old-cross-binutils/libiberty/simple-object-mach-o.c

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2010-11-02 15:20:47 +00:00
/* simple-object-mach-o.c -- routines to manipulate Mach-O object files.
Copyright 2010 Free Software Foundation, Inc.
Written by Ian Lance Taylor, Google.
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 2, or (at your option) any
later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, 51 Franklin Street - Fifth Floor,
Boston, MA 02110-1301, USA. */
#include "config.h"
#include "libiberty.h"
#include "simple-object.h"
#include <stddef.h>
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_STDINT_H
#include <stdint.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_INTTYPES_H
#include <inttypes.h>
#endif
#include "simple-object-common.h"
/* Mach-O structures and constants. */
/* Mach-O header (32-bit version). */
struct mach_o_header_32
{
unsigned char magic[4]; /* Magic number. */
unsigned char cputype[4]; /* CPU that this object is for. */
unsigned char cpusubtype[4]; /* CPU subtype. */
unsigned char filetype[4]; /* Type of file. */
unsigned char ncmds[4]; /* Number of load commands. */
unsigned char sizeofcmds[4]; /* Total size of load commands. */
unsigned char flags[4]; /* Flags for special featues. */
};
/* Mach-O header (64-bit version). */
struct mach_o_header_64
{
unsigned char magic[4]; /* Magic number. */
unsigned char cputype[4]; /* CPU that this object is for. */
unsigned char cpusubtype[4]; /* CPU subtype. */
unsigned char filetype[4]; /* Type of file. */
unsigned char ncmds[4]; /* Number of load commands. */
unsigned char sizeofcmds[4]; /* Total size of load commands. */
unsigned char flags[4]; /* Flags for special featues. */
unsigned char reserved[4]; /* Reserved. Duh. */
};
/* For magic field in header. */
#define MACH_O_MH_MAGIC 0xfeedface
#define MACH_O_MH_MAGIC_64 0xfeedfacf
/* For filetype field in header. */
#define MACH_O_MH_OBJECT 0x01
/* A Mach-O file is a list of load commands. This is the header of a
load command. */
struct mach_o_load_command
{
unsigned char cmd[4]; /* The type of load command. */
unsigned char cmdsize[4]; /* Size in bytes of entire command. */
};
/* For cmd field in load command. */
#define MACH_O_LC_SEGMENT 0x01
#define MACH_O_LC_SEGMENT_64 0x19
/* LC_SEGMENT load command. */
struct mach_o_segment_command_32
{
unsigned char cmd[4]; /* The type of load command (LC_SEGMENT). */
unsigned char cmdsize[4]; /* Size in bytes of entire command. */
unsigned char segname[16]; /* Name of this segment. */
unsigned char vmaddr[4]; /* Virtual memory address of this segment. */
unsigned char vmsize[4]; /* Size there, in bytes. */
unsigned char fileoff[4]; /* Offset in bytes of the data to be mapped. */
unsigned char filesize[4]; /* Size in bytes on disk. */
unsigned char maxprot[4]; /* Maximum permitted vmem protection. */
unsigned char initprot[4]; /* Initial vmem protection. */
unsigned char nsects[4]; /* Number of sections in this segment. */
unsigned char flags[4]; /* Flags that affect the loading. */
};
/* LC_SEGMENT_64 load command. */
struct mach_o_segment_command_64
{
unsigned char cmd[4]; /* The type of load command (LC_SEGMENT_64). */
unsigned char cmdsize[4]; /* Size in bytes of entire command. */
unsigned char segname[16]; /* Name of this segment. */
unsigned char vmaddr[8]; /* Virtual memory address of this segment. */
