC code from which shared libraries 65can be built by 66.Xr ld 1 . 67The compiler also includes size information of any initialized data items 68through the .size assembler directive. PIC code differs from conventional code 69in that it accesses data variables through an indirection table, the |
| 70Global Offset Table, by convention accessable by the reserved name | 70Global Offset Table, by convention accessible by the reserved name |
| 71.Em _GLOBAL_OFFSET_TABLE_. 72The exact mechanism used for this is machine dependent, usually a machine 73register is reserved for the purpose. The rational behind this construct 74is to generate code that is independent of the actual load address. Only 75the values contained in the Global Offset Table may need updating at run-time 76depending on the load addresses of the various shared objects in the address 77space. 78.Pp --- 82 unchanged lines hidden (view full) --- 161.It Fa sdt_loaded 162A pointer to the first link map loaded (see below). This field is set by 163.Xr ld.so. 164.It Fa sdt_sods 165The start of a (linked) list of shared object descriptors needed by 166.Em this 167object. 168.It Fa sdt_filler1 | 71.Em _GLOBAL_OFFSET_TABLE_. 72The exact mechanism used for this is machine dependent, usually a machine 73register is reserved for the purpose. The rational behind this construct 74is to generate code that is independent of the actual load address. Only 75the values contained in the Global Offset Table may need updating at run-time 76depending on the load addresses of the various shared objects in the address 77space. 78.Pp --- 82 unchanged lines hidden (view full) --- 161.It Fa sdt_loaded 162A pointer to the first link map loaded (see below). This field is set by 163.Xr ld.so. 164.It Fa sdt_sods 165The start of a (linked) list of shared object descriptors needed by 166.Em this 167object. 168.It Fa sdt_filler1 |
| 169Depricated (used by SunOS to specify library search rules). | 169Deprecated (used by SunOS to specify library search rules). |
| 170.It Fa sdt_got 171The location of the Global Offset Table within this image. 172.It Fa sdt_plt 173The location of the Procedure Linkage Table within this image. 174.It Fa sdt_rel 175The location of an array of 176.Fa relocation_info 177structures --- 20 unchanged lines hidden (view full) --- 198.It Fa sdt_text_sz 199The size of the object's text segment. 200.It Fa sdt_plt_sz 201The size of the Procedure Linkage Table. 202.El 203.Pp 204A 205.Fa sod | 170.It Fa sdt_got 171The location of the Global Offset Table within this image. 172.It Fa sdt_plt 173The location of the Procedure Linkage Table within this image. 174.It Fa sdt_rel 175The location of an array of 176.Fa relocation_info 177structures --- 20 unchanged lines hidden (view full) --- 198.It Fa sdt_text_sz 199The size of the object's text segment. 200.It Fa sdt_plt_sz 201The size of the Procedure Linkage Table. 202.El 203.Pp 204A 205.Fa sod |
| 206structure descibes a shared object that is needed | 206structure describes a shared object that is needed |
| 207to complete the link edit process of the object containing it. 208A list of such objects 209.Po 210chained through 211.Fa sod_next 212.Pc 213is pointed at 214by the --- 347 unchanged lines hidden --- | 207to complete the link edit process of the object containing it. 208A list of such objects 209.Po 210chained through 211.Fa sod_next 212.Pc 213is pointed at 214by the --- 347 unchanged lines hidden --- |