lib/raster: Fix race condition in fileinfo slot allocation and release (#6616)

lib/raster/close.c

@@ -11,7 +11,6 @@
  *
  * \author USACERL and many others
  */
-
 #ifdef _WIN32
 #include <windows.h>
 #endif
@@ -82,7 +81,6 @@ static void write_fp_format(int fd);
  * overwrite the support files. See \ref
  * Raster_Map_Layer_Support_Routines for routines which write raster
  * support files.
- *
  * If the map is a new floating point, move the <tt>.tmp</tt> file
  * into the <tt>fcell</tt> element, create an empty file in the
  * <tt>cell</tt> directory; write the floating-point range file; write
@@ -91,7 +89,6 @@ static void write_fp_format(int fd);
  * file, with max cat = max value (for backwards compatibility). Move
  * the <tt>.tmp</tt> NULL-value bitmap file to the <tt>cell_misc</tt>
  * directory.
- *
  * \param fd file descriptor
  *
  * \return void
@@ -124,9 +121,7 @@ void Rast_close(int fd)
  * eventually remove the temporary file, but the file can be quite
  * large and will take up disk space until GRASS does remove it. Use
  * this routine as a courtesy to the user.
- *
  * \param fd file descriptor
- *
  * \return void
  */
 void Rast_unopen(int fd)
@@ -144,13 +139,11 @@ void Rast_unopen(int fd)
 
 /*!
  * \brief Unopen all raster maps
- *
  * Unopen all raster maps opened for write. Memory allocated for
  * raster processing is freed, and the temporary file created when the
  * raster map was opened is removed (see \ref
  * Creating_and_Opening_New_Raster_Files). This routine is useful when
  * errors are detected and it is desired to remove temporary files.
- *
  * \return void
  */
 void Rast__unopen_all(void)
@@ -198,14 +191,16 @@ static int close_old(int fd)
     G_free(fcb->name);
     if (fcb->reclass_flag)
         Rast_free_reclass(&fcb->reclass);
-    fcb->open_mode = -1;
+    // fcb->open_mode = -1;
 
     if (fcb->map_type != CELL_TYPE) {
         Rast_quant_free(&fcb->quant);
     }
     if (fcb->data_fd >= 0)
         close(fcb->data_fd);
 
+#pragma omp critical(R_RASTER_OPEN)
+    fcb->open_mode = -1;
     return 1;
 }
 
@@ -347,7 +342,7 @@ static int close_new_gdal(int fd, int ok)
         Rast_close_gdal_link(fcb->gdal);
     }
 
-    fcb->open_mode = -1;
+    /* fcb->open_mode = -1; */
 
     if (fcb->data != NULL)
         G_free(fcb->data);
@@ -361,6 +356,9 @@ static int close_new_gdal(int fd, int ok)
     if (fcb->map_type != CELL_TYPE)
         Rast_quant_free(&fcb->quant);
 
+#pragma omp critical(R_RASTER_OPEN)
+    fcb->open_mode = -1;
+
     return stat;
 }
 
@@ -477,7 +475,7 @@ static int close_new(int fd, int ok)
 
     sync_and_close(fcb->data_fd,
                    (fcb->map_type == CELL_TYPE ? "cell" : "fcell"), fcb->name);
-    fcb->open_mode = -1;
+    /* fcb->open_mode = -1; */
 
     if (fcb->null_fd >= 0) {
         sync_and_close(fcb->null_fd,
@@ -531,6 +529,8 @@ static int close_new(int fd, int ok)
     if (fcb->map_type != CELL_TYPE)
         Rast_quant_free(&fcb->quant);
 
+#pragma omp critical(R_RASTER_OPEN)
+    fcb->open_mode = -1;
     return stat;
 }
 
@@ -577,6 +577,8 @@ void Rast__close_null(int fd)
 
     G_free(fcb->null_bits);
 
+    /* fcb->open_mode = -1; */
+#pragma omp critical(R_RASTER_OPEN)
     fcb->open_mode = -1;
 }
 
@@ -607,4 +609,4 @@ static void write_fp_format(int fd)
     G_write_key_value_file(path, format_kv);
 
     G_free_key_value(format_kv);
-}
+}

lib/raster/open.c

@@ -11,7 +11,6 @@
  *
  * \author USACERL and many others
  */
-
 #include <unistd.h>
 #include <string.h>
 #include <sys/types.h>
@@ -27,43 +26,59 @@
 #include "R.h"
 #define FORMAT_FILE "f_format"
 #define NULL_FILE   "null"
-/* cmpressed null file */
+// cmpressed null file
 #define NULLC_FILE  "nullcmpr"
 
 static int new_fileinfo(void)
 {
-    int oldsize = R__.fileinfo_count;
-    int newsize = oldsize;
+    int oldsize;
+    int newsize;
     int i;
+    int fd = -1;
 
