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author | Andreas Gruenbacher <agruenba@redhat.com> | 2018-08-17 14:07:31 +0200 |
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committer | Andreas Gruenbacher <agruenba@redhat.com> | 2018-08-17 14:25:18 +0200 |
commit | 14adc898a36948267bfe5c63b399996879e94c98 (patch) | |
tree | d013e3cd42ff303bd80fb0a490a458eace6b6270 | |
parent | b3dbcdc372afda73291dc3b52bfcdb4b97a2a7b6 (diff) | |
download | attr-14adc898a36948267bfe5c63b399996879e94c98.tar.gz |
Switch back to syscall()
Switch back to syscall() for the *xattr system calls. The current
mechanism of forwarding those calls to glibc breaks libraries like
libfakeroot (fakeroot) and libasan (the gcc address sanitizer; gcc
-fsanitize=address).
Those libraries provide wrappers for functions defined in other shared
libraries, usually glibc, do their own processing, and forward calls to
the original symbols looke dup via dlsym(RTLD_NEXT, "symbol_name"). In
our case, dlsym returns the libattr_*xattr wrappers. However, when our
wrappers try calling glibc, they end up calling the libfakeroot /
libasan wrappers instead because those override the original symbols =>
recursion.
The libattr_*xattr wrappers will only be used when symbols are looked up
at runtime (dlopen / dlsym). Programs linking against libattr will
directly use the glibc provided symbols. Therefore, the slightly worse
performance of syscall() won't affect any of the "normal" users of
libattr.
-rw-r--r-- | libattr/syscalls.c | 26 |
1 files changed, 14 insertions, 12 deletions
diff --git a/libattr/syscalls.c b/libattr/syscalls.c index 3013aa0..721ad7f 100644 --- a/libattr/syscalls.c +++ b/libattr/syscalls.c @@ -22,6 +22,8 @@ #include "config.h" +#include <unistd.h> +#include <sys/syscall.h> #include <sys/xattr.h> #ifdef HAVE_VISIBILITY_ATTRIBUTE @@ -31,67 +33,67 @@ int libattr_setxattr(const char *path, const char *name, void *value, size_t size, int flags) { - return setxattr(path, name, value, size, flags); + return syscall(__NR_setxattr, path, name, value, size, flags); } int libattr_lsetxattr(const char *path, const char *name, void *value, size_t size, int flags) { - return lsetxattr(path, name, value, size, flags); + return syscall(__NR_lsetxattr, path, name, value, size, flags); } int libattr_fsetxattr(int filedes, const char *name, void *value, size_t size, int flags) { - return fsetxattr(filedes, name, value, size, flags); + return syscall(__NR_fsetxattr, filedes, name, value, size, flags); } ssize_t libattr_getxattr(const char *path, const char *name, void *value, size_t size) { - return getxattr(path, name, value, size); + return syscall(__NR_getxattr, path, name, value, size); } ssize_t libattr_lgetxattr(const char *path, const char *name, void *value, size_t size) { - return lgetxattr(path, name, value, size); + return syscall(__NR_lgetxattr, path, name, value, size); } ssize_t libattr_fgetxattr(int filedes, const char *name, void *value, size_t size) { - return fgetxattr(filedes, name, value, size); + return syscall(__NR_fgetxattr, filedes, name, value, size); } ssize_t libattr_listxattr(const char *path, char *list, size_t size) { - return listxattr(path, list, size); + return syscall(__NR_listxattr, path, list, size); } ssize_t libattr_llistxattr(const char *path, char *list, size_t size) { - return llistxattr(path, list, size); + return syscall(__NR_llistxattr, path, list, size); } ssize_t libattr_flistxattr(int filedes, char *list, size_t size) { - return flistxattr(filedes, list, size); + return syscall(__NR_flistxattr, filedes, list, size); } int libattr_removexattr(const char *path, const char *name) { - return removexattr(path, name); + return syscall(__NR_removexattr, path, name); } int libattr_lremovexattr(const char *path, const char *name) { - return lremovexattr(path, name); + return syscall(__NR_lremovexattr, path, name); } int libattr_fremovexattr(int filedes, const char *name) { - return fremovexattr(filedes, name); + return syscall(__NR_fremovexattr, filedes, name); } #ifdef HAVE_VISIBILITY_ATTRIBUTE |