From 10f6e1b387eaea5f373b088c4d880e9c938a5871 Mon Sep 17 00:00:00 2001 From: Tobias Klauser Date: Sat, 12 Aug 2006 21:06:27 +0200 Subject: Improved error handling and more meaningful error messages --- inotail.c | 63 +++++++++++++++++++++++++++++++++++++-------------------------- 1 file changed, 37 insertions(+), 26 deletions(-) diff --git a/inotail.c b/inotail.c index b5cf134..7b8c716 100644 --- a/inotail.c +++ b/inotail.c @@ -65,11 +65,11 @@ static void write_header(const char *filename) first_file = 0; } -static off_t lines_to_offset(int fd, int file_size, unsigned int n_lines) +static off_t lines_to_offset(struct file_struct *f, unsigned int n_lines) { int i; char buf[BUFFER_SIZE]; - off_t offset = file_size; + off_t offset = f->st_size; memset(&buf, 0, sizeof(buf)); @@ -89,11 +89,13 @@ static off_t lines_to_offset(int fd, int file_size, unsigned int n_lines) /* Start of current block */ offset -= block_size; - lseek(fd, offset, SEEK_SET); + lseek(f->fd, offset, SEEK_SET); - rc = read(fd, &buf, block_size); - if (rc < 0) - return rc; + rc = read(f->fd, &buf, block_size); + if (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--) { if (buf[i] == '\n') { @@ -113,42 +115,44 @@ static off_t lines_to_offset(int fd, int file_size, unsigned int n_lines) static int tail_file(struct file_struct *f, int n_lines, char mode) { - int fd; ssize_t rc = 0; off_t offset = 0; char buf[BUFFER_SIZE]; struct stat finfo; - fd = open(f->name, O_RDONLY); - if (fd < 0) { - perror("open()"); + f->fd = open(f->name, O_RDONLY); + if (f->fd < 0) { + fprintf(stderr, "Error: Could not open file '%s' (%s)\n", f->name, strerror(errno)); return -1; } - if (fstat(fd, &finfo) < 0) { - perror("fstat()"); + if (fstat(f->fd, &finfo) < 0) { + fprintf(stderr, "Error: Could not stat file '%s' (%s)\n", f->name, strerror(errno)); return -1; } f->st_size = finfo.st_size; if (mode == M_LINES) - offset = lines_to_offset(fd, f->st_size, n_lines); + offset = lines_to_offset(f, n_lines); else /* Bytewise tail */ offset = f->st_size - n_lines; + if (offset < 0) + return -1; + if (verbose) write_header(f->name); - lseek(fd, offset, SEEK_SET); + lseek(f->fd, offset, SEEK_SET); - while ((rc = read(fd, &buf, BUFFER_SIZE)) != 0) { + while ((rc = read(f->fd, &buf, BUFFER_SIZE)) != 0) { dprintf(" f->st_size - offset: %lu\n", f->st_size - offset); dprintf(" rc: %d\n", rc); write(STDOUT_FILENO, buf, (size_t) rc); } - close(fd); + close(f->fd); return 0; } @@ -158,11 +162,11 @@ static int watch_files(struct file_struct *f, int n_files) int ifd, i; off_t offset; struct inotify_event *inev; - char buf[BUFFER_SIZE]; + char buf[sizeof(struct inotify_event) * 32]; /* Let's hope we don't get more than 32 events at a time */ ifd = inotify_init(); if (ifd < 0) { - fprintf(stderr, "Inotify is not supported by the kernel you're currently running.\n"); + fprintf(stderr, "Error: Inotify is not supported by the kernel you're currently running.\n"); exit(EXIT_FAILURE); } @@ -192,7 +196,7 @@ static int watch_files(struct file_struct *f, int n_files) } if (inev->mask & IN_MODIFY) { - int ffd, block_size; + int block_size; char fbuf[BUFFER_SIZE]; struct stat finfo; @@ -201,9 +205,14 @@ static int watch_files(struct file_struct *f, int n_files) dprintf(" File '%s' modified.\n", fil->name); dprintf(" offset: %lu.\n", offset); - ffd = open(fil->name, O_RDONLY); - if (fstat(ffd, &finfo) < 0) { - perror("fstat()"); + fil->fd = open(fil->name, O_RDONLY); + if (fil->fd < 0) { + fprintf(stderr, "Error: Could not open file '%s' (%s)\n", f->name, strerror(errno)); + return -1; + } + + if (fstat(fil->fd, &finfo) < 0) { + fprintf(stderr, "Error: Could not stat file '%s' (%s)\n", f->name, strerror(errno)); return -1; } @@ -224,12 +233,12 @@ static int watch_files(struct file_struct *f, int n_files) write_header(fil->name); memset(&fbuf, 0, sizeof(fbuf)); - lseek(ffd, offset, SEEK_SET); - while (read(ffd, &fbuf, block_size) != 0) { + lseek(fil->fd, offset, SEEK_SET); + while (read(fil->fd, &fbuf, block_size) != 0) { write(STDOUT_FILENO, fbuf, block_size); } - close(ffd); + close(fil->fd); } if (inev->mask & IN_DELETE_SELF) { @@ -303,7 +312,9 @@ int main(int argc, char **argv) files = malloc(n_files * sizeof(struct file_struct)); for (i = 0; i < n_files; i++) { files[i].name = filenames[i]; - ret &= tail_file(&files[i], n_lines, mode); + ret = tail_file(&files[i], n_lines, mode); + if (ret < 0) + files[i].ignore = 1; } if (forever) -- cgit v1.2.3-54-g00ecf