From 538e4b2054e9802ebc860943e0a43baf2ee46741 Mon Sep 17 00:00:00 2001 From: Tavian Barnes Date: Tue, 31 Jan 2017 21:01:14 -0500 Subject: Don't trust st_size when reading symlinks Linux /proc, for example, reports a st_size of 0 for everything. It's nice to be able to use -lname on them anyway. --- util.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) (limited to 'util.c') diff --git a/util.c b/util.c index ce0b458..f3f2c5f 100644 --- a/util.c +++ b/util.c @@ -29,6 +29,36 @@ int xreaddir(DIR *dir, struct dirent **de) { } } +char *xreadlinkat(int fd, const char *path, size_t size) { + ++size; // NUL-terminator + ssize_t len; + char *name = NULL; + + while (true) { + char *new_name = realloc(name, size); + if (!new_name) { + goto error; + } + name = new_name; + + len = readlinkat(fd, path, name, size); + if (len < 0) { + goto error; + } else if (len >= size) { + size *= 2; + } else { + break; + } + } + + name[len] = '\0'; + return name; + +error: + free(name); + return NULL; +} + bool isopen(int fd) { return fcntl(fd, F_GETFD) >= 0 || errno != EBADF; } -- cgit v1.2.3