xref: /freebsd/contrib/elftoolchain/libelf/elf_memory.3 (revision 8ddb146abcdf061be9f2c0db7e391697dafad85c)
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24.\" $Id: elf_memory.3 3639 2018-10-14 14:07:02Z jkoshy $
25.\"
26.Dd June 28, 2006
27.Dt ELF_MEMORY 3
28.Os
29.Sh NAME
30.Nm elf_memory
31.Nd process an ELF or ar(1) archive mapped into memory
32.Sh LIBRARY
33.Lb libelf
34.Sh SYNOPSIS
35.In libelf.h
36.Ft "Elf *"
37.Fn elf_memory "char *image" "size_t size"
38.Sh DESCRIPTION
39Function
40.Fn elf_memory
41is used to process an ELF file or
42.Xr ar 1
43archive whose image is present in memory.
44.Pp
45Argument
46.Ar image
47points to the start of the memory image of the file or archive.
48Argument
49.Ar size
50contains the size in bytes of the memory image.
51.Pp
52The ELF descriptor is created for reading (i.e., analogous to the
53use of
54.Xr elf_begin 3
55with a command argument value of
56.Dv ELF_C_READ Ns ).
57.Sh RETURN VALUES
58Function
59.Fn elf_memory
60returns a pointer to a new ELF descriptor if successful, or NULL if an
61error occurred.
62.Pp
63The return value may be queried for the file type using
64.Xr elf_kind 3 .
65.Sh EXAMPLES
66To read parse an elf file, use:
67.Bd -literal -offset indent
68int fd;
69void *p;
70struct stat sb;
71Elf *e;
72\&...
73if ((fd = open("./elf-file", O_RDONLY)) < 0 ||
74    fstat(fd, &sb) < 0 ||
75    (p = mmap(NULL, sb.st_size, PROT_READ, MAP_PRIVATE, fd, (off_t) 0)) ==
76    MAP_FAILED) {
77	... handle system error ...
78}
79
80if ((e = elf_memory(p, sb.st_size)) == NULL) {
81	... handle elf(3) error ...
82}
83\&... use ELF descriptor "e" here ...
84.Ed
85.Sh ERRORS
86Function
87.Fn elf_memory
88can fail with the following errors:
89.Bl -tag -width "[ELF_E_RESOURCE]"
90.It Bq Er ELF_E_ARGUMENT
91A NULL value was used for argument
92.Ar image
93or the value of argument
94.Ar sz
95was zero.
96.It Bq Er ELF_E_HEADER
97The header of the ELF object contained an unsupported value in its
98.Va e_ident[EI_CLASS]
99field.
100.It Bq Er ELF_E_HEADER
101The header of the ELF object contained an unsupported value in its
102.Va e_ident[EI_DATA]
103field.
104.It Bq Er ELF_E_RESOURCE
105An out of memory condition was detected.
106.It Bq Er ELF_E_SEQUENCE
107Function
108.Fn elf_memory
109was called before a working version was set using
110.Xr elf_version 3 .
111.It Bq Er ELF_E_VERSION
112The ELF object referenced by argument
113.Ar image
114was of an unsupported ELF version.
115.El
116.Sh SEE ALSO
117.Xr elf 3 ,
118.Xr elf_begin 3 ,
119.Xr elf_end 3 ,
120.Xr elf_errno 3 ,
121.Xr elf_kind 3 ,
122.Xr gelf 3
123