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Commit a9090253 authored by William Roberts's avatar William Roberts Committed by Eric Paris
Browse files

mm: Create utility function for accessing a tasks commandline value 



introduce get_cmdline() for retreiving the value of a processes
proc/self/cmdline value.

Acked-by: default avatarDavid Rientjes <rientjes@google.com>
Acked-by: default avatarStephen Smalley <sds@tycho.nsa.gov>
Acked-by: default avatarRichard Guy Briggs <rgb@redhat.com>

Signed-off-by: default avatarWilliam Roberts <wroberts@tresys.com>
Signed-off-by: default avatarEric Paris <eparis@redhat.com>
parent 147d2601

include/linux/mm.h

+1 −0
Original line number Diff line number Diff line
@@ -1134,6 +1134,7 @@ void account_page_writeback(struct page *page); 
int set_page_dirty(struct page *page);

int set_page_dirty_lock(struct page *page);

int clear_page_dirty_for_io(struct page *page);

int get_cmdline(struct task_struct *task, char *buffer, int buflen);



/* Is the vma a continuation of the stack vma above it? */

static inline int vma_growsdown(struct vm_area_struct *vma, unsigned long addr)

mm/util.c

+48 −0
Original line number Diff line number Diff line
@@ -413,6 +413,54 @@ unsigned long vm_commit_limit(void) 
		* sysctl_overcommit_ratio / 100) + total_swap_pages;

}



/**

 * get_cmdline() - copy the cmdline value to a buffer.

 * @task:     the task whose cmdline value to copy.

 * @buffer:   the buffer to copy to.

 * @buflen:   the length of the buffer. Larger cmdline values are truncated

 *            to this length.

 * Returns the size of the cmdline field copied. Note that the copy does

 * not guarantee an ending NULL byte.

 */

int get_cmdline(struct task_struct *task, char *buffer, int buflen)

{

	int res = 0;

	unsigned int len;

	struct mm_struct *mm = get_task_mm(task);

	if (!mm)

		goto out;

	if (!mm->arg_end)

		goto out_mm;	/* Shh! No looking before we're done */



	len = mm->arg_end - mm->arg_start;



	if (len > buflen)

		len = buflen;



	res = access_process_vm(task, mm->arg_start, buffer, len, 0);



	/*

	 * If the nul at the end of args has been overwritten, then

	 * assume application is using setproctitle(3).

	 */

	if (res > 0 && buffer[res-1] != '\0' && len < buflen) {

		len = strnlen(buffer, res);

		if (len < res) {

			res = len;

		} else {

			len = mm->env_end - mm->env_start;

			if (len > buflen - res)

				len = buflen - res;

			res += access_process_vm(task, mm->env_start,

						 buffer+res, len, 0);

			res = strnlen(buffer, res);

		}

	}

out_mm:

	mmput(mm);

out:

	return res;

}



/* Tracepoints definitions. */

EXPORT_TRACEPOINT_SYMBOL(kmalloc);