From: Armaan Bhojwani <me@armaanb.net>
Date: Sat, 10 Apr 2021 23:49:54 +0000 (-0400)
Subject: tides: new program, simple fetch program
X-Git-Tag: v0.0.1~2
X-Git-Url: https://git.armaanb.net/?p=bin.git;a=commitdiff_plain;h=b510e2b26e17ea765afe6ae164d482982a63053a

tides: new program, simple fetch program

Preliminary version of a simple fetch program. Mostly for learning C
and the Linux APIs.
---

diff --git a/.gitignore b/.gitignore
index 0993049..b307a43 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 *cache*
 bin
+a.out
diff --git a/tides.c b/tides.c
new file mode 100644
index 0000000..d1eba77
--- /dev/null
+++ b/tides.c
@@ -0,0 +1,56 @@
+// Yet another (tm) fetch program
+
+#include <unistd.h>
+#include <sys/utsname.h> 
+#include <sys/sysinfo.h> 
+#include <time.h>
+
+#include <limits.h>
+#include <string.h>
+#include <stdio.h>
+
+int
+main(void)
+{
+	// Get hostname
+	char hostname[HOST_NAME_MAX];
+	gethostname(hostname, HOST_NAME_MAX);
+
+	// Get username
+	char username[LOGIN_NAME_MAX];
+	getlogin_r(username, LOGIN_NAME_MAX);
+
+	// Get kernel info
+	struct utsname kernel;
+	uname(&kernel);
+
+	// Get assorted system info
+	struct sysinfo info;
+	sysinfo(&info);
+
+	/* Get memory info from /proc. Inspired by busybox free.c, which is
+		 GPLv2 licensed */
+	char buf[60]; // actual lines we expect are ~30 chars or less
+	int counter = 2; // Number of things being scanned for in the file
+	unsigned long total_kb, avail_kb;
+
+	FILE *fp = fopen("/proc/meminfo", "r");
+	total_kb = avail_kb = 0;
+	while (fgets(buf, sizeof(buf), fp)) {
+		if (sscanf(buf, "MemTotal: %lu %*s\n", &total_kb) == 1)
+			if (--counter == 0)
+				break;
+		if (sscanf(buf, "MemAvailable: %lu %*s\n", &avail_kb) == 1)
+			if (--counter == 0)
+				break;
+	}
+	fclose(fp);
+
+	// Display
+	printf("%s@%s\n", username, hostname);
+	printf("%s %s\n", kernel.sysname, kernel.release);
+	struct tm *uptime = gmtime(&info.uptime);
+	printf("Up %02dh %02dm %02ds\n", uptime->tm_hour, uptime->tm_min,
+				 uptime->tm_sec);
+	printf("%0.0f/%0.0f MB RAM\n", (total_kb - avail_kb)/1024.0, total_kb/1024.0);
+}