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authorWilliam Roberts <bill.c.roberts@gmail.com>2014-02-11 10:11:59 -0800
committerEric Paris <eparis@redhat.com>2014-03-07 11:52:45 -0500
commita90902531a06a030a252a07fbff7f45a189a64fe (patch)
tree676cd6bd7530f5187af569baf93a138d085737c0 /mm
parent147d2601d8fabf9451364f2d58098530a37eb3c9 (diff)
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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: David Rientjes <rientjes@google.com> Acked-by: Stephen Smalley <sds@tycho.nsa.gov> Acked-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: William Roberts <wroberts@tresys.com> Signed-off-by: Eric Paris <eparis@redhat.com>
Diffstat (limited to 'mm')
-rw-r--r--mm/util.c48
1 files changed, 48 insertions, 0 deletions
diff --git a/mm/util.c b/mm/util.c
index 808f375648e7..43b44199c5e3 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -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);