Hello!
I have reviewed all occurrences of mmap() in git and fixed three types of errors/defects:
1) The result is not checked. 2) The file descriptor is closed if mmap() succeeds, but not when it fails. 3) Various casts applied to -1 are used instead of MAP_FAILED, which is specifically defined to check mmap() return value.
I have verified that successful close() after failed mmap() won't reset the output of perror() to "Success".
Signed-off-by: Pavel Roskin <proski@gnu.org>
Show changes to 8 files +15 −15
diff.c, diffcore-order.c, local-pull.c, read-cache.c, rev-cache.c, sha1_file.c, test-delta.c, tools/mailsplit.c
diff --git a/diff.c b/diff.c --- a/diff.c +++ b/diff.c @@ -377,8 +377,10 @@ int diff_populate_filespec(struct diff_f if (fd < 0) goto err_empty; s->data = mmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0); - s->should_munmap = 1; close(fd); + if (s->data == MAP_FAILED) + goto err_empty; + s->should_munmap = 1; } else { char type[20]; diff --git a/diffcore-order.c b/diffcore-order.c --- a/diffcore-order.c +++ b/diffcore-order.c @@ -28,7 +28,7 @@ static void prepare_order(const char *or } map = mmap(NULL, st.st_size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0); close(fd); - if (-1 == (int)(long)map) + if (map == MAP_FAILED) return; endp = map + st.st_size; for (pass = 0; pass < 2; pass++) { diff --git a/local-pull.c b/local-pull.c --- a/local-pull.c +++ b/local-pull.c @@ -54,7 +54,7 @@ int fetch(unsigned char *sha1) } map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, ifd, 0); close(ifd); - if (-1 == (int)(long)map) { + if (map == MAP_FAILED) { fprintf(stderr, "cannot mmap %s\n", filename); return -1; } diff --git a/read-cache.c b/read-cache.c --- a/read-cache.c +++ b/read-cache.c @@ -392,7 +392,7 @@ int read_cache(void) return (errno == ENOENT) ? 0 : error("open failed"); size = 0; // avoid gcc warning - map = (void *)-1; + map = MAP_FAILED; if (!fstat(fd, &st)) { size = st.st_size; errno = EINVAL; @@ -400,7 +400,7 @@ int read_cache(void) map = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0); } close(fd); - if (-1 == (int)(long)map) + if (map == MAP_FAILED) return error("mmap failed"); hdr = map; diff --git a/rev-cache.c b/rev-cache.c --- a/rev-cache.c +++ b/rev-cache.c @@ -212,11 +212,9 @@ int read_rev_cache(const char *path, FIL return -1; } map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0); - if (map == MAP_FAILED) { - close(fd); - return -1; - } close(fd); + if (map == MAP_FAILED) + return -1; memset(last_sha1, 0, 20); ofs = 0; diff --git a/sha1_file.c b/sha1_file.c --- a/sha1_file.c +++ b/sha1_file.c @@ -518,7 +518,7 @@ static void *map_sha1_file_internal(cons } map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0); close(fd); - if (-1 == (int)(long)map) + if (map == MAP_FAILED) return NULL; *size = st.st_size; return map; @@ -1363,7 +1363,7 @@ int index_fd(unsigned char *sha1, int fd if (size) buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0); close(fd); - if ((int)(long)buf == -1) + if (buf == MAP_FAILED) return -1; if (!type) diff --git a/test-delta.c b/test-delta.c --- a/test-delta.c +++ b/test-delta.c @@ -39,11 +39,11 @@ int main(int argc, char *argv[]) } from_size = st.st_size; from_buf = mmap(NULL, from_size, PROT_READ, MAP_PRIVATE, fd, 0); + close(fd); if (from_buf == MAP_FAILED) { perror(argv[2]); return 1; } - close(fd); fd = open(argv[3], O_RDONLY); if (fd < 0 || fstat(fd, &st)) { @@ -52,11 +52,11 @@ int main(int argc, char *argv[]) } data_size = st.st_size; data_buf = mmap(NULL, data_size, PROT_READ, MAP_PRIVATE, fd, 0); + close(fd); if (data_buf == MAP_FAILED) { perror(argv[3]); return 1; } - close(fd); if (argv[1][1] == 'd') out_buf = diff_delta(from_buf, from_size, diff --git a/tools/mailsplit.c b/tools/mailsplit.c --- a/tools/mailsplit.c +++ b/tools/mailsplit.c @@ -116,11 +116,11 @@ int main(int argc, char **argv) } size = st.st_size; map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0); - if (-1 == (int)(long)map) { + close(fd); + if (map == MAP_FAILED) { perror("mmap"); exit(1); } - close(fd); nr = 0; do { char name[10];
-- Regards, Pavel Roskin
