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authorCameron Katri <me@cameronkatri.com>2021-05-09 14:20:58 -0400
committerCameron Katri <me@cameronkatri.com>2021-05-09 14:20:58 -0400
commit5fd83771641d15c418f747bd343ba6738d3875f7 (patch)
tree5abf0f78f680d9837dbd93d4d4c3933bb7509599 /system_cmds/dynamic_pager.tproj/dynamic_pager.c
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Import macOS userland
adv_cmds-176 basic_cmds-55 bootstrap_cmds-116.100.1 developer_cmds-66 diskdev_cmds-667.40.1 doc_cmds-53.60.1 file_cmds-321.40.3 mail_cmds-35 misc_cmds-34 network_cmds-606.40.1 patch_cmds-17 remote_cmds-63 shell_cmds-216.60.1 system_cmds-880.60.2 text_cmds-106
Diffstat (limited to 'system_cmds/dynamic_pager.tproj/dynamic_pager.c')
-rw-r--r--system_cmds/dynamic_pager.tproj/dynamic_pager.c114
1 files changed, 114 insertions, 0 deletions
diff --git a/system_cmds/dynamic_pager.tproj/dynamic_pager.c b/system_cmds/dynamic_pager.tproj/dynamic_pager.c
new file mode 100644
index 0000000..deb9379
--- /dev/null
+++ b/system_cmds/dynamic_pager.tproj/dynamic_pager.c
@@ -0,0 +1,114 @@
+#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);
+}