Add support for basenames (short executable names)

Since we now store a full command line for each process, a few problems are
apparent. For example, the names displayed by ${top ...} are verbose. This has
been partially addressed by the top_name_verbose option, but it is broken
whenever an executable name contains spaces. Another example is ${if_running},
which only matches the input if it exactly matches the entire command line.

This commit adds a basename (i.e. executable filename) entry to the process
struct. The intention is to store the executable filename from /proc/<pid>/stat,
which was the old 1.9.x behavior. This way, we have the best of both worlds.
Those who like the full command line can have it, and those who prefer the old
way can be satisfied too.

src/linux.cc

@@ -2628,6 +2628,7 @@ static void process_parse_stat(struct process *process)
 {
 	char line[BUFFER_LEN] = { 0 }, filename[BUFFER_LEN], procname[BUFFER_LEN];
 	char cmdline[BUFFER_LEN] = { 0 }, cmdline_filename[BUFFER_LEN], cmdline_procname[BUFFER_LEN];
+	char basename[BUFFER_LEN] = { 0 };
 	char tmpstr[BUFFER_LEN] = { 0 };
 	char state[4];
 	int ps, cmdline_ps;
@@ -2722,6 +2723,7 @@ static void process_parse_stat(struct process *process)
 	rc = MIN((unsigned)(rparen - lparen - 1), sizeof(procname) - 1);
 	strncpy(procname, lparen + 1, rc);
 	procname[rc] = '\0';
+	strncpy(basename, procname, strlen(procname) + 1);
 
 	if (strlen(procname) < strlen(cmdline_procname))
 		strncpy(procname, cmdline_procname, strlen(cmdline_procname) + 1);
@@ -2770,7 +2772,9 @@ static void process_parse_stat(struct process *process)
 	}
 
 	free_and_zero(process->name);
+	free_and_zero(process->basename);
 	process->name = strndup(procname, text_buffer_size.get(*::state));
+	process->basename = strndup(basename, text_buffer_size.get(*::state));
 	process->rss *= getpagesize();
 
 	process->total_cpu_time = process->user_time + process->kernel_time;

src/top.cc

@@ -117,6 +117,7 @@ void free_all_processes(void)
 	while (pr) {
 		next = pr->next;
 		free_and_zero(pr->name);
+		free_and_zero(pr->basename);
 		free(pr);
 		pr = next;
 	}
@@ -165,6 +166,7 @@ static struct process *new_process(pid_t pid)
 
 	p->pid = pid;
 	p->name = 0;
+	p->basename = 0;
 	p->amount = 0;
 	p->user_time = 0;
 	p->total = 0;
@@ -230,6 +232,7 @@ static void delete_process(struct process *p)
 		first_process = p->next;
 
 	free_and_zero(p->name);
+	free_and_zero(p->basename);
 	/* remove the process from the hash table */
 	unhash_process(p);
 	free(p);

src/top.h

@@ -87,6 +87,7 @@ struct process {
 
 	pid_t pid;
 	char *name;
+	char *basename;
 	uid_t uid;
 	float amount;
 	// User and kernel times are in hundredths of seconds