From: kremlin <ian@kremlin.cc>
Date: Thu, 25 Sep 2014 23:04:29 +0000 (-0400)
Subject: completed homework 4
X-Git-Url: https://uglyman.kremlin.cc/gitweb/gitweb.cgi?a=commitdiff_plain;h=ed3a7f092f7068fcd45914826cbdf31710c6a5a2;p=assignments.git

completed homework 4
---

diff --git a/assgn4/Makefile b/assgn4/Makefile
new file mode 100644
index 0000000..e907691
--- /dev/null
+++ b/assgn4/Makefile
@@ -0,0 +1,7 @@
+.PHONY: all
+
+CC=/usr/bin/cc
+CFLAGS= -Wall -Wextra -Werror -Wno-format -std=c89 
+
+all: hw4.c
+	$(CC) -o hw4.bin $(CFLAGS) hw4.c
diff --git a/assgn4/hw4.c b/assgn4/hw4.c
new file mode 100644
index 0000000..81b7a79
--- /dev/null
+++ b/assgn4/hw4.c
@@ -0,0 +1,80 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include <pwd.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+int main(int argc, char *argv[]) {
+
+	struct stat    file_stat;
+	struct passwd *file_pd;
+
+	int argc_decr;
+	mode_t *ft;
+
+	extern int errno;
+
+	argc_decr = argc; /* K&R 117(§5.10) warns against decrementing argc directly */
+
+	if(argc <= 1 || argc >= 5) {
+
+		printf("USAGE: %s <file> [-o, -c]\n", argv[0]);
+		return 1;
+
+	} else if(stat(argv[1], &file_stat)) {
+
+		if(errno == ENOENT)
+			printf("provided file does not exist.\n");
+		else if(errno == EACCES)
+			printf("improper permissions to read from file.\n");
+		else if(errno == ENAMETOOLONG)
+			printf("provided path is too long.\n");
+		else if(errno == ENOTDIR)
+			printf("provided path contains a non-existant directory.\n");
+		else if(errno == EOVERFLOW)
+			printf("provided file cannot be properly contained into a stat buf.\n");
+		else if(errno == ELOOP)
+			printf("provided file points to an irresolvable symlink chain.\n");
+
+		return errno;
+	}
+
+	printf("file size in bytes: %llu\n", file_stat.st_size);
+
+	while(argc_decr > 2) {
+
+		if(!strncmp(argv[argc_decr - 1], "-o", 5)) {
+
+			if((file_pd = getpwuid(file_stat.st_uid)) != NULL)
+				printf("file owned by user %s.\n", file_pd->pw_name);
+
+			else
+				printf("file owned by uid %d.\n", file_stat.st_uid);
+
+		} else if(!strncmp(argv[argc_decr - 1], "-t", 5)) {
+
+			printf("file is a ");
+			ft = &(file_stat.st_mode);
+
+			if     (S_ISBLK(*ft))  printf("block device.\n");
+			else if(S_ISCHR(*ft))  printf("character device.\n");
+			else if(S_ISFIFO(*ft)) printf("fifo pipe.\n");
+			else if(S_ISREG(*ft))  printf("regular file.\n");
+			else if(S_ISDIR(*ft))  printf("directory.\n");
+			else if(S_ISLNK(*ft))  printf("symbolic link.\n");
+				
+				
+		} else {
+
+			printf("provided argument is invalid, must be '-t' or '-o'.\n");
+			return 1;
+		}
+
+		argc_decr--;
+	}
+
+	return 0;
+}