1 files changed, 235 insertions, 0 deletions
diff --git a/src/sash/cmd_file.c b/src/sash/cmd_file.c
new file mode 100644
index 0000000..caf2a30
--- /dev/null
+++ b/src/sash/cmd_file.c
@@ -0,0 +1,235 @@
+/*
+ * Copyright (c) 2014 by David I. Bell
+ * Permission is granted to use, distribute, or modify this source,
+ * provided that this copyright notice remains intact.
+ *
+ * The "file" built-in command.
+ */
+
+#include <ctype.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include "sash.h"
+
+
+static const char *	checkFile(const char * name);
+
+
+int
+do_file(int argc, const char ** argv)
+{
+	const char *	name;
+	const char *	info;
+
+	argc--;
+	argv++;
+
+	while (argc-- > 0)
+	{
+		name = *argv++;
+
+		info = checkFile(name);
+
+		if (info == NULL)
+			info = "No information available";
+
+		printf("%s: %s\n", name, info);
+	}
+
+	return 0;
+}
+
+
+/*
+ * Examine the specified file and return a static string which
+ * describes the file type.  Returns NULL on a failure.
+ */
+static const char *
+checkFile(const char * name)
+{
+	int		mode;
+	int		fd;
+	int		cc;
+	int		i;
+	int		ch;
+	int		badCount;
+	char *		cp;
+	struct	stat	statBuf;
+	char		data[8192];
+	static	char	info[1024];
+
+	cp = info;
+	*cp = '\0';
+
+	if (lstat(name, &statBuf) < 0)
+	{
+		if (errno == ENOENT)
+			return "non-existent";
+
+		sprintf(cp, "stat failed: %s", strerror(errno));
+
+		return info;
+	}
+
+	/*
+	 * Check the file type.
+	 */
+	mode = statBuf.st_mode;
+
+	if (S_ISDIR(mode))
+		return "directory";
+
+	if (S_ISCHR(mode))
+		return "character device";
+
+	if (S_ISBLK(mode))
+		return "block device";
+
+	if (S_ISFIFO(mode))
+		return "named pipe";
+
+#ifdef	S_ISLNK
+	if (S_ISLNK(mode))
+		return "symbolic link";
+#endif
+
+#ifdef	S_ISSOCK
+	if (S_ISSOCK(mode))
+		return "socket";
+#endif
+
+	/*
+	 * If the file is not a regular file mention that.
+	 */
+	if (!S_ISREG(mode))
+	{
+		sprintf(cp, "unknown mode 0x%x, \n", mode);
+
+		cp += strlen(cp);
+	}
+
+	/*
+	 * Check for an executable file.
+	 */
+	if ((mode & (S_IEXEC | S_IXGRP | S_IXOTH)) != 0)
+	{
+		strcpy(cp, "executable, ");
+
+		cp += strlen(cp);
+	}
+
+	/*
+	 * The file is a normal file.
+	 * Open it if we can and read in the first block.
+	 */
+	fd = open(name, O_RDONLY);
+
+	if (fd < 0)
+	{
+		sprintf(cp, "unreadable: %s", strerror(errno));
+
+		return info;
+	}
+
+	cc = read(fd, data, sizeof(data));
+
+	if (cc < 0)
+	{
+		sprintf(cp, "read error: %s", strerror(errno));
+
+		(void) close(fd);
+
+		return info;
+	}
+
+	(void) close(fd);
+
+	/*
+	 * Check for an empty file.
+	 */
+	if (cc == 0)
+	{
+		strcpy(cp, "empty file");
+
+		return info;
+	}
+
+	/*
+	 * Check for a script file.
+	 */
+	if ((cc > 2) && (data[0] == '#') && (data[1] == '!'))
+	{
+		char *	begin;
+		char *	end;
+
+		data[sizeof(data) - 1] = '\0';
+
+		begin = &data[2];
+
+		while (*begin == ' ')
+			begin++;
+
+		end = begin;
+
+		while (*end && (*end != ' ') && (*end != '\n'))
+			end++;
+
+		*end = '\0';
+
+		sprintf(cp, "script for \"%s\"", begin);
+
+		return info;
+	}
+
+	/*
+	 * Check for special binary data types.
+	 */
+	if ((data[0] == '\037') && (data[1] == '\235'))
+		return "compressed file";
+
+	if ((data[0] == '\037') && (data[1] == '\213'))
+		return "GZIP file";
+
+	if ((data[0] == '\177') && (memcmp(&data[1], "ELF", 3) == 0))
+	{
+		strcpy(cp, "ELF program");
+
+		return info;
+	}
+
+	/*
+	 * Check for binary data.
+	 */
+	badCount = 0;
+
+	for (i = 0; i < cc; i++)
+	{
+		ch = data[i];
+
+		if ((ch == '\n') || (ch == '\t'))
+			continue;
+
+		if (isspace(ch) || isprint(ch))
+			continue;
+
+		badCount++;
+	}
+
+	if (badCount != 0)
+	{
+		strcpy(cp, "binary");
+
+		return info;
+	}
+
+	/*
+	 * It is just a text file.
+	 */
+	strcpy(cp, "text file");
+
+	return info;
+}
+
+/* END CODE */