util.c

   1 #include <stdio.h>
   2 #include <stdarg.h>
   3 #include <unistd.h>
   4 #include <ctype.h>
   5 #include <signal.h>
   6 #include <sys/types.h>
   7 #include <sys/wait.h>
   8 #include "util.h"
   9
  10 void eprint(const char *errstr, ...) {
  11         va_list ap;
  12         va_start(ap, errstr);
  13         vfprintf(stderr, errstr, ap);
  14         va_end(ap);
  15 }
  16
  17 void skip_until(char** str, char c) {
  18         while (**str && **str != c)
  19                 (*str)++;
  20 }
  21
  22 void skip_spaces(char **str) {
  23         while (isspace(**str))
  24                 (*str)++;
  25 }
  26
  27 int fexecw(const char *path, char *const argv[], char *const envp[]) {
  28         pid_t pid;
  29         struct sigaction ignore, old_int, old_quit;
  30         sigset_t masked, oldmask;
  31         int status;
  32
  33         /* Block SIGCHLD and ignore SIGINT and SIGQUIT before forking
  34          * restore the original signal handlers afterwards. */
  35
  36         ignore.sa_handler = SIG_IGN;
  37         sigemptyset(&ignore.sa_mask);
  38         ignore.sa_flags = 0;
  39         sigaction(SIGINT, &ignore, &old_int);
  40         sigaction(SIGQUIT, &ignore, &old_quit);
  41
  42         sigemptyset(&masked);
  43         sigaddset(&masked, SIGCHLD);
  44         sigprocmask(SIG_BLOCK, &masked, &oldmask);
  45
  46         pid = fork();
  47
  48         if (pid < 0)
  49                 return -1; /* can't fork */
  50         else if (pid == 0) { /* child process */
  51                 sigaction(SIGINT, &old_int, NULL);
  52                 sigaction(SIGQUIT, &old_quit, NULL);
  53                 sigprocmask(SIG_SETMASK, &oldmask, NULL);
  54                 execve(path, (char *const *)argv, (char *const *)envp);
  55                 _exit(127);
  56         }
  57
  58         /* wait for our child and store it's exit status */
  59         waitpid(pid, &status, 0);
  60
  61         /* restore signal handlers */
  62         sigaction(SIGINT, &old_int, NULL);
  63         sigaction(SIGQUIT, &old_quit, NULL);
  64         sigprocmask(SIG_SETMASK, &oldmask, NULL);
  65
  66         return status;
  67 }