unsigned char vmsize[8]; /* Size there, in bytes. */
unsigned char fileoff[8]; /* Offset in bytes of the data to be mapped. */
unsigned char filesize[8]; /* Size in bytes on disk. */
unsigned char maxprot[4]; /* Maximum permitted vmem protection. */
unsigned char initprot[4]; /* Initial vmem protection. */
unsigned char nsects[4]; /* Number of sections in this segment. */
unsigned char flags[4]; /* Flags that affect the loading. */
};
/* 32-bit section header. */
struct mach_o_section_32
{
unsigned char sectname[16]; /* Section name. */
unsigned char segname[16]; /* Segment that the section belongs to. */
unsigned char addr[4]; /* Address of this section in memory. */
unsigned char size[4]; /* Size in bytes of this section. */
unsigned char offset[4]; /* File offset of this section. */
unsigned char align[4]; /* log2 of this section's alignment. */
unsigned char reloff[4]; /* File offset of this section's relocs. */
unsigned char nreloc[4]; /* Number of relocs for this section. */
unsigned char flags[4]; /* Section flags/attributes. */
unsigned char reserved1[4];
unsigned char reserved2[4];
};
/* 64-bit section header. */
struct mach_o_section_64
{
unsigned char sectname[16]; /* Section name. */
unsigned char segname[16]; /* Segment that the section belongs to. */
unsigned char addr[8]; /* Address of this section in memory. */
unsigned char size[8]; /* Size in bytes of this section. */
unsigned char offset[4]; /* File offset of this section. */
unsigned char align[4]; /* log2 of this section's alignment. */
unsigned char reloff[4]; /* File offset of this section's relocs. */
unsigned char nreloc[4]; /* Number of relocs for this section. */
unsigned char flags[4]; /* Section flags/attributes. */
unsigned char reserved1[4];
unsigned char reserved2[4];
unsigned char reserved3[4];
};
/* Flags for Mach-O sections. */
#define MACH_O_S_ATTR_DEBUG 0x02000000
/* The length of a segment or section name. */
#define MACH_O_NAME_LEN (16)
/* A GNU specific extension for long section names. */
#define GNU_SECTION_NAMES "__section_names"
/* Private data for an simple_object_read. */
struct simple_object_mach_o_read
{
/* User specified segment name. */
char *segment_name;
/* Magic number. */
unsigned int magic;
/* Whether this file is big-endian. */
int is_big_endian;
/* CPU type from header. */
unsigned int cputype;
/* CPU subtype from header. */
unsigned int cpusubtype;
/* Number of commands, from header. */
unsigned int ncmds;
/* Flags from header. */
unsigned int flags;
/* Reserved field from header, only used on 64-bit. */
unsigned int reserved;
};
/* Private data for an simple_object_attributes. */
struct simple_object_mach_o_attributes
{
/* Magic number. */
unsigned int magic;
/* Whether this file is big-endian. */
int is_big_endian;
/* CPU type from header. */
unsigned int cputype;
/* CPU subtype from header. */
unsigned int cpusubtype;
/* Flags from header. */
unsigned int flags;
/* Reserved field from header, only used on 64-bit. */
unsigned int reserved;
};
/* See if we have a Mach-O file. */
static void *
simple_object_mach_o_match (
unsigned char header[SIMPLE_OBJECT_MATCH_HEADER_LEN],
int descriptor,
off_t offset,
const char *segment_name,
const char **errmsg,
int *err)
{
unsigned int magic;
int is_big_endian;
unsigned int (*fetch_32) (const unsigned char *);
unsigned int filetype;
struct simple_object_mach_o_read *omr;
