From ad7e695784296d9e4058ebe5e27a20864076f53b Mon Sep 17 00:00:00 2001 From: Tobias Klauser Date: Wed, 18 Apr 2007 12:28:08 +0200 Subject: Update sourec for inotail 0.3 --- inotail.c | 293 +++++++++++++++++++++++++++++++++----------------------------- 1 file changed, 156 insertions(+), 137 deletions(-) (limited to 'inotail.c') diff --git a/inotail.c b/inotail.c index 7b58477..6f8be7c 100644 --- a/inotail.c +++ b/inotail.c @@ -3,7 +3,7 @@ * A fast implementation of tail which uses the inotify API present in * recent versions of the Linux kernel. * - * Copyright (C) 2005-2006, Tobias Klauser + * Copyright (C) 2005-2007, Tobias Klauser * * The idea was taken from turbotail. * @@ -30,6 +30,7 @@ #include #include #include +#include #include #include @@ -40,10 +41,8 @@ #define PROGRAM_NAME "inotail" #define BUFFER_SIZE 4096 - -/* (ino)tail works on these file types */ -#define IS_TAILABLE(mode) \ - (S_ISREG(mode) || S_ISFIFO(mode) || S_ISSOCK(mode) || S_ISCHR(mode)) +/* inotify event buffer length for one file */ +#define INOTIFY_BUFLEN (4 * sizeof(struct inotify_event)) /* Print header with filename before tailing the file? */ static char verbose = 0; @@ -51,20 +50,23 @@ static char verbose = 0; /* Tailing relative to begin or end of file */ static char from_begin = 0; +/* Number of ignored files */ +static int n_ignored = 0; + /* Command line options */ static const struct option long_opts[] = { - {"bytes", required_argument, NULL, 'c'}, - {"follow", optional_argument, NULL, 'f'}, - {"lines", required_argument, NULL, 'n'}, - {"verbose", no_argument, NULL, 'v'}, - {"help", no_argument, NULL, 'h'}, - {"version", no_argument, NULL, 'V'}, - {NULL, 0, NULL, 0} + { "bytes", required_argument, NULL, 'c' }, + { "follow", optional_argument, NULL, 'f' }, + { "lines", required_argument, NULL, 'n' }, + { "verbose", no_argument, NULL, 'v' }, + { "help", no_argument, NULL, 'h' }, + { "version", no_argument, NULL, 'V' }, + { NULL, 0, NULL, 0 } }; static void usage(const int status) { - fprintf(stderr, "Usage: %s [OPTION]... [FILE]...\n\n" + fprintf(stdout, "Usage: %s [OPTION]... [FILE]...\n\n" " -c N, --bytes=N output the last N bytes\n" " -f, --follow output as the file grows\n" " -n N, --lines=N output the last N lines (default: %d)\n" @@ -78,7 +80,7 @@ static void usage(const int status) exit(status); } -static void setup_file(struct file_struct *f) +static inline void setup_file(struct file_struct *f) { f->fd = -1; f->st_size = 0; @@ -86,30 +88,43 @@ static void setup_file(struct file_struct *f) f->i_watch = -1; } +static void ignore_file(struct file_struct *f) +{ + if (f->fd != -1) { + close(f->fd); + f->fd = -1; + } + f->ignore = 1; + n_ignored++; +} + static inline char *pretty_name(char *filename) { - return (strncmp(filename, "-", 1) == 0) ? "standard input" : filename; + return (strcmp(filename, "-") == 0) ? "standard input" : filename; } static void write_header(char *filename) { static unsigned short first_file = 1; + static char *last = NULL; + + if (last != filename) + fprintf(stdout, "%s==> %s <==\n", (first_file ? "" : "\n"), pretty_name(filename)); - fprintf(stdout, "%s==> %s <==\n", (first_file ? "" : "\n"), pretty_name(filename)); first_file = 0; + last = filename; } -static off_t lines_to_offset_from_end(struct file_struct *f, unsigned int n_lines) +static off_t lines_to_offset_from_end(struct file_struct *f, unsigned long n_lines) { char buf[BUFFER_SIZE]; off_t offset = f->st_size; n_lines++; /* We also count the last \n */ - memset(&buf, 0, sizeof(buf)); while (offset > 0 && n_lines > 0) { - int i, rc; - int block_size = BUFFER_SIZE; /* Size of the current block we're reading */ + int i; + ssize_t rc, block_size = BUFFER_SIZE; /* Size of the current block we're reading */ if (offset < BUFFER_SIZE) block_size = offset; @@ -120,28 +135,23 @@ static off_t lines_to_offset_from_end(struct file_struct *f, unsigned int n_line lseek(f->fd, offset, SEEK_SET); rc = read(f->fd, &buf, block_size); - if (rc < 0) { + if (unlikely(rc < 0)) { fprintf(stderr, "Error: Could not read from file '%s' (%s)\n", f->name, strerror(errno)); return -1; } - for (i = block_size; i > 0; i--) { + for (i = block_size - 1; i > 0; i--) { if (buf[i] == '\n') { - n_lines--; - - if (n_lines == 0) { - offset += i + 1; /* We don't want the first \n */ - break; - } + if (--n_lines == 0) + return offset += i + 1; /* We don't want the first \n */ } } } return offset; - } -static off_t lines_to_offset_from_begin(struct file_struct *f, unsigned int n_lines) +static off_t lines_to_offset_from_begin(struct file_struct *f, unsigned long n_lines) { char buf[BUFFER_SIZE]; off_t offset = 0; @@ -151,27 +161,24 @@ static off_t lines_to_offset_from_begin(struct file_struct *f, unsigned int n_li return 0; n_lines--; - memset(&buf, 0, sizeof(buf)); while (offset <= f->st_size && n_lines > 0) { - int i, rc; - int block_size = BUFFER_SIZE; + int i; + ssize_t rc, block_size = BUFFER_SIZE; lseek(f->fd, offset, SEEK_SET); rc = read(f->fd, &buf, block_size); - if (rc < 0) { + if (unlikely(rc < 0)) { fprintf(stderr, "Error: Could not read from file '%s' (%s)\n", f->name, strerror(errno)); return -1; - } + } else if (rc < block_size) + block_size = rc; for (i = 0; i < block_size; i++) { if (buf[i] == '\n') { - n_lines--; - if (n_lines == 0) { - offset += i + 1; - return offset; - } + if (--n_lines == 0) + return offset + i + 1; } } @@ -181,7 +188,7 @@ static off_t lines_to_offset_from_begin(struct file_struct *f, unsigned int n_li return offset; } -static off_t lines_to_offset(struct file_struct *f, unsigned int n_lines) +static off_t lines_to_offset(struct file_struct *f, unsigned long n_lines) { if (from_begin) return lines_to_offset_from_begin(f, n_lines); @@ -189,18 +196,25 @@ static off_t lines_to_offset(struct file_struct *f, unsigned int n_lines) return lines_to_offset_from_end(f, n_lines); } -static inline off_t bytes_to_offset(struct file_struct *f, unsigned int n_bytes) +static off_t bytes_to_offset(struct file_struct *f, unsigned long n_bytes) { + off_t offset = 0; + /* tail everything for 'inotail -c +0' */ - if (from_begin && n_bytes == 0) - return 0; - else - return (from_begin ? ((off_t) n_bytes - 1) : (f->st_size - (off_t) n_bytes)); + if (from_begin) { + if (n_bytes > 0) + offset = (off_t) n_bytes - 1; + } else { + if ((off_t) n_bytes < f->st_size) + offset = f->st_size - (off_t) n_bytes; + } + + return offset; } -static int tail_pipe(struct file_struct *f) +static ssize_t tail_pipe(struct file_struct *f) { - int rc; + ssize_t rc; char buf[BUFFER_SIZE]; if (verbose) @@ -213,36 +227,38 @@ static int tail_pipe(struct file_struct *f) return rc; } -static int tail_file(struct file_struct *f, unsigned int n_units, char mode) +static int tail_file(struct file_struct *f, unsigned long n_units, char mode, char forever) { - int ret = -1; ssize_t bytes_read = 0; off_t offset = 0; char buf[BUFFER_SIZE]; struct stat finfo; - if (strncmp(f->name, "-", 1) == 0) + if (strcmp(f->name, "-") == 0) f->fd = STDIN_FILENO; else { f->fd = open(f->name, O_RDONLY); - if (f->fd < 0) { + if (unlikely(f->fd < 0)) { fprintf(stderr, "Error: Could not open file '%s' (%s)\n", f->name, strerror(errno)); + ignore_file(f); return -1; } } if (fstat(f->fd, &finfo) < 0) { fprintf(stderr, "Error: Could not stat file '%s' (%s)\n", f->name, strerror(errno)); - goto out; + ignore_file(f); + return -1; } if (!IS_TAILABLE(finfo.st_mode)) { fprintf(stderr, "Error: '%s' of unsupported file type\n", f->name); - goto out; + ignore_file(f); + return -1; } - /* We cannot seek on these */ - if (S_ISFIFO(finfo.st_mode) || S_ISSOCK(finfo.st_mode) || f->fd == STDIN_FILENO) + /* Cannot seek on these */ + if (IS_PIPELIKE(finfo.st_mode) || f->fd == STDIN_FILENO) return tail_pipe(f); f->st_size = finfo.st_size; @@ -253,8 +269,10 @@ static int tail_file(struct file_struct *f, unsigned int n_units, char mode) offset = bytes_to_offset(f, n_units); /* We only get negative offsets on errors */ - if (offset < 0) - goto out; + if (unlikely(offset < 0)) { + ignore_file(f); + return -1; + } if (verbose) write_header(f->name); @@ -264,132 +282,129 @@ static int tail_file(struct file_struct *f, unsigned int n_units, char mode) while ((bytes_read = read(f->fd, &buf, BUFFER_SIZE)) > 0) write(STDOUT_FILENO, buf, (size_t) bytes_read); - ret = 0; -out: - if (close(f->fd) < 0) { - fprintf(stderr, "Error: Could not close file '%s' (%s)\n", f->name, strerror(errno)); - ret = -1; - } + if (!forever) { + if (close(f->fd) < 0) { + fprintf(stderr, "Error: Could not close file '%s' (%s)\n", f->name, strerror(errno)); + return -1; + } + } /* Let the fd open otherwise, we'll need it */ - return ret; + return 0; } -static int handle_inotify_event(struct inotify_event *inev, struct file_struct *fil, int n_ignored) +static int handle_inotify_event(struct inotify_event *inev, struct file_struct *f) { - off_t offset; + int ret = 0; if (inev->mask & IN_MODIFY) { - int rc; + ssize_t rc; char fbuf[BUFFER_SIZE]; struct stat finfo; - fil->fd = open(fil->name, O_RDONLY); - if (fil->fd < 0) { - fprintf(stderr, "Error: Could not open file '%s' (%s)\n", fil->name, strerror(errno)); - goto ignore; - } - - if (fstat(fil->fd, &finfo) < 0) { - fprintf(stderr, "Error: Could not stat file '%s' (%s)\n", fil->name, strerror(errno)); - close(fil->fd); - goto ignore; - } - - offset = fil->st_size; - fil->st_size = finfo.st_size; - if (verbose) - write_header(fil->name); + write_header(f->name); - memset(&fbuf, 0, sizeof(fbuf)); + lseek(f->fd, f->st_size, SEEK_SET); /* Old file size */ + while ((rc = read(f->fd, &fbuf, BUFFER_SIZE)) != 0) + write(STDOUT_FILENO, fbuf, (size_t) rc); - lseek(fil->fd, offset, SEEK_SET); - while ((rc = read(fil->fd, &fbuf, BUFFER_SIZE)) != 0) - write(STDOUT_FILENO, fbuf, rc); + if (fstat(f->fd, &finfo) < 0) { + fprintf(stderr, "Error: Could not stat file '%s' (%s)\n", f->name, strerror(errno)); + ret = -1; + goto ignore; + } - close(fil->fd); + f->st_size = finfo.st_size; - return n_ignored; + return ret; } else if (inev->mask & IN_DELETE_SELF) { - fprintf(stderr, "File '%s' deleted.\n", fil->name); + fprintf(stderr, "File '%s' deleted.\n", f->name); } else if (inev->mask & IN_MOVE_SELF) { - /* TODO: Try to follow file/fd */ - fprintf(stderr, "File '%s' moved.\n", fil->name); + fprintf(stderr, "File '%s' moved.\n", f->name); + return 0; } else if (inev->mask & IN_UNMOUNT) { - fprintf(stderr, "Device containing file '%s' unmounted.\n", fil->name); + fprintf(stderr, "Device containing file '%s' unmounted.\n", f->name); } ignore: - fil->ignore = 1; - n_ignored++; + ignore_file(f); - return n_ignored; + return ret; } -static int watch_files(struct file_struct *f, int n_files) +static int watch_files(struct file_struct *files, int n_files) { - int ifd, i, n_ignored = 0; - unsigned buflen = 2 * n_files * sizeof(struct inotify_event); - struct inotify_event *inev; - char *buf; + int ifd, i; + char buf[n_files * INOTIFY_BUFLEN]; ifd = inotify_init(); - if (ifd < 0) { + if (errno == ENOSYS) { fprintf(stderr, "Error: Inotify is not supported by the kernel you're currently running.