From 1652ed72479279c701c0779fc01aceed40ca4101 Mon Sep 17 00:00:00 2001
From: =?utf8?q?J=C3=A9r=C3=B4me=20Benoit?= <jerome.benoit@piment-noir.org>
Date: Mon, 26 Feb 2018 23:12:52 +0100
Subject: [PATCH] Add shared mem course example code.
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Signed-off-by: Jérôme Benoit <jerome.benoit@piment-noir.org>
---
 .gitignore   |  1 +
 mem/Makefile | 83 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 mem/mem.c    | 49 +++++++++++++++++++++++++++++++
 3 files changed, 133 insertions(+)
 create mode 100644 mem/Makefile
 create mode 100644 mem/mem.c

diff --git a/.gitignore b/.gitignore
index 4e21bb1..728eb36 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,5 @@
 TD3/exo2/monexec/monexec
+mem/mem
 philosophe/philosophe
 prodcons/prodcons
 rw/reader/reader
diff --git a/mem/Makefile b/mem/Makefile
new file mode 100644
index 0000000..0b7d853
--- /dev/null
+++ b/mem/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=mem
+BUILD_TYPE=debug
+#BUILD_TYPE=release
+LDLIBS=-lrt
+
+# ====================================
+# 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/mem/mem.c b/mem/mem.c
new file mode 100644
index 0000000..95e43f9
--- /dev/null
+++ b/mem/mem.c
@@ -0,0 +1,49 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <fcntl.h>
+
+#define nbchar 4096
+
+int main()
+{
+	int fd, res;
+	char *partage = NULL;
+	char *message = "";
+	fd = shm_open("partage.mem", O_RDWR | O_CREAT, 0600);	/* ouverture du segment partagé */
+	if (fd == -1) {		                                    /* et création du nom (du fichier) */
+		perror("shm_open");
+		exit(1);
+	}
+	res = ftruncate(fd, nbchar);	/* choix de la taille du segment */
+	if (res == -1) {
+		perror("ftruncate");
+		exit(1);
+	}
+	partage = (char *)mmap(NULL, nbchar, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+	if (partage == MAP_FAILED) {
+		perror("mmap");
+		exit(1);
+	}
+	strncpy(partage, message, nbchar);
+	while (strcmp(partage, message) == 0) {
+		sleep(1);
+	}
+	fprintf(stdout, "la réponse est %s\n", partage);
+	res = munmap(partage, nbchar);
+	if (res == -1) {
+		perror("munmap");
+		exit(1);
+	}
+	close(fd);		/* fermeture du fichier */
+	res = shm_unlink("partage.mem");	/* suppression du nom */
+	if (res == -1) {
+		perror("shm_unlink");
+		exit(1);
+	}
+	return 0;
+}
-- 
2.34.1