Minix2.0/src/boot/bootimage.c
/* bootimage.c - Load an image and start it. Author: Kees J. Bot
* 19 Jan 1992
*/
#define nil 0
#define _POSIX_SOURCE 1
#define _MINIX 1
#include <stddef.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <limits.h>
#include <string.h>
#include <errno.h>
#include <a.out.h>
#include <minix/config.h>
#include <minix/const.h>
#include <minix/type.h>
#include <kernel/const.h>
#include <kernel/type.h>
#include <ibm/partition.h>
#include "rawfs.h"
#include "image.h"
#include "boot.h"
void printk(char *fmt, ...);
#define printf printk
#define click_shift clck_shft /* 7 char clash with click_size. */
/* Some kernels have extra features: */
#define K_I386 0x0001 /* Make the 386 transition before you call me. */
#define K_CLAIM 0x0002 /* I will acquire my own bss pages, thank you. */
#define K_CHMEM 0x0004 /* This kernel listens to chmem for its stack size. */
#define K_HIGH 0x0008 /* Load mm, fs, etc. in extended memory. */
#define K_HDR 0x0010 /* No need to patch sizes, kernel uses the headers. */
#define K_RET 0x0020 /* Returns to the monitor on reboot. */
/* Data about the different processes. */
#define PROCESS_MAX 16 /* Must match the space in kernel/mpx.x */
#define KERNEL 0 /* The first process is the kernel. */
#define FS 2 /* The third must be fs. */
struct process {
char name[IM_NAME_MAX + 1]; /* Nice to have a name for the thing. */
u32_t entry; /* Entry point. */
u32_t cs; /* Code segment. */
u32_t ds; /* Data segment. */
u32_t data; /* To access the data segment. */
u32_t end; /* End of this process, size = (end - cs). */
} process[PROCESS_MAX];
int n_procs; /* Number of processes. */
/* Magic numbers in process' data space. */
#define MAGIC_OFF 0 /* Offset of magic # in data seg. */
#define CLICK_OFF 2 /* Offset in kernel text to click_shift. */
#define FLAGS_OFF 4 /* Offset in kernel text to flags. */
#define KERNEL_D_MAGIC 0x526F /* Kernel magic number. */
/* Offsets of sizes to be patched into kernel and fs. */
#define P_SIZ_OFF 0 /* Process' sizes into kernel data. */
#define P_INIT_OFF 4 /* Init cs & sizes into fs data. */
#define between(a, c, z) ((unsigned) ((c) - (a)) <= ((z) - (a)))
void pretty_image(char *image)
/* Pretty print the name of the image to load. Translate '/' and '_' to
* space, first letter goes uppercase. An 'r' before a digit prints as
* 'revision'. E.g. 'minix/1.6.16r10' -> 'Minix 1.6.16 revision 10'.
* The idea is that the part before the 'r' is the official Minix release
* and after the 'r' you can put version numbers for your own changes.
*/
{
int up= 0, c;
while ((c= *image++) != 0) {
if (c == '/' || c == '_') c= ' ';
if (c == 'r' && between('0', *image, '9')) {
printf(" revision ");
continue;
}
if (!up && between('a', c, 'z')) c= c - 'a' + 'A';
if (between('A', c, 'Z')) up= 1;
putchar(c);
}
}
void raw_clear(u32_t addr, u32_t count)
/* Clear "count" bytes at absolute address "addr". */
{
static char zeros[128];
u32_t dst;
u32_t zct;
zct= sizeof(zeros);
if (zct > count) zct= count;
raw_copy(addr, mon2abs(&zeros), zct);
count-= zct;
while (count > 0) {
dst= addr + zct;
if (zct > count) zct= count;
raw_copy(dst, addr, zct);
count-= zct;
zct*= 2;
}
}
/* Align a to a multiple of n (a power of 2): */
#define align(a, n) (((u32_t)(a) + ((u32_t)(n) - 1)) & ~((u32_t)(n) - 1))
unsigned click_shift;
unsigned click_size; /* click_size = Smallest kernel memory object. */
unsigned k_flags; /* Not all kernels are created equal. */
void patch_sizes(void)
/* Patch sizes of each process into kernel data space, kernel ds into kernel
* text space, and sizes of init into data space of fs. All the patched
* numbers are based on the kernel click size, not hardware segments.
