From 2a31b73a32982e67aff32f8b23d5f0916fd7485d Mon Sep 17 00:00:00 2001
From: Andrew Wood <andrew.wood@ivarch.com>
Date: Sat, 25 Apr 2026 22:04:38 +0100
Subject: [PATCH] Replace the fixed-sized buffers file_fdinfo and
 file_fdsymlink with dynamically allocated equivalents.

---
 src/include/pv-internal.h |  6 ++----
 src/pv/watchpid.c         | 44 ++++++++++++++++++++++++++++++++++-----
 2 files changed, 41 insertions(+), 9 deletions(-)

diff --git a/src/include/pv-internal.h b/src/include/pv-internal.h
index 1884d1c..80fc11e 100644
--- a/src/include/pv-internal.h
+++ b/src/include/pv-internal.h
@@ -48,8 +48,6 @@ extern "C" {
 #define PV_SIZEOF_PREVLINE_BUFFER	1024
 #define PV_FORMAT_ARRAY_MAX		100
 #define PV_SIZEOF_FORMAT_SEGMENTS_BUF	4096
-#define PV_SIZEOF_FILE_FDINFO		4096
-#define PV_SIZEOF_FILE_FDSYMLINK	4096
 #define PV_SIZEOF_FILE_FDPATH		4096
 #define PV_SIZEOF_DISPLAY_NAME		512
 
@@ -494,8 +492,8 @@ struct pvwatchfd_s {
 	struct pvdisplay_s display;	 /* display data */
 #ifdef __APPLE__
 #else
-	char file_fdinfo[PV_SIZEOF_FILE_FDINFO]; /* path to /proc fdinfo file */
-	char file_fdsymlink[PV_SIZEOF_FILE_FDSYMLINK];	 /* path to /proc fd symlink  */
+	nullable_string_ptr file_fdinfo; /* path to /proc fdinfo file */
+	nullable_string_ptr file_fdsymlink;	 /* path to /proc fd symlink  */
 #endif
 	char file_fdpath[PV_SIZEOF_FILE_FDPATH]; /* path to file that was opened */
 	/*@keep@ */ char display_name[PV_SIZEOF_DISPLAY_NAME]; /* name to show on progress bar */
diff --git a/src/pv/watchpid.c b/src/pv/watchpid.c
index 71e052f..b45adb1 100644
--- a/src/pv/watchpid.c
+++ b/src/pv/watchpid.c
@@ -184,11 +184,32 @@ int pv_watchfd_info(pvstate_t state, pvwatchfd_t info, bool automatic)
 			pv_perror("%s %u", _("pid"), info->watch_pid);
 		return 1;
 	}
-	(void) pv_snprintf(info->file_fdinfo, PV_SIZEOF_FILE_FDINFO,
-			   "/proc/%u/fdinfo/%d", info->watch_pid, info->watch_fd);
-	(void) pv_snprintf(info->file_fdsymlink, PV_SIZEOF_FILE_FDSYMLINK, "/proc/%u/fd/%d", info->watch_pid,
-			   info->watch_fd);
 
+	/* Build the string containing the path to the /proc fdinfo file. */
+	if (NULL != info->file_fdinfo) {
+		free(info->file_fdinfo);
+		info->file_fdinfo = NULL;
+	}
+	if ((pv_asprintf(&(info->file_fdinfo), "/proc/%u/fdinfo/%d", info->watch_pid, info->watch_fd) < 0)
+	    || (NULL == info->file_fdinfo)) {
+		if (!automatic)
+			pv_perror("%s %u", _("pid"), info->watch_pid);
+		return 2;
+	}
+
+	/* Build the string containing the path to the /proc fd symlink. */
+	if (NULL != info->file_fdsymlink) {
+		free(info->file_fdsymlink);
+		info->file_fdsymlink = NULL;
+	}
+	if ((pv_asprintf(&(info->file_fdsymlink), "/proc/%u/fd/%d", info->watch_pid, info->watch_fd) < 0)
+	    || (NULL == info->file_fdsymlink)) {
+		if (!automatic)
+			pv_perror("%s %u", _("pid"), info->watch_pid);
+		return 2;
+	}
+
+	/* Get a string containing the path that the /proc fd symlink points to. */
 	memset(info->file_fdpath, 0, PV_SIZEOF_FILE_FDPATH);
 	if (readlink(info->file_fdsymlink, info->file_fdpath, PV_SIZEOF_FILE_FDPATH - 1) < 0) {	/* flawfinder: ignore */
 		/*
@@ -203,6 +224,7 @@ int pv_watchfd_info(pvstate_t state, pvwatchfd_t info, bool automatic)
 		return 2;
 	}
 
+	/* Run stat() on the /proc fd symlink and the path it points to. */
 	if (!((0 == stat(info->file_fdsymlink, &(info->sb_fd)))
 	      && (0 == lstat(info->file_fdsymlink, &(info->sb_fd_link))))) {
 		if (!automatic)
@@ -211,8 +233,8 @@ int pv_watchfd_info(pvstate_t state, pvwatchfd_t info, bool automatic)
 		return 3;
 	}
 
+	/* Find the size of the path pointed to. */
 	info->size = 0;
-
 	if (!filesize(info)) {
 		if (!automatic)
 			pv_error("%s %u: %s %d: %s: %s",
@@ -242,6 +264,8 @@ bool pv_watchfd_changed(pvwatchfd_t info)
 
 	if (NULL == info)
 		return false;
+	if (NULL == info->file_fdsymlink)
+		return false;
 
 	memset(&sb_fd, 0, sizeof(sb_fd));
 	memset(&sb_fd_link, 0, sizeof(sb_fd_link));
@@ -292,6 +316,8 @@ off_t pv_watchfd_position(pvwatchfd_t info)
 	if (pv_watchfd_changed(info))
 		return -1;
 
+	if (NULL == info->file_fdinfo)
+		return -1;
 	fptr = fopen(info->file_fdinfo, "r");	/* flawfinder: ignore */
 	/* flawfinder: trusted location (/proc). */
 	if (NULL == fptr)
@@ -422,6 +448,14 @@ void pv_freecontents_watchfd(pvwatchfd_t info)
 	pv_freecontents_calc(&(info->calc));
 	pv_freecontents_transfer(&(info->transfer));
 	pv_freecontents_display(&(info->display));
+	if (NULL != info->file_fdinfo) {
+		free(info->file_fdinfo);
+		info->file_fdinfo = NULL;
+	}
+	if (NULL != info->file_fdsymlink) {
+		free(info->file_fdsymlink);
+		info->file_fdsymlink = NULL;
+	}
 }