[PATCH 15/32] vsprintf: Refactor ip_addr_string()

From: Kent Overstreet
Date: Sun Aug 14 2022 - 17:22:19 EST


From: Kent Overstreet <kent.overstreet@xxxxxxxxx>

- We're attempting to consolidate printf_spec and format string
handling in the top level vpr_buf(), this changes ip_addr_string() to
not take printf_spec

- With the new printbuf helpers there's no need to use a separate stack
allocated buffer, so this patch deletes it.

Signed-off-by: Kent Overstreet <kent.overstreet@xxxxxxxxx>
Cc: Petr Mladek <pmladek@xxxxxxxx>
Cc: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
---
lib/vsprintf.c | 114 ++++++++++++++++---------------------------------
1 file changed, 37 insertions(+), 77 deletions(-)

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index e3189c9f2d..27d23e82f5 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -1276,13 +1276,13 @@ void mac_address_string(struct printbuf *out, u8 *addr,
}

static noinline_for_stack
-void ip4_string(struct printbuf *out,
- const u8 *addr, const char *fmt)
+void ip4_string(struct printbuf *out, const u8 *addr, const char *fmt)
{
- int i;
- bool leading_zeros = (fmt[0] == 'i');
- int index;
- int step;
+ struct printf_spec spec = default_dec_spec;
+ int i, index, step;
+
+ if (fmt[0] == 'i')
+ spec.precision = 3;

switch (fmt[2]) {
case 'h':
@@ -1306,19 +1306,9 @@ void ip4_string(struct printbuf *out,
break;
}
for (i = 0; i < 4; i++) {
- char temp[4] __aligned(2); /* hold each IP quad in reverse order */
- int digits = put_dec_trunc8(temp, addr[index]) - temp;
- if (leading_zeros) {
- if (digits < 3)
- prt_char(out, '0');
- if (digits < 2)
- prt_char(out, '0');
- }
- /* reverse the digits in the quad */
- while (digits--)
- prt_char(out, temp[digits]);
- if (i < 3)
+ if (i)
prt_char(out, '.');
+ number(out, addr[index], spec);
index += step;
}
}
@@ -1401,8 +1391,6 @@ void ip6_compressed_string(struct printbuf *out, const char *addr)
__prt_char(out, ':');
ip4_string(out, &in6.s6_addr[12], "I4");
}
-
- printbuf_nul_terminate(out);
}

static noinline_for_stack
@@ -1420,41 +1408,20 @@ void ip6_string(struct printbuf *out, const char *addr, const char *fmt)

static noinline_for_stack
void ip6_addr_string(struct printbuf *out, const u8 *addr,
- struct printf_spec spec, const char *fmt)
+ const char *fmt)
{
- char ip6_addr_buf[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255")];
- struct printbuf ip6_addr = PRINTBUF_EXTERN(ip6_addr_buf, sizeof(ip6_addr_buf));
-
if (fmt[0] == 'I' && fmt[2] == 'c')
- ip6_compressed_string(&ip6_addr, addr);
+ ip6_compressed_string(out, addr);
else
- ip6_string(&ip6_addr, addr, fmt);
-
- string_nocheck(out, ip6_addr_buf, spec);
-}
-
-static noinline_for_stack
-void ip4_addr_string(struct printbuf *out, const u8 *addr,
- struct printf_spec spec, const char *fmt)
-{
- char ip4_addr_buf[sizeof("255.255.255.255")];
- struct printbuf ip4_addr = PRINTBUF_EXTERN(ip4_addr_buf, sizeof(ip4_addr_buf));
-
- ip4_string(&ip4_addr, addr, fmt);
-
- string_nocheck(out, ip4_addr_buf, spec);
+ ip6_string(out, addr, fmt);
}

static noinline_for_stack
void ip6_addr_string_sa(struct printbuf *out,
const struct sockaddr_in6 *sa,
- struct printf_spec spec, const char *fmt)
+ const char *fmt)
{
bool have_p = false, have_s = false, have_f = false, have_c = false;
- char ip6_addr_buf[sizeof("[xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255]") +
- sizeof(":12345") + sizeof("/123456789") +
- sizeof("%1234567890")];
- struct printbuf ip6_addr = PRINTBUF_EXTERN(ip6_addr_buf, sizeof(ip6_addr_buf));
const u8 *addr = (const u8 *) &sa->sin6_addr;
char fmt6[2] = { fmt[0], '6' };

