From d71fd5f57f0aa66e9b19916626fea98b0b3bfc57 Mon Sep 17 00:00:00 2001
From: =?utf8?q?J=C3=A9r=C3=B4me=20Benoit?= <jerome.benoit@piment-noir.org>
Date: Sat, 3 Mar 2018 22:40:11 +0100
Subject: [PATCH] Add lockf course code.
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Signed-off-by: Jérôme Benoit <jerome.benoit@piment-noir.org>
---
 .gitignore     |  1 +
 lockf/Makefile | 83 ++++++++++++++++++++++++++++++++++++++++++++++++++
 lockf/lockf.c  | 39 ++++++++++++++++++++++++
 3 files changed, 123 insertions(+)
 create mode 100644 lockf/Makefile
 create mode 100644 lockf/lockf.c

diff --git a/.gitignore b/.gitignore
index ad86cec..18fc99f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,6 +1,7 @@
 TD3/exo2/monexec/monexec
 fils/fils
 lecteursredacteurs/lecteursredacteurs
+lockf/lockf
 mem/mem
 peterson/peterson
 philosophe/philosophe
diff --git a/lockf/Makefile b/lockf/Makefile
new file mode 100644
index 0000000..4d06f1f
--- /dev/null
+++ b/lockf/Makefile
@@ -0,0 +1,83 @@
+# Sample Makefile to build simple project.
+#
+# This Makefile expect all source files (.c) to be at the same level, in the
+# current working directory.
+#
+# It will automatically generate dependencies, compile all files, and produce a
+# binary using the provided name.
+#
+# Set BINARY_NAME to the name of the binary file to build.
+# Set BUILD_TYPE to either debug or release
+#
+# Automatic dependencies code from:
+# http://make.mad-scientist.net/papers/advanced-auto-dependency-generation/#tldr
+BINARY_NAME=lockf
+BUILD_TYPE=debug
+#BUILD_TYPE=release
+LDLIBS=-lpthread
+
+# ====================================
+# DO NOT CHANGE STUFF BEYOND THIS LINE
+# ====================================
+
+all: $(BINARY_NAME)
+
+CC=gcc
+LD=gcc
+
+WARN_FLAGS = -Wall -Wextra
+STD_FLAG = -std=gnu11
+
+ifeq ($(BUILD_TYPE),debug)
+BUILDDIR := .build/debug
+DEBUG_FLAG = -g
+DEBUG = 1
+STRIP_FLAG =
+OPTI_FLAG = -O0
+else
+BUILDDIR := .build/release
+DEBUG_FLAG =
+DEBUG = 0
+STRIP_FLAG = -s
+OPTI_FLAG = -O3
+endif
+
+CFLAGS := -DDEBUG=$(DEBUG) $(CFLAGS) $(WARN_FLAGS) $(STD_FLAG) $(OPTI_FLAG) $(DEBUG_FLAG)
+LDFLAGS := $(LDFLAGS) $(STRIP_FLAG)
+
+OBJDIR := $(BUILDDIR)/objs
+$(shell mkdir -p $(OBJDIR))
+
+SRCS=$(wildcard *.c)
+OBJS=$(patsubst %.c,$(OBJDIR)/%.o,$(SRCS))
+
+DEPDIR := $(BUILDDIR)/deps
+$(shell mkdir -p $(DEPDIR))
+DEPFLAGS = -MT $@ -MMD -MP -MF $(DEPDIR)/$*.Td
+POSTCOMPILE = mv -f $(DEPDIR)/$*.Td $(DEPDIR)/$*.d
+
+$(BINARY_NAME): $(OBJS)
+	@echo "[LD ] $@"
+	@$(LD) $(CFLAGS) $(LDFLAGS) $^ $(LDLIBS) -o $@
+
+$(OBJDIR)/%.o: %.c $(DEPDIR)/%.d
+	@echo "[C  ] $*"
+	@$(CC) $(DEPFLAGS) $(CFLAGS) -c $< -o $@
+	@$(POSTCOMPILE)
+
+$(DEPDIR)/%.d: ;
+
+.PRECIOUS: $(DEPDIR)/%.d
+
+include $(wildcard $(patsubst %,$(DEPDIR)/%.d,$(basename $(SRCS))))
+
+clean:
+	@echo "[CLN]"
+	-@rm -r $(BUILDDIR)
+	-@rm $(BINARY_NAME)
+
+disassemble: $(BINARY_NAME)
+	objdump -d $< | less
+
+symbols: $(BINARY_NAME)
+	objdump -t $< | sort | less
diff --git a/lockf/lockf.c b/lockf/lockf.c
new file mode 100644
index 0000000..f684b17
--- /dev/null
+++ b/lockf/lockf.c
@@ -0,0 +1,39 @@
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/wait.h>
+
+int main() {
+    int i, fd = 1;
+
+    if (fork()) //il s'agit du père
+    {
+        lseek(fd, 0, 0);
+        if (lockf(fd, F_LOCK, 1) < 0) {
+            write(fd, "pere lockf failed\n", 18);
+            return -1;
+        }
+        for (i = 0; i < 5; i++) {
+            write(fd, "pere ecrit\n", 12);
+            sleep(1);
+        }
+        write(fd, "pere va liberer le verrou\n", 26);
+        lseek(fd, 0, 0);
+        lockf(fd, F_ULOCK, 0);
+        wait(NULL);
+    } else { //il s'agit du fils
+        lseek(fd, 0, 0); //verrouillé l'octet 0
+        if (lockf(fd, F_LOCK, 1) < 0) {
+            write(fd, "fils lockf failed\n", 18);
+            return -1;
+        }
+        for (i = 0; i < 4; i++) {
+            write(fd, "fils ecrit\n", 12);
+            sleep(1);
+        }
+        write(fd, "fils va liberer le verrou\n", 26);
+        lseek(fd, 0, 0);
+        lockf(fd, F_ULOCK, 0);
+    }
+    close(fd);
+    return 0;
+}
-- 
2.34.1