102 lines
2.4 KiB
C
102 lines
2.4 KiB
C
/*
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* @(#)readfile.c 1.1 94/10/31 Copyright (c) 1985 by Sun Microsystems, Inc.
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*/
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#include <stand/saio.h>
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#include <a.out.h>
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/*
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* Read in a Unix executable file and return its entry point.
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* Handle the various a.out formats correctly.
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* "Io" is the standalone file descriptor to read from.
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* Print informative little messages if "print" is on.
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* Returns -1 for errors.
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*
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* The parameter <LOAD> must be set in the command line to cc, e.g.
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* cc -DLOAD=0x4000 -o readfile.c
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* The makefile takes care of this.
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*/
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int (*
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readfile(io, print))()
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register int io;
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int print;
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{
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struct exec x;
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register int i;
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register char *addr;
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register int shared = 0;
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register int loadaddr;
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register int segsiz;
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register int datasize;
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extern char start[];
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i = read(io, (char *)&x, sizeof x);
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if (x.a_magic == ZMAGIC || x.a_magic == NMAGIC)
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shared = 1;
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if (i != sizeof x || (!shared && x.a_magic != OMAGIC)) {
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printf("Not executable\n");
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return ((int (*)()) -1);
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}
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if (print)
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printf("Size: %d", x.a_text);
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datasize = x.a_data;
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if (!shared) {
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x.a_text = x.a_text + x.a_data;
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x.a_data = 0;
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}
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if (lseek(io, N_TXTOFF(x), 0) == -1)
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goto shread;
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addr = (char *)(x.a_text + LOAD);
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if (addr > (char *)start) {
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printf("\nProgram text overlaps boot code! 0x%x > 0x%x\n",
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addr, start);
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goto shread;
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}
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#ifdef NFS_BOOT
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#define FUDGE (0x2000-0x20)
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if (read(io, (char *)LOAD, FUDGE) != FUDGE)
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goto shread;
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if (read(io, (char *)(LOAD+FUDGE), (int)x.a_text-FUDGE) !=
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(x.a_text-FUDGE))
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goto shread;
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#else
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if (read(io, (char *)LOAD, (int)x.a_text) != x.a_text)
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goto shread;
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#endif NFS_BOOT
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if (x.a_machtype == M_OLDSUN2)
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segsiz = OLD_SEGSIZ;
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else
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segsiz = SEGSIZ;
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if (shared)
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while ((int)addr & (segsiz-1))
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*addr++ = 0;
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if (addr + x.a_data > (char *)start) {
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printf("\nProgram data overlaps boot code!\n");
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goto shread;
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}
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if (print)
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printf("+%d", datasize);
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if ((int)x.a_data != 0) /* Avoid zero length read */
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if (read(io, addr, (int)x.a_data) < x.a_data)
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goto shread;
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close(io); /* Done with it. */
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if (print)
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printf("+%d", x.a_bss);
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addr += x.a_data;
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for (i = 0; i < x.a_bss && addr < (char *)start; i++)
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*addr++ = 0;
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if (print)
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printf(" bytes\n");
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if (x.a_machtype != M_OLDSUN2 && x.a_magic == ZMAGIC)
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loadaddr = LOAD + sizeof (struct exec);
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else
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loadaddr = LOAD;
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return (int (*)()) (loadaddr);
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shread:
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printf("Truncated file\n");
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return ((int (*)()) -1);
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}
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