lsof/backport-linux-Fix-handling-of-empty-command-name-closing-246.patch
2023-03-23 14:14:59 +08:00

233 lines
7.0 KiB
Diff

From 849655be491b2fe3023bc87f6a650c2917e0c198 Mon Sep 17 00:00:00 2001
From: Jiajie Chen <c@jia.je>
Date: Wed, 18 Jan 2023 21:36:12 +0800
Subject: [PATCH] [linux] Fix handling of empty command name, closing #246
Add test from #246, where lsof returns stale command name when the
command name is empty.
If getting command name failed, return NULL instead of empty string.
---
dialects/linux/dproc.c | 88 +++++++++++++++------------
print.c | 11 ++--
tests/case-22-empty-process-name.bash | 29 +++++++++
3 files changed, 84 insertions(+), 44 deletions(-)
create mode 100755 tests/case-22-empty-process-name.bash
diff --git a/dialects/linux/dproc.c b/dialects/linux/dproc.c
index e2dce74..922db6e 100644
--- a/dialects/linux/dproc.c
+++ b/dialects/linux/dproc.c
@@ -339,12 +339,12 @@ gather_proc_info()
continue;
uid = (UID_ARG)sb.st_uid;
ht = pidts = 0;
- /*
- * Get the PID's command name.
- */
+ /*
+ * Get the PID's command name.
+ */
(void) make_proc_path(pidpath, n, &path, &pathl, "stat");
if ((prv = read_id_stat(path, pid, &cmd, &ppid, &pgid)) < 0)
- cmd = "(unknown)";
+ cmd = NULL; /* NULL means failure to get command name */
#if defined(HASTASKS)
/*
@@ -356,11 +356,16 @@ gather_proc_info()
* options work properly.
*/
else if (!IgnTasks && (Selflags & SELTASK)) {
+ /*
+ * Copy cmd before next call to read_id_stat due to static
+ * variables
+ */
if (cmd) {
strncpy(cmdbuf, cmd, sizeof(cmdbuf) - 1);
+ cmdbuf[sizeof(cmdbuf) - 1] = '\0';
+ cmd = cmdbuf;
}
- cmdbuf[sizeof(cmdbuf) - 1] = '\0';
- cmd = cmdbuf;
+
(void) make_proc_path(pidpath, n, &taskpath, &taskpathl,
"task");
tx = n + 4;
@@ -1436,10 +1441,9 @@ compare_mntns(pid)
*/
static void
-process_proc_map(p, s, ss)
- char *p; /* path to process maps file */
- struct stat *s; /* executing text file state buffer */
- int ss; /* *s status -- i.e., SB_* values */
+process_proc_map(char *p, /* path to process maps file */
+ struct stat *s, /* executing text file state buffer */
+ int ss) /* *s status -- i.e., SB_* values */
{
char buf[MAXPATHLEN + 1], *ep, fmtbuf[32], **fp, nmabuf[MAXPATHLEN + 1];
dev_t dev;
@@ -1705,14 +1709,12 @@ process_proc_map(p, s, ss)
* 1 == ID is a zombie
* 2 == ID is a thread
*/
-
static int
-read_id_stat(p, id, cmd, ppid, pgid)
- char *p; /* path to status file */
- int id; /* ID: PID or LWP */
- char **cmd; /* malloc'd command name */
- int *ppid; /* returned parent PID for PID type */
- int *pgid; /* returned process group ID for PID
+read_id_stat(char *p, /* path to status file */
+ int id, /* ID: PID or LWP */
+ char **cmd, /* malloc'd command name */
+ int *ppid, /* returned parent PID for PID type */
+ int *pgid) /* returned process group ID for PID
* type */
{
char buf[MAXPATHLEN], *cp, *cp1, **fp;
@@ -1757,14 +1759,22 @@ read_id_stat(p, id, cmd, ppid, pgid)
goto read_id_stat_exit;
cp++;
pc = 1; /* start the parenthesis balance count at 1 */
-/*
- * Enter the command characters safely. Supply them from the initial read
- * of the stat file line, a '\n' if the initial read didn't yield a ')'
- * command closure, or by reading the rest of the command a character at
- * a time from the stat file. Count embedded '(' characters and balance
- * them with embedded ')' characters. The opening '(' starts the balance
- * count at one.
