1.\" Copyright (c) 2011 Kai Wang 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. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.\" $Id: dwarf_get_section_bytes.3 2071 2011-10-27 03:20:00Z jkoshy $ 26.\" 27.Dd August 26, 2011 28.Os 29.Dt DWARF_GET_SECTION_BYTES 3 30.Sh NAME 31.Nm dwarf_get_section_bytes 32.Nd retrieve ELF section byte streams 33.Sh LIBRARY 34.Lb libdwarf 35.Sh SYNOPSIS 36.In libdwarf.h 37.Ft Dwarf_Ptr 38.Fo dwarf_get_section_bytes 39.Fa "Dwarf_P_Debug dbg" 40.Fa "Dwarf_Signed dwarf_section" 41.Fa "Dwarf_Signed *elf_section_index" 42.Fa "Dwarf_Unsigned *length" 43.Fa "Dwarf_Error *err" 44.Fc 45.Sh DESCRIPTION 46Function 47.Fn dwarf_get_section_bytes 48returns the ELF section byte streams generated by a prior call 49to function 50.Xr dwarf_transform_to_disk_form 3 . 51.Pp 52Each call to function 53.Fn dwarf_get_section_bytes 54will return the byte stream for one ELF section. 55The first call to this function will always return the first ELF 56section, and the subsequent calls will return the rest of sections 57in the order when they were generated, until the last one. 58The total number of sections generated is returned by the function 59.Xr dwarf_transform_to_disk_form 3 . 60.Pp 61Argument 62.Ar dbg 63should reference a DWARF producer instance allocated using the 64functions 65.Xr dwarf_producer_init 3 66or 67.Xr dwarf_producer_init_b 3 . 68.Pp 69Argument 70.Ar dwarf_section 71is currently ignored. 72.Pp 73Argument 74.Ar elf_section_index 75should point to a location which will be set to the section index value 76of the returned ELF section. 77.Pp 78Argument 79.Ar length 80should point to a location which will hold the length in bytes of the 81returned ELF section. 82.Pp 83If argument 84.Ar err 85is not NULL, it will be used to store error information in case of an 86error. 87.Ss Memory Management 88The memory areas used for the returned ELF section byte streams should 89be freed using the function 90.Fn dwarf_producer_finish . 91.Sh RETURN VALUES 92On success, function 93.Fn dwarf_get_section_bytes 94returns a pointer to a ELF section byte stream. 95In case of an error, function 96.Fn dwarf_get_section_bytes 97will return NULL and set the argument 98.Ar err . 99.Sh ERRORS 100Function 101.Fn dwarf_get_section_bytes 102can fail with: 103.Bl -tag -width ".Bq Er DW_DLE_NO_ENTRY" 104.It Bq Er DW_DLE_ARGUMENT 105One of the arguments 106.Ar dbg , 107.Ar elf_section_index , 108or 109.Ar length 110was NULL. 111.It Bq Er DW_DLE_NO_ENTRY 112There were no more ELF sections to retrieve, or the function was 113called before a call to 114.Xr dwarf_transform_to_disk_form 3 . 115.El 116.Sh EXAMPLES 117To generate and retrieve ELF section byte streams, use: 118.Bd -literal -offset indent 119Dwarf_P_Debug dbg; 120Dwarf_Signed count, i, sec_index; 121Dwarf_Unsigned len; 122Dwarf_Ptr bytes; 123Dwarf_Error de; 124 125/* ... Assume that `dbg' refers to a DWARF producer instance, 126 * and that application code has added DWARF debugging 127 * information to the producer instance. ... 128 */ 129if ((count = dwarf_transform_to_disk_form(dbg, &de)) == 130 DW_DLV_NOCOUNT) { 131 warnx("dwarf_transform_to_disk_form failed: %s", 132 dwarf_errmsg(-1)); 133 return; 134} 135 136/* Retrieve section data. */ 137for (i = 0; i < count; i++) { 138 bytes = dwarf_get_section_bytes(dbg, i, &sec_index, &len, 139 &de); 140 if (bytes == NULL) { 141 warnx("dwarf_get_section_bytes failed: %s", 142 dwarf_errmsg(-1)); 143 continue; 144 } 145 /* ... use the returned byte stream ... */ 146} 147 148/* Release resources. */ 149dwarf_producer_finish(dbg, &de); 150.Ed 151.Sh SEE ALSO 152.Xr dwarf 3 , 153.Xr dwarf_reset_section_bytes 3 , 154.Xr dwarf_producer_finish 3 , 155.Xr dwarf_producer_init 3 , 156.Xr dwarf_producer_init_b 3 , 157.Xr dwarf_transform_to_disk_form 3 158