cmd-string.c

   1 /* $OpenBSD$ */
   2
   3 /*
   4  * Copyright (c) 2008 Nicholas Marriott <nicm@users.sourceforge.net>
   5  *
   6  * Permission to use, copy, modify, and distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
  15  * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
  16  * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18
  19 #include <sys/types.h>
  20
  21 #include <errno.h>
  22 #include <pwd.h>
  23 #include <stdio.h>
  24 #include <string.h>
  25 #include <stdlib.h>
  26 #include <unistd.h>
  27
  28 #include "tmux.h"
  29
  30 /*
  31  * Parse a command from a string.
  32  */
  33
  34 int     cmd_string_getc(const char *, size_t *);
  35 void    cmd_string_ungetc(size_t *);
  36 char   *cmd_string_string(const char *, size_t *, char, int);
  37 char   *cmd_string_variable(const char *, size_t *);
  38 char   *cmd_string_expand_tilde(const char *, size_t *);
  39
  40 int
  41 cmd_string_getc(const char *s, size_t *p)
  42 {
  43         const u_char    *ucs = s;
  44
  45         if (ucs[*p] == '\0')
  46                 return (EOF);
  47         return (ucs[(*p)++]);
  48 }
  49
  50 void
  51 cmd_string_ungetc(size_t *p)
  52 {
  53         (*p)--;
  54 }
  55
  56 /*
  57  * Parse command string. Returns -1 on error. If returning -1, cause is error
  58  * string, or NULL for empty command.
  59  */
  60 int
  61 cmd_string_parse(const char *s, struct cmd_list **cmdlist, char **cause)
  62 {
  63         size_t          p;
  64         int             ch, i, argc, rval;
  65         char          **argv, *buf, *t;
  66         const char     *whitespace, *equals;
  67         size_t          len;
  68
  69         argv = NULL;
  70         argc = 0;
  71
  72         buf = NULL;
  73         len = 0;
  74
  75         *cause = NULL;
  76
  77         *cmdlist = NULL;
  78         rval = -1;
  79
  80         p = 0;
  81         for (;;) {
  82                 ch = cmd_string_getc(s, &p);
  83                 switch (ch) {
  84                 case '\'':
  85                         if ((t = cmd_string_string(s, &p, '\'', 0)) == NULL)
  86                                 goto error;
  87                         buf = xrealloc(buf, 1, len + strlen(t) + 1);
  88                         strlcpy(buf + len, t, strlen(t) + 1);
  89                         len += strlen(t);
  90                         xfree(t);
  91                         break;
  92                 case '"':
  93                         if ((t = cmd_string_string(s, &p, '"', 1)) == NULL)
  94                                 goto error;
  95                         buf = xrealloc(buf, 1, len + strlen(t) + 1);
  96                         strlcpy(buf + len, t, strlen(t) + 1);
  97                         len += strlen(t);
  98                         xfree(t);
  99                         break;
 100                 case '$':
 101                         if ((t = cmd_string_variable(s, &p)) == NULL)
 102                                 goto error;
 103                         buf = xrealloc(buf, 1, len + strlen(t) + 1);
 104                         strlcpy(buf + len, t, strlen(t) + 1);
 105                         len += strlen(t);
 106                         xfree(t);
 107                         break;
 108                 case '#':
 109                         /* Comment: discard rest of line. */
 110                         while ((ch = cmd_string_getc(s, &p)) != EOF)
 111                                 ;
 112                         /* FALLTHROUGH */
 113                 case EOF:
 114                 case ' ':
 115                 case '\t':
 116                         if (buf != NULL) {
 117                                 buf = xrealloc(buf, 1, len + 1);
 118                                 buf[len] = '\0';
 119
 120                                 argv = xrealloc(argv, argc + 1, sizeof *argv);
 121                                 argv[argc++] = buf;
 122
 123                                 buf = NULL;
 124                                 len = 0;
 125                         }
 126
 127                         if (ch != EOF)
 128                                 break;
 129
 130                         while (argc != 0) {
 131                                 equals = strchr(argv[0], '=');
 132                                 whitespace = argv[0] + strcspn(argv[0], " \t");
 133                                 if (equals == NULL || equals > whitespace)
 134                                         break;
 135                                 environ_put(&global_environ, argv[0]);
 136                                 argc--;
 137                                 memmove(argv, argv + 1, argc * (sizeof *argv));
 138                         }
 139                         if (argc == 0)
 140                                 goto out;
 141
 142                         *cmdlist = cmd_list_parse(argc, argv, cause);
 143                         if (*cmdlist == NULL)
 144                                 goto out;
 145
 146                         rval = 0;
 147                         goto out;
 148                 case '~':
 149                         if (buf == NULL) {
 150                                 if ((t = cmd_string_expand_tilde(s, &p)) == NULL)
 151                                         goto error;
 152                                 buf = xrealloc(buf, 1, len + strlen(t) + 1);
 153                                 strlcpy(buf + len, t, strlen(t) + 1);
 154                                 len += strlen(t);
 155                                 xfree(t);
 156                                 break;
 157                         }
 158                         /* FALLTHROUGH */
 159                 default:
 160                         if (len >= SIZE_MAX - 2)
 161                                 goto error;
 162
 163                         buf = xrealloc(buf, 1, len + 1);
 164                         buf[len++] = ch;
