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Tidy up comments.

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This commit is contained in:
Andrew Wood
2026-04-18 17:41:14 +01:00
parent fec4253f07
commit 17d9ee59e7
1 changed files with 45 additions and 20 deletions
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src/pv/watchpid.c
+45 -20
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@@ -36,9 +36,9 @@
/*
* Set info->size to the size of the file info->file_fdpath points to,
* assuming that info->sb_fd has been populated by stat(), or to 0 if the
* file size could not be determined or the file was opened in write mode;
* returns false if the file was not a block device or regular file.
* assuming that info->sb_fd has already been populated by stat(), or to 0
* if the file size could not be determined or the file was opened in write
* mode; returns false if the file was not a block device or regular file.
*/
static bool filesize(pvwatchfd_t info)
{
@@ -48,13 +48,13 @@ static bool filesize(pvwatchfd_t info)
int fd;
/*
* Get the size of block devices by opening
* them and seeking to the end.
* Get the size of block devices by opening them and seeking
* to the end.
*/
fd = open(info->file_fdpath, O_RDONLY); /* flawfinder: ignore */
/*
* flawfinder: redirection check below; risk is minimal as
* we are not actually reading any data here.
* no reads are performed.
*/
if (fd >= 0) {
/*
@@ -74,10 +74,14 @@ static bool filesize(pvwatchfd_t info)
info->size = 0;
}
} else if (S_ISREG(info->sb_fd.st_mode)) {
/* Regular file - use its st_size. */
if ((info->sb_fd_link.st_mode & S_IWUSR) == 0) {
info->size = info->sb_fd.st_size;
}
} else {
/* Not a block device or a file, so the size is unknown. */
return false;
}
@@ -87,6 +91,22 @@ static bool filesize(pvwatchfd_t info)
/*@+type@*/
#ifdef __APPLE__
/*
* Populate the "info" structure with the file paths and stat details of the
* process and file descriptor pair given within that structure.
*
* Returns nonzero on error - error codes are:
*
* -1 - info or state were NULL
* 1 - process does not exist
* 2 - not applicable (see the alternative pv_watchfd_info() below)
* 3 - lookup of the file descriptor destination failed
* 4 - file descriptor is not opened on a regular file
*
* If "automatic" is true, then this fd was picked automatically, and so if
* it's not readable or not a regular file, no error is reported with
* pv_error() when returning the error code.
*/
int pv_watchfd_info(pvstate_t state, pvwatchfd_t info, bool automatic)
{
struct vnode_fdinfowithpath vnodeInfo = { };
@@ -138,9 +158,8 @@ int pv_watchfd_info(pvstate_t state, pvwatchfd_t info, bool automatic)
#else
/*
* Fill in the given information structure with the file paths and stat
* details of the given file descriptor within the given process (given
* within the info structure).
* Populate the "info" structure with the file paths and stat details of the
* process and file descriptor pair given within that structure.
*
* Returns nonzero on error - error codes are:
*
@@ -151,8 +170,8 @@ int pv_watchfd_info(pvstate_t state, pvwatchfd_t info, bool automatic)
* 4 - file descriptor is not opened on a regular file
*
* If "automatic" is true, then this fd was picked automatically, and so if
* it's not readable or not a regular file, no error is displayed and the
* function just returns an error code.
* it's not readable or not a regular file, no error is reported with
* pv_error() when returning the error code.
*/
int pv_watchfd_info(pvstate_t state, pvwatchfd_t info, bool automatic)
{
@@ -174,11 +193,10 @@ int pv_watchfd_info(pvstate_t state, pvwatchfd_t info, bool automatic)
if (readlink(info->file_fd, info->file_fdpath, PV_SIZEOF_FILE_FDPATH - 1) < 0) { /* flawfinder: ignore */
/*
* flawfinder: memset() has put \0 at the end already, and
* we tell readlink() to use 1 byte less than the buffer
* length, so \0 termination is assured. There is no
* mitigation for the risk of the link changing while we
* read it, but we are only reading from the destination,
* and then only if it's a block device - see filesize().
* readlink() is given 1 byte less than the buffer length,
* so \0 termination is assured. See filesize() above for
* the mitigation of the risk that the link could change
* while it is being read.
*/
if (!automatic)
pv_error("%s %u: %s %d: %s",
@@ -218,7 +236,7 @@ bool pv_watchfd_changed(pvwatchfd_t info)
#else
/*
* Return true if the given file descriptor has changed in some way since
* we started looking at it (i.e. changed destination or permissions).
* it was first detected (i.e. changed destination or permissions).
*/
bool pv_watchfd_changed(pvwatchfd_t info)
{
@@ -300,6 +318,13 @@ off_t pv_watchfd_position(pvwatchfd_t info)
#ifdef __APPLE__
/*
* Allocate an array of proc_fdinfo structs containing details of the file
* descriptors opened by process "pid", placing the pointer to the array
* into *fds and the number of entries in it into *count.
*
* Returns nonzero on error, and reports the error.
*/
static int pidfds(pvstate_t state, unsigned int pid, struct proc_fdinfo **fds, int *count)
{
int size_needed = proc_pidinfo(pid, PROC_PIDLISTFDS, 0, 0, 0);
@@ -425,7 +450,7 @@ static int pv_compare_watchfd(const void *a, const void *b)
/*
* Scan the given process and update the arrays with any new file
* Scan the process "watch_pid" and update the arrays with any new file
* descriptors. If "watch_fd" is not -1, then all other file descriptor
* numbers will be ignored,
*
@@ -494,7 +519,7 @@ int pv_watchpid_scanfds(pvstate_t state, pid_t watch_pid, int watch_fd, int *arr
continue;
/*
* Skip if this fd is already known to us.
* Skip if this fd is already known.
*/
found_idx = -1;
for (check_idx = 0; check_idx < array_length && NULL != info_array; check_idx++) {
@@ -519,7 +544,7 @@ int pv_watchpid_scanfds(pvstate_t state, pid_t watch_pid, int watch_fd, int *arr
continue;
/*
* See if there's an empty slot we can re-use.
* Check for an empty slot to re-use.
*/
use_idx = -1;
for (check_idx = 0; check_idx < array_length && NULL != info_array; check_idx++) {