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authorAlexander Clouter <[email protected]>2018-09-27 20:33:16 +0100
committerAlexander Clouter <[email protected]>2018-09-29 00:11:10 +0100
commitf2ca9d9cb14527fb5dd3016cbccd45355cc2a6c7 (patch)
tree885e38d07dd4849dc472a99ba4af802e925a4358 /lib/os_mon/c_src
parentf29c1d4bc5ac7cb578206a1193867c9037741bd3 (diff)
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Make Erlang's cpu_sup function better on Android
Due to `/proc` restrictions in newer Android releases enforced by SELinux, Erlang needs a fix so that it can get some basic CPU stats (use the `sysinfo` syscall rather than reading `/proc/loadavg`).
Diffstat (limited to 'lib/os_mon/c_src')
-rw-r--r--lib/os_mon/c_src/cpu_sup.c50
1 files changed, 44 insertions, 6 deletions
diff --git a/lib/os_mon/c_src/cpu_sup.c b/lib/os_mon/c_src/cpu_sup.c
index 17ef48c26e..c96a5c9f7c 100644
--- a/lib/os_mon/c_src/cpu_sup.c
+++ b/lib/os_mon/c_src/cpu_sup.c
@@ -152,6 +152,8 @@ static void util_measure(unsigned int **result_vec, int *result_sz);
#if defined(__sun__)
static unsigned int misc_measure(char* name);
+#elif defined(__linux__)
+static unsigned int misc_measure(char cmd);
#endif
static void sendi(unsigned int data);
static void sendv(unsigned int data[], int ints);
@@ -231,6 +233,11 @@ int main(int argc, char** argv) {
case AVG1: sendi(misc_measure("avenrun_1min")); break;
case AVG5: sendi(misc_measure("avenrun_5min")); break;
case AVG15: sendi(misc_measure("avenrun_15min")); break;
+#elif defined(__linux__)
+ case NPROCS:
+ case AVG1:
+ case AVG5:
+ case AVG15: sendi(misc_measure(cmd)); break;
#elif defined(__OpenBSD__) || (defined(__APPLE__) && defined(__MACH__)) || defined(__FreeBSD__) || defined(__DragonFly__)
case NPROCS: bsd_count_procs(); break;
case AVG1: bsd_loadavg(0); break;
@@ -238,7 +245,7 @@ int main(int argc, char** argv) {
case AVG15: bsd_loadavg(2); break;
#endif
#if defined(__sun__) || defined(__linux__) || (defined(__APPLE__) && defined(__MACH__)) || defined(__FreeBSD__)
- case UTIL: util_measure(&rv,&sz); sendv(rv, sz); break;
+ case UTIL: util_measure(&rv,&sz); sendv(rv, sz); break;
#endif
case QUIT: free((void*)rv); return 0;
default: error("Bad command"); break;
@@ -329,6 +336,22 @@ static void bsd_count_procs(void) {
#if defined(__linux__)
+static unsigned int misc_measure(char cmd) {
+ struct sysinfo info;
+
+ if (sysinfo(&info))
+ error(strerror(errno));
+
+ switch (cmd) {
+ case AVG1: return (unsigned int)(info.loads[0] / 256);
+ case AVG5: return (unsigned int)(info.loads[1] / 256);
+ case AVG15: return (unsigned int)(info.loads[2] / 256);
+ case NPROCS: return info.procs;
+ }
+
+ return -1;
+}
+
static cpu_t *read_procstat(FILE *fp, cpu_t *cpu) {
char buffer[BUFFERSIZE];
@@ -357,8 +380,24 @@ static void util_measure(unsigned int **result_vec, int *result_sz) {
FILE *fp;
unsigned int *rv = NULL;
cpu_t cpu;
-
+
+ rv = *result_vec;
+ rv[0] = no_of_cpus;
+
if ( (fp = fopen(PROCSTAT,"r")) == NULL) {
+ if (errno == EACCES) { /* SELinux */
+ rv[1] = 1; /* just the cpu id */
+ ++rv; /* first value is number of cpus */
+ ++rv; /* second value is number of entries */
+ for (i = 0; i < no_of_cpus; ++i) {
+ rv[0] = CU_CPU_ID;
+ rv[1] = i;
+ rv += 1*2;
+ }
+ *result_sz = 2 + 2*1 * no_of_cpus;
+ return;
+ }
+
/* Check if procfs is mounted,
* otherwise:
* try and try again, bad procsfs.
@@ -367,20 +406,19 @@ static void util_measure(unsigned int **result_vec, int *result_sz) {
return;
}
- /*ignore read*/
+ /*ignore read*/
if (fgets(buffer, BUFFERSIZE, fp) == NULL) {
*result_sz = 0;
return;
}
- rv = *result_vec;
- rv[0] = no_of_cpus;
+
rv[1] = CU_VALUES;
++rv; /* first value is number of cpus */
++rv; /* second value is number of entries */
for (i = 0; i < no_of_cpus; ++i) {
read_procstat(fp, &cpu);
-
+
rv[ 0] = CU_CPU_ID; rv[ 1] = cpu.id;
rv[ 2] = CU_USER; rv[ 3] = cpu.user;
rv[ 4] = CU_NICE_USER; rv[ 5] = cpu.nice_user;