From 72b63109b2e695d0c0d47c280298df2871d2b42d Mon Sep 17 00:00:00 2001
From: Kevin Lange <kevin.lange@dakko.us>
Date: Thu, 5 Jun 2014 23:41:33 -0700
Subject: [PATCH] Add a simple pstree [not fancy yet]

---
 userspace/core/pstree.c | 122 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 122 insertions(+)
 create mode 100644 userspace/core/pstree.c

diff --git a/userspace/core/pstree.c b/userspace/core/pstree.c
new file mode 100644
index 00000000..b24352bc
--- /dev/null
+++ b/userspace/core/pstree.c
@@ -0,0 +1,122 @@
+/*
+ * pstree
+ *
+ * Prints running processes as a tree of 
+ */
+
+
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <syscall.h>
+#include <unistd.h>
+#include <dirent.h>
+
+#include "lib/list.h"
+#include "lib/tree.h"
+
+typedef struct process {
+	int pid;
+	int ppid;
+	char name[100];
+} p_t;
+
+#define LINE_LEN 4096
+
+p_t * build_entry(struct dirent * dent) {
+	char tmp[256], buf[4096];
+	FILE * f;
+	int read = 1;
+	char line[LINE_LEN];
+
+	int pid, uid;
+
+	snprintf(tmp, 256, "/proc/%s/status", dent->d_name);
+	f = fopen(tmp, "r");
+
+	p_t * proc = malloc(sizeof(p_t));
+
+	while (fgets(line, LINE_LEN, f) != NULL) {
+		if (strstr(line, "Pid:") == line) {
+			sscanf(line, "%s %d", &buf, &proc->pid);
+		} else if (strstr(line, "PPid:") == line) {
+			sscanf(line, "%s %d", &buf, &proc->ppid);
+		} else if (strstr(line, "Name:") == line) {
+			sscanf(line, "%s %s", &buf, &proc->name);
+		}
+	}
+
+	fclose(f);
+
+	return proc;
+}
+
+uint8_t find_pid(void * proc_v, void * pid_v) {
+	p_t * p = proc_v;
+	pid_t i = (pid_t)pid_v;
+
+	return (uint8_t)(p->pid == i);
+}
+
+void print_process_tree_node(tree_node_t * node, size_t height) {
+	/* End recursion on a blank entry */
+	if (!node) return;
+	char * tmp = malloc(512);
+	memset(tmp, 0, 512);
+	char * c = tmp;
+	/* Indent output */
+	for (uint32_t i = 0; i < height; ++i) {
+		c += sprintf(c, "  ");
+	}
+	/* Get the current process */
+	p_t * proc = node->value;
+	/* Print the process name */
+	c += sprintf(c, "%s", proc->name);
+	/* Linefeed */
+	printf("%s\n", tmp);
+	free(tmp);
+	foreach(child, node->children) {
+		/* Recursively print the children */
+		print_process_tree_node(child->value, height + 1);
+	}
+}
+
+int main (int argc, char * argv[]) {
+
+	/* Open the directory */
+	DIR * dirp = opendir("/proc");
+
+	/* Read the entries in the directory */
+	tree_t * procs = tree_create();
+
+	struct dirent * ent = readdir(dirp);
+	while (ent != NULL) {
+		if (ent->d_name[0] >= '0' && ent->d_name[0] <= '9') {
+			p_t * proc = build_entry(ent);
+
+			if (proc->ppid == 0) {
+				tree_set_root(procs, proc);
+			} else {
+				tree_node_t * parent = tree_find(procs,(void *)proc->ppid,find_pid);
+				if (parent) {
+					tree_node_insert_child(procs, parent, proc);
+				}
+			}
+		}
+		ent = readdir(dirp);
+	}
+	closedir(dirp);
+
+	print_process_tree_node(procs->root, 0);
+
+	return 0;
+}
+
+/*
+ * vim: tabstop=4
+ * vim: shiftwidth=4
+ * vim: noexpandtab
+ */