sambuc/codezero
1
0
Fork 0
mirror of https://github.com/drasko/codezero.git synced 2026-01-13 11:23:16 +01:00
Code Issues Actions Packages Projects Releases Wiki Activity

Now using a common method for copying variable size strings and pointer array.

Browse Source
This commit is contained in:
Bahadir Balban
2008-11-25 12:28:50 +02:00
parent a9e6aabcae
commit 321b5b2b73
1 changed files with 64 additions and 32 deletions
Download Patch File Download Diff File Expand all files Collapse all files

96
tasks/mm0/src/execve.c
View File

@@ -187,32 +187,7 @@ Dynamic Linking.
#endif
return -1;
}
/*
* Copy from one buffer to another. Stop if maxlength or
* a page boundary is hit.
*/
int strncpy_page(char *to, char *from, int maxlength)
{
int count = 0;
do {
if ((to[count] = from[count]) == '\0') {
count++;
break;
} else
count++;
} while (count < maxlength && !page_boundary(&from[count]));
if (page_boundary(&from[count]))
return -EFAULT;
if (count == maxlength)
return -E2BIG;
return count;
}
#if 0
/*
* Copies a userspace string into buffer. If a page boundary is hit,
* unmaps the previous page, validates and maps the new page.
@@ -250,15 +225,42 @@ int copy_user_string(struct tcb *task, char *buf, char *user, int maxlength)
return total;
}
#endif
/*
* Copy from one buffer to another. Stop if maxlength or
* a page boundary is hit.
*/
int strncpy_page(void *to_ptr, void *from_ptr, int maxlength)
{
int count = 0;
char *to = to_ptr, *from = from_ptr;
do {
if ((to[count] = from[count]) == '\0') {
count++;
break;
} else
count++;
} while (count < maxlength && !page_boundary(&from[count]));
if (page_boundary(&from[count]))
return -EFAULT;
if (count == maxlength)
return -E2BIG;
return count;
}
/*
* Copy from one buffer to another. Stop if maxlength or
* a page boundary is hit. Breaks if unsigned long sized copy value is 0,
* as opposed to a 0 byte as in string copy.
*/
int bufncpy_page(unsigned long *to, unsigned long *from, int maxlength)
int bufncpy_page(void *to_ptr, void *from_ptr, int maxlength)
{
int count = 0;
unsigned long *to = to_ptr, *from = from_ptr;
do {
if ((to[count] = from[count]) == 0) {
@@ -280,11 +282,20 @@ int bufncpy_page(unsigned long *to, unsigned long *from, int maxlength)
* Copies a userspace string into buffer. If a page boundary is hit,
* unmaps the previous page, validates and maps the new page.
*/
int copy_user_buf(struct tcb *task, char *buf, char *user, int maxlength)
int copy_user_buf(struct tcb *task, void *buf, char *user, int maxlength,
int elem_size)
{
int count = maxlength;
int copied = 0, ret = 0, total = 0;
unsigned long *mapped = 0;
void *mapped = 0;
int (*copy_func)(void *, void *, int count);
if (elem_size == sizeof(char))
copy_func = strncpy_page;
else if (elem_size == sizeof(unsigned long))
copy_func = bufncpy_page;
else
return -EINVAL;
/* Map the first page the user buffer is in */
if (!(mapped = pager_validate_map_user_range(task, user,
@@ -292,10 +303,15 @@ int copy_user_buf(struct tcb *task, char *buf, char *user, int maxlength)
VM_READ)))
return -EINVAL;
while ((ret = bufncpy_page((unsigned long *)&buf[copied], mapped, count)) < 0) {
while ((ret = copy_func(buf + copied, mapped, count)) < 0) {
if (ret == -E2BIG)
return ret;
else if (ret == -EFAULT) {
/*
* Copied is always in bytes no matter what elem_size is
* because we know we hit a page boundary and we increase
* by the page boundary bytes
*/
pager_unmap_user_range(mapped, TILL_PAGE_ENDS(mapped));
copied += TILL_PAGE_ENDS(mapped);
count -= TILL_PAGE_ENDS(mapped);
@@ -306,7 +322,9 @@ int copy_user_buf(struct tcb *task, char *buf, char *user, int maxlength)
return -EINVAL;
}
}
total = copied + ret;
/* Note copied is always in bytes */
total = (copied / elem_size) + ret;
/* Unmap the final page */
pager_unmap_user_range(mapped, TILL_PAGE_ENDS(mapped));
@@ -314,6 +332,20 @@ int copy_user_buf(struct tcb *task, char *buf, char *user, int maxlength)
return total;
}
static inline int
copy_user_string(struct tcb *task, void *buf, char *user,
int maxlength)
{
return copy_user_buf(task, buf, user, maxlength, sizeof(char));
}
static inline int
copy_user_ptrs(struct tcb *task, void *buf, char *user,
int maxlength)
{
return copy_user_buf(task, buf, user, maxlength, sizeof(unsigned long));
}
struct args_struct {
int argc;
char **argv;
@@ -337,7 +369,7 @@ int copy_user_args(struct tcb *task, struct args_struct *args,
* First, copy the null-terminated array of
* pointers to argument strings.
*/
if ((count = copy_user_buf(task, argsbuf, argv_user, args_max)) < 0)
if ((count = copy_user_ptrs(task, argsbuf, argv_user, args_max)) < 0)
goto out;
/* On success, we get the number of arg strings + the terminator */