X-Git-Url: https://wimlib.net/git/?p=wimlib;a=blobdiff_plain;f=src%2Fwrite.c;h=5b586ceea23f8795cff7c28623ce2ff573df59a1;hp=a08bc8503a6c5a57f908ab7f535787205fe3fded;hb=277957c10e96a23f822b2e6ae22c8d126a93141a;hpb=9b9a502863318d6208da2818b1d522346e5eee9e

diff --git a/src/write.c b/src/write.c
index a08bc850..5b586cee 100644
--- a/src/write.c
+++ b/src/write.c
@@ -25,6 +25,15 @@
  * along with wimlib; if not, see http://www.gnu.org/licenses/.
  */
 
+#include "config.h"
+
+#if defined(HAVE_SYS_FILE_H) && defined(HAVE_FLOCK)
+/* On BSD, this should be included before "list.h" so that "list.h" can
+ * overwrite the LIST_HEAD macro. */
+#include <sys/file.h>
+#endif
+
+#include "list.h"
 #include "wimlib_internal.h"
 #include "io.h"
 #include "dentry.h"
@@ -32,14 +41,14 @@
 #include "xml.h"
 #include "lzx.h"
 #include "xpress.h"
-#include <unistd.h>
 
 #ifdef ENABLE_MULTITHREADED_COMPRESSION
-#include <semaphore.h>
 #include <pthread.h>
-#include <errno.h>
 #endif
 
+#include <unistd.h>
+#include <errno.h>
+
 #ifdef WITH_NTFS_3G
 #include <time.h>
 #include <ntfs-3g/attrib.h>
@@ -47,13 +56,13 @@
 #include <ntfs-3g/dir.h>
 #endif
 
-
 #ifdef HAVE_ALLOCA_H
 #include <alloca.h>
 #else
 #include <stdlib.h>
 #endif
 
+
 static int do_fflush(FILE *fp)
 {
 	int ret = fflush(fp);
@@ -537,13 +546,14 @@ out:
 
 #ifdef ENABLE_MULTITHREADED_COMPRESSION
 struct shared_queue {
-	sem_t filled_slots;
-	sem_t empty_slots;
-	pthread_mutex_t lock;
+	unsigned size;
 	unsigned front;
 	unsigned back;
+	unsigned filled_slots;
 	void **array;
-	unsigned size;
+	pthread_mutex_t lock;
+	pthread_cond_t msg_avail_cond;
+	pthread_cond_t space_avail_cond;
 };
 
 static int shared_queue_init(struct shared_queue *q, unsigned size)
@@ -551,46 +561,52 @@ static int shared_queue_init(struct shared_queue *q, unsigned size)
 	q->array = CALLOC(sizeof(q->array[0]), size);
 	if (!q->array)
 		return WIMLIB_ERR_NOMEM;
-
-	sem_init(&q->filled_slots, 0, 0);
-	sem_init(&q->empty_slots, 0, size);
-	pthread_mutex_init(&q->lock, NULL);
+	q->filled_slots = 0;
 	q->front = 0;
 	q->back = size - 1;
 	q->size = size;
+	pthread_mutex_init(&q->lock, NULL);
+	pthread_cond_init(&q->msg_avail_cond, NULL);
+	pthread_cond_init(&q->space_avail_cond, NULL);
 	return 0;
 }
 
 static void shared_queue_destroy(struct shared_queue *q)
 {
-	sem_destroy(&q->filled_slots);
-	sem_destroy(&q->empty_slots);
-	pthread_mutex_destroy(&q->lock);
 	FREE(q->array);
+	pthread_mutex_destroy(&q->lock);
+	pthread_cond_destroy(&q->msg_avail_cond);
+	pthread_cond_destroy(&q->space_avail_cond);
 }
 
 static void shared_queue_put(struct shared_queue *q, void *obj)
 {
-	sem_wait(&q->empty_slots);
 	pthread_mutex_lock(&q->lock);
+	while (q->filled_slots == q->size)
+		pthread_cond_wait(&q->space_avail_cond, &q->lock);
 
 	q->back = (q->back + 1) % q->size;
 	q->array[q->back] = obj;
+	q->filled_slots++;
 
-	sem_post(&q->filled_slots);
+	pthread_cond_broadcast(&q->msg_avail_cond);
 	pthread_mutex_unlock(&q->lock);
 }
 
 static void *shared_queue_get(struct shared_queue *q)
 {
-	sem_wait(&q->filled_slots);
+	void *obj;
+
 	pthread_mutex_lock(&q->lock);
+	while (q->filled_slots == 0)
+		pthread_cond_wait(&q->msg_avail_cond, &q->lock);
 
-	void *obj = q->array[q->front];
+	obj = q->array[q->front];
 	q->array[q->front] = NULL;
 	q->front = (q->front + 1) % q->size;
+	q->filled_slots--;
 
-	sem_post(&q->empty_slots);
+	pthread_cond_broadcast(&q->space_avail_cond);
 	pthread_mutex_unlock(&q->lock);
 	return obj;
 }
@@ -1486,6 +1502,61 @@ out:
 	return ret;
 }
 
+#if defined(HAVE_SYS_FILE_H) && defined(HAVE_FLOCK)
+int lock_wim(FILE *fp, const char *path)
+{
+	int ret = 0;
+	if (fp) {
+		ret = flock(fileno(fp), LOCK_EX | LOCK_NB);
+		if (ret != 0) {
+			if (errno == EWOULDBLOCK) {
+				ERROR("`%s' is already being modified or has been "
+				      "mounted read-write\n"
+				      "        by another process!", path);
+				ret = WIMLIB_ERR_ALREADY_LOCKED;
+			} else {
+				WARNING("Failed to lock `%s': %s",
+					path, strerror(errno));
+				ret = 0;
+			}
+		}
+	}
+	return ret;
+}
+#endif
+
+static int open_wim_writable(WIMStruct *w, const char *path,
+			     bool trunc, bool readable)
+{
+	const char *mode;
+	int ret = 0;
+	if (trunc)
+		if (readable)
+			mode = "w+b";
+		else
+			mode = "wb";
+	else
+		mode = "r+b";
+
+	DEBUG("Opening `%s' read-write", path);
+	wimlib_assert(w->out_fp == NULL);
+	wimlib_assert(path != NULL);
+	w->out_fp = fopen(path, mode);
+	if (!w->out_fp) {
+		ERROR_WITH_ERRNO("Failed to open `%s' for writing", path);
+		return WIMLIB_ERR_OPEN;
+	}
+	if (trunc) {
+		ret = lock_wim(w->out_fp, path);
+		if (ret != 0) {
+			fclose(w->out_fp);
+			w->out_fp = NULL;
+		}
+	}
+	return ret;
+}
+
+
 static void close_wim_writable(WIMStruct *w)
 {
 	if (w->out_fp) {