dedup

commit 2fcad321a15f6d09e77b70650e9737bd2d370a6e
parent 3a24ddb8e397799f7af86d11941bd9c7e73470fd
Author: sin <sin@2f30.org>
Date:   Sun,  5 May 2019 17:34:48 +0100

Implement {lock,unlock}repo()

Diffstat:
M
Makefile
 | 
2
++
A
lock.c
 | 
55
+++++++++++++++++++++++++++++++++++++++++++++++++++++++
A
lock.h
 | 
2
++

3 files changed, 59 insertions(+), 0 deletions(-)
diff --git a/Makefile b/Makefile
@@ -9,6 +9,7 @@ HDR = \
         chunker.h \
         config.h \
         key.h \
+        lock.h \
         misc.h \
         queue.h \
         snap.h \
@@ -22,6 +23,7 @@ COMMOBJ = \
         bstorage.o \
         chunker.o \
         key.o \
+        lock.o \
         misc.o \
         pack.o \
         snap.o \
diff --git a/lock.c b/lock.c
@@ -0,0 +1,55 @@
+#include <fcntl.h>
+#include <limits.h>
+#include <stdio.h>
+#include <unistd.h>
+
+int
+lockrepo(char *repo)
+{
+	char path[PATH_MAX];
+	struct flock fl;
+	int fd;
+
+	if (snprintf(path, sizeof(path), "%s/lock", repo) >=
+	    sizeof(path))
+		return -1;
+
+	fd = open(path, O_RDWR | O_CREAT, 0600);
+	if (fd < 0)
+		return -1;
+
+	fl.l_type = F_WRLCK;
+	fl.l_whence = SEEK_SET;
+	fl.l_start = 0;
+	fl.l_len = 0;
+	if (fcntl(fd, F_SETLK, &fl) < 0) {
+		close(fd);
+		return -1;
+	}
+	return fd;
+}
+
+int
+unlockrepo(char *repo, int fd)
+{
+	char path[PATH_MAX];
+	struct flock fl;
+
+	if (snprintf(path, sizeof(path), "%s/lock", repo) >=
+	    sizeof(path))
+		return -1;
+
+	if (unlink(path) < 0)
+		return -1;
+
+	fl.l_type = F_UNLCK;
+	fl.l_whence = SEEK_SET;
+	fl.l_start = 0;
+	fl.l_len = 0;
+	if (fcntl(fd, F_SETLK, &fl) < 0)
+		return -1;
+
+	if (close(fd) < 0)
+		return -1;
+	return 0;
+}
diff --git a/lock.h b/lock.h
@@ -0,0 +1,2 @@
+int lockrepo(char *);
+int unlockrepo(char *, int);