From 5fd83771641d15c418f747bd343ba6738d3875f7 Mon Sep 17 00:00:00 2001
From: Cameron Katri <me@cameronkatri.com>
Date: Sun, 9 May 2021 14:20:58 -0400
Subject: 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
---
 system_cmds/dynamic_pager.tproj/dynamic_pager.c | 114 ++++++++++++++++++++++++
 1 file changed, 114 insertions(+)
 create mode 100644 system_cmds/dynamic_pager.tproj/dynamic_pager.c

(limited to 'system_cmds/dynamic_pager.tproj/dynamic_pager.c')

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);
+}
-- 
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