fd3c512f8

Denys Vlasenko

2020-12-14

SUCCESS Duration: 148s

Subject

libbb: create and use mmap() helpers

No binary (build failed)

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

—

(log yok)

archival/rpm.c+1 -1

@@ -145,7 +145,7 @@ static int rpm_gettags(const char *filename)
	/* remember size for munmap */
	G.mapsize = storepos;
	/* some NOMMU systems prefer MAP_PRIVATE over MAP_SHARED */
-	G.map = mmap(0, storepos, PROT_READ, MAP_PRIVATE, fd, 0);
+	G.map = mmap_read(fd, storepos);
	if (G.map == MAP_FAILED)
	bb_perror_msg_and_die("mmap '%s'", filename);

include/libbb.h+3 -0

@@ -387,6 +387,9 @@ void* xrealloc_vector_helper(void *vector, unsigned sizeof_and_shift, int idx) F
	char xstrdup(const char s) FAST_FUNC RETURNS_MALLOC;
	char xstrndup(const char s, int n) FAST_FUNC RETURNS_MALLOC;
	void xmemdup(const void s, int n) FAST_FUNC RETURNS_MALLOC;
+	void *mmap_read(int fd, size_t size) FAST_FUNC;
+	void *mmap_anon(size_t size) FAST_FUNC;
+	void *xmmap_anon(size_t size) FAST_FUNC;


	//TODO: supply a pointer to char[11] buffer (avoid statics)?

libbb/copyfd.c+1 -4

@@ -75,10 +75,7 @@ static off_t bb_full_fd_action(int src_fd, int dst_fd, off_t size)
	goto use_small_buf;
	/* We want page-aligned buffer, just in case kernel is clever
	* and can do page-aligned io more efficiently */
-	buffer = mmap(NULL, CONFIG_FEATURE_COPYBUF_KB * 1024,
-	PROT_READ \| PROT_WRITE,
-	MAP_PRIVATE \| MAP_ANON,
-	/* ignored: */ -1, 0);
+	buffer = mmap_anon(CONFIG_FEATURE_COPYBUF_KB * 1024);
	buffer_size = CONFIG_FEATURE_COPYBUF_KB * 1024;
	if (buffer == MAP_FAILED) {
	use_small_buf:

libbb/xfuncs_printf.c+21 -0

@@ -111,6 +111,27 @@ void* FAST_FUNC xmemdup(const void *s, int n)
	return memcpy(xmalloc(n), s, n);
	}

+	void* FAST_FUNC mmap_read(int fd, size_t size)
+	{
+	return mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
+	}
+
+	void* FAST_FUNC mmap_anon(size_t size)
+	{
+	return mmap(NULL, size,
+	PROT_READ \| PROT_WRITE,
+	MAP_PRIVATE \| MAP_ANONYMOUS,
+	/* ignored: */ -1, 0);
+	}
+
+	void* FAST_FUNC xmmap_anon(size_t size)
+	{
+	void *p = mmap_anon(size);
+	if (p == MAP_FAILED)
+	bb_die_memory_exhausted();
+	return p;
+	}
+
	// Die if we can't open a file and return a FILE* to it.
	// Notice we haven't got xfread(), This is for use with fscanf() and friends.
	FILE* FAST_FUNC xfopen(const char path, const char mode)

modutils/modutils.c+1 -1

@@ -169,7 +169,7 @@ void* FAST_FUNC try_to_mmap_module(const char filename, size_t image_size_p)
	/* st.st_size is off_t, we can't just pass it to mmap */
	if (st.st_size <= *image_size_p) {
	size_t image_size = st.st_size;
-	image = mmap(NULL, image_size, PROT_READ, MAP_PRIVATE, fd, 0);
+	image = mmap_read(fd, image_size);
	if (image == MAP_FAILED) {
	image = NULL;
	} else if ((uint32_t)image != SWAP_BE32(0x7f454C46)) {

util-linux/uevent.c+1 -6

@@ -74,12 +74,7 @@ int uevent_main(int argc UNUSED_PARAM, char **argv)
	// for a new uevent notification to come in.
	// We use a fresh mmap so that buffer is not allocated
	// until kernel actually starts filling it.
-	netbuf = mmap(NULL, USER_RCVBUF,
-	PROT_READ \| PROT_WRITE,
-	MAP_PRIVATE \| MAP_ANON,
-	/* ignored: */ -1, 0);
-	if (netbuf == MAP_FAILED)
-	bb_simple_perror_msg_and_die("mmap");
+	netbuf = xmmap_anon(USER_RCVBUF);

	// Here we block, possibly for a very long time
	len = safe_read(fd, netbuf, USER_RCVBUF - 1);