+ if (result) {
+ if (pipe(pipefds) != 0) {
+ err("pipe failed");
+ return -1;
+ }
+ }
+
+ pid = fork();
+ switch(pid) {
+ case 0:
+ /* child dup2 write side of pipe to STDOUT */
+ devnull = open("/dev/null", O_RDWR);
+ if (devnull >= 0) {
+ dup2(devnull, STDIN_FILENO);
+ if (!result)
+ dup2(devnull, STDOUT_FILENO);
+ dup2(devnull, STDERR_FILENO);
+ close(devnull);
+ }
+ if (result)
+ dup2(pipefds[1], STDOUT_FILENO);
+ execv(arg, argv);
+ err("exec of program failed");
+ _exit(1);
+ case -1:
+ err("fork of '%s' failed", arg);
+ return -1;
+ default:
+ /* parent reads from pipefds[0] */
+ if (result) {
+ close(pipefds[1]);
+ len = 0;
+ while (1) {
+ count = read(pipefds[0], result + len, ressize - len-1);
+ if (count < 0) {
+ err("read failed with '%s'", strerror(errno));
+ retval = -1;
+ break;
+ }
+
+ if (count == 0)
+ break;
+
+ len += count;
+ if (len >= ressize-1) {
+ err("ressize %d too short", ressize);
+ retval = -1;
+ break;
+ }
+ }
+ result[len] = '\0';
+ close(pipefds[0]);
+ if (reslen)
+ *reslen = len;
+ }
+ waitpid(pid, &status, 0);