+ rv = access_remote_vm(mm, arg_end - 1, &c, 1, 0);
+ if (rv <= 0)
+ goto out_free_page;
+
+ rv = 0;
+
+ if (c == '\0') {
+ /* Command line (set of strings) occupies whole ARGV. */
+ if (len1 <= *pos)
+ goto out_free_page;
+
+ p = arg_start + *pos;
+ len = len1 - *pos;
+ while (count > 0 && len > 0) {
+ unsigned int _count;
+ int nr_read;
+
+ _count = min3(count, len, PAGE_SIZE);
+ nr_read = access_remote_vm(mm, p, page, _count, 0);
+ if (nr_read < 0)
+ rv = nr_read;
+ if (nr_read <= 0)
+ goto out_free_page;
+
+ if (copy_to_user(buf, page, nr_read)) {
+ rv = -EFAULT;
+ goto out_free_page;
+ }
+
+ p += nr_read;
+ len -= nr_read;
+ buf += nr_read;
+ count -= nr_read;
+ rv += nr_read;
+ }
+ } else {
+ /*
+ * Command line (1 string) occupies ARGV and maybe
+ * extends into ENVP.
+ */
+ if (len1 + len2 <= *pos)
+ goto skip_argv_envp;
+ if (len1 <= *pos)
+ goto skip_argv;
+
+ p = arg_start + *pos;
+ len = len1 - *pos;
+ while (count > 0 && len > 0) {
+ unsigned int _count, l;
+ int nr_read;
+ bool final;
+
+ _count = min3(count, len, PAGE_SIZE);
+ nr_read = access_remote_vm(mm, p, page, _count, 0);
+ if (nr_read < 0)
+ rv = nr_read;
+ if (nr_read <= 0)
+ goto out_free_page;
+
+ /*
+ * Command line can be shorter than whole ARGV
+ * even if last "marker" byte says it is not.
+ */
+ final = false;
+ l = strnlen(page, nr_read);
+ if (l < nr_read) {
+ nr_read = l;
+ final = true;
+ }
+
+ if (copy_to_user(buf, page, nr_read)) {
+ rv = -EFAULT;
+ goto out_free_page;
+ }
+
+ p += nr_read;
+ len -= nr_read;
+ buf += nr_read;
+ count -= nr_read;
+ rv += nr_read;
+
+ if (final)
+ goto out_free_page;
+ }
+skip_argv:
+ /*
+ * Command line (1 string) occupies ARGV and
+ * extends into ENVP.
+ */
+ if (len1 <= *pos) {
+ p = env_start + *pos - len1;
+ len = len1 + len2 - *pos;
+ } else {
+ p = env_start;
+ len = len2;
+ }
+ while (count > 0 && len > 0) {
+ unsigned int _count, l;
+ int nr_read;
+ bool final;
+
+ _count = min3(count, len, PAGE_SIZE);
+ nr_read = access_remote_vm(mm, p, page, _count, 0);
+ if (nr_read < 0)
+ rv = nr_read;
+ if (nr_read <= 0)
+ goto out_free_page;
+
+ /* Find EOS. */
+ final = false;
+ l = strnlen(page, nr_read);
+ if (l < nr_read) {
+ nr_read = l;
+ final = true;
+ }
+
+ if (copy_to_user(buf, page, nr_read)) {
+ rv = -EFAULT;
+ goto out_free_page;
+ }
+
+ p += nr_read;
+ len -= nr_read;
+ buf += nr_read;
+ count -= nr_read;
+ rv += nr_read;
+
+ if (final)
+ goto out_free_page;
+ }
+skip_argv_envp:
+ ;
+ }
+
+out_free_page:
+ free_page((unsigned long)page);
+out_mmput:
+ mmput(mm);
+ if (rv > 0)
+ *pos += rv;
+ return rv;