ref: 41e27b2d10c6a60c49931332e8677438736a1e36
dir: /os/boot/puma/zqs.c/
#include "boot.h" #include "squeeze.h" #define EXECHDRLEN (8*4) typedef struct Squeeze Squeeze; struct Squeeze { int n; ulong tab[7*256]; }; #define GET4(p) (((((((p)[0]<<8)|(p)[1])<<8)|(p)[2])<<8)|(p)[3]) /* * for speed of unsqueezing from Flash, certain checks are * not done inside the loop (as they would be in the unsqueeze program zqs), * but instead the checksum is expected to catch corrupted files. * in fact the Squeeze array bounds can't be exceeded in practice * because the tables are always full for a squeezed kernel. */ enum { QFLAG = 1, /* invert powerpc-specific code transformation */ CHECK = 0, /* check precise bounds in Squeeze array (otherwise checksum detects error) */ }; static ulong chksum; static int rdtab(Block*, Squeeze*, int); static ulong* unsqueeze(ulong*, uchar*, uchar*, Squeeze*, Squeeze*, ulong); static uchar* unsqzseg(uchar*, Block*, long, long, char*); static Alarm* unsqzal; int issqueezed(uchar *b) { return GET4(b) == SQMAGIC? GET4(b+SQHDRLEN): 0; } static void unsqzdot(void*) { unsqzal = alarm(500, unsqzdot, nil); print("."); } long unsqueezef(Block *b, ulong *entryp) { uchar *loada, *wp; ulong toptxt, topdat, oldsum; long asis, nst, nsd; Sqhdr *sqh; Exec *ex; if(BLEN(b) < SQHDRLEN+EXECHDRLEN) return -1; sqh = (Sqhdr*)b->rp; if(GET4(sqh->magic) != SQMAGIC) return -1; chksum = 0; toptxt = GET4(sqh->toptxt); topdat = GET4(sqh->topdat); oldsum = GET4(sqh->sum); asis = GET4(sqh->asis); nst = GET4(sqh->text); nsd = GET4(sqh->data); b->rp += SQHDRLEN; ex = (Exec*)b->rp; if(GET4(ex->magic) != E_MAGIC){ print("zqs: not StrongARM executable\n"); return -1; } *entryp = GET4(ex->entry); b->rp += EXECHDRLEN; loada = KADDR(PADDR(*entryp)); wp = unsqzseg(loada, b, nst, toptxt, "text"); if(wp == nil){ print("zqs: format error\n"); return -1; } if(nsd){ wp = (uchar*)PGROUND((ulong)wp); wp = unsqzseg(wp, b, nsd, topdat, "data"); if(wp == nil){ print("zqs: format error\n"); return -1; } } if(asis){ memmove(wp, b->rp, asis); wp += asis; b->rp += asis; } if(chksum != oldsum){ print("\nsqueezed kernel: checksum error: %8.8lux need %8.8lux\n", chksum, oldsum); return -1; } return wp-loada; } static uchar * unsqzseg(uchar *wp, Block *b, long ns, long top, char *what) { static Squeeze sq3, sq4; print("unpack %s %8.8lux %lud:", what, wp, ns); if(ns == 0) return wp; if(rdtab(b, &sq3, 0) < 0) return nil; if(rdtab(b, &sq4, 8) < 0) return nil; if(BLEN(b) < ns){ print(" **size error\n"); return nil; } unsqzal = alarm(500, unsqzdot, nil); wp = (uchar*)unsqueeze((ulong*)wp, b->rp, b->rp+ns, &sq3, &sq4, top); cancel(unsqzal); unsqzal = nil; print("\n"); if(wp == nil){ print("zqs: corrupt squeezed data stream\n"); return nil; } b->rp += ns; return wp; } static ulong* unsqueeze(ulong *wp, uchar *rp, uchar *ep, Squeeze *sq3, Squeeze *sq4, ulong top) { ulong nx, csum; int code, n; if(QFLAG){ QREMAP(top); /* adjust top just once, outside the loop */ } csum = chksum; while(rp < ep){ /* no function calls within this loop for speed */ code = *rp; rp++; n = 0; nx = code>>4; do{ if(nx == 0){ nx = top; }else{ if(nx==1){ nx = (((((rp[3]<<8)|rp[2])<<8)|rp[1])<<8)|rp[0]; rp += 4; }else if(nx <= 8){ /* 2 to 8 */ nx = ((nx-2)<<8) | rp[0]; if(CHECK && nx >= sq4->n) return nil; /* corrupted file */ nx = sq4->tab[nx] | rp[1]; rp += 2; }else{ /* 9 to 15 */ nx = ((nx-9)<<8) | rp[0]; if(CHECK && nx >= sq3->n) return nil; /* corrupted file */ nx = sq3->tab[nx]; rp++; } if(rp > ep) return nil; /* corrupted file */ if(QFLAG){ QREMAP(nx); } } *wp = nx; wp++; csum += nx; nx = code & 0xF; }while(++n == 1); } chksum = csum; return wp; } static int rdtab(Block *b, Squeeze *sq, int shift) { uchar *p, *ep; ulong v, w; int i; if(BLEN(b) < 2) return -1; i = (b->rp[0]<<8) | b->rp[1]; if(1) print(" T%d", i); b->rp += 2; if((i -= 2) > 0){ if(BLEN(b) < i) return -1; } sq->n = 0; p = b->rp; ep = b->rp+i; b->rp += i; v = 0; while(p < ep){ w = 0; do{ if(p >= ep) return -1; w = (w<<7) | (*p & 0x7F); }while(*p++ & 0x80); v += w; if(0) print("%d %8.8lux %8.8lux\n", sq->n, v, w); sq->tab[sq->n++] = v<<shift; } return 0; }