5433 at(1) doesn't properly handle being invoked from a path containing spaces
Reviewed by: Gary Mills <gary_mills@fastmail.fm>

*** 99,108 ****
--- 99,109 ----
  static void atime(struct tm *, struct tm *);
  static int not_this_project(char *);
  static char *mkjobname(time_t);
  static time_t parse_time(char *);
  static time_t gtime(struct tm *);
+ static void escapestr(const char *);
  void atabort(char *)__NORETURN;
  void yyerror(void);
  extern int yyparse(void);
  
  extern void     audit_at_delete(char *, char *, int);
*** 544,553 ****
--- 545,571 ----
          tv = 60 * tv + tptr->tm_sec;
          return (tv);
  }
  
  /*
+  * Escape a string to be used inside the job shell script.
+  */
+ static void
+ escapestr(const char *str)
+ {
+         char c;
+         (void) putchar('\'');
+         while ((c = *str++) != '\0') {
+                 if (c != '\'')
+                         (void) putchar(c);
+                 else
+                         (void) fputs("'\\''", stdout); /* ' -> '\'' */
+         }
+         (void) putchar('\'');
+ }
+ 
+ /*
   * make job file from proto + stdin
   */
  static void
  copy(char *jobfile, FILE *inputfile, int when)
  {
*** 631,646 ****
                                  (void) printf(": project: %d\n", project);
                  }
          }
  
          for (ep = environ; *ep; ep++) {
-                 if (strchr(*ep, '\'') != NULL)
-                         continue;
                  if ((val = strchr(*ep, '=')) == NULL)
                          continue;
                  *val++ = '\0';
!                 printf("export %s; %s='%s'\n", *ep, *ep, val);
                  *--val = '=';
          }
          if ((pfp = fopen(pname1, "r")) == NULL &&
              (pfp = fopen(pname, "r")) == NULL)
                  atabort("no prototype");
--- 649,664 ----
                                  (void) printf(": project: %d\n", project);
                  }
          }
  
          for (ep = environ; *ep; ep++) {
                  if ((val = strchr(*ep, '=')) == NULL)
                          continue;
                  *val++ = '\0';
!                 (void) printf("export %s; %s=", *ep, *ep);
!                 escapestr(val);
!                 (void) putchar('\n');
                  *--val = '=';
          }
          if ((pfp = fopen(pname1, "r")) == NULL &&
              (pfp = fopen(pname, "r")) == NULL)
                  atabort("no prototype");
*** 676,686 ****
                          }
                          /* change back afterwards */
                          if (seteuid(effeusr) < 0) {
                                  atabort(CANTCHUID);
                          }
!                         printf("%s", dirbuf);
                          break;
                  case 'm':
                          printf("%o", um);
                          break;
                  case '<':
--- 694,704 ----
                          }
                          /* change back afterwards */
                          if (seteuid(effeusr) < 0) {
                                  atabort(CANTCHUID);
                          }
!                         escapestr(dirbuf);
                          break;
                  case 'm':
                          printf("%o", um);
                          break;
                  case '<':