swaponoff: add support for -e

Signed-off-by: René Rhéaume <rene.rheaume@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/util-linux/swaponoff.c b/util-linux/swaponoff.c
index 75487267ba8d2a99266361097b73762699c46a5c..5cd1fbe703cabe0da23af2d2ae8e9738acb32c5a 100644 (file)
--- a/util-linux/swaponoff.c
+++ b/util-linux/swaponoff.c
@@ -8,7 +8,7 @@
  */
 
 //usage:#define swapon_trivial_usage
-//usage:       "[-a]" IF_FEATURE_SWAPON_DISCARD(" [-d[POL]]") IF_FEATURE_SWAPON_PRI(" [-p PRI]") " [DEVICE]"
+//usage:       "[-a] [-e]" IF_FEATURE_SWAPON_DISCARD(" [-d[POL]]") IF_FEATURE_SWAPON_PRI(" [-p PRI]") " [DEVICE]"
 //usage:#define swapon_full_usage "\n\n"
 //usage:       "Start swapping on DEVICE\n"
 //usage:     "\n       -a      Start swapping on all swap devices"
@@ -16,15 +16,17 @@
 //usage:     "\n       -d[POL] Discard blocks at swapon (POL=once),"
 //usage:     "\n               as freed (POL=pages), or both (POL omitted)"
 //usage:       )
+//usage:     "\n       -e      Silently skip devices that do not exist"
 //usage:       IF_FEATURE_SWAPON_PRI(
 //usage:     "\n       -p PRI  Set swap device priority"
 //usage:       )
 //usage:
 //usage:#define swapoff_trivial_usage
-//usage:       "[-a] [DEVICE]"
+//usage:       "[-a] [-e] [DEVICE]"
 //usage:#define swapoff_full_usage "\n\n"
 //usage:       "Stop swapping on DEVICE\n"
 //usage:     "\n       -a      Stop swapping on all swap devices"
+//usage:     "\n       -e      Silently skip devices that do not exist"
 
 #include "libbb.h"
 #include <mntent.h>
@@ -77,15 +79,18 @@ struct globals {
 /* Command line options */
 enum {
        OPTBIT_a,                              /* -a all      */
+       OPTBIT_e,                              /* -e ifexists */
        IF_FEATURE_SWAPON_DISCARD( OPTBIT_d ,) /* -d discard  */
        IF_FEATURE_SWAPON_PRI    ( OPTBIT_p ,) /* -p priority */
        OPT_a = 1 << OPTBIT_a,
+       OPT_e = 1 << OPTBIT_e,
        OPT_d = IF_FEATURE_SWAPON_DISCARD((1 << OPTBIT_d)) + 0,
        OPT_p = IF_FEATURE_SWAPON_PRI    ((1 << OPTBIT_p)) + 0,
 };
 
 #define OPT_ALL      (option_mask32 & OPT_a)
 #define OPT_DISCARD  (option_mask32 & OPT_d)
+#define OPT_IFEXISTS (option_mask32 & OPT_e)
 #define OPT_PRIO     (option_mask32 & OPT_p)
 
 static int swap_enable_disable(char *device)
@@ -95,6 +100,8 @@ static int swap_enable_disable(char *device)
        struct stat st;
 
        resolve_mount_spec(&device);
+       if (!OPT_IFEXISTS)
+               xstat(device, &st);
 
        if (do_swapoff) {
                err = swapoff(device);
@@ -112,7 +119,8 @@ static int swap_enable_disable(char *device)
                        }
                        err = swapon(device, g_flags);
                        /* Don't complain on swapon -a if device is already in use */
-                       quiet = (OPT_ALL && errno == EBUSY);
+                       /* Don't complain if file does not exist with -e option */
+                       quiet = (OPT_ALL && errno == EBUSY) || (OPT_IFEXISTS && errno == ENOENT);
                }
        }
 
@@ -229,7 +237,7 @@ static int do_all_in_proc_swaps(void)
        return err;
 }
 
-#define OPTSTR_SWAPON "a" \
+#define OPTSTR_SWAPON "ae" \
        IF_FEATURE_SWAPON_DISCARD("d::") \
        IF_FEATURE_SWAPON_PRI("p:")
 
@@ -242,7 +250,7 @@ int swap_on_off_main(int argc UNUSED_PARAM, char **argv)
 
        INIT_G();
 
-       getopt32(argv, do_swapoff ? "a" : OPTSTR_SWAPON
+       getopt32(argv, do_swapoff ? "ae" : OPTSTR_SWAPON
                        IF_FEATURE_SWAPON_DISCARD(, &discard)
                        IF_FEATURE_SWAPON_PRI(, &prio)
        );