commands/simple/strip.c

   1 /* strip - remove symbols.              Author: Dick van Veen */
   2
   3 #include <sys/types.h>
   4 #include <sys/stat.h>
   5 #include <fcntl.h>
   6 #include <a.out.h>
   7 #include <unistd.h>
   8 #include <string.h>
   9 #include <stdlib.h>
  10 #include <stdio.h>
  11
  12 /* Strip [file] ...
  13  *
  14  *      -       when no file is present, a.out is assumed.
  15  *
  16  */
  17
  18 #define A_OUT           "a.out"
  19 #define NAME_LENGTH     128     /* max file path name */
  20
  21 char buffer[BUFSIZ];            /* used to copy executable */
  22 char new_file[NAME_LENGTH];     /* contains name of temporary */
  23 struct exec header;
  24
  25 _PROTOTYPE(int main, (int argc, char **argv));
  26 _PROTOTYPE(void strip, (char *file));
  27 _PROTOTYPE(int read_header, (int fd));
  28 _PROTOTYPE(int write_header, (int fd));
  29 _PROTOTYPE(int make_tmp, (char *new_name, char *name));
  30 _PROTOTYPE(int copy_file, (int fd1, int fd2, long size));
  31
  32 int main(argc, argv)
  33 int argc;
  34 char **argv;
  35 {
  36   argv++;
  37   if (*argv == NULL)
  38         strip(A_OUT);
  39   else
  40         while (*argv != NULL) {
  41                 strip(*argv);
  42                 argv++;
  43         }
  44   return(0);
  45 }
  46
  47 void strip(file)
  48 char *file;
  49 {
  50   int fd, new_fd;
  51   struct stat buf;
  52   long symb_size, relo_size;
  53
  54   fd = open(file, O_RDONLY);
  55   if (fd == -1) {
  56         fprintf(stderr, "can't open %s\n", file);
  57         close(fd);
  58         return;
  59   }
  60   if (read_header(fd)) {
  61         fprintf(stderr, "%s: not an executable file\n", file);
  62         close(fd);
  63         return;
  64   }
  65   if (header.a_syms == 0L) {
  66         close(fd);              /* no symbol table present */
  67         return;
  68   }
  69   symb_size = header.a_syms;
  70   header.a_syms = 0L;           /* remove table size */
  71   fstat(fd, &buf);
  72   relo_size = buf.st_size - (A_MINHDR + header.a_text + header.a_data + symb_size);
  73   new_fd = make_tmp(new_file, file);
  74   if (new_fd == -1) {
  75         fprintf(stderr, "can't create temporary file\n");
  76         close(fd);
  77         return;
  78   }
  79   if (write_header(new_fd)) {
  80         fprintf(stderr, "can't write temporary file\n");
  81         unlink(new_file);
  82         close(fd);
  83         close(new_fd);
  84         return;
  85   }
  86   if (copy_file(fd, new_fd, header.a_text + header.a_data)) {
  87         fprintf(stderr, "can't copy %s\n", file);
  88         unlink(new_file);
  89         close(fd);
  90         close(new_fd);
  91         return;
  92   }
  93   if (relo_size != 0) {
  94         lseek(fd, symb_size, 1);
  95         if (copy_file(fd, new_fd, relo_size)) {
  96             fprintf(stderr, "can't copy %s\n", file);
  97             unlink(new_file);
  98             close(fd);
  99             close(new_fd);
 100             return;
 101         }
 102   }
 103   close(fd);
 104   close(new_fd);
 105   if (unlink(file) == -1) {
 106         fprintf(stderr, "can't unlink %s\n", file);
 107         unlink(new_file);
 108         return;
 109   }
 110   link(new_file, file);
 111   unlink(new_file);
 112   chmod(file, buf.st_mode);
 113 }
 114
 115 int read_header(fd)
 116 int fd;
 117 {
 118   if (read(fd, (char *) &header, A_MINHDR) != A_MINHDR) return(1);
 119   if (BADMAG(header)) return (1);
 120   if (header.a_hdrlen > sizeof(struct exec)) return (1);
 121   lseek(fd, 0L, SEEK_SET);      /* variable size header */
 122   if (read(fd, (char *)&header, (int)header.a_hdrlen) != (int) header.a_hdrlen)
 123         return(1);
 124   return(0);
 125 }
 126
 127 int write_header(fd)
 128 int fd;
 129 {
 130   lseek(fd, 0L, SEEK_SET);
 131   if (write(fd, (char *)&header, (int)header.a_hdrlen) != (int)header.a_hdrlen)
 132         return(1);
 133   return(0);
 134 }
 135
 136 int make_tmp(new_name, name)
 137 char *new_name, *name;
 138 {
 139   int len;
 140   char *nameptr;
 141
 142   len = strlen(name);
 143   if (len + 1 > NAME_LENGTH) return(-1);
 144   strcpy(new_name, name);
 145   nameptr = strrchr(new_name, '/');
 146   if (nameptr == NULL) nameptr = new_name - 1;
 147   if (nameptr - new_name + 6 + 1 > NAME_LENGTH) return (-1);
 148   strcpy(nameptr + 1, "XXXXXX");
 149   mktemp(new_name);
 150   return(creat(new_name, 0777));
 151 }
 152
 153 int copy_file(fd1, fd2, size)
 154 int fd1, fd2;
 155 long size;
 156 {
 157   int length;
 158
 159   while (size > 0) {
 160         if (size < sizeof(buffer))
 161                 length = size;
 162         else
 163                 length = sizeof(buffer);
 164         if (read(fd1, buffer, length) != length) return(1);
 165         if (write(fd2, buffer, length) != length) return (1);
 166         size -= length;
 167   }
 168   return(0);
 169 }