/*tildexpand.cAuthor: Tatu Ylonen <ylo@cs.hut.fi>Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland                   All rights reservedCreated: Wed Jul 12 01:07:36 1995 ylo*//* * $Id: tildexpand.c,v 1.2 1995/07/13 01:41:03 ylo Exp $ * $Log: tildexpand.c,v $ * Revision 1.2  1995/07/13  01:41:03  ylo * 	Removed "Last modified" header. * 	Added cvs log. * * $Endlog$ */#include <sys/types.h>#include <string.h>#include <pwd.h>#include <assert.h>void fatal(char *msg){  fprintf(stderr, "%s\n", msg);  exit(-1);}char *tilde_expand_filename(const char *filename, uid_t my_uid){  const char *cp;  unsigned int userlen;  char *expanded;  struct passwd *pw;  char user[100];  const char *homedir;  /* Return immediately if no tilde. */  if (filename[0] != '~')    return strdup(filename); /* x */  /* Skiop the tilde. */  filename++;  /* Find where the username ends. */  cp = strchr(filename, '/');  if (cp)    userlen = cp - filename;  /* Have something after username. */  else    userlen = strlen(filename); /* Nothign after username. */  if (userlen == 0)    pw = getpwuid(my_uid);  /* Own home directory. */  else    {      /* Tilde refers to someone elses home directory. */      if (userlen > sizeof(user) - 1)	fatal("User name after tilde too long.");      memcpy(user, filename, userlen);      user[userlen] = 0;      pw = getpwnam(user);    }    /* Check that we found the user. */  if (!pw)    fatal(strcat("Unknown user %100s.", user));    homedir = pw->pw_dir;  /* If referring to someones home directory, return it now. */  if (!cp)    { /* Only home directory specified */      return strdup(homedir); /* x */    }    /* Build a path combining the specified directory and path. */  expanded = (char *)malloc(strlen(homedir) + strlen(cp + 1) + 2);  assert(expanded);  sprintf(expanded, "%s/%s", homedir, cp + 1);  return expanded;}