68e9b6bc94
Internally, replace the watchlist array with a hashmap since the array
assumes properties are enumerated in a consistent order and foreach()
probably won't. (find_nth() never guaranteed this either but it usually
worked in practice.)
Signed-off-by: Greg Hackmann <ghackmann@google.com>
(cherry picked from commit 389e358017)
Change-Id: I1db3137b130474f4bb205f01f0bdcf37cf974764
95 lines
2.1 KiB
C
95 lines
2.1 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <time.h>
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#include <errno.h>
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#include <cutils/properties.h>
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#include <cutils/hashmap.h>
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#include <sys/atomics.h>
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#define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
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#include <sys/_system_properties.h>
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static int str_hash(void *key)
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{
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return hashmapHash(key, strlen(key));
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}
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static bool str_equals(void *keyA, void *keyB)
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{
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return strcmp(keyA, keyB) == 0;
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}
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static void announce(char *name, char *value)
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{
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char *x;
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for(x = value; *x; x++) {
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if((*x < 32) || (*x > 127)) *x = '.';
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}
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fprintf(stderr,"%10d %s = '%s'\n", (int) time(0), name, value);
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}
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static void add_to_watchlist(Hashmap *watchlist, const char *name,
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const prop_info *pi)
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{
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char *key = strdup(name);
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unsigned *value = malloc(sizeof(unsigned));
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if (!key || !value)
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exit(1);
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*value = __system_property_serial(pi);
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hashmapPut(watchlist, key, value);
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}
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static void populate_watchlist(const prop_info *pi, void *cookie)
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{
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Hashmap *watchlist = cookie;
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char name[PROP_NAME_MAX];
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char value_unused[PROP_VALUE_MAX];
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__system_property_read(pi, name, value_unused);
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add_to_watchlist(watchlist, name, pi);
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}
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static void update_watchlist(const prop_info *pi, void *cookie)
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{
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Hashmap *watchlist = cookie;
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char name[PROP_NAME_MAX];
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char value[PROP_VALUE_MAX];
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unsigned *serial;
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__system_property_read(pi, name, value);
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serial = hashmapGet(watchlist, name);
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if (!serial) {
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add_to_watchlist(watchlist, name, pi);
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announce(name, value);
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} else {
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unsigned tmp = __system_property_serial(pi);
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if (*serial != tmp) {
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*serial = tmp;
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announce(name, value);
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}
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}
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}
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int watchprops_main(int argc, char *argv[])
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{
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unsigned serial = 0;
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unsigned count = 0;
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unsigned n;
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Hashmap *watchlist = hashmapCreate(1024, str_hash, str_equals);
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if (!watchlist)
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exit(1);
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__system_property_foreach(populate_watchlist, watchlist);
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for(;;) {
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serial = __system_property_wait_any(serial);
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__system_property_foreach(update_watchlist, watchlist);
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}
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return 0;
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}
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