pipe_progress: make it independent of printf machinery

function                                             old     new   delta
bb_putchar_stderr                                      -      24     +24
ParseField                                           494     471     -23
progress_meter                                       212     188     -24
xargs_main                                           888     842     -46
pipe_progress_main                                   151     105     -46
------------------------------------------------------------------------------
(add/remove: 2/0 grow/shrink: 0/4 up/down: 24/-139)          Total: -115 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 374 insertions, 0 deletions

diff --git a/libbb/read_printf.c b/libbb/read_printf.c
new file mode 100644
index 000000000..53f528f5a
--- /dev/null
+++ b/libbb/read_printf.c
@@ -0,0 +1,374 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Utility routines.
+ *
+ * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ */
+#include "libbb.h"
+
+#define ZIPPED (ENABLE_FEATURE_SEAMLESS_LZMA \
+	|| ENABLE_FEATURE_SEAMLESS_BZ2 \
+	|| ENABLE_FEATURE_SEAMLESS_GZ \
+	/* || ENABLE_FEATURE_SEAMLESS_Z */ \
+)
+
+#if ZIPPED
+# include "unarchive.h"
+#endif
+
+
+/* Suppose that you are a shell. You start child processes.
+ * They work and eventually exit. You want to get user input.
+ * You read stdin. But what happens if last child switched
+ * its stdin into O_NONBLOCK mode?
+ *
+ * *** SURPRISE! It will affect the parent too! ***
+ * *** BIG SURPRISE! It stays even after child exits! ***
+ *
+ * This is a design bug in UNIX API.
+ *      fcntl(0, F_SETFL, fcntl(0, F_GETFL) | O_NONBLOCK);
+ * will set nonblocking mode not only on _your_ stdin, but
+ * also on stdin of your parent, etc.
+ *
+ * In general,
+ *      fd2 = dup(fd1);
+ *      fcntl(fd2, F_SETFL, fcntl(fd2, F_GETFL) | O_NONBLOCK);
+ * sets both fd1 and fd2 to O_NONBLOCK. This includes cases
+ * where duping is done implicitly by fork() etc.
+ *
+ * We need
+ *      fcntl(fd2, F_SETFD, fcntl(fd2, F_GETFD) | O_NONBLOCK);
+ * (note SETFD, not SETFL!) but such thing doesn't exist.
+ *
+ * Alternatively, we need nonblocking_read(fd, ...) which doesn't
+ * require O_NONBLOCK dance at all. Actually, it exists:
+ *      n = recv(fd, buf, len, MSG_DONTWAIT);
+ *      "MSG_DONTWAIT:
+ *      Enables non-blocking operation; if the operation
+ *      would block, EAGAIN is returned."
+ * but recv() works only for sockets!
+ *
+ * So far I don't see any good solution, I can only propose
+ * that affected readers should be careful and use this routine,
+ * which detects EAGAIN and uses poll() to wait on the fd.
+ * Thankfully, poll() doesn't care about O_NONBLOCK flag.
+ */
+ssize_t FAST_FUNC nonblock_safe_read(int fd, void *buf, size_t count)
+{
+	struct pollfd pfd[1];
+	ssize_t n;
+
+	while (1) {
+		n = safe_read(fd, buf, count);
+		if (n >= 0 || errno != EAGAIN)
+			return n;
+		/* fd is in O_NONBLOCK mode. Wait using poll and repeat */
+		pfd[0].fd = fd;
+		pfd[0].events = POLLIN;
+		safe_poll(pfd, 1, -1); /* note: this pulls in printf */
+	}
+}
+
+// Reads one line a-la fgets (but doesn't save terminating '\n').
+// Reads byte-by-byte. Useful when it is important to not read ahead.
+// Bytes are appended to pfx (which must be malloced, or NULL).
+char* FAST_FUNC xmalloc_reads(int fd, char *buf, size_t *maxsz_p)
+{
+	char *p;
+	size_t sz = buf ? strlen(buf) : 0;
+	size_t maxsz = maxsz_p ? *maxsz_p : (INT_MAX - 4095);
+
+	goto jump_in;
+	while (sz < maxsz) {
+		if ((size_t)(p - buf) == sz) {
+ jump_in:
+			buf = xrealloc(buf, sz + 128);
+			p = buf + sz;
+			sz += 128;
+		}
+		/* nonblock_safe_read() because we are used by e.g. shells */
+		if (nonblock_safe_read(fd, p, 1) != 1) { /* EOF/error */
+			if (p == buf) { /* we read nothing */
+				free(buf);
+				return NULL;
+			}
+			break;
+		}
+		if (*p == '\n')
+			break;
+		p++;
+	}
+	*p = '\0';
+	if (maxsz_p)
+		*maxsz_p  = p - buf;
+	p++;
+	return xrealloc(buf, p - buf);
+}
+
+// Read (potentially big) files in one go. File size is estimated
+// by stat. Extra '\0' byte is appended.
