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