\n"); exit(EXIT_FAILURE); + } else if (unlikely(ifd < 0)) { + fprintf(stderr, "Error: Could not initialize Inotify (%s)\n", strerror(errno)); + exit(EXIT_FAILURE); } for (i = 0; i < n_files; i++) { - if (!f[i].ignore) - f[i].i_watch = inotify_add_watch(ifd, f[i].name, + if (!files[i].ignore) { + files[i].i_watch = inotify_add_watch(ifd, files[i].name, IN_MODIFY|IN_DELETE_SELF|IN_MOVE_SELF|IN_UNMOUNT); - else - n_ignored++; - } - buf = malloc(buflen); - memset(buf, 0, buflen); + if (files[i].i_watch < 0) { + fprintf(stderr, "Error: Could not create inotify watch on file '%s' (%s)\n", + files[i].name, strerror(errno)); + ignore_file(&files[i]); + } + } + } while (n_ignored < n_files) { - int len; + ssize_t len; + int ev_idx = 0; - len = read(ifd, buf, buflen); - inev = (struct inotify_event *) buf; + len = read(ifd, &buf, (n_files * INOTIFY_BUFLEN)); + if (unlikely(len < 0)) { + fprintf(stderr, "Error: Could not read inotify events (%s)\n", strerror(errno)); + exit(EXIT_FAILURE); + } + + while (ev_idx < len) { + struct inotify_event *inev; + struct file_struct *f = NULL; - while (len > 0) { - struct file_struct *fil = NULL; + inev = (struct inotify_event *) &buf[ev_idx]; /* Which file has produced the event? */ for (i = 0; i < n_files; i++) { - if (!f[i].ignore && f[i].fd >= 0 && f[i].i_watch == inev->wd) { - fil = &f[i]; + if (!files[i].ignore && files[i].fd >= 0 && files[i].i_watch == inev->wd) { + f = &files[i]; break; } } - if (unlikely(!fil)) + if (unlikely(!f)) break; - n_ignored = handle_inotify_event(inev, fil, n_ignored); - len -= sizeof(struct inotify_event) + inev->len; - inev = (struct inotify_event *) ((char *) inev + sizeof(struct inotify_event) + inev->len); + if (handle_inotify_event(inev, f) < 0) + break; + ev_idx += INOTIFY_BUFLEN + inev->len; } } - free(buf); close(ifd); - return n_ignored; + return -1; } int main(int argc, char **argv) { int i, c, ret = 0; - int n_files = 0; - int n_units = DEFAULT_N_LINES; + int n_files; + unsigned long n_units = DEFAULT_N_LINES; char forever = 0, mode = M_LINES; char **filenames; - struct file_struct *files; + struct file_struct *files = NULL; while ((c = getopt_long(argc, argv, "c:n:fvVh", long_opts, NULL)) != -1) { switch (c) { @@ -397,13 +412,17 @@ int main(int argc, char **argv) mode = M_BYTES; /* fall through */ case 'n': - if (*optarg == '+') + if (*optarg == '+') { from_begin = 1; - else if (*optarg == '-') optarg++; + } else if (*optarg == '-') + optarg++; + + if (!isdigit(*optarg)) { + fprintf(stderr, "Invalid number of lines: %s\n", optarg); + exit(EXIT_FAILURE); + } n_units = strtoul(optarg, NULL, 0); - if (n_units < 0) - n_units = 0; break; case 'f': forever = 1; @@ -412,8 +431,8 @@ int main(int argc, char **argv) verbose = 1; break; case 'V': - fprintf(stderr, "%s %s\n", PROGRAM_NAME, VERSION); - return 0; + fprintf(stdout, "%s %s\n", PROGRAM_NAME, VERSION); + exit(EXIT_SUCCESS); case 'h': usage(EXIT_SUCCESS); default: @@ -428,7 +447,7 @@ int main(int argc, char **argv) } else { /* It must be stdin then */ static char *dummy_stdin = "-"; - n_files++; + n_files = 1; filenames = &dummy_stdin; /* POSIX says that -f is ignored if no file operand is @@ -436,13 +455,13 @@ int main(int argc, char **argv) if (forever) { struct stat finfo; if (fstat(STDIN_FILENO, &finfo) == 0 - && (S_ISFIFO(finfo.st_mode) || S_ISSOCK(finfo.st_mode))) + && IS_PIPELIKE(finfo.st_mode)) forever = 0; } } files = malloc(n_files * sizeof(struct file_struct)); - if (!files) { + if (unlikely(!files)) { fprintf(stderr, "Error: Not enough memory (%s)\n", strerror(errno)); exit(EXIT_FAILURE); } @@ -450,9 +469,9 @@ int main(int argc, char **argv) for (i = 0; i < n_files; i++) { files[i].name = filenames[i]; setup_file(&files[i]); - ret = tail_file(&files[i], n_units, mode); + ret = tail_file(&files[i], n_units, mode, forever); if (ret < 0) - files[i].ignore = 1; + ignore_file(&files[i]); } if (forever) -- cgit v1.2.3-54-g00ecf