add support for zram compressed tmpfs

[project/procd.git] / initd / zram.c

diff --git a/initd/zram.c b/initd/zram.c
new file mode 100644 (file)
index 0000000..4dc1d2e
--- /dev/null
+++ b/initd/zram.c
@@ -0,0 +1,128 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <fcntl.h>
+
+#include <sys/utsname.h>
+#include <sys/mount.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/stat.h>
+
+#include "../log.h"
+
+#include "init.h"
+
+#define KB(x) (x * 1024)
+
+#define ZRAM_MOD_PATH "/lib/modules/%s/zram.ko"
+#define EXT4_MOD_PATH "/lib/modules/%s/ext4.ko"
+
+static long
+proc_meminfo(void)
+{
+       FILE *fp;
+       char line[256];
+       char *key;
+       long val = KB(16);
+
+       fp = fopen("/proc/meminfo", "r");
+       if (fp == NULL) {
+               ERROR("Can't open /proc/meminfo: %s\n", strerror(errno));
+               return errno;
+       }
+
+       while (fgets(line, sizeof(line), fp)) {
+               key = strtok(line, ":");
+               if (strcasecmp(key, "MemTotal"))
+                       continue;
+               val = atol(strtok(NULL, " kB\n"));
+               break;
+       }
+       fclose(fp);
+
+       if (val > KB(32))
+               val = KB(16);
+
+       return val;
+}
+
+static int
+early_insmod(char *module)
+{
+       pid_t pid = fork();
+
+       if (!pid) {
+               char *modprobe[] = { "/usr/sbin/modprobe", NULL, NULL };
+               char *path;
+               struct utsname ver;
+
+               uname(&ver);
+               path = alloca(sizeof(module) + strlen(ver.release) + 1);
+               sprintf(path, module, ver.release);
+               modprobe[1] = path;
+               execvp(modprobe[0], modprobe);
+               ERROR("Can't exec /usr/sbin/modprobe\n");
+               exit(-1);
+       }
+
+       if (pid <= 0) {
+               ERROR("Can't exec /usr/sbin/modprobe\n");
+               return -1;
+       } else {
+               waitpid(pid, NULL, 0);
+       }
+
+       return 0;
+}
+
+
+int
+mount_zram_on_tmp(void)
+{
+       char *mkfs[] = { "/usr/sbin/mkfs.ext4", "-b", "4096", "-F", "-L", "TEMP", "-m", "0", "/dev/zram0", NULL };
+       FILE *fp;
+       long zramsize;
+       pid_t pid;
+       int ret;
+
+       if (early_insmod(ZRAM_MOD_PATH) || early_insmod(EXT4_MOD_PATH)) {
+               ERROR("failed to insmod zram support\n");
+               return -1;
+       }
+
+       mkdev("*", 0600);
+
+       zramsize = proc_meminfo() / 2;
+       fp = fopen("/sys/block/zram0/disksize", "r+");
+       if (fp == NULL) {
+               ERROR("Can't open /sys/block/zram0/disksize: %s\n", strerror(errno));
+               return errno;
+       }
+       fprintf(fp, "%ld", KB(zramsize));
+       fclose(fp);
+
+       pid = fork();
+       if (!pid) {
+               execvp(mkfs[0], mkfs);
+               ERROR("Can't exec /sbin/mkfs.ext4\n");
+               exit(-1);
+       } else if (pid <= 0) {
+               ERROR("Can't exec /sbin/mkfs.ext4\n");
+               return -1;
+       } else {
+               waitpid(pid, NULL, 0);
+       }
+
+       ret = mount("/dev/zram0", "/tmp", "ext4", MS_NOSUID | MS_NODEV | MS_NOATIME, "errors=continue,noquota");
+       if (ret < 0) {
+               ERROR("Can't mount /dev/zram0 on /tmp: %s\n", strerror(errno));
+               return errno;
+       }
+
+       LOG("Using up to %ld kB of RAM as ZRAM storage on /mnt\n", zramsize);
+
+       return 0;
+}