*
* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
*
- * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
#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
-
ssize_t FAST_FUNC safe_read(int fd, void *buf, size_t count)
{
ssize_t n;
return n;
}
-/* 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);
- }
-}
-
/*
* Read all of the supplied buffer from a file.
* This does multiple reads as necessary.
return total;
}
-/* 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;
-}
-
-// 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);
-}
-
ssize_t FAST_FUNC read_close(int fd, void *buf, size_t size)
{
/*int e;*/
return fd;
return read_close(fd, buf, size);
}
-
-
-// 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;
-}
-
-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;
- unsigned char magic[8];
- 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, 2);
- if (ENABLE_FEATURE_SEAMLESS_GZ
- && magic[0] == 0x1f && magic[1] == 0x8b
- ) {
-# if BB_MMU
- xformer = unpack_gz_stream;
-# else
- xformer_prog = "gunzip";
-# endif
- goto found_magic;
- }
- if (ENABLE_FEATURE_SEAMLESS_BZ2
- && magic[0] == 'B' && magic[1] == 'Z'
- ) {
-# if BB_MMU
- xformer = unpack_bz2_stream;
-# else
- xformer_prog = "bunzip2";
-# endif
- goto found_magic;
- }
- if (ENABLE_FEATURE_SEAMLESS_XZ
- && magic[0] == 0xfd && magic[1] == '7'
- ) {
- /* .xz signature: 0xfd, '7', 'z', 'X', 'Z', 0x00 */
- /* More info at: http://tukaani.org/xz/xz-file-format.txt */
- offset = -6;
- xread(fd, magic + 2, 4);
- if (strcmp((char*)magic + 2, "zXZ") == 0) {
-# if BB_MMU
- xformer = unpack_xz_stream;
-# else
- xformer_prog = "unxz";
-# endif
- xlseek(fd, offset, SEEK_CUR);
- 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;
-}
projects / platform / upstream / busybox.git / blobdiff