-    for (i = 0; i < oldsize; i++)
-        if (R__.fileinfo[i].open_mode <= 0) {
-            memset(&R__.fileinfo[i], 0, sizeof(struct fileinfo));
-            R__.fileinfo[i].open_mode = -1;
-            return i;
+#pragma omp critical(R_RASTER_OPEN)
+    {
+        oldsize = R__.fileinfo_count;
+        newsize = oldsize;
+
+        for (i = 0; i < oldsize; i++) {
+            if (R__.fileinfo[i].open_mode <= 0) {
+                memset(&R__.fileinfo[i], 0, sizeof(struct fileinfo));
+                // mark as reserved
+                R__.fileinfo[i].open_mode = 200;
+                fd = i;
+                break;
+            }
         }
 
-    if (newsize < 20)
-        newsize += 20;
-    else
-        newsize *= 2;
+        if (fd < 0) {
+            if (newsize < 20)
+                newsize += 20;
+            else
+                newsize *= 2;
 
-    R__.fileinfo = G_realloc(R__.fileinfo, newsize * sizeof(struct fileinfo));
+            R__.fileinfo =
+                G_realloc(R__.fileinfo, newsize * sizeof(struct fileinfo));
 
-    /* Mark all cell files as closed */
-    for (i = oldsize; i < newsize; i++) {
-        memset(&R__.fileinfo[i], 0, sizeof(struct fileinfo));
-        R__.fileinfo[i].open_mode = -1;
-    }
+            // Mark all cell files as closed
+            for (i = oldsize; i < newsize; i++) {
+                memset(&R__.fileinfo[i], 0, sizeof(struct fileinfo));
+                R__.fileinfo[i].open_mode = -1;
+            }
 
-    R__.fileinfo_count = newsize;
+            R__.fileinfo_count = newsize;
 
-    return oldsize;
+            // mark as reserved
+            R__.fileinfo[oldsize].open_mode = 200;
+            fd = oldsize;
+        }
+    }
+
+    return fd;
 }
 
 /*!
  * \brief Open raster file
- *
  * Arrange for the NULL-value bitmap to be read as well as the raster
  * map. If no NULL-value bitmap exists, arrange for the production of
  * NULL-values based on zeros in the raster map. If the map is
@@ -73,11 +88,9 @@ static int new_fileinfo(void)
  * the floating point map using uing quant rules other than the ones
  * stored in map's quant file, he/she should call Rast_set_quant_rules()
  * after the call to Rast_open_old().
- *
  * \param name map name
  * \param open_mode mode
  * \param map_type map type (CELL, FCELL, DCELL)
- *
  * \return open file descriptor ( >= 0) if successful
  */
 static int open_raster_new(const char *name, int open_mode,
@@ -302,7 +315,7 @@ int Rast__open_old(const char *name, const char *mapset)
     fcb->null_bits = Rast__allocate_null_bits(cellhd.cols);
 
     /* mark closed */
-    fcb->open_mode = -1;
+    /* fcb->open_mode = -1; */
 
     /* save name and mapset */
     fcb->name = G_store(name);
@@ -528,7 +541,7 @@ static int open_raster_new_gdal(char *map, char *mapset,
 
     /* mark closed */
     fcb->map_type = map_type;
-    fcb->open_mode = -1;
+    /* fcb->open_mode = -1; */
 
     fcb->gdal = Rast_create_gdal_link(map, map_type);
     if (!fcb->gdal)
@@ -644,7 +657,7 @@ static int open_raster_new(const char *name, int open_mode,
 
     /* mark closed */
     fcb->map_type = map_type;
-    fcb->open_mode = -1;
+    /* fcb->open_mode = -1; */
     fcb->gdal = NULL;
     fcb->vrt = NULL;
 
@@ -1057,4 +1070,4 @@ void Rast_set_quant_rules(int fd, struct Quant *q)
         Rast_quant_set_neg_infinite_rule(&fcb->quant, dcell, cell);
     if (Rast_quant_get_pos_infinite_rule(q, &dcell, &cell) > 0)
         Rast_quant_set_pos_infinite_rule(&fcb->quant, dcell, cell);
-}
+}