cutils: sched_policy: Make getSchedulerGroup() play nicely with multiple control groups
Signed-off-by: San Mehat <san@google.com>
diff --git a/libcutils/sched_policy.c b/libcutils/sched_policy.c
index 8134aa1..2333762 100644
--- a/libcutils/sched_policy.c
+++ b/libcutils/sched_policy.c
@@ -90,8 +90,9 @@
/*
* Try to get the scheduler group.
*
- * The data from /proc/<pid>/cgroup looks like:
+ * The data from /proc/<pid>/cgroup looks (something) like:
* 2:cpu:/bg_non_interactive
+ * 1:cpuacct:/
*
* We return the part after the "/", which will be an empty string for
* the default cgroup. If the string is longer than "bufLen", the string
@@ -101,34 +102,57 @@
{
#ifdef HAVE_ANDROID_OS
char pathBuf[32];
- char readBuf[256];
- ssize_t count;
- int fd;
+ char lineBuf[256];
+ FILE *fp;
snprintf(pathBuf, sizeof(pathBuf), "/proc/%d/cgroup", tid);
- if ((fd = open(pathBuf, O_RDONLY)) < 0) {
+ if (!(fp = fopen(pathBuf, "r"))) {
return -1;
}
- count = read(fd, readBuf, sizeof(readBuf));
- if (count <= 0) {
- close(fd);
- errno = ENODATA;
- return -1;
- }
- close(fd);
+ while(fgets(lineBuf, sizeof(lineBuf) -1, fp)) {
+ char *next = lineBuf;
+ char *subsys;
+ char *grp;
+ size_t len;
- readBuf[--count] = '\0'; /* remove the '\n', now count==strlen */
+ /* Junk the first field */
+ if (!strsep(&next, ":")) {
+ goto out_bad_data;
+ }
- char* cp = strchr(readBuf, '/');
- if (cp == NULL) {
- readBuf[sizeof(readBuf)-1] = '\0';
- errno = ENODATA;
- return -1;
+ if (!(subsys = strsep(&next, ":"))) {
+ goto out_bad_data;
+ }
+
+ if (strcmp(subsys, "cpu")) {
+ /* Not the subsys we're looking for */
+ continue;
+ }
+
+ if (!(grp = strsep(&next, ":"))) {
+ goto out_bad_data;
+ }
+ grp++; /* Drop the leading '/' */
+ len = strlen(grp);
+ grp[len-1] = '\0'; /* Drop the trailing '\n' */
+
+ if (bufLen <= len) {
+ len = bufLen - 1;
+ }
+ strncpy(buf, grp, len);
+ buf[len] = '\0';
+ fclose(fp);
+ return 0;
}
- memcpy(buf, cp+1, count); /* count-1 for cp+1, count+1 for NUL */
- return 0;
+ LOGE("Failed to find cpu subsys");
+ fclose(fp);
+ return -1;
+ out_bad_data:
+ LOGE("Bad cgroup data {%s}", lineBuf);
+ fclose(fp);
+ return -1;
#else
errno = ENOSYS;
return -1;