unsigned char buf[sizeof (struct mach_o_header_64)];
unsigned char *b;
magic = simple_object_fetch_big_32 (header);
if (magic == MACH_O_MH_MAGIC || magic == MACH_O_MH_MAGIC_64)
is_big_endian = 1;
else
{
magic = simple_object_fetch_little_32 (header);
if (magic == MACH_O_MH_MAGIC || magic == MACH_O_MH_MAGIC_64)
is_big_endian = 0;
else
{
*errmsg = NULL;
*err = 0;
return NULL;
}
}
#ifndef UNSIGNED_64BIT_TYPE
if (magic == MACH_O_MH_MAGIC_64)
{
*errmsg = "64-bit Mach-O objects not supported";
*err = 0;
return NULL;
}
#endif
/* We require the user to provide a segment name. This is
unfortunate but I don't see any good choices here. */
if (segment_name == NULL)
{
*errmsg = "Mach-O file found but no segment name specified";
*err = 0;
return NULL;
}
if (strlen (segment_name) > MACH_O_NAME_LEN)
{
*errmsg = "Mach-O segment name too long";
*err = 0;
return NULL;
}
/* The 32-bit and 64-bit headers are similar enough that we can use
the same code. */
fetch_32 = (is_big_endian
? simple_object_fetch_big_32
: simple_object_fetch_little_32);
if (!simple_object_internal_read (descriptor, offset, buf,
(magic == MACH_O_MH_MAGIC
? sizeof (struct mach_o_header_32)
: sizeof (struct mach_o_header_64)),
errmsg, err))
return NULL;
b = &buf[0];
filetype = (*fetch_32) (b + offsetof (struct mach_o_header_32, filetype));
if (filetype != MACH_O_MH_OBJECT)
{
*errmsg = "Mach-O file is not object file";
*err = 0;
return NULL;
}
omr = XNEW (struct simple_object_mach_o_read);
omr->segment_name = xstrdup (segment_name);
omr->magic = magic;
omr->is_big_endian = is_big_endian;
omr->cputype = (*fetch_32) (b + offsetof (struct mach_o_header_32, cputype));
omr->cpusubtype = (*fetch_32) (b
+ offsetof (struct mach_o_header_32,
cpusubtype));
omr->ncmds = (*fetch_32) (b + offsetof (struct mach_o_header_32, ncmds));
omr->flags = (*fetch_32) (b + offsetof (struct mach_o_header_32, flags));
if (magic == MACH_O_MH_MAGIC)
omr->reserved = 0;
else
omr->reserved = (*fetch_32) (b
+ offsetof (struct mach_o_header_64,
reserved));
return (void *) omr;
}
/* Get the file offset and size from a section header. */
static void
simple_object_mach_o_section_info (int is_big_endian, int is_32,
const unsigned char *sechdr, off_t *offset,
size_t *size)
{
unsigned int (*fetch_32) (const unsigned char *);
ulong_type (*fetch_64) (const unsigned char *);
fetch_32 = (is_big_endian
? simple_object_fetch_big_32
: simple_object_fetch_little_32);
fetch_64 = NULL;
#ifdef UNSIGNED_64BIT_TYPE
fetch_64 = (is_big_endian
? simple_object_fetch_big_64
: simple_object_fetch_little_64);
#endif
if (is_32)
{
*offset = fetch_32 (sechdr
+ offsetof (struct mach_o_section_32, offset));
*size = fetch_32 (sechdr
+ offsetof (struct mach_o_section_32, size));
}
else
{
*offset = fetch_32 (sechdr
+ offsetof (struct mach_o_section_64, offset));
*size = fetch_64 (sechdr
+ offsetof (struct mach_o_section_64, size));
}
}
/* Handle a segment in a Mach-O file. Return 1 if we should continue,
0 if the caller should return. */
static int
simple_object_mach_o_segment (simple_object_read *sobj, off_t offset,
const unsigned char *segbuf,
int (*pfn) (void *, const char *, off_t offset,
off_t length),
void *data,
const char **errmsg, int *err)
{
struct simple_object_mach_o_read *omr =
(struct simple_object_mach_o_read *) sobj->data;
unsigned int (*fetch_32) (const unsigned char *);
int is_32;
size_t seghdrsize;
size_t sechdrsize;