@@ -1477,41 +1444,35 @@ void ip6_addr_string_sa(struct printbuf *out,
}

if (have_p || have_s || have_f)
- prt_char(&ip6_addr, '[');
+ prt_char(out, '[');

if (fmt6[0] == 'I' && have_c)
- ip6_compressed_string(&ip6_addr, addr);
+ ip6_compressed_string(out, addr);
else
- ip6_string(&ip6_addr, addr, fmt6);
+ ip6_string(out, addr, fmt6);

if (have_p || have_s || have_f)
- prt_char(&ip6_addr, ']');
+ prt_char(out, ']');

if (have_p) {
- prt_char(&ip6_addr, ':');
- number(&ip6_addr, ntohs(sa->sin6_port), spec);
+ prt_char(out, ':');
+ prt_u64(out, ntohs(sa->sin6_port));
}
if (have_f) {
- prt_char(&ip6_addr, '/');
- number(&ip6_addr, ntohl(sa->sin6_flowinfo &
- IPV6_FLOWINFO_MASK), spec);
+ prt_char(out, '/');
+ prt_u64(out, ntohl(sa->sin6_flowinfo & IPV6_FLOWINFO_MASK));
}
if (have_s) {
- prt_char(&ip6_addr, '%');
- number(&ip6_addr, sa->sin6_scope_id, spec);
+ prt_char(out, '%');
+ prt_u64(out, sa->sin6_scope_id);
}
-
- string_nocheck(out, ip6_addr_buf, spec);
}

static noinline_for_stack
-void ip4_addr_string_sa(struct printbuf *out,
- const struct sockaddr_in *sa,
- struct printf_spec spec, const char *fmt)
+void ip4_addr_string_sa(struct printbuf *out, const struct sockaddr_in *sa,
+ const char *fmt)
{
bool have_p = false;
- char ip4_addr_buf[sizeof("255.255.255.255") + sizeof(":12345")];
- struct printbuf ip4_addr = PRINTBUF_EXTERN(ip4_addr_buf, sizeof(ip4_addr_buf));
const u8 *addr = (const u8 *) &sa->sin_addr.s_addr;
char fmt4[3] = { fmt[0], '4', 0 };

@@ -1530,29 +1491,27 @@ void ip4_addr_string_sa(struct printbuf *out,
}
}

- ip4_string(&ip4_addr, addr, fmt4);
+ ip4_string(out, addr, fmt4);
if (have_p) {
- prt_char(&ip4_addr, ':');
- number(&ip4_addr, ntohs(sa->sin_port), spec);
+ prt_char(out, ':');
+ prt_u64(out, ntohs(sa->sin_port));
}
-
- string_nocheck(out, ip4_addr_buf, spec);
}

static noinline_for_stack
void ip_addr_string(struct printbuf *out, const void *ptr,
- struct printf_spec spec, const char *fmt)
+ const char *fmt)
{
char *err_fmt_msg;

- if (check_pointer_spec(out, ptr, spec))
+ if (check_pointer(out, ptr))
return;

switch (fmt[1]) {
case '6':
- return ip6_addr_string(out, ptr, spec, fmt);
+ return ip6_addr_string(out, ptr, fmt);
case '4':
- return ip4_addr_string(out, ptr, spec, fmt);
+ return ip4_string(out, ptr, fmt);
case 'S': {
const union {
struct sockaddr raw;
@@ -1562,16 +1521,16 @@ void ip_addr_string(struct printbuf *out, const void *ptr,

switch (sa->raw.sa_family) {
case AF_INET:
- return ip4_addr_string_sa(out, &sa->v4, spec, fmt);
+ return ip4_addr_string_sa(out, &sa->v4, fmt);
case AF_INET6:
- return ip6_addr_string_sa(out, &sa->v6, spec, fmt);
+ return ip6_addr_string_sa(out, &sa->v6, fmt);
default:
- return error_string_spec(out, "(einval)", spec);
+ return error_string(out, "(einval)");
}}
}

err_fmt_msg = fmt[0] == 'i' ? "(%pi?)" : "(%pI?)";
- return error_string_spec(out, err_fmt_msg, spec);
+ error_string(out, err_fmt_msg);
}

static noinline_for_stack
@@ -2318,7 +2277,8 @@ void pointer(struct printbuf *out, const char *fmt,
* 4: 001.002.003.004
* 6: 000102...0f
*/
- return ip_addr_string(out, ptr, spec, fmt);
+ ip_addr_string(out, ptr, fmt);
+ return do_width_precision(out, prev_pos, spec);
case 'E':
return escaped_string(out, ptr, spec, fmt);
case 'U':
--
2.36.1