change mmap return MAP_FAILED on error and set errno

smartobjectoriented · Feb 19, 2025 · 3c6403c · 3c6403c
1 parent 2df5f22
commit 3c6403c
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Showing 6 changed files with 30 additions and 10 deletions.
diff --git a/so3/devices/mem.c b/so3/devices/mem.c
@@ -1,3 +1,4 @@
+#include <errno.h>
 #include <vfs.h>
 #include <common.h>
 #include <process.h>
@@ -19,11 +20,15 @@ static void *mem_mmap(int fd, addr_t virt_addr, uint32_t page_count, off_t offse
 
 	/* Detect physical or virtual address overflow */
 	if (((offset + remaining_size) < offset)
-	    || ((virt_addr + remaining_size) < virt_addr))
-		return NULL;
+	    || ((virt_addr + remaining_size) < virt_addr)) {
+		set_errno(EINVAL);
+		return MAP_FAILED;
+	}
 
-	if (!virt_addr)
-		return NULL;
+	if (!virt_addr) {
+		set_errno(EINVAL);
+		return MAP_FAILED;
+	}
 
 	pcb = current()->pcb;
 	BUG_ON(pcb == NULL);

diff --git a/so3/fs/vfs.c b/so3/fs/vfs.c
@@ -757,16 +757,18 @@ void *do_mmap(addr_t start, size_t length, int prot, int fd, off_t offset)
 
 	gfd = vfs_get_gfd(fd);
 	if (-1 == gfd) {
-		printk("%s: could not get global fd.", __func__);
-		return NULL;
+		printk("%s: could not get global fd.\n", __func__);
+		set_errno(EBADF);
+		return MAP_FAILED;
 	}
 
 	mutex_lock(&vfs_lock);
 	fops = vfs_get_fops(gfd);
 	if (!fops) {
-		printk("%s: could not get the framebuffer fops.", __func__);
+		printk("%s: could not get device fops.\n", __func__);
 		mutex_unlock(&vfs_lock);
-		return NULL;
+		set_errno(EBADF);
+		return MAP_FAILED;
 	}
 
 	mutex_unlock(&vfs_lock);
@@ -777,6 +779,12 @@ void *do_mmap(addr_t start, size_t length, int prot, int fd, off_t offset)
 		page_count++;
 	}
 
+	if (!fops->mmap) {
+		printk("%s: device doesn't support mmap.\n", __func__);
+		set_errno(EACCES);
+		return MAP_FAILED;
+	}
+
 	/* Call the mmap fops that will do the actual mapping. */
 	return fops->mmap(fd, start, page_count, offset);
 }

diff --git a/so3/include/vfs.h b/so3/include/vfs.h
@@ -91,6 +91,9 @@
 #define DT_LNK		10	/* Symbolic link */
 #define DT_SOCK		12	/* Socket device */
 
+/* Return error values */
+#define MAP_FAILED ((void *) -1)	/* mmap fail */
+
 #ifndef __ASSEMBLY__
 
 #include <types.h>

diff --git a/usr/src/fillfb.c b/usr/src/fillfb.c
@@ -68,6 +68,10 @@ int main(int argc, char **argv)
 
 	/* Map the framebuffer memory to a process virtual address. */
 	fbp = mmap(NULL, fb_size, 0, 0, fd, 0);
+	if (fbp == MAP_FAILED) {
+		printf("Couldn't map framebuffer.\n");
+		return -1;
+	}
 
 	/* Display lines of different colors. */
 	for (i = 0; i < vres; i++) {

diff --git a/usr/src/stress/lvgl_perf.c b/usr/src/stress/lvgl_perf.c
@@ -181,7 +181,7 @@ int fb_init(void)
 
 	/* Map the framebuffer into process memory. */
 	fbp = mmap(NULL, fb_size, 0, 0, fd, 0);
-	if (!fbp) {
+	if (fbp == MAP_FAILED) {
 		printf("Couldn't map framebuffer.\n");
 		return -1;
 	}

diff --git a/usr/src/widgets/demofb.c b/usr/src/widgets/demofb.c
@@ -158,7 +158,7 @@ int fb_init(void)
 
 	/* Map the framebuffer into process memory. */
 	fbp = mmap(NULL, fb_size, 0, 0, fd, 0);
-	if (!fbp) {
+	if (fbp == MAP_FAILED) {
 		printf("Couldn't map framebuffer.\n");
 		return -1;
 	}