Improve process cmdline basename matching with procExe path

The matchCmdlinePrefixWithExeSuffix() internal function (in Process.c)
can match basenames in multiple tries in case the
"cmdlineBasenameStart" input value is unreliable. Take advantage of
this and update "cmdlineBasenameStart" with the new offset detected by
the function.

Also make the matching behavior consistent regardless of
"showMergedCommand" setting.

Signed-off-by: Kang-Che Sung <[email protected]>

Author: Explorer09

Process.c

@@ -99,7 +99,7 @@ static bool findCommInCmdline(const char* comm, const char* cmdline, int cmdline
    return false;
 }
 
-static int matchCmdlinePrefixWithExeSuffix(const char* cmdline, int cmdlineBaseOffset, const char* exe, int exeBaseOffset, int exeBaseLen) {
+static int matchCmdlinePrefixWithExeSuffix(const char* cmdline, int* cmdlineBasenameStart, const char* exe, int exeBaseOffset, int exeBaseLen) {
    /* cmdline prefix is an absolute path: it must match whole exe. */
    if (cmdline[0] == '/') {
       int matchLen = exeBaseLen + exeBaseOffset;
@@ -124,6 +124,7 @@ static int matchCmdlinePrefixWithExeSuffix(const char* cmdline, int cmdlineBaseO
     *
     * So if needed, we adjust cmdlineBaseOffset to the previous (if any)
     * component of the cmdline relative path, and retry the procedure. */
+   int cmdlineBaseOffset = *cmdlineBasenameStart;
    bool delimFound = true; /* if valid basename delimiter found */
    do {
       /* match basename */
@@ -140,8 +141,10 @@ static int matchCmdlinePrefixWithExeSuffix(const char* cmdline, int cmdlineBaseO
             }
 
             /* full match, with exe suffix being a valid relative path */
-            if (i < 1 && j >= 1 && exe[j - 1] == '/')
+            if (i < 1 && j >= 1 && exe[j - 1] == '/') {
+               *cmdlineBasenameStart = cmdlineBaseOffset;
                return matchLen;
+            }
          }
       }
 
@@ -322,6 +325,26 @@ void Process_makeCommandStr(Process* this, const Settings* settings) {
    assert(cmdlineBasenameStart >= 0);
    assert(cmdlineBasenameStart <= (int)strlen(cmdline));
 
+   int exeLen = 0;
+   int exeBasenameOffset = 0;
+   int exeBasenameLen = 0;
+   int matchLen = 0;
+   if (procExe) {
+      exeLen = strlen(procExe);
+      exeBasenameOffset = this->procExeBasenameOffset;
+      exeBasenameLen = exeLen - exeBasenameOffset;
+
+      assert(exeBasenameOffset >= 0);
+      assert(exeBasenameOffset <= (int)strlen(procExe));
+
+      if (this->cmdline) {
+         matchLen = matchCmdlinePrefixWithExeSuffix(this->cmdline, &cmdlineBasenameStart, procExe, exeBasenameOffset, exeBasenameLen);
+      }
+      if (matchLen) {
+         cmdlineBasenameLen = exeBasenameLen;
+      }
+   }
+
    if (!showMergedCommand || !procExe || !procComm) { /* fall back to cmdline */
       if ((showMergedCommand || (Process_isUserlandThread(this) && showThreadNames)) && procComm && strlen(procComm)) { /* set column to or prefix it with comm */
          if (strncmp(cmdline + cmdlineBasenameStart, procComm, MINIMUM(TASK_COMM_LEN - 1, strlen(procComm))) != 0) {
@@ -352,13 +375,6 @@ void Process_makeCommandStr(Process* this, const Settings* settings) {
       return;
    }
 
-   int exeLen = strlen(this->procExe);
-   int exeBasenameOffset = this->procExeBasenameOffset;
-   int exeBasenameLen = exeLen - exeBasenameOffset;
-
-   assert(exeBasenameOffset >= 0);
-   assert(exeBasenameOffset <= (int)strlen(procExe));
-
    bool haveCommInExe = false;
    if (procExe && procComm && (!Process_isUserlandThread(this) || showThreadNames)) {
       haveCommInExe = strncmp(procExe + exeBasenameOffset, procComm, TASK_COMM_LEN - 1) == 0;
@@ -397,8 +413,6 @@ void Process_makeCommandStr(Process* this, const Settings* settings) {
       haveCommInCmdline = (!Process_isUserlandThread(this) || showThreadNames) && findCommInCmdline(procComm, cmdline, cmdlineBasenameStart, &commStart, &commLen);
    }
 
-   int matchLen = matchCmdlinePrefixWithExeSuffix(cmdline, cmdlineBasenameStart, procExe, exeBasenameOffset, exeBasenameLen);
-
    bool haveCommField = false;
 
    if (!haveCommInExe && !haveCommInCmdline && procComm && (!Process_isUserlandThread(this) || showThreadNames)) {