support specifying swap priority from the command line

Signed-off-by: Nathan Hintz <nlhintz@hotmail.com>

diff --git a/block.c b/block.c
index 2289b779a7a485642789cfc303091ee19a0f4b7a..941e4b825944aec08ff2667b9937cf1c48b5a7f4 100644 (file)
--- a/block.c
+++ b/block.c
@@ -13,6 +13,7 @@
  */
 
 #define _GNU_SOURCE
+#include <getopt.h>
 #include <stdio.h>
 #include <unistd.h>
 #include <syslog.h>
@@ -1036,50 +1037,75 @@ static int main_info(int argc, char **argv)
        return 0;
 }
 
+static int swapon_usage(void)
+{
+       fprintf(stderr, "Usage: swapon [-s] [-a] [[-p pri] DEVICE]\n\n"
+               "\tStart swapping on [DEVICE]\n"
+               " -a\tStart swapping on all swap devices\n"
+               " -p pri\tSet priority of swap device\n"
+               " -s\tShow summary\n");
+       return -1;
+}
+
 static int main_swapon(int argc, char **argv)
 {
-       if (argc != 2) {
-               fprintf(stderr, "Usage: swapon <-s> <-a> [DEVICE]\n\n\tStart swapping on [DEVICE]\n -a\tStart swapping on all swap devices\n -s\tShow summary\n");
-               return -1;
-       }
+       int ch;
+       FILE *fp;
+       char *lineptr;
+       size_t s;
+       struct blkid_struct_probe *pr;
+       int flags = 0;
+       int pri;
+       struct stat st;
+       int err;
 
-       if (!strcmp(argv[1], "-s")) {
-               FILE *fp = fopen("/proc/swaps", "r");
-               char *lineptr = NULL;
-               size_t s;
+       while ((ch = getopt(argc, argv, "ap:s")) != -1) {
+               switch(ch) {
+               case 's':
+                       fp = fopen("/proc/swaps", "r");
+                       lineptr = NULL;
 
-               if (!fp) {
-                       fprintf(stderr, "failed to open /proc/swaps\n");
-                       return -1;
+                       if (!fp) {
+                               fprintf(stderr, "failed to open /proc/swaps\n");
+                               return -1;
+                       }
+                       while (getline(&lineptr, &s, fp) > 0)
+                               printf(lineptr);
+                       if (lineptr)
+                               free(lineptr);
+                       fclose(fp);
+                       return 0;
+               case 'a':
+                       cache_load(0);
+                       list_for_each_entry(pr, &devices, list) {
+                               if (strcmp(pr->id->name, "swap"))
+                                       continue;
+                               if (swapon(pr->dev, 0))
+                                       fprintf(stderr, "failed to swapon %s\n", pr->dev);
+                       }
+                       return 0;
+               case 'p':
+                       pri = atoi(optarg);
+                       if (pri >= 0)
+                               flags = ((pri << SWAP_FLAG_PRIO_SHIFT) & SWAP_FLAG_PRIO_MASK) | SWAP_FLAG_PREFER;
+                       break;
+               default:
+                       return swapon_usage();
                }
-               while (getline(&lineptr, &s, fp) > 0)
-                       printf(lineptr);
-               if (lineptr)
-                       free(lineptr);
-               fclose(fp);
-       } else if (!strcmp(argv[1], "-a")) {
-               struct blkid_struct_probe *pr;
 
-               cache_load(0);
-               list_for_each_entry(pr, &devices, list) {
-                       if (strcmp(pr->id->name, "swap"))
-                               continue;
-                       if (swapon(pr->dev, 0))
-                               fprintf(stderr, "failed to swapon %s\n", pr->dev);
-               }
-       } else {
-               struct stat s;
-               int err;
+       }
 
-               if (stat(argv[1], &s) || (!S_ISBLK(s.st_mode) && !S_ISREG(s.st_mode))) {
-                       fprintf(stderr, "%s is not a block device or file\n", argv[1]);
-                       return -1;
-               }
-               err = swapon(argv[1], 0);
-               if (err) {
-                       fprintf(stderr, "failed to swapon %s (%d)\n", argv[1], err);
-                       return err;
-               }
+       if (optind != (argc - 1))
+               return swapon_usage();
+
+       if (stat(argv[optind], &st) || (!S_ISBLK(st.st_mode) && !S_ISREG(st.st_mode))) {
+               fprintf(stderr, "%s is not a block device or file\n", argv[optind]);
+               return -1;
+       }
+       err = swapon(argv[optind], flags);
+       if (err) {
+               fprintf(stderr, "failed to swapon %s (%d)\n", argv[optind], err);
+               return err;
        }
 
        return 0;
@@ -1088,7 +1114,9 @@ static int main_swapon(int argc, char **argv)
 static int main_swapoff(int argc, char **argv)
 {
        if (argc != 2) {
-               fprintf(stderr, "Usage: swapoff [-a] [DEVICE]\n\n\tStop swapping on DEVICE\n -a\tStop swapping on all swap devices\n");
+               fprintf(stderr, "Usage: swapoff [-a] [DEVICE]\n\n"
+                       "\tStop swapping on DEVICE\n"
+                       " -a\tStop swapping on all swap devices\n");
                return -1;
        }