9:22 a.m.
Improve readability of commandrvf() by replacing bare int values for
file descriptors with their symbolic names STD{IN,OUT,ERR}_FILENO.
Also add PIPE_READ and PIPE_WRITE for referencing relevant ends of a pipe.
---
daemon/guestfsd.c | 79 +++++++++++++++++++++++++++++--------------------------
1 file changed, 42 insertions(+), 37 deletions(-)
diff --git a/daemon/guestfsd.c b/daemon/guestfsd.c
index 5c84849..4b3dd5f 100644
--- a/daemon/guestfsd.c
+++ b/daemon/guestfsd.c
@@ -66,6 +66,10 @@ static char *read_cmdline (void);
# define O_CLOEXEC 0
#endif
+/* For improved readability dealing with pipe arrays */
+#define PIPE_READ 0
+#define PIPE_WRITE 1
+
/* If root device is an ext2 filesystem, this is the major and minor.
* This is so we can ignore this device from the point of view of the
* user, eg. in guestfs_list_devices and many other places.
@@ -834,22 +838,22 @@ commandrvf (char **stdoutput, char **stderror, int flags,
signal (SIGPIPE, SIG_DFL);
close (0);
if (flag_copy_stdin) {
- dup2 (stdin_fd[0], 0);
- close (stdin_fd[0]);
- close (stdin_fd[1]);
+ dup2 (stdin_fd[PIPE_READ], STDIN_FILENO);
+ close (stdin_fd[PIPE_READ]);
+ close (stdin_fd[PIPE_WRITE]);
} else {
/* Set stdin to /dev/null (ignore failure) */
ignore_value (open ("/dev/null", O_RDONLY|O_CLOEXEC));
}
- close (so_fd[0]);
- close (se_fd[0]);
+ close (so_fd[PIPE_READ]);
+ close (se_fd[PIPE_READ]);
if (!(flags & COMMAND_FLAG_FOLD_STDOUT_ON_STDERR))
- dup2 (so_fd[1], 1);
+ dup2 (so_fd[PIPE_WRITE], STDOUT_FILENO);
else
- dup2 (se_fd[1], 1);
- dup2 (se_fd[1], 2);
- close (so_fd[1]);
- close (se_fd[1]);
+ dup2 (se_fd[PIPE_WRITE], STDOUT_FILENO);
+ dup2 (se_fd[PIPE_WRITE], STDERR_FILENO);
+ close (so_fd[PIPE_WRITE]);
+ close (se_fd[PIPE_WRITE]);
execvp (argv[0], (void *) argv);
perror (argv[0]);
@@ -866,15 +870,15 @@ commandrvf (char **stdoutput, char **stderror, int flags,
}
if (stdin_pid == 0) { /* Child process copying stdin. */
- close (so_fd[0]);
- close (so_fd[1]);
- close (se_fd[0]);
- close (se_fd[1]);
+ close (so_fd[PIPE_READ]);
+ close (so_fd[PIPE_WRITE]);
+ close (se_fd[PIPE_READ]);
+ close (se_fd[PIPE_WRITE]);
- close (1);
- dup2 (stdin_fd[1], 1);
- close (stdin_fd[0]);
- close (stdin_fd[1]);
+ close (STDOUT_FILENO);
+ dup2 (stdin_fd[PIPE_WRITE], STDOUT_FILENO);
+ close (stdin_fd[PIPE_READ]);
+ close (stdin_fd[PIPE_WRITE]);
if (chroot (sysroot) == -1) {
perror ("chroot");
@@ -884,7 +888,7 @@ commandrvf (char **stdoutput, char **stderror, int flags,
ssize_t n;
char buffer[BUFSIZ];
while ((n = read (fd, buffer, sizeof buffer)) > 0) {
- if (xwrite (1, buffer, n) == -1)
+ if (xwrite (STDOUT_FILENO, buffer, n) == -1)
/* EPIPE error indicates the command process has exited
* early. If the command process fails that will be caught
* by the daemon, and if not, then it's not an error.
@@ -906,23 +910,24 @@ commandrvf (char **stdoutput, char **stderror, int flags,
}
close (fd);
- close (stdin_fd[0]);
- close (stdin_fd[1]);
+ close (stdin_fd[PIPE_READ]);
+ close (stdin_fd[PIPE_WRITE]);
}
/* Parent process. */
- close (so_fd[1]);
- close (se_fd[1]);
+ close (so_fd[PIPE_WRITE]);
+ close (se_fd[PIPE_WRITE]);
FD_ZERO (&rset);
- FD_SET (so_fd[0], &rset);
- FD_SET (se_fd[0], &rset);
+ FD_SET (so_fd[PIPE_READ], &rset);
+ FD_SET (se_fd[PIPE_READ], &rset);
quit = 0;
while (quit < 2) {
again:
rset2 = rset;
- r = select (MAX (so_fd[0], se_fd[0]) + 1, &rset2, NULL, NULL, NULL);
+ r = select (MAX (so_fd[PIPE_READ], se_fd[PIPE_READ]) + 1, &rset2,
+ NULL, NULL, NULL);
if (r == -1) {
if (errno == EINTR)
goto again;
@@ -943,20 +948,20 @@ commandrvf (char **stdoutput, char **stderror, int flags,
*stderror = strdup ("error running external command, "
"see debug output for details");
}
- close (so_fd[0]);
- close (se_fd[0]);
+ close (so_fd[PIPE_READ]);
+ close (se_fd[PIPE_READ]);
waitpid (pid, NULL, 0);
if (stdin_pid >= 0) waitpid (stdin_pid, NULL, 0);
return -1;
}
- if (FD_ISSET (so_fd[0], &rset2)) { /* something on stdout */
- r = read (so_fd[0], buf, sizeof buf);
+ if (FD_ISSET (so_fd[PIPE_READ], &rset2)) { /* something on stdout */
+ r = read (so_fd[PIPE_READ], buf, sizeof buf);
if (r == -1) {
perror ("read");
goto quit;
}
- if (r == 0) { FD_CLR (so_fd[0], &rset); quit++; }
+ if (r == 0) { FD_CLR (so_fd[PIPE_READ], &rset); quit++; }
if (r > 0 && stdoutput) {
so_size += r;
@@ -970,17 +975,17 @@ commandrvf (char **stdoutput, char **stderror, int flags,
}
}
- if (FD_ISSET (se_fd[0], &rset2)) { /* something on stderr */
- r = read (se_fd[0], buf, sizeof buf);
+ if (FD_ISSET (se_fd[PIPE_READ], &rset2)) { /* something on stderr */
+ r = read (se_fd[PIPE_READ], buf, sizeof buf);
if (r == -1) {
perror ("read");
goto quit;
}
- if (r == 0) { FD_CLR (se_fd[0], &rset); quit++; }
+ if (r == 0) { FD_CLR (se_fd[PIPE_READ], &rset); quit++; }
if (r > 0) {
if (verbose)
- ignore_value (write (2, buf, r));
+ ignore_value (write (STDERR_FILENO, buf, r));
if (stderror) {
se_size += r;
@@ -996,8 +1001,8 @@ commandrvf (char **stdoutput, char **stderror, int flags,
}
}
- close (so_fd[0]);
- close (se_fd[0]);
+ close (so_fd[PIPE_READ]);
+ close (se_fd[PIPE_READ]);
/* Make sure the output buffers are \0-terminated. Also remove any
* trailing \n characters from the error buffer (not from stdout).
--
1.7.11.7