Implement /proc/meminfo

mehfooz09 · Jan 6, 2019 · 900f7bf · 900f7bf
1 parent 88987ed
commit 900f7bf
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Showing 4 changed files with 75 additions and 7 deletions.
diff --git a/fs/proc/root.c b/fs/proc/root.c
@@ -1,4 +1,5 @@
 #include <sys/stat.h>
+#include <inttypes.h>
 #include "kernel/calls.h"
 #include "fs/proc.h"
 #include "platform/platform.h"
@@ -16,6 +17,30 @@ static ssize_t proc_show_stat(struct proc_entry *UNUSED(entry), char *buf) {
     return n;
 }
 
+static void show_kb(char *buf, size_t *n, const char *name, uint64_t value) {
+    *n += sprintf(buf + *n, "%s%8"PRIu64" kB\n", name, value / 1000);
+}
+
+static ssize_t proc_show_meminfo(struct proc_entry *UNUSED(entry), char *buf) {
+    struct mem_usage usage = get_mem_usage();
+    size_t n = 0;
+    show_kb(buf, &n, "MemTotal:       ", usage.total);
+    show_kb(buf, &n, "MemFree:        ", usage.free);
+    show_kb(buf, &n, "MemShared:      ", usage.free);
+    // a bunch of crap busybox top needs to see or else it gets stack garbage
+    show_kb(buf, &n, "Shmem:          ", 0);
+    show_kb(buf, &n, "Buffers:        ", 0);
+    show_kb(buf, &n, "Cached:         ", 0);
+    show_kb(buf, &n, "SwapTotal:      ", 0);
+    show_kb(buf, &n, "SwapFree:       ", 0);
+    show_kb(buf, &n, "Dirty:          ", 0);
+    show_kb(buf, &n, "Writeback:      ", 0);
+    show_kb(buf, &n, "AnonPages:      ", 0);
+    show_kb(buf, &n, "Mapped:         ", 0);
+    show_kb(buf, &n, "Slab:           ", 0);
+    return n;
+}
+
 static int proc_readlink_self(struct proc_entry *UNUSED(entry), char *buf) {
     sprintf(buf, "%d/", current->pid);
     return 0;
@@ -25,6 +50,7 @@ static int proc_readlink_self(struct proc_entry *UNUSED(entry), char *buf) {
 struct proc_dir_entry proc_root_entries[] = {
     {"version", .show = proc_show_version},
     {"stat", .show = proc_show_stat},
+    {"meminfo", .show = proc_show_meminfo},
     {"self", S_IFLNK, .readlink = proc_readlink_self},
 };
 #define PROC_ROOT_LEN sizeof(proc_root_entries)/sizeof(proc_root_entries[0])

diff --git a/platform/darwin.c b/platform/darwin.c
@@ -2,7 +2,7 @@
 #include "platform/platform.h"
 
 struct cpu_usage get_cpu_usage() {
-    struct host_cpu_load_info load;
+    host_cpu_load_info_data_t load;
     mach_msg_type_number_t fuck = HOST_CPU_LOAD_INFO_COUNT;
     host_statistics(mach_host_self(), HOST_CPU_LOAD_INFO, (host_info_t) &load, &fuck);
     struct cpu_usage usage;
@@ -12,3 +12,19 @@ struct cpu_usage get_cpu_usage() {
     usage.nice_ticks = load.cpu_ticks[CPU_STATE_NICE];
     return usage;
 }
+
+struct mem_usage get_mem_usage() {
+    host_basic_info_data_t basic;
+    mach_msg_type_number_t fuck = HOST_BASIC_INFO;
+    host_statistics(mach_host_self(), HOST_BASIC_INFO, (host_info_t) &basic, &fuck);
+    vm_statistics64_data_t vm;
+    fuck = HOST_VM_INFO64_COUNT;
+    host_statistics64(mach_host_self(), HOST_VM_INFO64, (host_info_t) &vm, &fuck);
+
+    struct mem_usage usage;
+    usage.total = basic.max_mem;
+    usage.free = vm.free_count * vm_page_size;
+    usage.active = vm.active_count * vm_page_size;
+    usage.inactive = vm.inactive_count * vm_page_size;
+    return usage;
+}
diff --git a/platform/linux.c b/platform/linux.c
@@ -1,20 +1,38 @@
+#include <inttypes.h>
 #include <stdio.h>
 #include <string.h>
 #include "platform/platform.h"
 #include "debug.h"
 
-static void read_proc_stat_line(const char *name, char *buf) {
-    FILE *proc_stat = fopen("/proc/stat", "r");
-    if (proc_stat == NULL) ERRNO_DIE("/proc/stat");
+static void read_proc_line(const char *file, const char *name, char *buf) {
+    FILE *f = fopen(file, "r");
+    if (f == NULL) ERRNO_DIE(file);
     do {
-        fgets(buf, 1234, proc_stat);
+        fgets(buf, 1234, f);
     } while (strncmp(name, buf, strlen(name)) != 0 || buf[strlen(name)] != ' ');
+    fclose(f);
 }
 
 struct cpu_usage get_cpu_usage() {
     struct cpu_usage usage = {};
     char buf[1234];
-    read_proc_stat_line("cpu", buf);
-    sscanf(buf, "cpu %llu %llu %llu %llu\n", &usage.user_ticks, &usage.system_ticks, &usage.idle_ticks, &usage.nice_ticks);
+    read_proc_line("/proc/stat", "cpu", buf);
+    sscanf(buf, "cpu %"SCNu64" %"SCNu64" %"SCNu64" %"SCNu64"\n", &usage.user_ticks, &usage.system_ticks, &usage.idle_ticks, &usage.nice_ticks);
+    return usage;
+}
+
+struct mem_usage get_mem_usage() {
+    struct mem_usage usage;
+    char buf[1234];
+
+    read_proc_line("/proc/meminfo", "MemTotal", buf);
+    sscanf(buf, "MemTotal: %"PRIu64" kB\n", &usage.total);
+    read_proc_line("/proc/meminfo", "MemFree", buf);
+    sscanf(buf, "MemFree: %"PRIu64" kB\n", &usage.free);
+    read_proc_line("/proc/meminfo", "MemActive", buf);
+    sscanf(buf, "MemActive: %"PRIu64" kB\n", &usage.active);
+    read_proc_line("/proc/meminfo", "MemInactive", buf);
+    sscanf(buf, "MemInactive: %"PRIu64" kB\n", &usage.inactive);
+
     return usage;
 }
diff --git a/platform/platform.h b/platform/platform.h
@@ -11,4 +11,12 @@ struct cpu_usage {
 };
 struct cpu_usage get_cpu_usage(void);
 
+struct mem_usage {
+    uint64_t total;
+    uint64_t free;
+    uint64_t active;
+    uint64_t inactive;
+};
+struct mem_usage get_mem_usage(void);
+
 #endif