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authorTobias Klauser <tklauser@xenon.tklauser.home>2006-08-12 21:06:27 +0200
committerTobias Klauser <tklauser@xenon.tklauser.home>2006-08-12 21:06:27 +0200
commit10f6e1b387eaea5f373b088c4d880e9c938a5871 (patch)
treef861ff83db909e2d9199e13af9c2dfb616827c1f
parent231a4558144c732837ede36a52bfc93b5a64bf7e (diff)
Improved error handling and more meaningful error messages
-rw-r--r--inotail.c63
1 files 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)