privsep: Close stdout/stderr after forking processes

Well, redirect them to /dev/null anyway.
Also tidy a few things in common whilst here.

diff --git a/src/common.c b/src/common.c
index eac1b256b337612d59ae3a1e2b410a9b960725a8..c4eecfee50d90cd0c86faccc741906548f7d3c8d 100644 (file)
--- a/src/common.c
+++ b/src/common.c
@@ -30,8 +30,6 @@
 
 #include <ctype.h>
 #include <errno.h>
-#include <fcntl.h>
-#include <paths.h>
 #include <stdio.h>
 #include <stdlib.h>
 
@@ -40,27 +38,6 @@
 #include "if-options.h"
 #include "logerr.h"
 
-/* Most route(4) messages are less than 256 bytes. */
-#define IOVEC_BUFSIZ   256
-
-int
-close_std(void)
-{
-       int fd, error = 0;
-
-       if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) == -1)
-               return -1;
-
-       if (dup2(fd, STDIN_FILENO) == -1)
-               error = -1;
-       if (dup2(fd, STDOUT_FILENO) == -1)
-               error = -1;
-       if (dup2(fd, STDERR_FILENO) == -1)
-               error = -1;
-       close(fd);
-       return error;
-}
-
 const char *
 hwaddr_ntoa(const void *hwaddr, size_t hwlen, char *buf, size_t buflen)
 {

diff --git a/src/common.h b/src/common.h
index 1d6f17227d98e0296168783b05125f364bb791b7..49ff36f91e50fd5794ab3693a8905320e1986592 100644 (file)
--- a/src/common.h
+++ b/src/common.h
@@ -135,11 +135,6 @@
 # endif
 #endif
 
-int close_std(void);
-void get_line_free(void);
-extern int clock_monotonic;
-int get_monotonic(struct timespec *);
-
 const char *hwaddr_ntoa(const void *, size_t, char *, size_t);
 size_t hwaddr_aton(uint8_t *, const char *);
 size_t read_hwaddr_aton(uint8_t **, const char *);

diff --git a/src/dhcpcd.c b/src/dhcpcd.c
index 31e21a5dc14529f26a3b418c4e7a251270057e17..f437977b70e5ebea8d054206908b597177ef0aed 100644 (file)
--- a/src/dhcpcd.c
+++ b/src/dhcpcd.c
@@ -41,6 +41,7 @@ const char dhcpcd_copyright[] = "Copyright (c) 2006-2020 Roy Marples";
 #include <fcntl.h>
 #include <getopt.h>
 #include <limits.h>
+#include <paths.h>
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -352,7 +353,8 @@ dhcpcd_daemonise(struct dhcpcd_ctx *ctx)
        eloop_event_delete(ctx->eloop, ctx->fork_fd);
        close(ctx->fork_fd);
        ctx->fork_fd = -1;
-       close_std();
+       freopen(_PATH_DEVNULL, "w", stdout);
+       freopen(_PATH_DEVNULL, "w", stderr);
 #endif
 }
 
@@ -611,7 +613,7 @@ configure_interface(struct interface *ifp, int argc, char **argv,
 
        /* If the mtime has changed drop any old lease */
        if (old != 0 && ifp->options->mtime != old) {
-               logwarnx("%s: confile file changed, expiring leases",
+               logwarnx("%s: config file changed, expiring leases",
                    ifp->name);
                dhcpcd_drop(ifp, 0);
        }
@@ -2009,6 +2011,7 @@ printpidfile:
 #endif
 
        logdebugx(PACKAGE "-" VERSION " starting");
+       freopen(_PATH_DEVNULL, "r", stdin);
 
 #ifdef PRIVSEP
        if (ps_init(&ctx) == -1 && errno != 0) {

diff --git a/src/privsep.c b/src/privsep.c
index 57b76b82ff6360194ae03a5ca4b178525863adbb..8fe7256a9fd2d44c42e262475ff2072e6be2f12f 100644 (file)
--- a/src/privsep.c
+++ b/src/privsep.c
@@ -47,7 +47,7 @@
 #include <pwd.h>
 #include <errno.h>
 #include <fcntl.h>
-#include <grp.h>
+#include <paths.h>
 #include <stddef.h>    /* For offsetof, struct padding debug */
 #include <signal.h>
 #include <stdlib.h>
@@ -196,10 +196,8 @@ ps_dostart(struct dhcpcd_ctx *ctx,
        if (callback(recv_ctx) == -1)
                goto errexit;
 
-#if 0
-       /* XXX Why does this cause processes to exit? */
-       close_std();
-#endif
+       freopen(_PATH_DEVNULL, "w", stdout);
+       freopen(_PATH_DEVNULL, "w", stderr);
 
        if (pw == NULL)
                return 0;
@@ -217,8 +215,8 @@ ps_dostart(struct dhcpcd_ctx *ctx,
 
 dropprivs:
        if (setgroups(1, &pw->pw_gid) == -1 ||
-            setgid(pw->pw_gid) == -1 ||
-            setuid(pw->pw_uid) == -1)
+           setgid(pw->pw_gid) == -1 ||
+           setuid(pw->pw_uid) == -1)
                logerr("failed to drop privileges");
 
        return 0;