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Diffstat (limited to 'rtemstoolkit/elftoolchain/libdwarf/dwarf_get_relocation_info.3')
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diff --git a/rtemstoolkit/elftoolchain/libdwarf/dwarf_get_relocation_info.3 b/rtemstoolkit/elftoolchain/libdwarf/dwarf_get_relocation_info.3 new file mode 100644 index 0000000..96166cf --- /dev/null +++ b/rtemstoolkit/elftoolchain/libdwarf/dwarf_get_relocation_info.3 @@ -0,0 +1,228 @@ +.\" Copyright (c) 2011 Kai Wang +.\" All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" $Id: dwarf_get_relocation_info.3 2071 2011-10-27 03:20:00Z jkoshy $ +.\" +.Dd September 3, 2011 +.Os +.Dt DWARF_GET_RELOCATION_INFO 3 +.Sh NAME +.Nm dwarf_get_relocation_info +.Nd retrieve generated relocation arrays +.Sh LIBRARY +.Lb libdwarf +.Sh SYNOPSIS +.In libdwarf.h +.Ft int +.Fo dwarf_get_relocation_info +.Fa "Dwarf_P_Debug dbg" +.Fa "Dwarf_Signed *elf_section_index" +.Fa "Dwarf_Signed *elf_section_link" +.Fa "Dwarf_Unsigned *reloc_entry_count" +.Fa "Dwarf_Relocation_Data *reloc_buf" +.Fa "Dwarf_Error *err" +.Fc +.Sh DESCRIPTION +The function +.Fn dwarf_get_relocation_info +is used to retrieve the relocation arrays generated by a prior call to +.Xr dwarf_transform_to_disk_form 3 . +.Pp +Each call to this function retrieves the next available relocation +array. +Application code should call this function repeatly to retrieve all +the relocation arrays. +The total number of generated relocation arrays retrievable +by this function may be obtained by calling function +.Xr dwarf_get_relocation_info_count 3 . +.Pp +Argument +.Ar dbg +should reference a DWARF producer instance allocated using +.Xr dwarf_producer_init 3 in sequence. +or +.Xr dwarf_producer_init_b 3 . +The +.Dv DW_DLC_SYMBOLIC_RELOCATIONS +flag should have been set on the DWARF producer instance. +.Pp +Argument +.Ar elf_section_index +should point to a location which will be set to the ELF section index +of the relocation section to which the retrieved relocation array +belongs. +.Pp +Argument +.Ar elf_section_link +should point to a location which will be set to the section index of +the ELF section to which the retrieved relocation array applies. +.Pp +Argument +.Ar reloc_entry_count +should point to a location which will be set to the total number of +relocation entries contained in the relocation array. +.Pp +Argument +.Ar reloc_buf +should point to a location which will be set to a pointer to the +retrieved array of relocation entries. +.Pp +If argument +.Ar err +is not NULL, it will be used to store error information in case +of an error. +.Pp +The retrieved relocation entries are described using structure +.Vt Dwarf_Relocation_Data_s , +defined in the header file +.In libdwarf.h : +.Bd -literal -offset indent +typedef struct Dwarf_Relocation_Data_s { + unsigned char drd_type; + unsigned char drd_length; + Dwarf_Unsigned drd_offset; + Dwarf_Unsigned drd_symbol_index; +} *Dwarf_Relocation_Data; +.Ed +.Pp +Struct +.Vt Dwarf_Relocation_Data_s +consists of following fields: +.Bl -tag -width ".Va drd_symbol_index" -compact -offset indent +.It Va drd_type +The type code of the relocation entry. +The +.Vt Dwarf_Rel_Type +enumeration defined in the header file +.In libdwarf.h +specifies legal values for this field. +.It Va drd_length +The size in bytes of the field to be relocated. +.It Va drd_offset +The section-relative offset of the field to be relocated. +.It Va drd_symbol_index +The symbol index associated with the relocation entry. +.El +.Ss Memory Management +The memory area used for the relocation arrays is managed by the +.Lb libdwarf . +The function +.Fn dwarf_producer_finish +may be used to release it, along with other resources associated +with the producer instance. +.Sh RETURN VALUES +On success, function +.Fn dwarf_get_relocation_info +returns +.Dv DW_DLV_OK . +It returns +.Dv DW_DLV_NO_ENTRY +if there were no more relocation arrays to retrieve, or if the flag +.Dv DW_DLC_SYMBOLIC_RELOCATIONS +was not set on the producer instance. +In case of an error, function +.Fn dwarf_get_relocation_info +returns +.Dv DW_DLV_ERROR +and sets the argument +.Ar err . +.Sh ERRORS +Function +.Fn dwarf_get_relocation_info +can fail with: +.Bl -tag -width ".Bq Er DW_DLE_NO_ENTRY" +.It Bq Er DW_DLE_ARGUMENT +One of the arguments +.Ar dbg , +.Ar elf_section_index , +.Ar elf_section_link , +.Ar reloc_entry_count +or +.Ar reloc_buf +was NULL. +.It Bq Er DW_DLE_NO_ENTRY +There were no more ELF relocation arrays to retrieve. +.It Bq Er DW_DLE_NO_ENTRY +The flag +.Dv DW_DLC_SYMBOLIC_RELOCATIONS +was not set on the producer instance. +.It Bq Er DW_DLE_NO_ENTRY +Function +.Xr dwarf_transform_to_disk_form 3 +was not called prior to calling function +.Fn dwarf_get_relocation_info . +.El +.Sh EXAMPLES +To generate relocation entries and retrieve them, use: +.Bd -literal -offset indent +Dwarf_P_Debug dbg; +Dwarf_Relocation_Data buf; +Dwarf_Signed count, index, link; +Dwarf_Unsigned reloc_cnt, entry_cnt; +Dwarf_Error de; +int version, i, j; + +/* + * Assume that dbg refers to a DWARF producer instance created + * created with DW_DLC_SYMBOLIC_RELOCATIONS flag set and that + * application code has added DWARF debugging information + * to the producer instance. + */ +if ((count = dwarf_transform_to_disk_form(dbg, &de)) == + DW_DLV_NOCOUNT) { + warnx("dwarf_transform_to_disk_form failed: %s", + dwarf_errmsg(-1)); + return; +} + +/* ... process generated section byte streams ... */ +if (dwarf_get_relocation_info_count(dbg, &reloc_cnt, &version, &de) != + DW_DLV_OK) { + warnx("dwarf_get_relocation_info_count failed: %s", + dwarf_errmsg(-1)); + return; +} + +for (i = 0; (Dwarf_Unsigned) i < reloc_cnt; i++) { + if (dwarf_get_relocation_info(dbg, &index, &link, &entry_cnt, + &buf, &de) != DW_DLV_OK) { + warnx("dwarf_get_relocation_info failed: %s", + dwarf_errmsg(-1)); + continue; + } + for (j = 0; (Dwarf_Unsigned) j < entry_cnt; j++) { + /* ...use each reloc data in buf[j]... */ + } +} + +dwarf_producer_finish(dbg, &de); +.Ed +.Sh SEE ALSO +.Xr dwarf 3 , +.Xr dwarf_get_relocation_info_count 3 , +.Xr dwarf_reset_section_bytes 3 , +.Xr dwarf_producer_finish 3 , +.Xr dwarf_producer_init 3 , +.Xr dwarf_producer_init_b 3 , +.Xr dwarf_transform_to_disk_form 3 |