Re: [Libguestfs] [PATCH INCOMPLETE] Rewrite virt-make-fs in C (originally Perl).

+/* Execute a command, sending output to a file. */ +static int +exec_command (char **argv, const char *file, int stderr_to_file) +{ + pid_t pid; + int status, fd; + FILE *fp; + char line[256]; + + pid = fork (); + if (pid == -1) { + perror ("fork"); + return -1; + } + if (pid > 0) { + if (waitpid (pid, &status, 0) == -1) { + perror ("waitpid"); + return -1; + } + if (!WIFEXITED (status) || WEXITSTATUS (status) != 0) { + /* If the command failed, dump out the contents of tmpfile which + * contains the exact error messages from qemu-img. + */ + fprintf (stderr, _("%s: %s command failed\n"), program_name, argv[0]); + + if (stderr_to_file) { + fp = fopen (tmpfile, "r"); + if (fp != NULL) { + while (fgets (line, sizeof line, fp) != NULL) + fprintf (stderr, "%s", line); + fclose (fp); + } + } + + return -1; + } + return 0; + } + + /* Child process. */ + fd = open (tmpfile, O_WRONLY|O_NOCTTY); + if (fd == -1) { + perror (tmpfile); + _exit (EXIT_FAILURE); + } + dup2 (fd, 1); + if (stderr_to_file) + dup2 (fd, 2); + close (fd); + + execvp (argv[0], argv); + perror ("execvp"); + _exit (EXIT_FAILURE); +} + +/* Execute a command in the background, sending output to a pipe. */ +static int +bg_command (char **argv, char **pipef) +{