- */
+
+ /* empty process name to avoid leaking previous process name,
+ * see issue #246
+ */
+ if (cbf) {
+ cbf[0] = '\0';
+ }
+
+ /*
+ * Enter the command characters safely. Supply them from the initial read
+ * of the stat file line, a '\n' if the initial read didn't yield a ')'
+ * command closure, or by reading the rest of the command a character at
+ * a time from the stat file. Count embedded '(' characters and balance
+ * them with embedded ')' characters. The opening '(' starts the balance
+ * count at one.
+ */
for (cx = es = 0;;) {
if (!es)
ch = *cp++;
@@ -1776,10 +1786,10 @@ read_id_stat(p, id, cmd, ppid, pgid)
pc++;
if (ch == ')') {
- /*
- * Balance parentheses when a closure is encountered. When
- * they are balanced, this is the end of the command.
- */
+ /*
+ * Balance parentheses when a closure is encountered. When
+ * they are balanced, this is the end of the command.
+ */
pc--;
if (!pc)
break;
@@ -1793,12 +1803,12 @@ read_id_stat(p, id, cmd, ppid, pgid)
es = 1; /* Switch to fgetc() when a '\0' appears. */
}
*cmd = cbf;
-/*
- * Read the remainder of the stat line if it was necessary to read command
- * characters individually from the stat file.
- *
- * Separate the reminder into fields.
- */
+ /*
+ * Read the remainder of the stat line if it was necessary to read command
+ * characters individually from the stat file.
+ *
+ * Separate the reminder into fields.
+ */
if (es)
cp = fgets(buf, sizeof(buf), fs);
(void) fclose(fs);
@@ -1841,13 +1851,11 @@ read_id_stat(p, id, cmd, ppid, pgid)
* This function should be used only when links have been successfully
* resolved in the /proc path by getlinksrc().
*/
-
static int
-statEx(p, s, ss)
- char *p; /* file path */
- struct stat *s; /* stat() result -- NULL if none
+statEx(char *p, /* file path */
+ struct stat *s, /* stat() result -- NULL if none
* wanted */
- int *ss; /* stat() status -- SB_* values */
+ int *ss) /* stat() status -- SB_* values */
{
static size_t ca = 0;
static char *cb = NULL;
diff --git a/print.c b/print.c
index 3671a69..4b9f14c 100644
--- a/print.c
+++ b/print.c
@@ -742,10 +742,13 @@ print_file()
(void) printf(" %*s %s\n", NodeColW, NODETTL, NMTTL);
Hdr++;
}
-/*
- * Size or print the command.
- */
- cp = (Lp->cmd && *Lp->cmd != '\0') ? Lp->cmd : "(unknown)";
+ /*
+ * Size or print the command.
+ *
+ * CAUTION: command can be empty, see issue #246,
+ * use NULL to represent failure instead of empty string
+ */
+ cp = Lp->cmd ? Lp->cmd : "(unknown)";
if (!PrPass) {
len = safestrlen(cp, 2);
if (CmdLim && (len > CmdLim))
diff --git a/tests/case-22-empty-process-name.bash b/tests/case-22-empty-process-name.bash
new file mode 100755
index 0000000..ce4039c
--- /dev/null
+++ b/tests/case-22-empty-process-name.bash
@@ -0,0 +1,29 @@
+#!/bin/bash
+# See https://github.com/lsof-org/lsof/issues/246
+source tests/common.bash
+
+{
+ perl -e '$0 = ""; sleep 999' &
+ pid=$!
+ sleep 1
+
+ output=$($lsof -w -ad cwd -F c -p "$pid")
+ echo "lsof output:" >> $report
+ echo "$output" >> $report
+ kill $pid
+ for entry in $output
+ do
+ if [[ $entry =~ ^p[0-9]+$ ]]; then
+ if [[ $entry != p$pid ]]; then
+ echo "Incorrect pid, expect p$pid, got $entry" >> $report
+ exit 1
+ fi
+ elif [[ $entry =~ c* ]]; then
+ if [[ $entry != c ]]; then
+ echo "Process name should be empty, expect c, got $entry" >> $report
+ exit 1
+ fi
+ fi
+ done
+ exit 0
+} > $report 2>&1
--
2.27.0