From 46086941cdaf6614fd47e033e35950210ea9be8a Mon Sep 17 00:00:00 2001
From: Mikhail Osipov <mike.osipov@gmail.com>
Date: Mon, 13 May 2019 16:50:38 +0300
Subject: print top memory usage

---
 TODO   |   2 +-
 main.c | 194 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 194 insertions(+), 2 deletions(-)

diff --git a/TODO b/TODO
index de7d302..9f395a7 100644
--- a/TODO
+++ b/TODO
@@ -1 +1 @@
-1. print top of memory consumers
+1. print top of memory consumers (DONE)
diff --git a/main.c b/main.c
index 39927f1..2bd6347 100644
--- a/main.c
+++ b/main.c
@@ -2,16 +2,49 @@
 #include <sys/sysinfo.h>
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <stdbool.h>
+#include <dirent.h>
 #include <unistd.h>
 #include <stdlib.h>
 #include <string.h>
 #include <assert.h>
+#include <ctype.h>
 #include <stdio.h>
 #include <err.h>
 
+#define TOPMEMCOUNT 8
+#define TOOLFONT "xos4 Terminus"
+
+struct proc_entry {
+	char *name;
+	int rss;
+};
+
 static char SYSPATH[] = "/sys/class/power_supply/BAT0/";
 static char charging[] = "↯";
 
+static struct proc_entry *proc_entry_new(const char *name)
+{
+	struct proc_entry *e = calloc(1, sizeof(*e));
+
+	e->name = strdup(name);
+
+	return e;
+}
+
+static void proc_entry_free(struct proc_entry *e)
+{
+	free(e->name);
+	free(e);
+}
+
+static int proc_entry_cmp(const void *a, const void *b)
+{
+#define PROC_ENTRY_CAST(pp) (*(struct proc_entry **) (pp))
+	return PROC_ENTRY_CAST(b)->rss - PROC_ENTRY_CAST(a)->rss;
+#undef PROC_ENTRY_CAST
+}
+
 static char *readline(char *dir, char *file)
 {
 	static char 	*line = NULL;
@@ -81,13 +114,166 @@ static void print_battery_status(void)
 	readline(NULL, NULL);
 }
 
+static bool is_proc_entry(struct dirent *de)
+{
+	if (de->d_type != DT_DIR)
+		return false;
+
+	for (int n = 0; de->d_name[n] != '\0'; n++) {
+		if (!isdigit(de->d_name[n]))
+			return false;
+	}
+
+	return true;
+}
+
+static char *get_proc_name(const char *pid)
+{
+	static char name[PATH_MAX];
+
+	char path[PATH_MAX];
+	ssize_t n;
+
+	snprintf(path, sizeof(path), "/proc/%s/exe", pid);
+
+	if ((n = readlink(path, name, sizeof(name) - 1)) <= 0)
+		return NULL;
+
+	name[n] = '\0';
+
+	return name;
+}
+
+static int get_proc_rss(const char *pid)
+{
+	char path[PATH_MAX];
+	FILE *fp;
+	int rss = -1;
+
+	char *buf = NULL;
+	size_t buflen = 0;
+
+	snprintf(path, sizeof(path), "/proc/%s/status", pid);
+
+	fp = fopen(path, "r");
+	if (!fp)
+		return -1;
+
+	while (getline(&buf, &buflen, fp) > 0) {
+		int val;
+
+		if (sscanf(buf, "VmRSS: %d kB", &val) == 1) {
+			rss = val;
+			break;
+		}
+	}
+
+	fclose(fp);
+	free(buf);
+
+	return rss;
+}
+
+static int proc_entries_print(struct proc_entry **ee, int nelem, int upto, int width)
+{
+	int maxwidth = 0;
+	char buf[512];
+
+	if (upto > nelem)
+		upto = nelem;
+
+	for (int n = 0; n < upto; n++) {
+		struct proc_entry *e = ee[n];
+		char *s = strrchr(e->name, '/');
+
+		if (s)
+			s++;
+		else
+			s = e->name;
+
+		snprintf(buf, sizeof(buf), "%s %d MB", s, e->rss);
+		int len = strlen(buf);
+
+		if (maxwidth < len)
+			maxwidth = len;
+
+		if (width) {
+			if (n)
+				printf("\n");
+
+			printf("%s%*s %d MB", s, width - len, "", e->rss);
+		}
+	}
+
+	if (!width)
+		proc_entries_print(ee, nelem, upto, maxwidth);
+
+	return maxwidth;
+}
+
+static void print_top_memory_usage(void)
+{
+	DIR *dir = opendir("/proc");
+	struct dirent *de;
+
+	struct proc_entry **entries = NULL;
+	int nentry = 0;
+
+	while ((de = readdir(dir)) != NULL) {
+		const char *pid = de->d_name;
+
+		if (!is_proc_entry(de))
+			continue;
+
+		const char *procname = get_proc_name(pid);
+		if (!procname)
+			continue;
+
+		int rss = get_proc_rss(pid);
+		if (rss < 0)
+			continue;
+
+		struct proc_entry *e = NULL;
+
+		for (int n = 0; n < nentry; n++) {
+			if (!strcmp(entries[n]->name, procname)) {
+				e = entries[n];
+				break;
+			}
+		}
+
+		if (!e) {
+			e = proc_entry_new(procname);
+			entries = realloc(entries, sizeof(*entries) * (nentry + 1));
+			entries[nentry++] = e;
+		}
+
+		e->rss += rss;
+	}
+
+	qsort(entries, nentry, sizeof(*entries), proc_entry_cmp);
+
+	proc_entries_print(entries, nentry, TOPMEMCOUNT, 0);
+
+	for (int n = 0; n < nentry; n++)
+		proc_entry_free(entries[n]);
+
+	free(entries);
+
+	closedir(dir);
+}
+
 int main(int argc, char *argv[])
 {
 	struct sysinfo si;
 
+	setuid(0);
+
 	if (sysinfo(&si) < 0)
 		return 1;
 
+	printf("<txt>");
+
 	printf("used: %ld", (si.totalram - si.freeram) * si.mem_unit >> 20);
 	printf(", free: %ld", si.freeram * si.mem_unit >> 20);
 #if 0
@@ -97,7 +283,13 @@ int main(int argc, char *argv[])
 
 	print_battery_status();
 
-	printf("\n");
+	printf("</txt>\n");
+
+	printf("<tool><span font_family=\"" TOOLFONT "\">");
+
+	print_top_memory_usage();
+
+	printf("</span></tool>\n");
 
 	return 0;
 }
-- 
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