contrib/cvs-1.12/src/expand_path.c

   1 /* expand_path.c -- expand environmental variables in passed in string
   2  *
   3  * Copyright (C) 1995-2005 The Free Software Foundation, Inc.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2, or (at your option)
   8  * any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * The main routine is expand_path(), it is the routine that handles
  16  * the '~' character in four forms:
  17  *     ~name
  18  *     ~name/
  19  *     ~/
  20  *     ~
  21  * and handles environment variables contained within the pathname
  22  * which are defined by:
  23  *     ${var_name}   (var_name is the name of the environ variable)
  24  *     $var_name     (var_name ends w/ non-alphanumeric char other than '_')
  25  */
  26
  27 #include "cvs.h"
  28 #include <sys/types.h>
  29
  30 /* User variables.  */
  31
  32 List *variable_list;
  33
  34 static void variable_delproc (Node *);
  35
  36 static void
  37 variable_delproc (Node *node)
  38 {
  39     free (node->data);
  40 }
  41
  42 /* Currently used by -s option; we might want a way to set user
  43    variables in a file in the $CVSROOT/CVSROOT directory too.  */
  44
  45 void
  46 variable_set (char *nameval)
  47 {
  48     char *p;
  49     char *name;
  50     Node *node;
  51
  52     p = nameval;
  53     while (isalnum ((unsigned char) *p) || *p == '_')
  54         ++p;
  55     if (*p != '=')
  56         error (1, 0, "invalid character in user variable name in %s", nameval);
  57     if (p == nameval)
  58         error (1, 0, "empty user variable name in %s", nameval);
  59     name = xmalloc (p - nameval + 1);
  60     strncpy (name, nameval, p - nameval);
  61     name[p - nameval] = '\0';
  62     /* Make p point to the value.  */
  63     ++p;
  64     if (strchr (p, '\012'))
  65         error (1, 0, "linefeed in user variable value in %s", nameval);
  66
  67     if (!variable_list)
  68         variable_list = getlist ();
  69
  70     node = findnode (variable_list, name);
  71     if (!node)
  72     {
  73         node = getnode ();
  74         node->type = VARIABLE;
  75         node->delproc = variable_delproc;
  76         node->key = name;
  77         node->data = xstrdup (p);
  78         (void) addnode (variable_list, node);
  79     }
  80     else
  81     {
  82         /* Replace the old value.  For example, this means that -s
  83            options on the command line override ones from .cvsrc.  */
  84         free (node->data);
  85         node->data = xstrdup (p);
  86         free (name);
  87     }
  88 }
  89
  90
  91
  92 /* Expand variable NAME into its contents, per the rules above.
  93  *
  94  * CVSROOT is used to expanding $CVSROOT.
  95  *
  96  * RETURNS
  97  *   A pointer to the requested variable contents or NULL when the requested
  98  *   variable is not found.
  99  *
 100  * ERRORS
 101  *   None, though this function may generate warning messages when NAME is not
 102  *   found.
