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  1. /* Copyright (c) 2008, Tim Post <tinkertim@gmail.com>
  2.  * All rights reserved.
  3.  *
  4.  * Redistribution and use in source and binary forms, with or without
  5.  * modification, are permitted provided that the following conditions are met:
  6.  *
  7.  * Redistributions of source code must retain the above copyright notice, this
  8.  * list of conditions and the following disclaimer.
  9.  *
  10.  * Redistributions in binary form must reproduce the above copyright notice,
  11.  * this list of conditions and the following disclaimer in the documentation
  12.  * and/or other materials provided with the distribution.
  13.  *
  14.  * Neither the name of the original program's authors nor the names of its
  15.  * contributors may be used to endorse or promote products derived from this
  16.  * software without specific prior written permission.
  17.  *
  18.  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  19.  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20.  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21.  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  22.  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  23.  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  24.  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  25.  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  26.  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  27.  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  28.  * POSSIBILITY OF SUCH DAMAGE.
  29.  */
  30.  
  31. /* The VERY basics of execute in place support. These are buggy, leaky
  32.  * and not nearly done. Only here for beta testing!! You were warned!!
  33.  * TODO:
  34.  * Hash command lookups to save time
  35.  * Create a running pointer to **path and advance/rewind it as we go */
  36.  
  37. #include <stdio.h>
  38. #include <stdlib.h>
  39. #include <unistd.h>
  40. #include <string.h>
  41. #include <fcntl.h>
  42.  
  43. #include "config.h"
  44. #include "util.h"
  45. #include "exec.h"
  46. #include "errors.h"
  47.  
  48. /* FIXME: Just have find_command() return an allocated string */
  49. static char *found;
  50.  
  51. static char *find_command(char *);
  52. static int try_access(const char *);
  53.  
  54. /* work-around for access() */
  55. static int try_access(const char *f)
  56. {
  57.     int fd;
  58.  
  59.     fd = open(f, O_RDONLY);
  60.     if (fd > -1) {
  61.         close(fd);
  62.         return 0;
  63.     } else
  64.         return -1;
  65. }
  66.  
  67. /* Returns the full path of "cmd" if cmd is found, else just hand back
  68.  * cmd as it was presented */
  69. static char *find_command(char *cmd)
  70. {
  71.     char *path_tok;
  72.     char *path[PATH_MAX];
  73.     int n = 0, i = 0;
  74.     size_t x = str_size(cmd) + 2;
  75.  
  76.     found = (char *)malloc(PATH_MAX);
  77.  
  78.     /* The user has specified a full or relative path, just give it back. */
  79.     if (-1 != try_access(cmd)) {
  80.         return (char *) cmd;
  81.     }
  82.  
  83.     path_tok = str_dup(PATH);
  84.  
  85.     /* Extract the PATH env to a path[] array */
  86.     path[n] = strtok(path_tok, PATH_DELIM);
  87.     while (NULL != path[n]) {
  88.         if ((str_size(path[n]) + x ) > PATH_MAX) {
  89.             cli_error(CL_ENOTSUP,
  90.                 "Segment %d of path is too large, search ends at segment %d",
  91.                 n, n-1);
  92.             break;
  93.         }
  94.         path[++n] = strtok(NULL, PATH_DELIM);
  95.     }
  96.  
  97.     /* We now have n places to look for the command */
  98.     for (i=0; path[i]; i++) {
  99.         memset(found, 0, sizeof(found));
  100.         snprintf(found, PATH_MAX, "%s/%s", path[i], cmd);
  101.         if (-1 != try_access(found)) {
  102.             free(path_tok);
  103.             return (char *) found;
  104.         }
  105.     }
  106.  
  107.     /* We didn't find it, just give it back as-is. */
  108.     free(path_tok);
  109.     return (char *) cmd;
  110. }
  111.  
  112. unsigned int try_exec(char *cmd, char **argv)
  113. {
  114.     task_id_t tid;
  115.     task_exit_t texit;
  116.     char *tmp;
  117.     int retval;
  118.  
  119.     tmp = str_dup(find_command(cmd));
  120.     free(found);
  121.  
  122.     tid = task_spawn((const char *)tmp, argv);
  123.     free(tmp);
  124.  
  125.     if (tid == 0) {
  126.         cli_error(CL_EEXEC, "Cannot spawn `%s'.", cmd);
  127.         return 1;
  128.     }
  129.    
  130.     task_wait(tid, &texit, &retval);
  131.     if (texit != TASK_EXIT_NORMAL) {
  132.         printf("Command failed (unexpectedly terminated).\n");
  133.     } else if (retval != 0) {
  134.         printf("Command failed (return value %d).\n", retval);
  135.     }
  136.  
  137.     return 0;
  138. }
  139.