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author | Rich Felker <dalias@aerifal.cx> | 2012-09-30 17:53:54 -0400 |
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committer | Rich Felker <dalias@aerifal.cx> | 2012-09-30 17:53:54 -0400 |
commit | 6e2372a86c7e862ed931910f8a5f4b908639d689 (patch) | |
tree | 57892b1e0d718fbb9ab86767915bca095cc5e307 /src/mman | |
parent | 2e3648b85db1c71bfc684233f7a521b0d4bbeb20 (diff) | |
download | musl-6e2372a86c7e862ed931910f8a5f4b908639d689.tar.gz musl-6e2372a86c7e862ed931910f8a5f4b908639d689.tar.bz2 musl-6e2372a86c7e862ed931910f8a5f4b908639d689.tar.xz musl-6e2372a86c7e862ed931910f8a5f4b908639d689.zip |
clean up, bugfixes, and general improvement for shm_open/shm_unlink
1. don't make non-cloexec file descriptors
2. cancellation safety (cleanup handlers were missing, now unneeded)
3. share name validation/mapping code between open/unlink functions
4. avoid wasteful/slow syscalls
Diffstat (limited to 'src/mman')
-rw-r--r-- | src/mman/shm_open.c | 37 | ||||
-rw-r--r-- | src/mman/shm_unlink.c | 21 |
2 files changed, 28 insertions, 30 deletions
diff --git a/src/mman/shm_open.c b/src/mman/shm_open.c index d368622d..a9be899b 100644 --- a/src/mman/shm_open.c +++ b/src/mman/shm_open.c @@ -3,19 +3,38 @@ #include <fcntl.h> #include <unistd.h> #include <string.h> +#include <limits.h> -int shm_open(const char *name, int flag, mode_t mode) -{ - int fd, dir; +char *__strchrnul(const char *, int); +static const char *mapname(const char *name, char *buf) +{ + char *p; while (*name == '/') name++; - if (strchr(name, '/')) { + if (*(p = __strchrnul(name, '/')) || p==name || + (p-name <= 2 && name[0]=='.' && p[-1]=='.')) { errno = EINVAL; - return -1; + return 0; } + if (p-name > NAME_MAX) { + errno = ENAMETOOLONG; + return 0; + } + memcpy(buf, "/dev/shm/", 9); + memcpy(buf+9, name, p-name+1); + return buf; +} - if ((dir = open("/dev/shm", O_DIRECTORY|O_RDONLY)) < 0) return -1; - fd = openat(dir, name, flag|O_NOFOLLOW|O_CLOEXEC|O_NONBLOCK, mode); - close(dir); - return fd; +int shm_open(const char *name, int flag, mode_t mode) +{ + char buf[NAME_MAX+10]; + if (!(name = mapname(name, buf))) return -1; + return open(name, flag|O_NOFOLLOW|O_CLOEXEC|O_NONBLOCK, mode); +} + +int shm_unlink(const char *name) +{ + char buf[NAME_MAX+10]; + if (!(name = mapname(name, buf))) return -1; + return unlink(name); } diff --git a/src/mman/shm_unlink.c b/src/mman/shm_unlink.c deleted file mode 100644 index 46e60b3b..00000000 --- a/src/mman/shm_unlink.c +++ /dev/null @@ -1,21 +0,0 @@ -#include <sys/mman.h> -#include <errno.h> -#include <fcntl.h> -#include <unistd.h> -#include <string.h> - -int shm_unlink(const char *name) -{ - int dir, ret; - - while (*name == '/') name++; - if (strchr(name, '/')) { - errno = EINVAL; - return -1; - } - - if ((dir = open("/dev/shm", O_DIRECTORY|O_RDONLY)) < 0) return -1; - ret = unlinkat(dir, name, 0); - close(dir); - return ret; -} |