size_t segname_offset;
size_t sectname_offset;
unsigned int nsects;
unsigned char *secdata;
unsigned int i;
unsigned int strtab_index;
char *strtab;
size_t strtab_size;
fetch_32 = (omr->is_big_endian
? simple_object_fetch_big_32
: simple_object_fetch_little_32);
is_32 = omr->magic == MACH_O_MH_MAGIC;
if (is_32)
{
seghdrsize = sizeof (struct mach_o_segment_command_32);
sechdrsize = sizeof (struct mach_o_section_32);
segname_offset = offsetof (struct mach_o_section_32, segname);
sectname_offset = offsetof (struct mach_o_section_32, sectname);
nsects = (*fetch_32) (segbuf
+ offsetof (struct mach_o_segment_command_32,
nsects));
}
else
{
seghdrsize = sizeof (struct mach_o_segment_command_64);
sechdrsize = sizeof (struct mach_o_section_64);
segname_offset = offsetof (struct mach_o_section_64, segname);
sectname_offset = offsetof (struct mach_o_section_64, sectname);
nsects = (*fetch_32) (segbuf
+ offsetof (struct mach_o_segment_command_64,
nsects));
}
secdata = XNEWVEC (unsigned char, nsects * sechdrsize);
if (!simple_object_internal_read (sobj->descriptor, offset + seghdrsize,
secdata, nsects * sechdrsize, errmsg, err))
{
XDELETEVEC (secdata);
return 0;
}
/* Scan for a __section_names section. This is in effect a GNU
extension that permits section names longer than 16 chars. */
for (i = 0; i < nsects; ++i)
{
size_t nameoff;
nameoff = i * sechdrsize + segname_offset;
if (strcmp ((char *) secdata + nameoff, omr->segment_name) != 0)
continue;
nameoff = i * sechdrsize + sectname_offset;
if (strcmp ((char *) secdata + nameoff, GNU_SECTION_NAMES) == 0)
break;
}
strtab_index = i;
if (strtab_index >= nsects)
{
strtab = NULL;
strtab_size = 0;
}
else
{
off_t strtab_offset;
simple_object_mach_o_section_info (omr->is_big_endian, is_32,
secdata + strtab_index * sechdrsize,
&strtab_offset, &strtab_size);
strtab = XNEWVEC (char, strtab_size);
if (!simple_object_internal_read (sobj->descriptor,
sobj->offset + strtab_offset,
(unsigned char *) strtab, strtab_size,
errmsg, err))
{
XDELETEVEC (strtab);
XDELETEVEC (secdata);
return 0;
}
}
/* Process the sections. */
for (i = 0; i < nsects; ++i)
{
const unsigned char *sechdr;
char namebuf[MACH_O_NAME_LEN + 1];
char *name;
off_t secoffset;
size_t secsize;
if (i == strtab_index)
continue;
sechdr = secdata + i * sechdrsize;
if (strcmp ((char *) sechdr + segname_offset, omr->segment_name) != 0)
continue;
memcpy (namebuf, sechdr + sectname_offset, MACH_O_NAME_LEN);
namebuf[MACH_O_NAME_LEN] = '\0';
name = &namebuf[0];
if (strtab != NULL && name[0] == '_' && name[1] == '_')
{
unsigned long stringoffset;
if (sscanf (name + 2, "%08lX", &stringoffset) == 1)
{
if (stringoffset >= strtab_size)
{
*errmsg = "section name offset out of range";
*err = 0;
XDELETEVEC (strtab);
XDELETEVEC (secdata);
return 0;
}
name = strtab + stringoffset;
}
}
simple_object_mach_o_section_info (omr->is_big_endian, is_32, sechdr,
&secoffset, &secsize);
if (!(*pfn) (data, name, secoffset, secsize))
{
*errmsg = NULL;
*err = 0;
XDELETEVEC (strtab);
XDELETEVEC (secdata);
return 0;
}
}
XDELETEVEC (strtab);
XDELETEVEC (secdata);
return 1;
}
/* Find all sections in a Mach-O file. */
static const char *
simple_object_mach_o_find_sections (simple_object_read *sobj,
int (*pfn) (void *, const char *,
off_t offset, off_t length),
void *data,
int *err)
{
struct simple_object_mach_o_read *omr =
(struct simple_object_mach_o_read *) sobj->data;
off_t offset;
