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-rw-r--r--applypatch/freecache.c172
1 files changed, 172 insertions, 0 deletions
diff --git a/applypatch/freecache.c b/applypatch/freecache.c
new file mode 100644
index 000000000..9827fda06
--- /dev/null
+++ b/applypatch/freecache.c
@@ -0,0 +1,172 @@
+#include <errno.h>
+#include <libgen.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/statfs.h>
+#include <unistd.h>
+#include <dirent.h>
+#include <ctype.h>
+
+#include "applypatch.h"
+
+static int EliminateOpenFiles(char** files, int file_count) {
+ DIR* d;
+ struct dirent* de;
+ d = opendir("/proc");
+ if (d == NULL) {
+ printf("error opening /proc: %s\n", strerror(errno));
+ return -1;
+ }
+ while ((de = readdir(d)) != 0) {
+ int i;
+ for (i = 0; de->d_name[i] != '\0' && isdigit(de->d_name[i]); ++i);
+ if (de->d_name[i]) continue;
+
+ // de->d_name[i] is numeric
+
+ char path[FILENAME_MAX];
+ strcpy(path, "/proc/");
+ strcat(path, de->d_name);
+ strcat(path, "/fd/");
+
+ DIR* fdd;
+ struct dirent* fdde;
+ fdd = opendir(path);
+ if (fdd == NULL) {
+ printf("error opening %s: %s\n", path, strerror(errno));
+ continue;
+ }
+ while ((fdde = readdir(fdd)) != 0) {
+ char fd_path[FILENAME_MAX];
+ char link[FILENAME_MAX];
+ strcpy(fd_path, path);
+ strcat(fd_path, fdde->d_name);
+
+ int count;
+ count = readlink(fd_path, link, sizeof(link)-1);
+ if (count >= 0) {
+ link[count] = '\0';
+
+ // This is inefficient, but it should only matter if there are
+ // lots of files in /cache, and lots of them are open (neither
+ // of which should be true, especially in recovery).
+ if (strncmp(link, "/cache/", 7) == 0) {
+ int j;
+ for (j = 0; j < file_count; ++j) {
+ if (files[j] && strcmp(files[j], link) == 0) {
+ printf("%s is open by %s\n", link, de->d_name);
+ free(files[j]);
+ files[j] = NULL;
+ }
+ }
+ }
+ }
+ }
+ closedir(fdd);
+ }
+ closedir(d);
+
+ return 0;
+}
+
+int FindExpendableFiles(char*** names, int* entries) {
+ DIR* d;
+ struct dirent* de;
+ int size = 32;
+ *entries = 0;
+ *names = malloc(size * sizeof(char*));
+
+ char path[FILENAME_MAX];
+
+ // We're allowed to delete unopened regular files in any of these
+ // directories.
+ const char* dirs[2] = {"/cache", "/cache/recovery/otatest"};
+
+ unsigned int i;
+ for (i = 0; i < sizeof(dirs)/sizeof(dirs[0]); ++i) {
+ d = opendir(dirs[i]);
+ if (d == NULL) {
+ printf("error opening %s: %s\n", dirs[i], strerror(errno));
+ continue;
+ }
+
+ // Look for regular files in the directory (not in any subdirectories).
+ while ((de = readdir(d)) != 0) {
+ strcpy(path, dirs[i]);
+ strcat(path, "/");
+ strcat(path, de->d_name);
+
+ // We can't delete CACHE_TEMP_SOURCE; if it's there we might have
+ // restarted during installation and could be depending on it to
+ // be there.
+ if (strcmp(path, CACHE_TEMP_SOURCE) == 0) continue;
+
+ struct stat st;
+ if (stat(path, &st) == 0 && S_ISREG(st.st_mode)) {
+ if (*entries >= size) {
+ size *= 2;
+ *names = realloc(*names, size * sizeof(char*));
+ }
+ (*names)[(*entries)++] = strdup(path);
+ }
+ }
+
+ closedir(d);
+ }
+
+ printf("%d regular files in deletable directories\n", *entries);
+
+ if (EliminateOpenFiles(*names, *entries) < 0) {
+ return -1;
+ }
+
+ return 0;
+}
+
+int MakeFreeSpaceOnCache(size_t bytes_needed) {
+ size_t free_now = FreeSpaceForFile("/cache");
+ printf("%ld bytes free on /cache (%ld needed)\n",
+ (long)free_now, (long)bytes_needed);
+
+ if (free_now >= bytes_needed) {
+ return 0;
+ }
+
+ char** names;
+ int entries;
+
+ if (FindExpendableFiles(&names, &entries) < 0) {
+ return -1;
+ }
+
+ if (entries == 0) {
+ // nothing we can delete to free up space!
+ printf("no files can be deleted to free space on /cache\n");
+ return -1;
+ }
+
+ // We could try to be smarter about which files to delete: the
+ // biggest ones? the smallest ones that will free up enough space?
+ // the oldest? the newest?
+ //
+ // Instead, we'll be dumb.
+
+ int i;
+ for (i = 0; i < entries && free_now < bytes_needed; ++i) {
+ if (names[i]) {
+ unlink(names[i]);
+ free_now = FreeSpaceForFile("/cache");
+ printf("deleted %s; now %ld bytes free\n", names[i], (long)free_now);
+ free(names[i]);
+ }
+ }
+
+ for (; i < entries; ++i) {
+ free(names[i]);
+ }
+ free(names);
+
+ return (free_now >= bytes_needed) ? 0 : -1;
+}