*/
{
u16_t text_size, data_size;
int i;
struct process *procp, *initp;
u32_t doff;
if (k_flags & K_HDR) return; /* Uses the headers. */
/* Patch text and data sizes of the processes into kernel data space.
*/
doff= process[KERNEL].data + P_SIZ_OFF;
for (i= 0; i < n_procs; i++) {
procp= &process[i];
text_size= (procp->ds - procp->cs) >> click_shift;
data_size= (procp->end - procp->ds) >> click_shift;
/* Two words per process, the text and data size: */
put_word(doff, text_size); doff+= 2;
put_word(doff, data_size); doff+= 2;
initp= procp; /* The last process must be init. */
}
if (k_flags & K_HIGH) return; /* Doesn't need FS patching. */
/* Patch cs and sizes of init into fs data. */
put_word(process[FS].data + P_INIT_OFF+0, initp->cs >> click_shift);
put_word(process[FS].data + P_INIT_OFF+2, text_size);
put_word(process[FS].data + P_INIT_OFF+4, data_size);
}
int selected(char *name)
/* True iff name has no label or the proper label. */
{
char *colon, *label;
int cmp;
if ((colon= strchr(name, ':')) == nil) return 1;
if ((label= b_value("label")) == nil) return 1;
*colon= 0;
cmp= strcmp(label, name);
*colon= ':';
return cmp == 0;
}
u32_t proc_size(struct image_header *hdr)
/* Return the size of a process in sectors as found in an image. */
{
u32_t len= hdr->process.a_text;
if (hdr->process.a_flags & A_PAL) len+= hdr->process.a_hdrlen;
if (hdr->process.a_flags & A_SEP) len= align(len, SECTOR_SIZE);
len= align(len + hdr->process.a_data, SECTOR_SIZE);
return len >> SECTOR_SHIFT;
}
off_t image_off, image_size;
u32_t (*vir2sec)(u32_t vsec); /* Where is a sector on disk? */
u32_t file_vir2sec(u32_t vsec)
/* Translate a virtual sector number to an absolute disk sector. */
{
off_t blk;
if ((blk= r_vir2abs(vsec / RATIO)) == -1) {
errno= EIO;
return -1;
}
return blk == 0 ? 0 : lowsec + blk * RATIO + vsec % RATIO;
}
u32_t flat_vir2sec(u32_t vsec)
/* Simply add an absolute sector offset to vsec. */
{
return lowsec + image_off + vsec;
}
char *get_sector(u32_t vsec)
/* Read a sector "vsec" from the image into memory and return its address.
* Return nil on error. (This routine tries to read an entire track, so
* the next request is usually satisfied from the track buffer.)
