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#define mig_external
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/sysctl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <dirent.h>
/*
* We don't exit with a non-zero status anywhere here for 2 reasons:
* - the kernel can continue to create swapfiles in "/private/var/vm/swapfile<index>"
* - we want this job to run only once at boot and exit regardless of whether:
* -- it could clean up the swap directory
* -- it could set the prefix for the swapfile name.
*/
static void
clean_swap_directory(const char *path)
{
DIR *dir;
struct dirent *entry;
char buf[1024];
dir = opendir(path);
if (dir == NULL) {
fprintf(stderr,"dynamic_pager: cannot open swap directory %s\n", path);
exit(0);
}
while ((entry = readdir(dir)) != NULL) {
if (entry->d_namlen>= 4 && strncmp(entry->d_name, "swap", 4) == 0) {
snprintf(buf, sizeof buf, "%s/%s", path, entry->d_name);
unlink(buf);
}
}
closedir(dir);
}
int
main(int argc, char **argv)
{
int ch;
static char tmp[1024];
struct statfs sfs;
char *q;
char fileroot[512];
seteuid(getuid());
fileroot[0] = '\0';
while ((ch = getopt(argc, argv, "F:")) != EOF) {
switch((char)ch) {
case 'F':
strncpy(fileroot, optarg, 500);
break;
default:
(void)fprintf(stderr,
"usage: dynamic_pager [-F filename]\n");
exit(0);
}
}
/*
* set vm.swapfileprefix if a fileroot was passed from the command
* line, otherwise get the value from the kernel
*/
if (fileroot[0] != '\0') {
if (sysctlbyname("vm.swapfileprefix", NULL, 0, fileroot, sizeof(fileroot)) == -1) {
perror("Failed to set swapfile name prefix");
}
} else {
size_t fileroot_len = sizeof(fileroot);
if (sysctlbyname("vm.swapfileprefix", fileroot, &fileroot_len, NULL, 0) == -1) {
perror("Failed to get swapfile name prefix");
/*
* can't continue without a fileroot
*/
return (0);
}
}
/*
* get rid of the filename at the end of the swap file specification
* we only want the portion of the pathname that should already exist
*/
strcpy(tmp, fileroot);
if ((q = strrchr(tmp, '/')))
*q = 0;
/*
* Remove all files in the swap directory.
*/
clean_swap_directory(tmp);
if (statfs(tmp, &sfs) == -1) {
/*
* Setup the swap directory.
*/
if (mkdir(tmp, 0755) == -1) {
(void)fprintf(stderr, "dynamic_pager: cannot create swap directory %s\n", tmp);
}
}
chown(tmp, 0, 0);
return (0);
}
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