lib/libcompat_minix/nlist.c

   1 /*
   2  * "nlist.c", Peter Valkenburg, january 1989.
   3  */
   4
   5 #include <lib.h>
   6 #include <string.h>
   7 #include <a.out.h>
   8 #include <sys/types.h>
   9 #include <fcntl.h>
  10 #include <unistd.h>
  11 #include <stdio.h>
  12
  13 #define fail(fp)        (fclose(fp), -1)        /* ret. exp. when nlist fails */
  14
  15 _PROTOTYPE( int nlist, (char *file, struct nlist nl[]));
  16
  17 /*
  18  * Nlist fills fields n_sclass and n_value of array nl with values found in
  19  * non-stripped executable file.  Entries that are not found have their
  20  * n_value/n_sclass fields set to 0.  Nl ends with a 0 or nul string n_name.
  21  * The return value is -1 on failure, else the number of entries not found.
  22  */
  23 int nlist(file, nl)
  24 char *file;
  25 struct nlist nl[];
  26 {
  27         int nents, nsrch, nfound, i;
  28         struct nlist nlent;
  29         FILE *fp;
  30         struct exec hd;
  31
  32         /* open executable with namelist */
  33         if ((fp = fopen(file, "r")) == NULL)
  34                 return -1;
  35
  36         /* get header and seek to start of namelist */
  37         if (fread((char *) &hd, sizeof(struct exec), 1, fp) != 1 ||
  38             BADMAG(hd) || fseek(fp, A_SYMPOS(hd), SEEK_SET) != 0)
  39                 return fail(fp);
  40
  41         /* determine number of entries searched for & reset fields */
  42         nsrch = 0;
  43         while (nl[nsrch].n_name != NULL && *(nl[nsrch].n_name) != '\0') {
  44                 nl[nsrch].n_sclass = 0;
  45                 nl[nsrch].n_value = 0;
  46                 nl[nsrch].n_type = 0;           /* for compatability */
  47                 nsrch++;
  48         }
  49
  50         /* loop through namelist & fill in user array */
  51         nfound = 0;
  52         for (nents = (hd.a_syms & 0xFFFF) / sizeof(struct nlist);
  53              nents > 0; nents--) {
  54                 if (nsrch == nfound)
  55                         break;                  /* no need to look further */
  56                 if (fread((char *) &nlent, sizeof(struct nlist), 1, fp) != 1)
  57                         return fail(fp);
  58                 for (i = 0; i < nsrch; i++)
  59                         if (nl[i].n_sclass == 0 &&
  60                             strncmp(nl[i].n_name, nlent.n_name,
  61                                     sizeof(nlent.n_name)) == 0) {
  62                                 nl[i] = nlent;
  63                                 nfound++;
  64                                 break;
  65                         }
  66         }
  67
  68         (void) fclose(fp);
  69
  70         return nsrch - nfound;
  71 }