*/
{
u32_t sec;
int r;
static char buf[32 * SECTOR_SIZE];
static size_t count; /* Number of sectors in the buffer. */
static u32_t bufsec; /* First Sector now in the buffer. */
if (vsec == 0) count= 0; /* First sector; initialize. */
if ((sec= (*vir2sec)(vsec)) == -1) return nil;
if (sec == 0) {
/* A hole. */
count= 0;
memset(buf, 0, SECTOR_SIZE);
return buf;
}
/* Can we return a sector from the buffer? */
if ((sec - bufsec) < count) {
return buf + ((size_t) (sec - bufsec) << SECTOR_SHIFT);
}
/* Not in the buffer. */
count= 0;
bufsec= sec;
/* Read a whole track if possible. */
while (++count < 32 && (bufsec + count) % sectors != 0) {
vsec++;
if ((sec= (*vir2sec)(vsec)) == -1) break;
/* Consecutive? */
if (sec != bufsec + count) break;
}
/* Actually read the sectors. */
if ((r= readsectors(mon2abs(buf), bufsec, count)) != 0) {
readerr(bufsec, r);
count= 0;
errno= 0;
return nil;
}
return buf;
}
int get_clickshift(u32_t ksec, struct image_header *hdr)
/* Get the click shift and special flags from kernel text. */
{
char *textp;
if ((textp= get_sector(ksec)) == nil) return 0;
if (hdr->process.a_flags & A_PAL) textp+= hdr->process.a_hdrlen;
click_shift= * (u16_t *) (textp + CLICK_OFF);
k_flags= * (u16_t *) (textp + FLAGS_OFF);
if (click_shift < HCLICK_SHIFT || click_shift > 16) {
printf("%s click size is bad\n", hdr->name);
errno= 0;
return 0;
}
click_size= 1 << click_shift;
return 1;
}
int get_segment(u32_t *vsec, long *size, u32_t *addr, u32_t limit)
/* Read *size bytes starting at virtual sector *vsec to memory at *addr. */
{
char *buf;
size_t cnt, n;
cnt= 0;
while (*size > 0) {
if (cnt == 0) {
if ((buf= get_sector((*vsec)++)) == nil) return 0;
cnt= SECTOR_SIZE;
}
if (*addr + click_size > limit) { errno= ENOMEM; return 0; }
n= click_size;
if (n > cnt) n= cnt;
raw_copy(*addr, mon2abs(buf), n);
*addr+= n;
*size-= n;
buf+= n;
cnt-= n;
}
/* Zero extend to a click. */
n= align(*addr, click_size) - *addr;
raw_clear(*addr, n);
*addr+= n;
*size-= n;
return 1;
}
void exec_image(char *image, char *params, size_t paramsize)
/* Get a Minix image into core, patch it up and execute. */
{
int i;
struct image_header hdr;
char *buf;
u32_t vsec= 0; /* Load this sector from image next. */
u32_t addr= MINIXPOS; /* Put it at this address. */
u32_t limit= caddr; /* But no further than this address. */
u32_t n;
struct process *procp; /* Process under construction. */
long a_text, a_data, a_bss, a_stack;
char *msec, *console;
u16_t mode;
int banner= 0;
long processor= a2l(b_value("processor"));
/* Clear the area where the headers will be placed. */
raw_clear(HEADERPOS, PROCESS_MAX * A_MINHDR);
/* Read the many different processes: */
for (i= 0; vsec < image_size; i++) {
if (i == PROCESS_MAX) {
printf("There are more then %d programs in %s\n",
PROCESS_MAX, image);
errno= 0;
return;
}
procp= &process[i];
/* Read header. */
for (;;) {
if ((buf= get_sector(vsec++)) == nil) return;
memcpy(&hdr, buf, sizeof(hdr));
if (BADMAG(hdr.process)) { errno= ENOEXEC; return; }
/* Check the optional label on the process. */
if (selected(hdr.name)) break;
/* Bad label, skip this process. */
vsec+= proc_size(&hdr);
}
/* Place a copy of the header where the kernel can get it. */
raw_copy(HEADERPOS + i * A_MINHDR, mon2abs(&hdr.process),
A_MINHDR);
/* Sanity check: an 8086 can't run a 386 kernel. */
if (hdr.process.a_cpu == A_I80386 && processor < 386) {
printf("You can't run a 386 kernel on this 80%ld\n",
processor);
errno= 0;
return;
}
/* Get the click shift from the kernel text segment. */
if (i == KERNEL) {
if (!get_clickshift(vsec, &hdr)) return;
addr= align(addr, click_size);
}
if (!banner) {
printf(" cs ds text data bss");
if (k_flags & K_CHMEM) printf(" stack");
putchar('\n');
banner= 1;
}
/* Segment sizes. */
a_text= hdr.process.a_text;
a_data= hdr.process.a_data;
a_bss= hdr.process.a_bss;
if (k_flags & K_CHMEM) {
a_stack= hdr.process.a_total - a_data - a_bss;
if (!(hdr.process.a_flags & A_SEP)) a_stack-= a_text;
} else {
a_stack= 0;
}
/* Collect info about the process to be. */
strcpy(procp->name, hdr.name);
procp->cs= addr;
/* Process may be page aligned so that the text segment contains
* the header, or have an unmapped zero page against vaxisms.