 103  */
 104 static const char *
 105 expand_variable (const char *name, const char *cvsroot,
 106                  const char *file, int line)
 107 {
 108     if (!strcmp (name, CVSROOT_ENV))
 109         return cvsroot;
 110     else if (!strcmp (name, "RCSBIN"))
 111     {
 112         error (0, 0, "RCSBIN internal variable is no longer supported");
 113         return NULL;
 114     }
 115     else if (!strcmp (name, EDITOR1_ENV))
 116         return Editor;
 117     else if (!strcmp (name, EDITOR2_ENV))
 118         return Editor;
 119     else if (!strcmp (name, EDITOR3_ENV))
 120         return Editor;
 121     else if (!strcmp (name, "USER"))
 122         return getcaller ();
 123     else if (!strcmp (name, "SESSIONID")
 124              || !strcmp (name, "COMMITID"))
 125         return global_session_id;
 126     else if (isalpha (name[0]))
 127     {
 128         /* These names are reserved for future versions of CVS,
 129            so that is why it is an error.  */
 130         if (line)
 131             error (0, 0, "%s:%d: no such internal variable $%s",
 132                    file, line, name);
 133         else
 134             error (0, 0, "%s: no such internal variable $%s",
 135                    file, name);
 136         return NULL;
 137     }
 138     else if (name[0] == '=')
 139     {
 140         Node *node;
 141         /* Crazy syntax for a user variable.  But we want
 142            *something* that lets the user name a user variable
 143            anything he wants, without interference from
 144            (existing or future) internal variables.  */
 145         node = findnode (variable_list, name + 1);
 146         if (!node)
 147         {
 148             if (line)
 149                 error (0, 0, "%s:%d: no such user variable ${%s}",
 150                        file, line, name);
 151             else
 152                 error (0, 0, "%s: no such user variable ${%s}",
 153                        file, name);
 154             return NULL;
 155         }
 156         return node->data;
 157     }
 158     else
 159     {
 160         /* It is an unrecognized character.  We return an error to
 161            reserve these for future versions of CVS; it is plausible
 162            that various crazy syntaxes might be invented for inserting
 163            information about revisions, branches, etc.  */
 164         if (line)
 165             error (0, 0, "%s:%d: unrecognized variable syntax %s",
 166                    file, line, name);
 167         else
 168             error (0, 0, "%s: unrecognized variable syntax %s",
 169                    file, name);
 170         return NULL;
 171     }
 172 }
 173
 174
 175
 176 /* This routine will expand the pathname to account for ~ and $
 177  * characters as described above.  Returns a pointer to a newly
 178  * malloc'd string.  If an error occurs, an error message is printed
 179  * via error() and NULL is returned.  FILE and LINE are the filename
 180  * and linenumber to include in the error message.  FILE must point
 181  * to something; LINE can be zero to indicate the line number is not
 182  * known.
 183  *
 184  * When FORMATSAFE is set, percent signs (`%') in variable contents are doubled
 185  * to prevent later expansion by format_cmdline.
 186  *
 187  * CVSROOT is used to expanding $CVSROOT.
 188  */
 189 char *
 190 expand_path (const char *name, const char *cvsroot, bool formatsafe,
 191              const char *file, int line)
 192 {
 193     size_t s, d, p;
 194     const char *e;
 195
 196     char *mybuf = NULL;
 197     size_t mybuf_size = 0;
 198     char *buf = NULL;
 199     size_t buf_size = 0;
 200
 201     char inquotes = '\0';
 202
 203     char *result;
 204
 205     /* Sorry this routine is so ugly; it is a head-on collision
 206        between the `traditional' unix *d++ style and the need to
 207        dynamically allocate.  It would be much cleaner (and probably
 208        faster, not that this is a bottleneck for CVS) with more use of
 209        strcpy & friends, but I haven't taken the effort to rewrite it
 210        thusly.  */
 211
 212     /* First copy from NAME to MYBUF, expanding $<foo> as we go.  */
 213     s = d = 0;
 214     expand_string (&mybuf, &mybuf_size, d + 1);
 215     while ((mybuf[d++] = name[s]) != '\0')
 216     {
 217         if (name[s] == '\\')
 218         {
 219             /* The next character is a literal.  Leave the \ in the string
 220              * since it will be needed again when the string is split into
 221              * arguments.
 222              */
 223             /* if we have a \ as the last character of the string, just leave
 224              * it there - this is where we would set the escape flag to tell
 225              * our parent we want another line if we cared.
 226              */
 227             if (name[++s])
 228             {
 229                 expand_string (&mybuf, &mybuf_size, d + 1);
 230                 mybuf[d++] = name[s++];
 231             }
 232         }
 233         /* skip $ variable processing for text inside single quotes */
 234         else if (inquotes == '\'')
 235         {
 236             if (name[s++] == '\'')
 237             {
 238                 inquotes = '\0';
 239             }
 240         }
 241         else if (name[s] == '\'')
 242         {
 243             s++;
 244             inquotes = '\'';
 245         }
 246         else if (name[s] == '"')
 247         {
 248             s++;
 249             if (inquotes) inquotes = '\0';
 250             else inquotes = '"';
 251         }
 252         else if (name[s++] == '$')
 253         {
 254             int flag = (name[s] == '{');
 255             p = d;
 256
 257             expand_string (&mybuf, &mybuf_size, d + 1);
 258             for (; (mybuf[d++] = name[s]); s++)
 259             {
 260                 if (flag
 261                     ? name[s] =='}'
 262                     : !isalnum (name[s]) && name[s] != '_')
 263                     break;
 264                 expand_string (&mybuf, &mybuf_size, d + 1);
 265             }
 266             mybuf[--d] = '\0';
 267             e = expand_variable (&mybuf[p+flag], cvsroot, file, line);
 268
 269             if (e)
 270             {
 271                 expand_string (&mybuf, &mybuf_size, d + 1);
 272                 for (d = p - 1; (mybuf[d++] = *e++); )
 273                 {
 274                     expand_string (&mybuf, &mybuf_size, d + 1);
 275                     if (mybuf[d-1] == '"')
 276                     {
 277                         /* escape the double quotes if we're between a matched
 278                          * pair of double quotes so that this sub will be
 279                          * passed inside as or as part of a single argument
 280                          * during the argument split later.
