Merge branch 'lt/readlink'

* lt/readlink:
combine-diff.c: use strbuf_readlink()
builtin-blame.c: use strbuf_readlink()
make_absolute_path(): check bounds when seeing an overlong symlink
Make 'prepare_temp_file()' ignore st_size for symlinks
Make 'diff_populate_filespec()' use the new 'strbuf_readlink()'
Make 'index_path()' use 'strbuf_readlink()'
Make 'ce_compare_link()' use the new 'strbuf_readlink()'
Add generic 'strbuf_readlink()' helper function

diff --git a/abspath.c b/abspath.c
index 8194ce1256525105d07eedf2f964ad51d9162d95..649f34f83365db3513c5166b897c4f033831444d 100644 (file)
--- a/abspath.c
+++ b/abspath.c
@@ -64,6 +64,8 @@ const char *make_absolute_path(const char *path)
                        len = readlink(buf, next_buf, PATH_MAX);
                        if (len < 0)
                                die ("Invalid symlink: %s", buf);
+                       if (PATH_MAX <= len)
+                               die("symbolic link too long: %s", buf);
                        next_buf[len] = '\0';
                        buf = next_buf;
                        buf_index = 1 - buf_index;

diff --git a/builtin-apply.c b/builtin-apply.c
index 4c4d1e1774ade358dbc3283df5d1b764a32821b8..07244b0736047d6cfe67db7f059f7755906579f0 100644 (file)
--- 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/builtin-blame.c b/builtin-blame.c
index a0d60145f26d32e45f4d04c22164cbe8060739ca..aae14ef8bb63abc598e2e3ce99bf64d5c07e0067 100644 (file)
--- a/builtin-blame.c
+++ b/builtin-blame.c
@@ -1996,7 +1996,6 @@ static struct commit *fake_working_tree_commit(const char *path, const char *con
        if (!contents_from || strcmp("-", contents_from)) {
                struct stat st;
                const char *read_from;
-               unsigned long fin_size;
 
                if (contents_from) {
                        if (stat(contents_from, &st) < 0)
@@ -2008,7 +2007,6 @@ static struct commit *fake_working_tree_commit(const char *path, const char *con
                                die("Cannot lstat %s", path);
                        read_from = path;
                }
-               fin_size = xsize_t(st.st_size);
                mode = canon_mode(st.st_mode);
                switch (st.st_mode & S_IFMT) {
                case S_IFREG:
@@ -2016,9 +2014,8 @@ static struct commit *fake_working_tree_commit(const char *path, const char *con
                                die("cannot open or read %s", read_from);
                        break;
                case S_IFLNK:
-                       if (readlink(read_from, buf.buf, buf.alloc) != fin_size)
+                       if (strbuf_readlink(&buf, read_from, st.st_size) < 0)
                                die("cannot readlink %s", read_from);
-                       buf.len = fin_size;
                        break;
                default:
                        die("unsupported file type %s", read_from);

diff --git a/combine-diff.c b/combine-diff.c
index ec8df39bb01347eb035ad94553357b80af652b78..bccc018ab2666e769e7865d3cad1d61f04443700 100644 (file)
--- a/combine-diff.c
+++ b/combine-diff.c
@@ -703,15 +703,15 @@ static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
                        goto deleted_file;
 
                if (S_ISLNK(st.st_mode)) {
-                       size_t len = xsize_t(st.st_size);
-                       result_size = len;
-                       result = xmalloc(len + 1);
-                       if (result_size != readlink(elem->path, result, len)) {
+                       struct strbuf buf = STRBUF_INIT;
+
+                       if (strbuf_readlink(&buf, elem->path, st.st_size) < 0) {
                                error("readlink(%s): %s", elem->path,
                                      strerror(errno));
                                return;
                        }
-                       result[len] = 0;
+                       result_size = buf.len;
+                       result = strbuf_detach(&buf, NULL);
                        elem->mode = canon_mode(st.st_mode);
                }
                else if (0 <= (fd = open(elem->path, O_RDONLY)) &&