*/
procp->entry= hdr.process.a_entry;
if (hdr.process.a_flags & A_PAL) a_text+= hdr.process.a_hdrlen;
if (hdr.process.a_flags & A_UZP) procp->cs-= click_size;
/* Separate I&D: two segments. Common I&D: only one. */
if (hdr.process.a_flags & A_SEP) {
/* Read the text segment. */
if (!get_segment(&vsec, &a_text, &addr, limit)) return;
/* The data segment follows. */
procp->ds= addr;
if (hdr.process.a_flags & A_UZP) procp->ds-= click_size;
procp->data= addr;
} else {
/* Add text to data to form one segment. */
procp->data= addr + a_text;
procp->ds= procp->cs;
a_data+= a_text;
}
printf("%06lx %06lx%8ld%8ld%8ld",
procp->cs, procp->ds,
hdr.process.a_text, hdr.process.a_data,
hdr.process.a_bss
);
if (k_flags & K_CHMEM) printf("%8ld", a_stack);
printf(" %s\n", hdr.name);
/* Read the data segment. */
if (!get_segment(&vsec, &a_data, &addr, limit)) return;
/* Make space for bss and stack unless... */
if (i != KERNEL && (k_flags & K_CLAIM)) a_bss= a_stack= 0;
/* Note that a_data may be negative now, but we can look at it
* as -a_data bss bytes.
*/
/* Compute the number of bss clicks left. */
a_bss+= a_data;
n= align(a_bss, click_size);
a_bss-= n;
/* Zero out bss. */
if (addr + n > limit) { errno= ENOMEM; return; }
raw_clear(addr, n);
addr+= n;
/* And the number of stack clicks. */
a_stack+= a_bss;
n= align(a_stack, click_size);
a_stack-= n;
/* Add space for the stack. */
addr+= n;
/* Process endpoint. */
procp->end= addr;
if (i == 0 && (k_flags & K_HIGH)) {
/* Load the rest in extended memory. */
addr= 0x100000L;
limit= 0x100000L + get_ext_memsize() * 1024L;
}
}
if ((n_procs= i) == 0) {
printf("There are no programs in %s\n", image);
errno= 0;
return;
}
/* Check the kernel magic number. */
if (get_word(process[KERNEL].data + MAGIC_OFF) != KERNEL_D_MAGIC) {
printf("%s magic number is incorrect\n", process[KERNEL].name);
errno= 0;
return;
}
/* Patch sizes, etc. into kernel data. */
patch_sizes();
/* Wait a while if delay is set, bail out if ESC typed. */
msec= b_value("delay");
if (!delay(msec != nil ? msec : "0")) { errno= 0; return; }
/* Reset the screen setting the proper video mode. This is more
* important than it seems, Minix depends on the mode set right.