+void* FAST_FUNC xmalloc_read(int fd, size_t *maxsz_p)
+{
+	char *buf;
+	size_t size, rd_size, total;
+	size_t to_read;
+	struct stat st;
+
+	to_read = maxsz_p ? *maxsz_p : (INT_MAX - 4095); /* max to read */
+
+	/* Estimate file size */
+	st.st_size = 0; /* in case fstat fails, assume 0 */
+	fstat(fd, &st);
+	/* /proc/N/stat files report st_size 0 */
+	/* In order to make such files readable, we add small const */
+	size = (st.st_size | 0x3ff) + 1;
+
+	total = 0;
+	buf = NULL;
+	while (1) {
+		if (to_read < size)
+			size = to_read;
+		buf = xrealloc(buf, total + size + 1);
+		rd_size = full_read(fd, buf + total, size);
+		if ((ssize_t)rd_size == (ssize_t)(-1)) { /* error */
+			free(buf);
+			return NULL;
+		}
+		total += rd_size;
+		if (rd_size < size) /* EOF */
+			break;
+		if (to_read <= rd_size)
+			break;
+		to_read -= rd_size;
+		/* grow by 1/8, but in [1k..64k] bounds */
+		size = ((total / 8) | 0x3ff) + 1;
+		if (size > 64*1024)
+			size = 64*1024;
+	}
+	buf = xrealloc(buf, total + 1);
+	buf[total] = '\0';
+
+	if (maxsz_p)
+		*maxsz_p = total;
+	return buf;
+}
+
+#ifdef USING_LSEEK_TO_GET_SIZE
+/* Alternatively, file size can be obtained by lseek to the end.
+ * The code is slightly bigger. Retained in case fstat approach
+ * will not work for some weird cases (/proc, block devices, etc).
+ * (NB: lseek also can fail to work for some weird files) */
+
+// Read (potentially big) files in one go. File size is estimated by
+// lseek to end.
+void* FAST_FUNC xmalloc_open_read_close(const char *filename, size_t *maxsz_p)
+{
+	char *buf;
+	size_t size;
+	int fd;
+	off_t len;
+
+	fd = open(filename, O_RDONLY);
+	if (fd < 0)
+		return NULL;
+
+	/* /proc/N/stat files report len 0 here */
+	/* In order to make such files readable, we add small const */
+	size = 0x3ff; /* read only 1k on unseekable files */
+	len = lseek(fd, 0, SEEK_END) | 0x3ff; /* + up to 1k */
+	if (len != (off_t)-1) {
+		xlseek(fd, 0, SEEK_SET);
+		size = maxsz_p ? *maxsz_p : (INT_MAX - 4095);
+		if (len < size)
+			size = len;
+	}
+
+	buf = xmalloc(size + 1);
+	size = read_close(fd, buf, size);
+	if ((ssize_t)size < 0) {
+		free(buf);
+		return NULL;
+	}
+	buf = xrealloc(buf, size + 1);
+	buf[size] = '\0';
+
+	if (maxsz_p)
+		*maxsz_p = size;
+	return buf;
+}
+#endif
+
+// Read (potentially big) files in one go. File size is estimated
+// by stat.
+void* FAST_FUNC xmalloc_open_read_close(const char *filename, size_t *maxsz_p)
+{
+	char *buf;
+	int fd;
+
+	fd = open(filename, O_RDONLY);
+	if (fd < 0)
+		return NULL;
+
+	buf = xmalloc_read(fd, maxsz_p);
+	close(fd);
+	return buf;
+}
+
+/* Die with an error message if we can't read the entire buffer. */
+void FAST_FUNC xread(int fd, void *buf, size_t count)
+{
+	if (count) {
+		ssize_t size = full_read(fd, buf, count);
+		if ((size_t)size != count)
+			bb_error_msg_and_die("short read");
+	}
+}
+
+/* Die with an error message if we can't read one character. */
+unsigned char FAST_FUNC xread_char(int fd)
+{
+	char tmp;
+	xread(fd, &tmp, 1);
+	return tmp;
+}
+
+void* FAST_FUNC xmalloc_xopen_read_close(const char *filename, size_t *maxsz_p)
+{
+	void *buf = xmalloc_open_read_close(filename, maxsz_p);
+	if (!buf)
+		bb_perror_msg_and_die("can't read '%s'", filename);
+	return buf;
+}
+
+/* Used by e.g. rpm which gives us a fd without filename,
+ * thus we can't guess the format from filename's extension.
