#define PROG_NAME "desc"
#define PROG_TITLE "dump i386 CPU descriptor tables"
#define VERSION "0.61"
/* v0.61 : code cleanup, add more TSS fields */
#define AUTHOR "Chuck Ebbert [76306.1226@compuserve.com]"
#define LICENSE "Released under the GPL"
#include <stdio.h>
#include <fcntl.h>
#include <sys/types.h>
typedef struct { /* from Linux */
unsigned short back_link,__blh;
unsigned long esp0;
unsigned short ss0,__ss0h;
unsigned long esp1;
unsigned short ss1,__ss1h;
unsigned long esp2;
unsigned short ss2,__ss2h;
unsigned long __cr3;
unsigned long eip;
unsigned long eflags;
unsigned long eax,ecx,edx,ebx;
unsigned long esp;
unsigned long ebp;
unsigned long esi;
unsigned long edi;
unsigned short es, __esh;
unsigned short cs, __csh;
unsigned short ss, __ssh;
unsigned short ds, __dsh;
unsigned short fs, __fsh;
unsigned short gs, __gsh;
unsigned short ldt, __ldth;
unsigned short trace, bitmap;
} __attribute__ ((packed)) tss_t;
typedef struct {
unsigned short limit;
unsigned int base;
} __attribute__ ((packed)) dtr_t;
typedef struct {
unsigned short off1;
unsigned short sel;
unsigned char none,flags;
unsigned short off2;
} __attribute__ ((packed)) idt_entry_t;
typedef struct {
unsigned a,b;
} __attribute__ ((packed)) gdt_ldt_entry_t;
/* read/write from kmem */
#define BUILD_IO_FN(fn_name, fn_fn) \
static int fn_name(int fd, int offset, void *buf, int size) { \
if (lseek(fd, offset, 0) != offset) return 0; \
if (fn_fn(fd, buf, size) != size) return 0; \
return size; \
}
BUILD_IO_FN(rkm, read)
BUILD_IO_FN(wkm, write)
int kmem;
void perr(char *err) { /* exit with err msg */
perror(err), exit(1);
}
/* read/write wrapper with err handling */
#define xkm(f, p1, p2, p3, p4, msg) { \
int _p4 = (p4); if ((f)((p1), (p2), (p3), _p4) != _p4) perr(msg); }
#define TEST_BIT(v,b) ( !!((v) & (1 << (b))) )
void dump_sel(unsigned short s) {
printf("%04x <%s#%02d,RPL%d>",
s, (s & 4) ? "LDT" : "GDT", s >> 3, s & 3);
}
void dump_sys_desc(char *name, unsigned base, unsigned i) {
unsigned s, f;
idt_entry_t desc;
xkm(rkm, kmem, base + 8*i, &desc, sizeof(desc), "rkm sys");
s = desc.sel, f = desc.flags;
printf("%s#%3d [0x%02x]: flags:%02x <%s,DPL%d,%s>",
name, i, i, f, f & 0x80 ? "P" : "NP", (f & 0x60) >> 5,
(f & 0x1f) == 0x0e ? "intr" :
(f & 0x1f) == 0x0f ? "trap" :
(f & 0x1f) == 0x05 ? "task" :
(f & 0x1f) == 0x0c ? "call" : "????");
printf(" sel:"), dump_sel(s);
printf(" off:%08x\n", (unsigned)((desc.off2 << 16) | desc.off1));
}
void dump_gdt_ldt (char * name, unsigned base, unsigned num) {
unsigned dbase, dlimit, a, b, t, i, f;
gdt_ldt_entry_t desc;
tss_t tss;
printf("\n %s at %08x, %d entries:\n\n", name, base, num);
for (i = 0; i < num; i++) {
xkm(rkm, kmem, base + 8*i, &desc, sizeof(desc), "rkm gdtldt");
a = desc.a, b = desc.b, f = (b & 0xf0ff00) >> 8, t = f & 0x1f;
if (!a & !b) /* empty */
continue;
if ((t == 0x0c) | (t == 0x05)) { /* task/call gate */
dump_sys_desc(name, base, i);
continue;
}
dbase = (b & 0xff000000) | ((b & 0xff) << 16) | (a >> 16);
dlimit = (a & 0xffff) | (b & 0x0f0000);
printf("%s#%3d: base:%08x limit:%05x%s"
" flags:%04x <P:%d DPL:%d %s>\n",
name, i, dbase, dlimit, TEST_BIT(b,23) ? "fff" : " ",
f, TEST_BIT(b,15), (b & 0x6000) >> 13,
t == 0x0b ? "Busy TSS" :
t == 0x09 ? "Available TSS" :
t == 0x02 ? "LDT" :
(f & 0x401c) == 0x4018 ? "32-bit Code" :
(f & 0x401c) == 0x18 ? "16-bit Code" :
(t & 0x1c) == 0x1c ? "Conforming code" :
(t & 0x1e) == 0x10 ? "RO Data" :
(t & 0x1e) == 0x12 ? "RW Data" :
(t & 0x1c) == 0x14 ? "Exp-down data" :
"Unknown");
if (t == 0x02)
dump_gdt_ldt(" LDT", dbase, dlimit + 1 >> 3);
if ((t == 0x09) | (t == 0x0b)) {
xkm(rkm, kmem, dbase, &tss, sizeof(tss), "rkm tss");
printf("\n TSS at %08x, %d bytes:\n\n",
dbase, dlimit + 1);
printf(" CS:"), dump_sel(tss.cs);
printf(" EIP:%08x eflags:%08x\n",
tss.eip, tss.eflags);
printf(" SS0:"), dump_sel(tss.ss0);
printf(" ESP0:%08x\n", tss.esp0);
printf(" SS:"), dump_sel(tss.ss);
printf(" ESP:%08x\n", tss.esp);
printf(" DS:"), dump_sel(tss.ds);
printf(" ES:"), dump_sel(tss.es), printf("\n");
printf(" FS:"), dump_sel(tss.fs);
printf(" GS:"), dump_sel(tss.gs), printf("\n");
printf(" LDT:"), dump_sel(tss.ldt);
printf(" CR3:%08x\n\n", tss.__cr3);
}
}
printf("\n");
}
void dump_idt (unsigned base, unsigned num) {
int i;
printf(" IDT at %08x, %d entries:\n\n", base, num);
for (i = 0; i < num; i++)
dump_sys_desc("IDT", base, i);
}
main() {
dtr_t gdtr, idtr;
printf(PROG_NAME " v" VERSION " -- " PROG_TITLE "\n");
kmem = open("/dev/kmem", O_RDONLY);
if (kmem < 0) perr("open /dev/kmem");
asm("sgdt %0" : "=m" (gdtr));
dump_gdt_ldt("GDT", gdtr.base, (gdtr.limit + 1) >> 3);
asm("sidt %0" : "=m" (idtr));
dump_idt(idtr.base, (idtr.limit + 1) >> 3);
close(kmem);
}
-------
Chuck
-
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This archive was generated by hypermail 2b29 : Wed Apr 30 2003 - 22:00:27 EST