[PATCH perf/core v2 1/8] perf: Rewrite strbuf not to die

From: Masami Hiramatsu
Date: Fri Apr 29 2016 - 11:10:00 EST


Rewrite strbuf implementation not to use die() nor xrealloc().
Instead of die, now most of the API returns error code or 0 if
succeeded.

Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
---
tools/perf/util/strbuf.c | 93 +++++++++++++++++++++++++++++++++-------------
tools/perf/util/strbuf.h | 25 +++++++-----
2 files changed, 82 insertions(+), 36 deletions(-)

diff --git a/tools/perf/util/strbuf.c b/tools/perf/util/strbuf.c
index 8fb7329..a98bb60 100644
--- a/tools/perf/util/strbuf.c
+++ b/tools/perf/util/strbuf.c
@@ -1,3 +1,4 @@
+#include "debug.h"
#include "cache.h"
#include <linux/kernel.h>

@@ -17,12 +18,13 @@ int prefixcmp(const char *str, const char *prefix)
*/
char strbuf_slopbuf[1];

-void strbuf_init(struct strbuf *sb, ssize_t hint)
+int strbuf_init(struct strbuf *sb, ssize_t hint)
{
sb->alloc = sb->len = 0;
sb->buf = strbuf_slopbuf;
if (hint)
- strbuf_grow(sb, hint);
+ return strbuf_grow(sb, hint);
+ return 0;
}

void strbuf_release(struct strbuf *sb)
@@ -42,67 +44,104 @@ char *strbuf_detach(struct strbuf *sb, size_t *sz)
return res;
}

-void strbuf_grow(struct strbuf *sb, size_t extra)
+int strbuf_grow(struct strbuf *sb, size_t extra)
{
- if (sb->len + extra + 1 <= sb->len)
- die("you want to use way too much memory");
- if (!sb->alloc)
- sb->buf = NULL;
- ALLOC_GROW(sb->buf, sb->len + extra + 1, sb->alloc);
+ char *buf;
+ size_t nr = sb->len + extra + 1;
+
+ if (nr < sb->alloc)
+ return 0;
+
+ if (nr <= sb->len)
+ return -E2BIG;
+
+ if (alloc_nr(sb->alloc) > nr)
+ nr = alloc_nr(sb->alloc);
+
+ buf = malloc(nr * sizeof(*buf));
+ if (!buf)
+ return -ENOMEM;
+
+ if (sb->alloc) {
+ memcpy(buf, sb->buf, sb->alloc);
+ free(sb->buf);
+ }
+ sb->buf = buf;
+ sb->alloc = nr;
+ return 0;
}

-void strbuf_addch(struct strbuf *sb, int c)
+int strbuf_addch(struct strbuf *sb, int c)
{
- strbuf_grow(sb, 1);
+ int ret = strbuf_grow(sb, 1);
+ if (ret)
+ return ret;
+
sb->buf[sb->len++] = c;
sb->buf[sb->len] = '\0';
+ return 0;
}

-void strbuf_add(struct strbuf *sb, const void *data, size_t len)
+int strbuf_add(struct strbuf *sb, const void *data, size_t len)
{
- strbuf_grow(sb, len);
+ int ret = strbuf_grow(sb, len);
+ if (ret)
+ return ret;
+
memcpy(sb->buf + sb->len, data, len);
- strbuf_setlen(sb, sb->len + len);
+ return strbuf_setlen(sb, sb->len + len);
}

-static void strbuf_addv(struct strbuf *sb, const char *fmt, va_list ap)
+static int strbuf_addv(struct strbuf *sb, const char *fmt, va_list ap)
{
- int len;
+ int len, ret;
va_list ap_saved;