size_t seghdrsize;
unsigned int (*fetch_32) (const unsigned char *);
const char *errmsg;
unsigned int i;
if (omr->magic == MACH_O_MH_MAGIC)
{
offset = sizeof (struct mach_o_header_32);
seghdrsize = sizeof (struct mach_o_segment_command_32);
}
else
{
offset = sizeof (struct mach_o_header_64);
seghdrsize = sizeof (struct mach_o_segment_command_64);
}
fetch_32 = (omr->is_big_endian
? simple_object_fetch_big_32
: simple_object_fetch_little_32);
for (i = 0; i < omr->ncmds; ++i)
{
unsigned char loadbuf[sizeof (struct mach_o_load_command)];
unsigned int cmd;
unsigned int cmdsize;
if (!simple_object_internal_read (sobj->descriptor,
sobj->offset + offset,
loadbuf,
sizeof (struct mach_o_load_command),
&errmsg, err))
return errmsg;
cmd = (*fetch_32) (loadbuf + offsetof (struct mach_o_load_command, cmd));
cmdsize = (*fetch_32) (loadbuf
+ offsetof (struct mach_o_load_command, cmdsize));
if (cmd == MACH_O_LC_SEGMENT || cmd == MACH_O_LC_SEGMENT_64)
{
unsigned char segbuf[sizeof (struct mach_o_segment_command_64)];
int r;
if (!simple_object_internal_read (sobj->descriptor,
sobj->offset + offset,
segbuf, seghdrsize, &errmsg, err))
return errmsg;
r = simple_object_mach_o_segment (sobj, offset, segbuf, pfn,
data, &errmsg, err);
if (!r)
return errmsg;
}
offset += cmdsize;
}
return NULL;
}
/* Fetch the attributes for an simple_object_read. */
static void *
simple_object_mach_o_fetch_attributes (simple_object_read *sobj,
const char **errmsg ATTRIBUTE_UNUSED,
int *err ATTRIBUTE_UNUSED)
{
struct simple_object_mach_o_read *omr =
(struct simple_object_mach_o_read *) sobj->data;
struct simple_object_mach_o_attributes *ret;
ret = XNEW (struct simple_object_mach_o_attributes);
ret->magic = omr->magic;
ret->is_big_endian = omr->is_big_endian;
ret->cputype = omr->cputype;
ret->cpusubtype = omr->cpusubtype;
ret->flags = omr->flags;
ret->reserved = omr->reserved;
return ret;
}
/* Release the private data for an simple_object_read. */
static void
simple_object_mach_o_release_read (void *data)
{
struct simple_object_mach_o_read *omr =
(struct simple_object_mach_o_read *) data;
free (omr->segment_name);
XDELETE (omr);
}
/* Compare two attributes structures. */
static const char *
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simple_object_mach_o_attributes_merge (void *todata, void *fromdata, int *err)
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{
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struct simple_object_mach_o_attributes *to =
(struct simple_object_mach_o_attributes *) todata;
struct simple_object_mach_o_attributes *from =
(struct simple_object_mach_o_attributes *) fromdata;
if (to->magic != from->magic
|| to->is_big_endian != from->is_big_endian
|| to->cputype != from->cputype)
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{
*err = 0;
return "Mach-O object format mismatch";
}
return NULL;
}
/* Release the private data for an attributes structure. */
static void
simple_object_mach_o_release_attributes (void *data)
{
XDELETE (data);
}
/* Prepare to write out a file. */
static void *
simple_object_mach_o_start_write (void *attributes_data,
const char **errmsg ATTRIBUTE_UNUSED,
int *err ATTRIBUTE_UNUSED)
{
struct simple_object_mach_o_attributes *attrs =
(struct simple_object_mach_o_attributes *) attributes_data;
struct simple_object_mach_o_attributes *ret;
/* We're just going to record the attributes, but we need to make a
