diff options
Diffstat (limited to 'libbb/read.c')
| -rw-r--r-- | libbb/read.c | 365 |
1 files changed, 0 insertions, 365 deletions
diff --git a/libbb/read.c b/libbb/read.c index b1eb3f24b..1ed7c5f92 100644 --- a/libbb/read.c +++ b/libbb/read.c @@ -8,16 +8,6 @@ */ #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; @@ -29,58 +19,6 @@ ssize_t FAST_FUNC safe_read(int fd, void *buf, size_t count) 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. @@ -115,60 +53,6 @@ ssize_t FAST_FUNC full_read(int fd, void *buf, size_t len) 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;*/ @@ -186,252 +70,3 @@ ssize_t FAST_FUNC open_read_close(const char *filename, void *buf, size_t size) 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; - 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; -} |