diff --git a/diff.c b/diff.c
index afefe087bba00bc9ec98327a880fbefdcf44a1d1..f160c1a35b786c8b1bb4451c254915bffde0fae3 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -1773,19 +1773,17 @@ int diff_populate_filespec(struct diff_filespec *s, int size_only)
                s->size = xsize_t(st.st_size);
                if (!s->size)
                        goto empty;
-               if (size_only)
-                       return 0;
                if (S_ISLNK(st.st_mode)) {
-                       int ret;
-                       s->data = xmalloc(s->size);
-                       s->should_free = 1;
-                       ret = readlink(s->path, s->data, s->size);
-                       if (ret < 0) {
-                               free(s->data);
+                       struct strbuf sb = STRBUF_INIT;
+
+                       if (strbuf_readlink(&sb, s->path, s->size))
                                goto err_empty;
-                       }
+                       s->data = strbuf_detach(&sb, &s->size);
+                       s->should_free = 1;
                        return 0;
                }
+               if (size_only)
+                       return 0;
                fd = open(s->path, O_RDONLY);
                if (fd < 0)
                        goto err_empty;
@@ -1883,13 +1881,12 @@ static void prepare_temp_file(const char *name,
                if (S_ISLNK(st.st_mode)) {
                        int ret;
                        char buf[PATH_MAX + 1]; /* ought to be SYMLINK_MAX */
-                       size_t sz = xsize_t(st.st_size);
-                       if (sizeof(buf) <= st.st_size)
-                               die("symlink too long: %s", name);
-                       ret = readlink(name, buf, sz);
+                       ret = readlink(name, buf, sizeof(buf));
                        if (ret < 0)
                                die("readlink(%s)", name);
-                       prep_temp_blob(temp, buf, sz,
+                       if (ret == sizeof(buf))
+                               die("symlink too long: %s", name);
+                       prep_temp_blob(temp, buf, ret,
                                       (one->sha1_valid ?
                                        one->sha1 : null_sha1),
                                       (one->sha1_valid ?

diff --git a/read-cache.c b/read-cache.c
index c14b56231379b1aeaa5f648d208d77ab68818d94..b1475ffa0962e1f0238fdb9a6870aa4b0bfd6d3b 100644 (file)
--- a/read-cache.c
+++ b/read-cache.c
@@ -99,27 +99,21 @@ static int ce_compare_data(struct cache_entry *ce, struct stat *st)
 static int ce_compare_link(struct cache_entry *ce, size_t expected_size)
 {
        int match = -1;
-       char *target;
        void *buffer;
        unsigned long size;
        enum object_type type;
-       int len;
+       struct strbuf sb = STRBUF_INIT;
 
-       target = xmalloc(expected_size);
-       len = readlink(ce->name, target, expected_size);
-       if (len != expected_size) {
-               free(target);
+       if (strbuf_readlink(&sb, ce->name, expected_size))
                return -1;
-       }
+
        buffer = read_sha1_file(ce->sha1, &type, &size);
-       if (!buffer) {
-               free(target);
-               return -1;
+       if (buffer) {
+               if (size == sb.len)
+                       match = memcmp(buffer, sb.buf, size);
+               free(buffer);
        }
-       if (size == expected_size)
-               match = memcmp(buffer, target, size);
-       free(buffer);
-       free(target);
+       strbuf_release(&sb);
        return match;
 }
 

diff --git a/sha1_file.c b/sha1_file.c
index 0e021c5eca8ea1a85d7863c427e054fd24fcd95a..52d1ead15b4db62138d9cedd5fe04068bcd10461 100644 (file)
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -2523,8 +2523,7 @@ int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object,
 int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
 {
        int fd;
-       char *target;
-       size_t len;
+       struct strbuf sb = STRBUF_INIT;
 
        switch (st->st_mode & S_IFMT) {
        case S_IFREG:
@@ -2537,20 +2536,17 @@ int index_path(unsigned char *sha1, const char *path, struct stat *st, int write
                                     path);
                break;
        case S_IFLNK:
-               len = xsize_t(st->st_size);
-               target = xmalloc(len + 1);
-               if (readlink(path, target, len + 1) != st->st_size) {
+               if (strbuf_readlink(&sb, path, st->st_size)) {
                        char *errstr = strerror(errno);
-                       free(target);
                        return error("readlink(\"%s\"): %s", path,
                                     errstr);
                }
                if (!write_object)
-                       hash_sha1_file(target, len, blob_type, sha1);
-               else if (write_sha1_file(target, len, blob_type, sha1))
+                       hash_sha1_file(sb.buf, sb.len, blob_type, sha1);
+               else if (write_sha1_file(sb.buf, sb.len, blob_type, sha1))
                        return error("%s: failed to insert into database",
                                     path);
-               free(target);
+               strbuf_release(&sb);
                break;
        case S_IFDIR:
                return resolve_gitlink_ref(path, "HEAD", sha1);

diff --git a/strbuf.c b/strbuf.c
index 13be67e4d3e38472adbff019a34e3f5ce9621dd7..bdf49544d47b97475800b104ed9efe8f846db265 100644 (file)
--- 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 b1670d99456e96b5de01918e157e10df519cae13..89bd36e15a541e268117ff023afc6a43137cdd6e 100644 (file)
--- 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);