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Few fixes in libposix error checking.

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size_t is a non-negative type and negative error checking didn't work. Now fixed.
Fixed various issues with reading file pages in the sys_read() path.
This commit is contained in:
Bahadir Balban
2008-04-20 02:12:53 +01:00
parent 8b3fedc18d
commit 9992d100d7
6 changed files with 33 additions and 27 deletions
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39
tasks/mm0/src/file.c
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@@ -71,8 +71,8 @@ int vfs_write(unsigned long vnum, unsigned long file_offset,
* about that file so that it can serve that file's content (via
* read/write/mmap) later to that task.
*/
int vfs2pager_sys_open(l4id_t sender, l4id_t opener, int fd,
unsigned long vnum, unsigned long length)
int vfs_receive_sys_open(l4id_t sender, l4id_t opener, int fd,
unsigned long vnum, unsigned long length)
{
struct vm_file *vmfile;
struct tcb *t;
@@ -183,16 +183,18 @@ int read_file_pages(struct vm_file *vmfile, unsigned long pfn_start,
return 0;
}
/* Reads a page range from an ordered list of pages into buffer.
/*
* Reads a page range from an ordered list of pages into buffer.
* NOTE: This assumes the page range is consecutively available
* in the cache. To ensure this, read_file_pages must be called first.
*/
int read_cache_pages(struct vm_file *vmfile, void *buf, unsigned long pfn_start,
unsigned long pfn_end, unsigned long offset, int count)
{
struct page *head, *next;
struct page *head, *this;
int copysize, left;
void *page_virtual;
unsigned long last_offset; /* Last copied page's offset */
/* Find the head of consecutive pages */
list_for_each_entry(head, &vmfile->vm_obj.page_cache, list)
@@ -205,28 +207,30 @@ int read_cache_pages(struct vm_file *vmfile, void *buf, unsigned long pfn_start,
copy:
left = count;
/* FIXME: May need to map the page first */
/*
* This function assumes the pages are already in-memory and
* they are mapped into the current address space.
*/
page_virtual = phys_to_virt((void *)page_to_phys(head));
/* Map the page */
page_virtual = l4_map_helper((void *)page_to_phys(head), 1);
/* Copy the first page and unmap it from current task. */
/* Copy the first page and unmap. */
copysize = (left < PAGE_SIZE) ? left : PAGE_SIZE;
memcpy(buf, page_virtual + offset, copysize);
left -= copysize;
l4_unmap(page_virtual, 1, self_tid());
l4_unmap_helper(page_virtual, 1);
last_offset = head->offset;
/* Copy the rest and unmap. */
list_for_each_entry(next, &head->list, list) {
if (left == 0 || next->offset == pfn_end)
/* Map the rest, copy and unmap. */
list_for_each_entry(this, &head->list, list) {
if (left == 0 || this->offset == pfn_end)
break;
/* Make sure we're advancing on pages consecutively */
BUG_ON(this->offset != last_offset + 1);
copysize = (left < PAGE_SIZE) ? left : PAGE_SIZE;
page_virtual = phys_to_virt((void *)page_to_phys(next));
page_virtual = l4_map_helper((void *)page_to_phys(this), 1);
memcpy(buf + count - left, page_virtual, copysize);
l4_unmap(page_virtual, 1, self_tid());
l4_unmap_helper(page_virtual, 1);
left -= copysize;
last_offset = this->offset;
}
BUG_ON(left != 0);
@@ -240,6 +244,7 @@ int sys_read(l4id_t sender, int fd, void *buf, int count)
struct vm_file *vmfile;
struct tcb *t;
int cnt;
int err;
BUG_ON(!(t = find_task(sender)));