chapter 8 sample code 8.6

Author: Heatwave

chapter-8-the-unix-system-interface/dirent.h

@@ -0,0 +1,14 @@
+typedef struct {
+	long ino;
+	char name[NAME_MAX+1];
+} Dirent;
+
+typedef struct {
+	int fd;
+	Dirent d;
+} DIR;
+
+DIR *opendir(char *dirname);
+Dirent *readdir(DIR *dfd);
+void closedir(DIR *dfd);
+

chapter-8-the-unix-system-interface/fsize.c

@@ -0,0 +1,107 @@
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h> 
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include "dirent.h"
+
+void fsize(char *);
+
+main (int argc, char **argv)
+{
+	if (argc == 1)
+		fsize(".");
+	else
+		while (--argc > 0)
+			fsize(*++argv);
+	return 0;
+}
+
+int stat(char *, struct stat *);
+void dirwalk(char *, void (*fcn)(char *));
+
+void fsize(char *name)
+{
+	struct stat stbuf;
+
+	if (stat(name, &stbuf) == -1) {
+		fprintf(stderr, "fsize: can't access %s\n", name);
+		return;
+	}
+	if ((stbuf.st_mode & S_IFMT) == S_IFDIR)
+		dirwalk(name, fsize);
+	printf("%8ld %s\n", stbuf.st_size, name);
+}
+
+#define MAX_PATH 1024
+
+void dirwalk(char *dir, void (*fcn)(char *))
+{
+	char name[MAX_PATH];
+	Dirent *dp;
+	DIR *dfd;
+
+	if ((dfd = opendir(dir)) == NULL) {
+		fprintf(stderr, "dirwalk: can't open %s\n", dir);
+		return;
+	}
+	while ((dp = readdir(dfd)) != NULL) {
+		if (strcmp(dp->name, ".") == 0
+		 || strcmp(dp->name, "..") == 0)
+			continue;
+		if (strlen(dir) + strlen(dp->name) + 2 > sizeof(name))
+			fprintf(stderr, "dirwalk: name %s/%s too long\n",
+				dir, dp->name);
+		else {
+			sprintf(name, "%s/%s", dir, dp->name);
+			(*fcn)(name);
+		}
+	}
+	closedir(dfd);
+}
+
+int fstat(int fd, struct stat *);
+
+DIR *opendir(char *dirname)
+{
+	int fd;
+	struct stat stbuf;
+	DIR *dp;
+
+	if ((fd = open(dirname, O_RDONLY, 0)) == -1
+	 || fstat(fd, &stbuf) == -1
+	 || (stbuf.st_mode & S_IFMT) != S_IFDIR
+	 || (dp = (DIR *) malloc(sizeof(DIR))) == NULL)
+		return NULL;
+	dp->fd = fd;
+	return dp;
+}
+
+void closedir(DIR *dp)
+{
+	if (dp) {
+		close(dp->fd);
+		free(dp);
+	}
+}
+
+#include <sys/dir.h>
+
+Dirent *readdir(DIR *dp)
+{
+	struct direct dirbuf;
+	static Dirent d;
+
+	while (read(dp->fd, (char *) &dirbuf, sizeof(dirbuf))
+					== sizeof(dirbuf)) {
+		if (dirbuf.d_ino == 0)
+			continue;
+		d.ino = dirbuf.d_ino;
+		strncpy(d.name, dirbuf.d_name, DIRSIZ);
+		d.name[DIRSIZ] = '\0';
+		return &d;
+	}
+	return NULL;
+}
+