1 files changed, 54 insertions, 0 deletions
diff --git a/src/cmd/ps.c b/src/cmd/ps.c
new file mode 100644
index 0000000..c855251
--- /dev/null
+++ b/src/cmd/ps.c
@@ -0,0 +1,54 @@
+#include <_proc.h>
+#include <ctype.h>
+#include <dirent.h>
+#include <err.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+void
+usage(void)
+{
+	fprintf(stderr, "usage: ps [path]\n");
+	exit(1);
+}
+
+int
+main(int argc, const char *argv[])
+{
+	const char *path = argc >= 2 ? argv[1] : "/proc/";
+	if (argc > 2) usage();
+
+	char *procbuf = malloc(4096);
+	DIR *dir = opendir(path);
+	if (!dir) {
+		err(1, "couldn't open %s", path);
+	}
+
+	struct dirent *de;
+	while ((de = readdir(dir))) {
+		const char *name = de->d_name;
+		if (isdigit(name[0])) {
+			FILE *g;
+			sprintf(procbuf, "%s%smem", path, name);
+			g = fopen(procbuf, "r");
+			if (!g) {
+				warn("couldn't open \"%s\"", procbuf);
+				strcpy(procbuf, "(can't peek)");
+			} else {
+				fseek(g, (long)&_psdata_loc->desc, SEEK_SET);
+				if (fread(procbuf, 1, 128, g) <= 0) {
+					strcpy(procbuf, "(no psdata)");
+				}
+				procbuf[128] = '\0';
+				fclose(g);
+			}
+			*strchr(name, '/') = '\0';
+			printf("%s\t%s\n", name, procbuf);
+		}
+	}
+
+	free(procbuf);
+	closedir(dir);
+	return 0;
+}