vga: ppm_save(): add error handling

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>

hw/blizzard.c

@@ -939,7 +939,7 @@ static void blizzard_screen_dump(void *opaque, const char *filename,
 
     blizzard_update_display(opaque);
     if (s && ds_get_data(s->state))
-        ppm_save(filename, s->state->surface);
+        ppm_save(filename, s->state->surface, errp);
 }
 
 #define DEPTH 8

hw/qxl.c

@@ -1605,7 +1605,7 @@ static void qxl_hw_screen_dump(void *opaque, const char *filename, bool cswitch,
     case QXL_MODE_COMPAT:
     case QXL_MODE_NATIVE:
         qxl_render_update(qxl);
-        ppm_save(filename, qxl->ssd.ds->surface);
+        ppm_save(filename, qxl->ssd.ds->surface, errp);
         break;
     case QXL_MODE_VGA:
         vga->screen_dump(vga, filename, cswitch, errp);

hw/vga.c

@@ -2390,7 +2390,7 @@ void vga_init_vbe(VGACommonState *s, MemoryRegion *system_memory)
 /********************************************************/
 /* vga screen dump */
 
-int ppm_save(const char *filename, struct DisplaySurface *ds)
+void ppm_save(const char *filename, struct DisplaySurface *ds, Error **errp)
 {
     FILE *f;
     uint8_t *d, *d1;
@@ -2402,10 +2402,16 @@ int ppm_save(const char *filename, struct DisplaySurface *ds)
 
     trace_ppm_save(filename, ds);
     f = fopen(filename, "wb");
-    if (!f)
-        return -1;
-    fprintf(f, "P6\n%d %d\n%d\n",
-            ds->width, ds->height, 255);
+    if (!f) {
+        error_setg(errp, "failed to open file '%s': %s", filename,
+                   strerror(errno));
+        return;
+    }
+    ret = fprintf(f, "P6\n%d %d\n%d\n", ds->width, ds->height, 255);
+    if (ret < 0) {
+        linebuf = NULL;
+        goto write_err;
+    }
     linebuf = g_malloc(ds->width * 3);
     d1 = ds->data;
     for(y = 0; y < ds->height; y++) {
@@ -2426,12 +2432,24 @@ int ppm_save(const char *filename, struct DisplaySurface *ds)
             d += ds->pf.bytes_per_pixel;
         }
         d1 += ds->linesize;
+        clearerr(f);
         ret = fwrite(linebuf, 1, pbuf - linebuf, f);
         (void)ret;
+        if (ferror(f)) {
+            goto write_err;
+        }
     }
+
+out:
     g_free(linebuf);
     fclose(f);
-    return 0;
+    return;
+
+write_err:
+    error_setg(errp, "failed to write to file '%s': %s", filename,
+               strerror(errno));
+    unlink(filename);
+    goto out;
 }
 
 /* save the vga display in a PPM image even if no display is
@@ -2445,5 +2463,5 @@ static void vga_screen_dump(void *opaque, const char *filename, bool cswitch,
         vga_invalidate_display(s);
     }
     vga_hw_update();
-    ppm_save(filename, s->ds->surface);
+    ppm_save(filename, s->ds->surface, errp);
 }

hw/vga_int.h

@@ -23,6 +23,7 @@
  */
 
 #include <hw/hw.h>
+#include "error.h"
 #include "memory.h"
 
 #define ST01_V_RETRACE      0x08
@@ -204,7 +205,7 @@ void vga_ioport_write(void *opaque, uint32_t addr, uint32_t val);
 uint32_t vga_mem_readb(VGACommonState *s, target_phys_addr_t addr);
 void vga_mem_writeb(VGACommonState *s, target_phys_addr_t addr, uint32_t val);
 void vga_invalidate_scanlines(VGACommonState *s, int y1, int y2);
-int ppm_save(const char *filename, struct DisplaySurface *ds);
+void ppm_save(const char *filename, struct DisplaySurface *ds, Error **errp);
 
 int vga_ioport_invalid(VGACommonState *s, uint32_t addr);
 void vga_init_vbe(VGACommonState *s, MemoryRegion *address_space);

hw/vmware_vga.c

@@ -1015,7 +1015,7 @@ static void vmsvga_screen_dump(void *opaque, const char *filename, bool cswitch,
     if (s->depth == 32) {
         DisplaySurface *ds = qemu_create_displaysurface_from(s->width,
                 s->height, 32, ds_get_linesize(s->vga.ds), s->vga.vram_ptr);
-        ppm_save(filename, ds);
+        ppm_save(filename, ds, errp);
         g_free(ds);
     }
 }