copy because the user may delete them. */
ret = XNEW (struct simple_object_mach_o_attributes);
*ret = *attrs;
return ret;
}
/* Write out the header of a Mach-O file. */
static int
simple_object_mach_o_write_header (simple_object_write *sobj, int descriptor,
size_t nsects, const char **errmsg,
int *err)
{
struct simple_object_mach_o_attributes *attrs =
(struct simple_object_mach_o_attributes *) sobj->data;
void (*set_32) (unsigned char *, unsigned int);
unsigned char hdrbuf[sizeof (struct mach_o_header_64)];
unsigned char *hdr;
size_t wrsize;
set_32 = (attrs->is_big_endian
? simple_object_set_big_32
: simple_object_set_little_32);
memset (hdrbuf, 0, sizeof hdrbuf);
/* The 32-bit and 64-bit headers start out the same. */
hdr = &hdrbuf[0];
set_32 (hdr + offsetof (struct mach_o_header_32, magic), attrs->magic);
set_32 (hdr + offsetof (struct mach_o_header_32, cputype), attrs->cputype);
set_32 (hdr + offsetof (struct mach_o_header_32, cpusubtype),
attrs->cpusubtype);
set_32 (hdr + offsetof (struct mach_o_header_32, filetype), MACH_O_MH_OBJECT);
set_32 (hdr + offsetof (struct mach_o_header_32, ncmds), 1);
set_32 (hdr + offsetof (struct mach_o_header_32, flags), attrs->flags);
if (attrs->magic == MACH_O_MH_MAGIC)
{
wrsize = sizeof (struct mach_o_header_32);
set_32 (hdr + offsetof (struct mach_o_header_32, sizeofcmds),
(sizeof (struct mach_o_segment_command_32)
+ nsects * sizeof (struct mach_o_section_32)));
}
else
{
set_32 (hdr + offsetof (struct mach_o_header_64, sizeofcmds),
(sizeof (struct mach_o_segment_command_64)
+ nsects * sizeof (struct mach_o_section_64)));
set_32 (hdr + offsetof (struct mach_o_header_64, reserved),
attrs->reserved);
wrsize = sizeof (struct mach_o_header_64);
}
return simple_object_internal_write (descriptor, 0, hdrbuf, wrsize,
errmsg, err);
}
/* Write a Mach-O section header. */
static int
simple_object_mach_o_write_section_header (simple_object_write *sobj,
int descriptor,
size_t sechdr_offset,
const char *name, size_t secaddr,
size_t secsize, size_t offset,
unsigned int align,
const char **errmsg, int *err)
{
struct simple_object_mach_o_attributes *attrs =
(struct simple_object_mach_o_attributes *) sobj->data;
void (*set_32) (unsigned char *, unsigned int);
unsigned char hdrbuf[sizeof (struct mach_o_section_64)];
unsigned char *hdr;
size_t sechdrsize;
set_32 = (attrs->is_big_endian
? simple_object_set_big_32
: simple_object_set_little_32);
memset (hdrbuf, 0, sizeof hdrbuf);
hdr = &hdrbuf[0];
if (attrs->magic == MACH_O_MH_MAGIC)
{
strncpy ((char *) hdr + offsetof (struct mach_o_section_32, sectname),
name, MACH_O_NAME_LEN);
strncpy ((char *) hdr + offsetof (struct mach_o_section_32, segname),
sobj->segment_name, MACH_O_NAME_LEN);
set_32 (hdr + offsetof (struct mach_o_section_32, addr), secaddr);
set_32 (hdr + offsetof (struct mach_o_section_32, size), secsize);
set_32 (hdr + offsetof (struct mach_o_section_32, offset), offset);
set_32 (hdr + offsetof (struct mach_o_section_32, align), align);
/* reloff left as zero. */
/* nreloc left as zero. */
set_32 (hdr + offsetof (struct mach_o_section_32, flags),
MACH_O_S_ATTR_DEBUG);
/* reserved1 left as zero. */
/* reserved2 left as zero. */
sechdrsize = sizeof (struct mach_o_section_32);
}
else
{
#ifdef UNSIGNED_64BIT_TYPE
void (*set_64) (unsigned char *, ulong_type);
set_64 = (attrs->is_big_endian
? simple_object_set_big_64
: simple_object_set_little_64);