*/
mode= strcmp(b_value("chrome"), "color") == 0 ? COLOR_MODE : MONO_MODE;
console= b_value("console");
if (console != nil && a2x(console) != 0) mode= a2x(console);
reset_video(mode);
/* Minix. */
reboot_code= minix(process[KERNEL].entry, process[KERNEL].cs,
process[KERNEL].ds, params, paramsize);
/* Boot file system still around? */
fsok= r_super() != 0;
errno= 0;
}
char *params2params(size_t *size)
/* Repackage the environment settings for the kernel. */
{
char *parms;
size_t i, z;
environment *e;
i= 0;
z= 64;
parms= malloc(z * sizeof(char *));
for (e= env; e != nil; e= e->next) {
char *name= e->name, *value= e->value;
size_t n;
dev_t dev;
if (!(e->flags & E_VAR)) continue;
if (e->flags & E_DEV) {
if ((dev= name2dev(value)) == -1) {
free(parms);
errno= 0;
return nil;
}
value= u2a((u16_t) dev);
}
n= i + strlen(name) + 1 + strlen(value) + 1;
if (n > z) {
z+= n;
parms= realloc(parms, z * sizeof(char));
}
strcpy(parms + i, name);
strcat(parms + i, "=");
strcat(parms + i, value);
i= n;
}
parms[i++]= 0; /* End marked with empty string. */
*size= i;
return parms;
}
ino_t latest_version(char *version, struct stat *stp)
/* Recursively read the current directory, selecting the newest image on
* the way up. (One can't use r_stat while reading a directory.)
*/
{
char name[NAME_MAX + 1];
ino_t ino, newest;
time_t mtime;
if ((ino= r_readdir(name)) == 0) { stp->st_mtime= 0; return 0; }
newest= latest_version(version, stp);
mtime= stp->st_mtime;
r_stat(ino, stp);
if (S_ISREG(stp->st_mode) && stp->st_mtime > mtime) {
newest= ino;
strcpy(version, name);
} else {
stp->st_mtime= mtime;
}
return newest;
}
char *select_image(char *image)
/* Look image up on the filesystem, if it is a file then we're done, but
* if its a directory then we want the newest file in that directory. If
* it doesn't exist at all, then see if it is 'number:number' and get the
* image from that absolute offset off the disk.
*/
{
ino_t image_ino;
struct stat st;
image= strcpy(malloc((strlen(image) + 1 + NAME_MAX + 1)
* sizeof(char)), image);
if (!fsok || (image_ino= r_lookup(ROOT_INO, image)) == 0) {
char *size;
if (numprefix(image, &size) && *size++ == ':'
&& numeric(size)) {
vir2sec= flat_vir2sec;
image_off= a2l(image);
image_size= a2l(size);
strcpy(image, "Minix");
return image;
}
if (!fsok)
printf("No image selected\n");
else
printf("Can't load %s: %s\n", image, unix_err(errno));
goto bail_out;
}
r_stat(image_ino, &st);
if (!S_ISREG(st.st_mode)) {
char *version= image + strlen(image);
char dots[NAME_MAX + 1];
if (!S_ISDIR(st.st_mode)) {
printf("%s: %s\n", image, unix_err(ENOTDIR));
goto bail_out;
}
(void) r_readdir(dots);
(void) r_readdir(dots); /* "." & ".." */
*version++= '/';
*version= 0;
if ((image_ino= latest_version(version, &st)) == 0) {
printf("There are no images in %s/\n", image);
goto bail_out;
}
r_stat(image_ino, &st);
}
vir2sec= file_vir2sec;
image_size= (st.st_size + SECTOR_SIZE - 1) >> SECTOR_SHIFT;
return image;
bail_out:
free(image);
return nil;
}
void bootminix(void)
/* Load Minix and run it. (Given the size of this program it is surprising
* that it ever gets to that.)
*/
{
char *image;
char *minixparams;
size_t paramsize;
/* Translate the bootparameters to what Minix likes best. */
if ((minixparams= params2params(¶msize)) == nil) return;
if ((image= select_image(b_value("image"))) == nil) return;
/* Things are getting serious, kill the cache! */
invalidate_cache();
printf("\nLoading ");
pretty_image(image);
printf(".\n\n");
exec_image(image, minixparams, paramsize);
switch (errno) {
case ENOEXEC:
printf("%s contains a bad program header\n", image);
break;
case ENOMEM:
printf("Not enough memory to load %s\n", image);
break;
case EIO:
printf("Unsuspected EOF on %s\n", image);
case 0:
/* No error or error already reported. */;
}
/* Put all that free memory to use again. */
init_cache();
free(minixparams);
free(image);
}