87 lines
3.1 KiB
C
87 lines
3.1 KiB
C
#define _SYSTEM 1
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#include <minix/type.h>
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#include <minix/const.h>
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#include <a.out.h>
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#include <assert.h>
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#include <unistd.h>
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#include <errno.h>
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#include <libexec.h>
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int read_header_aout(
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const char *exec_hdr, /* executable header */
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size_t exec_len, /* executable file size */
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int *sep_id, /* true iff sep I&D */
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vir_bytes *text_bytes, /* place to return text size */
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vir_bytes *data_bytes, /* place to return initialized data size */
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vir_bytes *bss_bytes, /* place to return bss size */
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phys_bytes *tot_bytes, /* place to return total size */
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vir_bytes *pc, /* program entry point (initial PC) */
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int *hdrlenp
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)
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{
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/* Read the header and extract the text, data, bss and total sizes from it. */
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struct exec *hdr; /* a.out header is read in here */
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/* Read the header and check the magic number. The standard MINIX header
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* is defined in <a.out.h>. It consists of 8 chars followed by 6 longs.
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* Then come 4 more longs that are not used here.
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* Byte 0: magic number 0x01
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* Byte 1: magic number 0x03
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* Byte 2: normal = 0x10 (not checked, 0 is OK), separate I/D = 0x20
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* Byte 3: CPU type, Intel 16 bit = 0x04, Intel 32 bit = 0x10,
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* Motorola = 0x0B, Sun SPARC = 0x17
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* Byte 4: Header length = 0x20
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* Bytes 5-7 are not used.
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*
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* Now come the 6 longs
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* Bytes 8-11: size of text segments in bytes
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* Bytes 12-15: size of initialized data segment in bytes
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* Bytes 16-19: size of bss in bytes
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* Bytes 20-23: program entry point
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* Bytes 24-27: total memory allocated to program (text, data + stack)
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* Bytes 28-31: size of symbol table in bytes
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* The longs are represented in a machine dependent order,
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* little-endian on the 8088, big-endian on the 68000.
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* The header is followed directly by the text and data segments, and the
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* symbol table (if any). The sizes are given in the header. Only the
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* text and data segments are copied into memory by exec. The header is
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* used here only. The symbol table is for the benefit of a debugger and
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* is ignored here.
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*/
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assert(exec_hdr != NULL);
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hdr = (struct exec *)exec_hdr;
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if (exec_len < A_MINHDR) return(ENOEXEC);
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/* Check magic number, cpu type, and flags. */
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if (BADMAG(*hdr)) return(ENOEXEC);
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#if (CHIP == INTEL && _WORD_SIZE == 2)
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if (hdr->a_cpu != A_I8086) return(ENOEXEC);
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#endif
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#if (CHIP == INTEL && _WORD_SIZE == 4)
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if (hdr->a_cpu != A_I80386) return(ENOEXEC);
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#endif
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if ((hdr->a_flags & ~(A_NSYM | A_EXEC | A_SEP)) != 0) return(ENOEXEC);
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*sep_id = !!(hdr->a_flags & A_SEP); /* separate I & D or not */
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/* Get text and data sizes. */
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*text_bytes = (vir_bytes) hdr->a_text; /* text size in bytes */
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*data_bytes = (vir_bytes) hdr->a_data; /* data size in bytes */
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*bss_bytes = (vir_bytes) hdr->a_bss; /* bss size in bytes */
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*tot_bytes = hdr->a_total; /* total bytes to allocate for prog */
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if (*tot_bytes == 0) return(ENOEXEC);
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if (!*sep_id) {
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/* If I & D space is not separated, it is all considered data. Text=0*/
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*data_bytes += *text_bytes;
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*text_bytes = 0;
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}
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*pc = hdr->a_entry; /* initial address to start execution */
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*hdrlenp = hdr->a_hdrlen & BYTE; /* header length */
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return(OK);
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}
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