strncpy ((char *) hdr + offsetof (struct mach_o_section_64, sectname),
name, MACH_O_NAME_LEN);
strncpy ((char *) hdr + offsetof (struct mach_o_section_64, segname),
sobj->segment_name, MACH_O_NAME_LEN);
set_64 (hdr + offsetof (struct mach_o_section_64, addr), secaddr);
set_64 (hdr + offsetof (struct mach_o_section_64, size), secsize);
set_32 (hdr + offsetof (struct mach_o_section_64, offset), offset);
set_32 (hdr + offsetof (struct mach_o_section_64, align), align);
/* reloff left as zero. */
/* nreloc left as zero. */
set_32 (hdr + offsetof (struct mach_o_section_64, flags),
MACH_O_S_ATTR_DEBUG);
/* reserved1 left as zero. */
/* reserved2 left as zero. */
/* reserved3 left as zero. */
#endif
sechdrsize = sizeof (struct mach_o_section_64);
}
return simple_object_internal_write (descriptor, sechdr_offset, hdr,
sechdrsize, errmsg, err);
}
/* Write out the single segment and the sections of a Mach-O file. */
static int
simple_object_mach_o_write_segment (simple_object_write *sobj, int descriptor,
size_t nsects, const char **errmsg,
int *err)
{
struct simple_object_mach_o_attributes *attrs =
(struct simple_object_mach_o_attributes *) sobj->data;
void (*set_32) (unsigned char *, unsigned int);
size_t hdrsize;
size_t seghdrsize;
size_t sechdrsize;
size_t cmdsize;
size_t offset;
size_t sechdr_offset;
size_t secaddr;
unsigned int name_offset;
simple_object_write_section *section;
unsigned char hdrbuf[sizeof (struct mach_o_segment_command_64)];
unsigned char *hdr;
set_32 = (attrs->is_big_endian
? simple_object_set_big_32
: simple_object_set_little_32);
/* Write out the sections first. */
if (attrs->magic == MACH_O_MH_MAGIC)
{
hdrsize = sizeof (struct mach_o_header_32);
seghdrsize = sizeof (struct mach_o_segment_command_32);
sechdrsize = sizeof (struct mach_o_section_32);
}
else
{
hdrsize = sizeof (struct mach_o_header_64);
seghdrsize = sizeof (struct mach_o_segment_command_64);
sechdrsize = sizeof (struct mach_o_section_64);
}
sechdr_offset = hdrsize + seghdrsize;
cmdsize = seghdrsize + nsects * sechdrsize;
offset = hdrsize + cmdsize;
name_offset = 0;
secaddr = 0;
for (section = sobj->sections; section != NULL; section = section->next)
{
size_t mask;
size_t new_offset;
size_t secsize;
struct simple_object_write_section_buffer *buffer;
char namebuf[MACH_O_NAME_LEN + 1];
mask = (1U << section->align) - 1;
new_offset = offset + mask;
new_offset &= ~ mask;
while (new_offset > offset)
{
unsigned char zeroes[16];
size_t write;
memset (zeroes, 0, sizeof zeroes);
write = new_offset - offset;
if (write > sizeof zeroes)
write = sizeof zeroes;
if (!simple_object_internal_write (descriptor, offset, zeroes, write,
errmsg, err))
return 0;
offset += write;
}
secsize = 0;
for (buffer = section->buffers; buffer != NULL; buffer = buffer->next)
{
if (!simple_object_internal_write (descriptor, offset + secsize,
((const unsigned char *)
buffer->buffer),
buffer->size, errmsg, err))
return 0;
secsize += buffer->size;
}
snprintf (namebuf, sizeof namebuf, "__%08X", name_offset);
if (!simple_object_mach_o_write_section_header (sobj, descriptor,
sechdr_offset, namebuf,
secaddr, secsize, offset,
section->align,
errmsg, err))
return 0;
sechdr_offset += sechdrsize;
offset += secsize;
name_offset += strlen (section->name) + 1;
secaddr += secsize;
}
/* Write out the section names. */
if (!simple_object_mach_o_write_section_header (sobj, descriptor,
