usr/src/lib/libbc/libc/gen/common/getusershell.c

   1 /*
   2  * Copyright (c) 1985 Regents of the University of California.
   3  * All rights reserved.  The Berkeley software License Agreement
   4  * specifies the terms and conditions for redistribution.
   5  */
   6
   7 #pragma ident   "%Z%%M% %I%     %E% SMI"
   8
   9 #include <sys/param.h>
  10 #include <sys/file.h>
  11 #include <sys/stat.h>
  12 #include <ctype.h>
  13 #include <stdio.h>
  14 #include <malloc.h>
  15
  16 #define SHELLS "/etc/shells"
  17
  18 /*
  19  * Do not add local shells here.  They should be added in /etc/shells
  20  */
  21 static char *okshells[] =
  22     { "/bin/sh", "/bin/csh", "/usr/bin/sh", "/usr/bin/csh", 0 };
  23
  24 static char **shells, *strings;
  25 static char **curshell;
  26
  27 static char **initshells(void);
  28
  29 /*
  30  * Get a list of shells from SHELLS, if it exists.
  31  */
  32 char *
  33 getusershell(void)
  34 {
  35         char *ret;
  36
  37         if (curshell == NULL)
  38                 curshell = initshells();
  39         ret = *curshell;
  40         if (ret != NULL)
  41                 curshell++;
  42         return (ret);
  43 }
  44
  45 void
  46 endusershell(void)
  47 {
  48
  49         if (shells != NULL)
  50                 free((char *)shells);
  51         shells = NULL;
  52         if (strings != NULL)
  53                 free(strings);
  54         strings = NULL;
  55         curshell = NULL;
  56 }
  57
  58 void
  59 setusershell(void)
  60 {
  61
  62         curshell = initshells();
  63 }
  64
  65 static char **
  66 initshells(void)
  67 {
  68         char **sp, *cp;
  69         FILE *fp;
  70         struct stat statb;
  71
  72         if (shells != NULL)
  73                 free((char *)shells);
  74         shells = NULL;
  75         if (strings != NULL)
  76                 free(strings);
  77         strings = NULL;
  78         if ((fp = fopen(SHELLS, "r")) == (FILE *)0)
  79                 return (okshells);
  80         if (fstat(fileno(fp), &statb) == -1) {
  81                 (void)fclose(fp);
  82                 return (okshells);
  83         }
  84         if ((strings = malloc((unsigned)statb.st_size + 1)) == NULL) {
  85                 (void)fclose(fp);
  86                 return (okshells);
  87         }
  88         shells = (char **)calloc((unsigned)statb.st_size / 3, sizeof (char *));
  89         if (shells == NULL) {
  90                 (void)fclose(fp);
  91                 free(strings);
  92                 strings = NULL;
  93                 return (okshells);
  94         }
  95         sp = shells;
  96         cp = strings;
  97         while (fgets(cp, MAXPATHLEN + 1, fp) != NULL) {
  98                 while (*cp != '#' && *cp != '/' && *cp != '\0')
  99                         cp++;
 100                 if (*cp == '#' || *cp == '\0')
 101                         continue;
 102                 *sp++ = cp;
 103                 while (!isspace(*cp) && *cp != '#' && *cp != '\0')
 104                         cp++;
 105                 *cp++ = '\0';
 106         }
 107         *sp = (char *)0;
 108         (void)fclose(fp);
 109         return (shells);
 110 }