commit 0938c20fa3b44a09d20ba2eb05775b0c46d39129 Author: Andrea Shepard <andrea@torproject.org> Date: Wed Mar 19 11:17:55 2014 -0700 Eliminate lseek() with unchecked return in tor_mmap_file() --- src/common/compat.c | 28 ++++++++++++++++++++++++---- 1 file changed, 24 insertions(+), 4 deletions(-) diff --git a/src/common/compat.c b/src/common/compat.c index b43af88..ead96ca 100644 --- a/src/common/compat.c +++ b/src/common/compat.c @@ -35,6 +35,12 @@ #ifdef HAVE_UNAME #include <sys/utsname.h> #endif +#ifdef HAVE_SYS_TYPES_H +#include <sys/types.h> +#endif +#ifdef HAVE_SYS_STAT_H +#include <sys/stat.h> +#endif #ifdef HAVE_UNISTD_H #include <unistd.h> #endif @@ -178,9 +184,10 @@ tor_mmap_file(const char *filename) { int fd; /* router file */ char *string; - int page_size; + int page_size, result; tor_mmap_t *res; size_t size, filesize; + struct stat st; tor_assert(filename); @@ -194,9 +201,22 @@ tor_mmap_file(const char *filename) return NULL; } - /* XXXX why not just do fstat here? */ - size = filesize = (size_t) lseek(fd, 0, SEEK_END); - lseek(fd, 0, SEEK_SET); + /* Get the size of the file */ + result = fstat(fd, &st); + if (result != 0) { + int save_errno = errno; + log_warn(LD_FS, + "Couldn't fstat opened descriptor for \"%s\" during mmap: %s", + filename, strerror(errno)); + close(fd); + errno = save_errno; + return NULL; + } + size = filesize = (size_t)(st.st_size); + /* + * Should we check for weird crap like mmapping a named pipe here, + * or just wait for if (!size) below to fail? + */ /* ensure page alignment */ page_size = getpagesize(); size += (size%page_size) ? page_size-(size%page_size) : 0;