9 files changed, 170 insertions, 0 deletions
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..7eac15c
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,18 @@
+SRCS = $(wildcard src/*.c)
+BINS = $(patsubst src/%.c,bin/%,$(SRCS))
+
+CFLAGS =
+CC = gcc $(CFLAGS)
+
+all: build
+
+build: $(BINS)
+
+.SECONDEXPANSION:
+$(BINS): $$(patsubst bin/%,src/%.c,$$@)
+	@mkdir -pv bin
+	$(CC) -o $@ $(patsubst bin/%,src/%.c,$@)
+
+clean:
+	rm -f $(BINS)
+	rmdir bin
diff --git a/src/cat.c b/src/cat.c
new file mode 100644
index 0000000..bf618cc
--- /dev/null
+++ b/src/cat.c
@@ -0,0 +1,46 @@
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define error(...) ({ \
+    printf(__VA_ARGS__); \
+    exit(EXIT_FAILURE); \
+    })
+
+static void cat(char *s) {
+  int fd = STDIN_FILENO;
+  ssize_t in, out;
+  char buf[1024];
+
+  if(strcmp(s, "-")) {
+    fd = open(s, O_RDONLY);
+    if(fd < 0)
+      error("Error opening %s: %s\n", s, strerror(errno));
+  }
+
+  for(;;) {
+    in = read(fd, buf, sizeof(buf));
+    if(in < 0)
+      error("Error reading %s: %s\n", s, strerror(errno));
+    out = write(STDOUT_FILENO, buf, in);
+    if(out < in)
+      error("Error writiing output: %s\n", strerror(errno));
+    if(!in)
+      return;
+  }
+}
+
+int main(int argc, char **argv) {
+  if(argc == 1) {
+    cat("-");
+    return 0;
+  }
+
+  while(argc-- > 1)
+    cat(*(++argv));
+
+  return 0;
+}
diff --git a/src/chmod.c b/src/chmod.c
new file mode 100644
index 0000000..a16665f
--- /dev/null
+++ b/src/chmod.c
@@ -0,0 +1,32 @@
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+
+int main(int argc, char **argv) {
+  int ret;
+  char **f;
+  mode_t mode;
+
+  if(argc < 2) {
+    printf("Usage: %s <mode> <files>\n", argv[0]);
+    return EXIT_FAILURE;
+  }
+
+  ret = sscanf(argv[1], "%o", &mode);
+  if(ret < 1) {
+    fprintf(stderr, "Invalid mode: %s\n", argv[1]);
+    return EXIT_FAILURE;
+  }
+
+  f = &argv[2];
+  argc -= 2;
+
+  while(argc--) {
+    ret = chmod(*f, mode);
+    if(ret < 0)
+      fprintf(stderr, "Error changing mode on file %s: %s\n", *f, strerror(errno));
+    f++;
+  }
+}
diff --git a/src/chown.c b/src/chown.c
new file mode 100644
index 0000000..d4ba35a
--- /dev/null
+++ b/src/chown.c
@@ -0,0 +1,36 @@
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+int main(int argc, char **argv) {
+  int ret;
+  char **f;
+  uid_t uid;
+  gid_t gid;
+
+  if(argc < 2) {
+    printf("Usage: %s <uid>[:<gid>] <files>\n", argv[0]);
+    return EXIT_FAILURE;
+  }
+
+  ret = sscanf(argv[1], "%d:%d", &uid, &gid);
+  if(ret < 1) {
+    fprintf(stderr, "Invalid owner: %s\n", argv[1]);
+    return EXIT_FAILURE;
+  }
+
+  if(ret < 2)
+    gid = -1;
+
+  f = &argv[2];
+  argc -= 2;
+
+  while(argc--) {
+    ret = chown(*f, uid, gid);
+    if(ret < 0)
+      fprintf(stderr, "Error changing ownership on file %s: %s\n", *f, strerror(errno));
+    f++;
+  }
+}
diff --git a/src/echo.c b/src/echo.c
new file mode 100644
index 0000000..df70cce
--- /dev/null
+++ b/src/echo.c
@@ -0,0 +1,9 @@
+#include <stdio.h>
+
+int main(int argc, char **argv) {
+  argc--;
+  argv++;
+
+  while(argc--)
+    printf("%s%c", *(argv++), argc ? ' ' : '\n');
+}
diff --git a/src/false.c b/src/false.c
new file mode 100644
index 0000000..80eeb5d
--- /dev/null
+++ b/src/false.c
@@ -0,0 +1,3 @@
+int main(int argc, char **argv) {
+  return 1;
+}
diff --git a/src/nologin.c b/src/nologin.c
new file mode 100644
index 0000000..2fd7093
--- /dev/null
+++ b/src/nologin.c
@@ -0,0 +1,6 @@
+#include <stdio.h>
+
+int main(int argc, char **argv) {
+  puts("This account is currently not available.");
+  return 1;
+}
diff --git a/src/pwd.c b/src/pwd.c
new file mode 100644
index 0000000..b884933
--- /dev/null
+++ b/src/pwd.c
@@ -0,0 +1,17 @@
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+int main(int argc, char **argv) {
+  char buf[1024];
+
+  if(!getcwd(buf, sizeof(buf))) {
+    perror("Error getting current directory");
+    return EXIT_FAILURE;
+  }
+
+  puts(buf);
+  return 0;
+}
diff --git a/src/true.c b/src/true.c
new file mode 100644
index 0000000..5c2fa9b
--- /dev/null
+++ b/src/true.c
@@ -0,0 +1,3 @@
+int main(int argc, char **argv) {
+  return 0;
+}