xref: /illumos-gate/usr/src/cmd/sgs/libelf/common/newphdr.c (revision 42b53e0fbc5c05289c3d334bb864b784fafe5ce4)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*	Copyright (c) 1988 AT&T	*/
28 /*	  All Rights Reserved  	*/
29 
30 #include <stdlib.h>
31 #include <memory.h>
32 #include <errno.h>
33 #include "decl.h"
34 #include "msg.h"
35 
36 /*
37  * This module is compiled twice, the second time having
38  * -D_ELF64 defined.  The following set of macros, along
39  * with machelf.h, represent the differences between the
40  * two compilations.  Be careful *not* to add any class-
41  * dependent code (anything that has elf32 or elf64 in the
42  * name) to this code without hiding it behind a switch-
43  * able macro like these.
44  */
45 #if	defined(_ELF64)
46 
47 #define	ELFCLASS	ELFCLASS64
48 #define	elf_newphdr	elf64_newphdr
49 #define	elf_getehdr	elf64_getehdr
50 #define	_elf_msize	_elf64_msize
51 #define	elf_fsize	elf64_fsize
52 
53 #else	/* else ELF32 */
54 
55 #define	ELFCLASS	ELFCLASS32
56 #define	elf_newphdr	elf32_newphdr
57 #define	elf_getehdr	elf32_getehdr
58 #define	_elf_msize	_elf32_msize
59 #define	elf_fsize	elf32_fsize
60 
61 #endif /* ELF64 */
62 
63 
64 Phdr *
65 elf_newphdr(Elf * elf, size_t count)
66 {
67 	Elf_Void *	ph;
68 	size_t		sz;
69 	Phdr *		rc;
70 	unsigned	work;
71 
72 	if (elf == 0)
73 		return (0);
74 	ELFRLOCK(elf)
75 	if (elf->ed_class != ELFCLASS) {
76 		_elf_seterr(EREQ_CLASS, 0);
77 		ELFUNLOCK(elf)
78 		return (0);
79 	}
80 	ELFUNLOCK(elf)
81 	if (elf_getehdr(elf) == 0) {		/* this cooks if necessary */
82 		_elf_seterr(ESEQ_EHDR, 0);
83 		return (0);
84 	}
85 
86 	/*
87 	 * Free the existing header if appropriate.  This could reuse
88 	 * existing space if big enough, but that's unlikely, benefit
89 	 * would be negligible, and code would be more complicated.
90 	 */
91 
92 	ELFWLOCK(elf)
93 	if (elf->ed_myflags & EDF_PHALLOC) {
94 		elf->ed_myflags &= ~EDF_PHALLOC;
95 		rc = elf->ed_phdr;
96 		free(rc);
97 	}
98 
99 	/*
100 	 * Delete the header if count is zero.
101 	 */
102 
103 	ELFACCESSDATA(work, _elf_work)
104 	if ((sz = count * _elf_msize(ELF_T_PHDR, work)) == 0) {
105 		elf->ed_phflags &= ~ELF_F_DIRTY;
106 		elf->ed_phdr = 0;
107 		((Ehdr*)elf->ed_ehdr)->e_phnum = 0;
108 		((Ehdr*)elf->ed_ehdr)->e_phentsize = 0;
109 		elf->ed_phdrsz = 0;
110 		ELFUNLOCK(elf)
111 		return (0);
112 	}
113 
114 	if ((ph = malloc(sz)) == 0) {
115 		_elf_seterr(EMEM_PHDR, errno);
116 		elf->ed_phflags &= ~ELF_F_DIRTY;
117 		elf->ed_phdr = 0;
118 		((Ehdr*)elf->ed_ehdr)->e_phnum = 0;
119 		((Ehdr*)elf->ed_ehdr)->e_phentsize = 0;
120 		elf->ed_phdrsz = 0;
121 		ELFUNLOCK(elf)
122 		return (0);
123 	}
124 
125 	elf->ed_myflags |= EDF_PHALLOC;
126 	(void) memset(ph, 0, sz);
127 	elf->ed_phflags |= ELF_F_DIRTY;
128 	/* LINTED */
129 	((Ehdr*)elf->ed_ehdr)->e_phnum = (Half)count;
130 	((Ehdr*)elf->ed_ehdr)->e_phentsize
131 	    /* LINTED */
132 	    = (Half)elf_fsize(ELF_T_PHDR, 1, work);
133 	elf->ed_phdrsz = sz;
134 	elf->ed_phdr = rc = ph;
135 
136 	ELFUNLOCK(elf)
137 	return (rc);
138 }
139