sechdr_offset,
GNU_SECTION_NAMES, secaddr,
name_offset, offset, 0,
errmsg, err))
return 0;
for (section = sobj->sections; section != NULL; section = section->next)
{
size_t namelen;
namelen = strlen (section->name) + 1;
if (!simple_object_internal_write (descriptor, offset,
(const unsigned char *) section->name,
namelen, errmsg, err))
return 0;
offset += namelen;
}
/* Write out the segment header. */
memset (hdrbuf, 0, sizeof hdrbuf);
hdr = &hdrbuf[0];
if (attrs->magic == MACH_O_MH_MAGIC)
{
set_32 (hdr + offsetof (struct mach_o_segment_command_32, cmd),
MACH_O_LC_SEGMENT);
set_32 (hdr + offsetof (struct mach_o_segment_command_32, cmdsize),
cmdsize);
strncpy (((char *) hdr
+ offsetof (struct mach_o_segment_command_32, segname)),
sobj->segment_name, MACH_O_NAME_LEN);
/* vmaddr left as zero. */
/* vmsize left as zero. */
set_32 (hdr + offsetof (struct mach_o_segment_command_32, fileoff),
hdrsize + cmdsize);
set_32 (hdr + offsetof (struct mach_o_segment_command_32, filesize),
offset - (hdrsize + cmdsize));
/* maxprot left as zero. */
/* initprot left as zero. */
set_32 (hdr + offsetof (struct mach_o_segment_command_32, nsects),
nsects);
/* flags left as zero. */
}
else
{
#ifdef UNSIGNED_64BIT_TYPE
void (*set_64) (unsigned char *, ulong_type);
set_64 = (attrs->is_big_endian
? simple_object_set_big_64
: simple_object_set_little_64);
set_32 (hdr + offsetof (struct mach_o_segment_command_64, cmd),
MACH_O_LC_SEGMENT);
set_32 (hdr + offsetof (struct mach_o_segment_command_64, cmdsize),
cmdsize);
strncpy (((char *) hdr
+ offsetof (struct mach_o_segment_command_64, segname)),
sobj->segment_name, MACH_O_NAME_LEN);
/* vmaddr left as zero. */
/* vmsize left as zero. */
set_64 (hdr + offsetof (struct mach_o_segment_command_64, fileoff),
hdrsize + cmdsize);
set_64 (hdr + offsetof (struct mach_o_segment_command_64, filesize),
offset - (hdrsize + cmdsize));
/* maxprot left as zero. */
/* initprot left as zero. */
set_32 (hdr + offsetof (struct mach_o_segment_command_64, nsects),
nsects);
/* flags left as zero. */
#endif
}
return simple_object_internal_write (descriptor, hdrsize, hdr, seghdrsize,
errmsg, err);
}
/* Write out a complete Mach-O file. */
static const char *
simple_object_mach_o_write_to_file (simple_object_write *sobj, int descriptor,
int *err)
{
size_t nsects;
simple_object_write_section *section;
const char *errmsg;
/* Start at 1 for symbol_names section. */
nsects = 1;
for (section = sobj->sections; section != NULL; section = section->next)
++nsects;
if (!simple_object_mach_o_write_header (sobj, descriptor, nsects,
&errmsg, err))
return errmsg;
if (!simple_object_mach_o_write_segment (sobj, descriptor, nsects,
&errmsg, err))
return errmsg;
return NULL;
}
/* Release the private data for an simple_object_write structure. */
static void
simple_object_mach_o_release_write (void *data)
{
XDELETE (data);
}
/* The Mach-O functions. */
const struct simple_object_functions simple_object_mach_o_functions =
{
simple_object_mach_o_match,
simple_object_mach_o_find_sections,
simple_object_mach_o_fetch_attributes,
simple_object_mach_o_release_read,
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simple_object_mach_o_attributes_merge,
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simple_object_mach_o_release_attributes,
simple_object_mach_o_start_write,
simple_object_mach_o_write_to_file,
simple_object_mach_o_release_write
};