 165                         break;
 166                 }
 167         }
 168
 169 error:
 170         xasprintf(cause, "invalid or unknown command: %s", s);
 171
 172 out:
 173         if (buf != NULL)
 174                 xfree(buf);
 175
 176         if (argv != NULL) {
 177                 for (i = 0; i < argc; i++)
 178                         xfree(argv[i]);
 179                 xfree(argv);
 180         }
 181
 182         return (rval);
 183 }
 184
 185 char *
 186 cmd_string_string(const char *s, size_t *p, char endch, int esc)
 187 {
 188         int     ch;
 189         char   *buf, *t;
 190         size_t  len;
 191
 192         buf = NULL;
 193         len = 0;
 194
 195         while ((ch = cmd_string_getc(s, p)) != endch) {
 196                 switch (ch) {
 197                 case EOF:
 198                         goto error;
 199                 case '\\':
 200                         if (!esc)
 201                                 break;
 202                         switch (ch = cmd_string_getc(s, p)) {
 203                         case EOF:
 204                                 goto error;
 205                         case 'e':
 206                                 ch = '\033';
 207                                 break;
 208                         case 'r':
 209                                 ch = '\r';
 210                                 break;
 211                         case 'n':
 212                                 ch = '\n';
 213                                 break;
 214                         case 't':
 215                                 ch = '\t';
 216                                 break;
 217                         }
 218                         break;
 219                 case '$':
 220                         if (!esc)
 221                                 break;
 222                         if ((t = cmd_string_variable(s, p)) == NULL)
 223                                 goto error;
 224                         buf = xrealloc(buf, 1, len + strlen(t) + 1);
 225                         strlcpy(buf + len, t, strlen(t) + 1);
 226                         len += strlen(t);
 227                         xfree(t);
 228                         continue;
 229                 }
 230
 231                 if (len >= SIZE_MAX - 2)
 232                         goto error;
 233                 buf = xrealloc(buf, 1, len + 1);
 234                 buf[len++] = ch;
 235         }
 236
 237         buf = xrealloc(buf, 1, len + 1);
 238         buf[len] = '\0';
 239         return (buf);
 240
 241 error:
 242         if (buf != NULL)
 243                 xfree(buf);
 244         return (NULL);
 245 }
 246
 247 char *
 248 cmd_string_variable(const char *s, size_t *p)
 249 {
 250         int     ch, fch;
 251         char   *buf, *t;
 252         size_t  len;
 253
 254 #define cmd_string_first(ch) ((ch) == '_' || \
 255         ((ch) >= 'a' && (ch) <= 'z') || ((ch) >= 'A' && (ch) <= 'Z'))
 256 #define cmd_string_other(ch) ((ch) == '_' || \
 257         ((ch) >= 'a' && (ch) <= 'z') || ((ch) >= 'A' && (ch) <= 'Z') || \
 258         ((ch) >= '0' && (ch) <= '9'))
 259
 260         buf = NULL;
 261         len = 0;
 262
 263         fch = EOF;
 264         switch (ch = cmd_string_getc(s, p)) {
 265         case EOF:
 266                 goto error;
 267         case '{':
 268                 fch = '{';
 269
 270                 ch = cmd_string_getc(s, p);
 271                 if (!cmd_string_first(ch))
 272                         goto error;
 273                 /* FALLTHROUGH */
 274         default:
 275                 if (!cmd_string_first(ch)) {
 276                         xasprintf(&t, "$%c", ch);
 277                         return (t);
 278                 }
 279
 280                 buf = xrealloc(buf, 1, len + 1);
 281                 buf[len++] = ch;
 282
 283                 for (;;) {
 284                         ch = cmd_string_getc(s, p);
 285                         if (ch == EOF || !cmd_string_other(ch))
 286                                 break;
 287                         else {
 288                                 if (len >= SIZE_MAX - 3)
 289                                         goto error;
 290                                 buf = xrealloc(buf, 1, len + 1);
 291                                 buf[len++] = ch;
 292                         }
 293                 }
 294         }
 295
 296         if (fch == '{' && ch != '}')
 297                 goto error;
 298         if (ch != EOF && fch != '{')
 299                 cmd_string_ungetc(p); /* ch */
 300
 301         buf = xrealloc(buf, 1, len + 1);
 302         buf[len] = '\0';
 303
 304         if ((t = getenv(buf)) == NULL) {
 305                 xfree(buf);
 306                 return (xstrdup(""));
 307         }
 308         xfree(buf);
 309         return (xstrdup(t));
 310
 311 error:
 312         if (buf != NULL)
 313                 xfree(buf);
 314         return (NULL);
 315 }
 316
 317 char *
 318 cmd_string_expand_tilde(const char *s, size_t *p)
 319 {
 320         struct passwd   *pw;
 321         char            *home, *path, *username;
 322
 323         home = NULL;
 324         if (cmd_string_getc(s, p) == '/') {
 325                 if ((home = getenv("HOME")) == NULL || *home == '\0') {
 326                         if ((pw = getpwuid(getuid())) != NULL)
 327                                 home = pw->pw_dir;
 328                 }
 329         } else {
 330                 cmd_string_ungetc(p);
 331                 if ((username = cmd_string_string(s, p, '/', 0)) == NULL)
 332                         return (NULL);
 333                 if ((pw = getpwnam(username)) != NULL)
 334                         home = pw->pw_dir;
 335                 xfree(username);
 336         }
 337         if (home == NULL)
 338                 return (NULL);
 339
 340         xasprintf(&path, "%s/", home);
 341         return (path);
 342 }