diff options
Diffstat (limited to 'system_cmds/dynamic_pager.tproj/dynamic_pager.c')
-rw-r--r-- | system_cmds/dynamic_pager.tproj/dynamic_pager.c | 114 |
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); +} |