- if (!strbuf_avail(sb))
- strbuf_grow(sb, 64);
+ if (!strbuf_avail(sb)) {
+ ret = strbuf_grow(sb, 64);
+ if (ret)
+ return ret;
+ }

va_copy(ap_saved, ap);
len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
if (len < 0)
- die("your vsnprintf is broken");
+ return len;
if (len > strbuf_avail(sb)) {
- strbuf_grow(sb, len);
+ ret = strbuf_grow(sb, len);
+ if (ret)
+ return ret;
len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap_saved);
va_end(ap_saved);
if (len > strbuf_avail(sb)) {
- die("this should not happen, your vsnprintf is broken");
+ pr_debug("this should not happen, your vsnprintf is broken");
+ return -EINVAL;
}
}
- strbuf_setlen(sb, sb->len + len);
+ return strbuf_setlen(sb, sb->len + len);
}

-void strbuf_addf(struct strbuf *sb, const char *fmt, ...)
+int strbuf_addf(struct strbuf *sb, const char *fmt, ...)
{
va_list ap;
+ int ret;

va_start(ap, fmt);
- strbuf_addv(sb, fmt, ap);
+ ret = strbuf_addv(sb, fmt, ap);
va_end(ap);
+ return ret;
}

ssize_t strbuf_read(struct strbuf *sb, int fd, ssize_t hint)
{
size_t oldlen = sb->len;
size_t oldalloc = sb->alloc;
+ int ret;
+
+ ret = strbuf_grow(sb, hint ? hint : 8192);
+ if (ret)
+ return ret;

- strbuf_grow(sb, hint ? hint : 8192);
for (;;) {
ssize_t cnt;

@@ -112,12 +151,14 @@ ssize_t strbuf_read(struct strbuf *sb, int fd, ssize_t hint)
strbuf_release(sb);
else
strbuf_setlen(sb, oldlen);
- return -1;
+ return cnt;
}
if (!cnt)
break;
sb->len += cnt;
- strbuf_grow(sb, 8192);
+ ret = strbuf_grow(sb, 8192);
+ if (ret)
+ return ret;
}

sb->buf[sb->len] = '\0';
diff --git a/tools/perf/util/strbuf.h b/tools/perf/util/strbuf.h
index ab9be0fb..54b4092 100644
--- a/tools/perf/util/strbuf.h
+++ b/tools/perf/util/strbuf.h
@@ -51,7 +51,7 @@ struct strbuf {
#define STRBUF_INIT { 0, 0, strbuf_slopbuf }

/*----- strbuf life cycle -----*/
-void strbuf_init(struct strbuf *buf, ssize_t hint);
+int strbuf_init(struct strbuf *buf, ssize_t hint);
void strbuf_release(struct strbuf *buf);
char *strbuf_detach(struct strbuf *buf, size_t *);

@@ -60,26 +60,31 @@ static inline ssize_t strbuf_avail(const struct strbuf *sb) {
return sb->alloc ? sb->alloc - sb->len - 1 : 0;
}

-void strbuf_grow(struct strbuf *buf, size_t);
+int strbuf_grow(struct strbuf *buf, size_t);

-static inline void strbuf_setlen(struct strbuf *sb, size_t len) {
- if (!sb->alloc)
- strbuf_grow(sb, 0);
+static inline int strbuf_setlen(struct strbuf *sb, size_t len) {
+ int ret;
+ if (!sb->alloc) {
+ ret = strbuf_grow(sb, 0);
+ if (ret)
+ return ret;
+ }
assert(len < sb->alloc);
sb->len = len;
sb->buf[len] = '\0';
+ return 0;
}

/*----- add data in your buffer -----*/
-void strbuf_addch(struct strbuf *sb, int c);
+int strbuf_addch(struct strbuf *sb, int c);

-void strbuf_add(struct strbuf *buf, const void *, size_t);
-static inline void strbuf_addstr(struct strbuf *sb, const char *s) {
- strbuf_add(sb, s, strlen(s));
+int strbuf_add(struct strbuf *buf, const void *, size_t);
+static inline int strbuf_addstr(struct strbuf *sb, const char *s) {
+ return strbuf_add(sb, s, strlen(s));
}

__attribute__((format(printf,2,3)))
-void strbuf_addf(struct strbuf *sb, const char *fmt, ...);
+int strbuf_addf(struct strbuf *sb, const char *fmt, ...);

/* XXX: if read fails, any partial read is undone */
ssize_t strbuf_read(struct strbuf *, int fd, ssize_t hint);