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-rw-r--r--builtin-apply.c6
-rw-r--r--strbuf.c27
-rw-r--r--strbuf.h1
3 files changed, 30 insertions, 4 deletions
diff --git a/builtin-apply.c b/builtin-apply.c
index 4c4d1e1774..07244b0736 100644
--- a/builtin-apply.c
+++ b/builtin-apply.c
@@ -1559,10 +1559,8 @@ static int read_old_data(struct stat *st, const char *path, struct strbuf *buf)
{
switch (st->st_mode & S_IFMT) {
case S_IFLNK:
- strbuf_grow(buf, st->st_size);
- if (readlink(path, buf->buf, st->st_size) != st->st_size)
- return -1;
- strbuf_setlen(buf, st->st_size);
+ if (strbuf_readlink(buf, path, st->st_size) < 0)
+ return error("unable to read symlink %s", path);
return 0;
case S_IFREG:
if (strbuf_read_file(buf, path, st->st_size) != st->st_size)
diff --git a/strbuf.c b/strbuf.c
index 13be67e4d3..bdf49544d4 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -288,6 +288,33 @@ ssize_t strbuf_read(struct strbuf *sb, int fd, size_t hint)
return sb->len - oldlen;
}
+#define STRBUF_MAXLINK (2*PATH_MAX)
+
+int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint)
+{
+ if (hint < 32)
+ hint = 32;
+
+ while (hint < STRBUF_MAXLINK) {
+ int len;
+
+ strbuf_grow(sb, hint);
+ len = readlink(path, sb->buf, hint);
+ if (len < 0) {
+ if (errno != ERANGE)
+ break;
+ } else if (len < hint) {
+ strbuf_setlen(sb, len);
+ return 0;
+ }
+
+ /* .. the buffer was too small - try again */
+ hint *= 2;
+ }
+ strbuf_release(sb);
+ return -1;
+}
+
int strbuf_getline(struct strbuf *sb, FILE *fp, int term)
{
int ch;
diff --git a/strbuf.h b/strbuf.h
index b1670d9945..89bd36e15a 100644
--- a/strbuf.h
+++ b/strbuf.h
@@ -124,6 +124,7 @@ extern size_t strbuf_fread(struct strbuf *, size_t, FILE *);
/* XXX: if read fails, any partial read is undone */
extern ssize_t strbuf_read(struct strbuf *, int fd, size_t hint);
extern int strbuf_read_file(struct strbuf *sb, const char *path, size_t hint);
+extern int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint);
extern int strbuf_getline(struct strbuf *, FILE *, int);