+ */
+#if ZIPPED
+void FAST_FUNC setup_unzip_on_fd(int fd /*, int fail_if_not_detected*/)
+{
+	const int fail_if_not_detected = 1;
+	union {
+		uint8_t b[4];
+		uint16_t b16[2];
+		uint32_t b32[1];
+	} magic;
+	int offset = -2;
+# if BB_MMU
+	IF_DESKTOP(long long) int FAST_FUNC (*xformer)(int src_fd, int dst_fd);
+	enum { xformer_prog = 0 };
+# else
+	enum { xformer = 0 };
+	const char *xformer_prog;
+# endif
+
+	/* .gz and .bz2 both have 2-byte signature, and their
+	 * unpack_XXX_stream wants this header skipped. */
+	xread(fd, magic.b16, sizeof(magic.b16));
+	if (ENABLE_FEATURE_SEAMLESS_GZ
+	 && magic.b16[0] == GZIP_MAGIC
+	) {
+# if BB_MMU
+		xformer = unpack_gz_stream;
+# else
+		xformer_prog = "gunzip";
+# endif
+		goto found_magic;
+	}
+	if (ENABLE_FEATURE_SEAMLESS_BZ2
+	 && magic.b16[0] == BZIP2_MAGIC
+	) {
+# if BB_MMU
+		xformer = unpack_bz2_stream;
+# else
+		xformer_prog = "bunzip2";
+# endif
+		goto found_magic;
+	}
+	if (ENABLE_FEATURE_SEAMLESS_XZ
+	 && magic.b16[0] == XZ_MAGIC1
+	) {
+		/* .xz signature: 0xfd, '7', 'z', 'X', 'Z', 0x00 */
+		/* More info at: http://tukaani.org/xz/xz-file-format.txt */
+		offset = -6;
+		xread(fd, magic.b32, sizeof(magic.b32));
+		if (magic.b32[0] == XZ_MAGIC2) {
+# if BB_MMU
+			xformer = unpack_xz_stream;
+			/* unpack_xz_stream wants fd at position 0 */
+			xlseek(fd, offset, SEEK_CUR);
+# else
+			xformer_prog = "unxz";
+# endif
+			goto found_magic;
+		}
+	}
+
+	/* No known magic seen */
+	if (fail_if_not_detected)
+		bb_error_msg_and_die("no gzip"
+			IF_FEATURE_SEAMLESS_BZ2("/bzip2")
+			IF_FEATURE_SEAMLESS_XZ("/xz")
+			" magic");
+	xlseek(fd, offset, SEEK_CUR);
+	return;
+
+ found_magic:
+# if !BB_MMU
+	/* NOMMU version of open_transformer execs
+	 * an external unzipper that wants
+	 * file position at the start of the file */
+	xlseek(fd, offset, SEEK_CUR);
+# endif
+	open_transformer(fd, xformer, xformer_prog);
+}
+#endif /* ZIPPED */
+
+int FAST_FUNC open_zipped(const char *fname)
+{
+#if !ZIPPED
+	return open(fname, O_RDONLY);
+#else
+	char *sfx;
+	int fd;
+
+	fd = open(fname, O_RDONLY);
+	if (fd < 0)
+		return fd;
+
+	sfx = strrchr(fname, '.');
+	if (sfx) {
+		sfx++;
+		if (ENABLE_FEATURE_SEAMLESS_LZMA && strcmp(sfx, "lzma") == 0)
+			/* .lzma has no header/signature, just trust it */
+			open_transformer(fd, unpack_lzma_stream, "unlzma");
+		else
+		if ((ENABLE_FEATURE_SEAMLESS_GZ && strcmp(sfx, "gz") == 0)
+		 || (ENABLE_FEATURE_SEAMLESS_BZ2 && strcmp(sfx, "bz2") == 0)
+		 || (ENABLE_FEATURE_SEAMLESS_XZ && strcmp(sfx, "xz") == 0)
+		) {
+			setup_unzip_on_fd(fd /*, fail_if_not_detected: 1*/);
+		}
+	}
+
+	return fd;
+#endif
+}
+
+void* FAST_FUNC xmalloc_open_zipped_read_close(const char *fname, size_t *maxsz_p)
+{
+	int fd;
+	char *image;
+
+	fd = open_zipped(fname);
+	if (fd < 0)
+		return NULL;
+
+	image = xmalloc_read(fd, maxsz_p);
+	if (!image)
+		bb_perror_msg("read error from '%s'", fname);
+	close(fd);
+
+	return image;
+}