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authorAlexey Dobriyan <adobriyan@gmail.com>2018-06-07 17:10:02 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-06-07 17:34:38 -0700
commit3cb4e162e4e258d906c07c411283b42b7f20a285 (patch)
tree3a1d74c7ebd16d3dc9f3fbe7edce9a926b29251b /fs/proc
parent6a6cbe75dbdfaed6c4bbc2f109d69808f9cfa421 (diff)
downloadlinux-3cb4e162e4e258d906c07c411283b42b7f20a285.tar.bz2
proc: deduplicate /proc/*/cmdline implementation
Code can be sonsolidated if a dummy region of 0 length is used in normal case of \0-separated command line: 1) [arg_start, arg_end) + [dummy len=0] 2) [arg_start, arg_end) + [env_start, env_end) Link: http://lkml.kernel.org/r/20180221193335.GB28678@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/proc')
-rw-r--r--fs/proc/base.c53
1 files changed, 20 insertions, 33 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 3fcca77d45f1..3954f50805b8 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -213,9 +213,12 @@ static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf,
char *page;
unsigned long count = _count;
unsigned long arg_start, arg_end, env_start, env_end;
- unsigned long len1, len2, len;
- unsigned long p;
+ unsigned long len1, len2;
char __user *buf0 = buf;
+ struct {
+ unsigned long p;
+ unsigned long len;
+ } cmdline[2];
char c;
int rv;
@@ -264,43 +267,21 @@ static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf,
if (access_remote_vm(mm, arg_end - 1, &c, 1, FOLL_ANON) != 1)
goto end;
+ cmdline[0].p = arg_start;
+ cmdline[0].len = len1;
if (c == '\0') {
/* Command line (set of strings) occupies whole ARGV. */
- if (len1 <= *pos)
- goto end;
-
- p = arg_start + *pos;
- len = len1 - *pos;
- while (count > 0 && len > 0) {
- unsigned int nr_read;
-
- nr_read = min3(count, len, PAGE_SIZE);
- nr_read = access_remote_vm(mm, p, page, nr_read, FOLL_ANON);
- if (nr_read == 0)
- goto end;
-
- 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;
- }
+ cmdline[1].len = 0;
} else {
/*
* Command line (1 string) occupies ARGV and
* extends into ENVP.
*/
- struct {
- unsigned long p;
- unsigned long len;
- } cmdline[2] = {
- { .p = arg_start, .len = len1 },
- { .p = env_start, .len = len2 },
- };
+ cmdline[1].p = env_start;
+ cmdline[1].len = len2;
+ }
+
+ {
loff_t pos1 = *pos;
unsigned int i;
@@ -310,6 +291,9 @@ static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf,
i++;
}
while (i < 2) {
+ unsigned long p;
+ unsigned long len;
+
p = cmdline[i].p + pos1;
len = cmdline[i].len - pos1;
while (count > 0 && len > 0) {
@@ -324,7 +308,10 @@ static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf,
* Command line can be shorter than whole ARGV
* even if last "marker" byte says it is not.
*/
- nr_write = strnlen(page, nr_read);
+ if (c == '\0')
+ nr_write = nr_read;
+ else
+ nr_write = strnlen(page, nr_read);
if (copy_to_user(buf, page, nr_write)) {
rv = -EFAULT;