 281                          */
 282                         if (inquotes)
 283                         {
 284                             mybuf[d-1] = '\\';
 285                             expand_string (&mybuf, &mybuf_size, d + 1);
 286                             mybuf[d++] = '"';
 287                         }
 288                     }
 289                     else if (formatsafe && mybuf[d-1] == '%')
 290                     {
 291                         /* escape '%' to get past printf style format strings
 292                          * later (in make_cmdline).
 293                          */
 294                         expand_string (&mybuf, &mybuf_size, d + 1);
 295                         mybuf[d] = '%';
 296                         d++;
 297                     }
 298                 }
 299                 --d;
 300                 if (flag && name[s])
 301                     s++;
 302             }
 303             else
 304                 /* expand_variable has already printed an error message.  */
 305                 goto error_exit;
 306         }
 307         expand_string (&mybuf, &mybuf_size, d + 1);
 308     }
 309     expand_string (&mybuf, &mybuf_size, d + 1);
 310     mybuf[d] = '\0';
 311
 312     /* Then copy from MYBUF to BUF, expanding ~.  */
 313     s = d = 0;
 314     /* If you don't want ~username ~/ to be expanded simply remove
 315      * This entire if statement including the else portion
 316      */
 317     if (mybuf[s] == '~')
 318     {
 319         p = d;
 320         while (mybuf[++s] != '/' && mybuf[s] != '\0')
 321         {
 322             expand_string (&buf, &buf_size, p + 1);
 323             buf[p++] = name[s];
 324         }
 325         expand_string (&buf, &buf_size, p + 1);
 326         buf[p] = '\0';
 327
 328         if (p == d)
 329             e = get_homedir ();
 330         else
 331         {
 332 #ifdef GETPWNAM_MISSING
 333             if (line)
 334                 error (0, 0,
 335                        "%s:%d:tilde expansion not supported on this system",
 336                        file, line);
 337             else
 338                 error (0, 0, "%s:tilde expansion not supported on this system",
 339                        file);
 340             goto error_exit;
 341 #else
 342             struct passwd *ps;
 343             ps = getpwnam (buf + d);
 344             if (ps == NULL)
 345             {
 346                 if (line)
 347                     error (0, 0, "%s:%d: no such user %s",
 348                            file, line, buf + d);
 349                 else
 350                     error (0, 0, "%s: no such user %s", file, buf + d);
 351                 goto error_exit;
 352             }
 353             e = ps->pw_dir;
 354 #endif
 355         }
 356         if (!e)
 357             error (1, 0, "cannot find home directory");
 358
 359         p = strlen (e);
 360         expand_string (&buf, &buf_size, d + p);
 361         memcpy (buf + d, e, p);
 362         d += p;
 363     }
 364     /* Kill up to here */
 365     p = strlen (mybuf + s) + 1;
 366     expand_string (&buf, &buf_size, d + p);
 367     memcpy (buf + d, mybuf + s, p);
 368
 369     /* OK, buf contains the value we want to return.  Clean up and return
 370        it.  */
 371     free (mybuf);
 372     /* Save a little memory with xstrdup; buf will tend to allocate
 373        more than it needs to.  */
 374     result = xstrdup (buf);
 375     free (buf);
 376     return result;
 377
 378  error_exit:
 379     if (mybuf) free (mybuf);
 380     if (buf) free (buf);
 381     return NULL;
 382 }