[PATCH v3 1/2] abspath: add a function to resolve paths with missing components
- From
brian m. carlson <sandals@crustytoothpaste.net>
- Date
- Nov 27, 2020, 23:19 UTC
- Message-ID
- <20201127231916.609852-2-sandals@crustytoothpaste.net>
- In-Reply-To
- <20201127231916.609852-1-sandals@crustytoothpaste.net>
We'd like to canonicalize paths such that we can preserve any number of trailing components that may be missing. Let's add a function to do that, taking the number of components to canonicalize, and make strbuf_realpath a wrapper around it that allows just one component.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> --- abspath.c | 33 ++++++++++++++++++++++++++++++++- cache.h | 2 ++ 2 files changed, 34 insertions(+), 1 deletion(-)
diff --git a/abspath.c b/abspath.c index 6f15a418bb..1d8f3d007c 100644 --- a/abspath.c +++ b/abspath.c @@ -20,6 +20,7 @@ static void strip_last_component(struct strbuf *path) /* Find start of the last component */ while (offset < len && !is_dir_sep(path->buf[len - 1])) len--; + /* Skip sequences of multiple path-separators */ while (offset < len && is_dir_sep(path->buf[len - 1])) len--; @@ -66,6 +67,22 @@ static void get_root_part(struct strbuf *resolved, struct strbuf *remaining) #define MAXSYMLINKS 32 #endif +/* Count non-contiguous directory separators, not including a trailing one. */ +static int count_dir_separators(const char *s) +{ + int count = 0; + int last_sep = 0; + const char *p = s; + while (*p) { + int is_sep = is_dir_sep(*p++); + if (is_sep && !last_sep) + count++; + last_sep = is_sep; + } + return count; +} + + /* * Return the real path (i.e., absolute path, with symlinks resolved * and extra slashes removed) equivalent to the specified path. (If @@ -80,6 +97,16 @@ static void get_root_part(struct strbuf *resolved, struct strbuf *remaining) */ char *strbuf_realpath(struct strbuf *resolved, const char *path, int die_on_error) +{ + return strbuf_realpath_missing(resolved, path, 1, die_on_error); +} + +/* + * Just like strbuf_realpath, but allows specifying how many missing components + * are permitted. -1 may be specified to allow an unlimited number. + */ +char *strbuf_realpath_missing(struct strbuf *resolved, const char *path, + int missing_components, int die_on_error) { struct strbuf remaining = STRBUF_INIT; struct strbuf next = STRBUF_INIT; @@ -128,8 +155,12 @@ char *strbuf_realpath(struct strbuf *resolved, const char *path, strbuf_addbuf(resolved, &next); if (lstat(resolved->buf, &st)) { + int trailing_components = count_dir_separators(remaining.buf) + + (remaining.len != 0); /* error out unless this was the last component */ - if (errno != ENOENT || remaining.len) { + if (errno != ENOENT || + !(missing_components == -1 || + trailing_components < missing_components)) { if (die_on_error) die_errno("Invalid path '%s'", resolved->buf); diff --git a/cache.h b/cache.h index c0072d43b1..ee4bc5ec04 100644 --- a/cache.h +++ b/cache.h @@ -1320,6 +1320,8 @@ static inline int is_absolute_path(const char *path) int is_directory(const char *); char *strbuf_realpath(struct strbuf *resolved, const char *path, int die_on_error); +char *strbuf_realpath_missing(struct strbuf *resolved, const char *path, + int missing_components, int die_on_error); char *real_pathdup(const char *path, int die_on_error); const char *absolute_path(const char *path); char *absolute_pathdup(const char *path);