From Mitch.Dsouza@Dubai.Sun.COM Fri Jun 16 16:02:36 1995
Date: Fri, 16 Jun 1995 19:09:14 +0400
From: Mitch.Dsouza@Dubai.Sun.COM (Mitch DSouza)
To: daniel.barlow@st-johns.oxford.ac.uk
Subject: New file.c patch
X-Sun-Charset: US-ASCII
Content-Length: 3109

[...]

*** file.c.orig	Tue Mar  7 19:12:13 1995
--- file.c	Wed Jun 14 03:08:02 1995
***************
*** 42,52 ****
  #include <utime.h>
  #endif
  #include <unistd.h>	/* for read() */
! 
  #include "patchlevel.h"
  #include "file.h"
  
  #ifdef S_IFLNK
  # define USAGE  "Usage: %s [-vczL] [-f namefile] [-m magicfile] file...\n"
  #else
  # define USAGE  "Usage: %s [-vcz] [-f namefile] [-m magicfile] file...\n"
--- 42,63 ----
  #include <utime.h>
  #endif
  #include <unistd.h>	/* for read() */
! #ifdef HAVE_ELF
! #include <elf.h>
! static void swapbytes(char *p, int len) {
! 	char c, i;
! 	for (i=0; i<(len>>1); i++) {
! 		c=p[i];
! 		p[i]=p[len-i-1];
! 		p[len-i-1]=c;
! 	}
! }
! #endif
  #include "patchlevel.h"
  #include "file.h"
  
  #ifdef S_IFLNK
+ 
  # define USAGE  "Usage: %s [-vczL] [-f namefile] [-m magicfile] file...\n"
  #else
  # define USAGE  "Usage: %s [-vcz] [-f namefile] [-m magicfile] file...\n"
***************
*** 258,263 ****
--- 269,339 ----
  		tryit(buf, nbytes, zflag);
  	}
  
+ #ifdef HAVE_ELF
+ 	/*
+ 	 * ELF can have an arbitrary number of sections and thus file(1)
+ 	 * cannot use a fixed position in the file to determine its type.
+ 	 * Instead we must traverse all sections to see if one is a symbol
+ 	 * table section.
+ 	 */
+ 
+ 	if (nbytes > sizeof(Elf32_Ehdr) &&
+ 	    buf[EI_MAG0] == ELFMAG0 &&
+ 	    buf[EI_MAG1] == ELFMAG1 &&
+ 	    buf[EI_MAG2] == ELFMAG2 &&
+ 	    buf[EI_MAG3] == ELFMAG3) {
+ 		Elf32_Ehdr elfhdr;
+ 		int stripped = 1, dynamic = 0, crossendian = 0;
+ 
+ 		(void) memcpy (&elfhdr, buf, sizeof (Elf32_Ehdr));
+ 
+ 		/*
+ 		 *	Little Endian Host: (char *)&stripped[0] == 1 
+ 		 *	Big    Endian Host: (char *)&stripped[0] == 0
+ 		 */
+ 
+ 		if ((((char *)&stripped)[0]==1 && buf[EI_DATA]==ELFDATA2MSB) ||
+ 		    (((char *)&stripped)[0]==0 && buf[EI_DATA]==ELFDATA2LSB)) {
+ 
+ 			crossendian = 1;
+ 
+ 			swapbytes((char *)&elfhdr.e_shoff,
+ 					sizeof elfhdr.e_shoff);
+ 
+ 			swapbytes((char *)&elfhdr.e_shnum,
+ 					sizeof elfhdr.e_shnum);
+ 
+ 			swapbytes((char *)&elfhdr.e_shentsize,
+ 					sizeof elfhdr.e_shentsize);
+ 		}
+ 
+ 		if (lseek(fd, elfhdr.e_shoff, SEEK_SET)<0)
+ 			error("seek failed (%s).\n", strerror(errno));
+ 
+ 		for (;elfhdr.e_shnum;elfhdr.e_shnum--) {
+ 			if (read(fd, (char *)buf, elfhdr.e_shentsize)<0)
+ 			    error("read failed (%s).\n", strerror(errno));
+ 
+ 			if (crossendian)
+ 				swapbytes((char *)&((Elf32_Shdr *)buf)->sh_type,
+ 					  sizeof (((Elf32_Shdr *)buf)->sh_type));
+ 
+ 			if (((Elf32_Shdr *)buf)->sh_type==SHT_SYMTAB)
+ 					stripped = 0;
+ 
+ 			if (((Elf32_Shdr *)buf)->sh_type==SHT_DYNAMIC)
+ 					dynamic = 1;
+ 		}
+ 		if (dynamic)
+ 			(void) printf(", dynamically");
+ 		else
+ 			(void) printf(", statically");
+ 		(void) printf(" linked, ");
+ 		if (!stripped)
+ 			(void) printf("not ");
+ 		(void) printf("stripped");
+ 	}
+ #endif
  	if (inname != stdname) {
  		/*
  		 * Try to restore access, modification times if read it.