This reworks get_process_cmdline() quite substantially, fixing the following:
- Fixes:
https://github.com/elogind/elogind/pull/3512/commits/
a4e3bf4d7ac2de51191ce136ee9361ba319e106c#r66837630
- The passed max_length is also applied to the "comm" name, if comm_fallback is
set.
- The right thing happens if max_length == 1 is specified
- when the cmdline "foobar" is abbreviated to 6 characters the result is not
"foobar" instead of "foo...".
- trailing whitespace are removed before the ... suffix is appended. The 7
character abbreviation of "foo barz" is hence "foo..." instead of "foo ...".
- leading whitespace are suppressed from the cmdline
- a comprehensive test case is added
assert(line);
assert(pid >= 0);
assert(line);
assert(pid >= 0);
+ /* Retrieves a process' command line. Replaces unprintable characters while doing so by whitespace (coalescing
+ * multiple sequential ones into one). If max_length is != 0 will return a string of the specified size at most
+ * (the trailing NUL byte does count towards the length here!), abbreviated with a "..." ellipsis. If
+ * comm_fallback is true and the process has no command line set (the case for kernel threads), or has a
+ * command line that resolves to the empty string will return the "comm" name of the process instead.
+ *
+ * Returns -ESRCH if the process doesn't exist, and -ENOENT if the process has no command line (and
+ * comm_fallback is false). */
+
p = procfs_file_alloca(pid, "cmdline");
f = fopen(p, "re");
p = procfs_file_alloca(pid, "cmdline");
f = fopen(p, "re");
+ if (max_length == 1) {
+
+ /* If there's only room for one byte, return the empty string */
+ r = new0(char, 1);
+ if (!r)
+ return -ENOMEM;
+
+ *line = r;
+ return 0;
+
+ } else if (max_length == 0) {
size_t len = 0, allocated = 0;
while ((c = getc(f)) != EOF) {
size_t len = 0, allocated = 0;
while ((c = getc(f)) != EOF) {
- if (!GREEDY_REALLOC(r, allocated, len+2)) {
+ if (!GREEDY_REALLOC(r, allocated, len+3)) {
free(r);
return -ENOMEM;
}
free(r);
return -ENOMEM;
}
+ bool dotdotdot = false;
size_t left;
r = new(char, max_length);
size_t left;
r = new(char, max_length);
while ((c = getc(f)) != EOF) {
if (isprint(c)) {
while ((c = getc(f)) != EOF) {
if (isprint(c)) {
+ if (left <= 2) {
+ dotdotdot = true;
*(k++) = ' ';
left--;
space = false;
}
*(k++) = ' ';
left--;
space = false;
}
+ if (left <= 1) {
+ dotdotdot = true;
*(k++) = (char) c;
left--;
*(k++) = (char) c;
left--;
- if (left <= 4) {
- size_t n = MIN(left-1, 3U);
- memcpy(k, "...", n);
- k[n] = 0;
+ if (dotdotdot) {
+ if (max_length <= 4) {
+ k = r;
+ left = max_length;
+ } else {
+ k = r + max_length - 4;
+ left = 4;
+
+ /* Eat up final spaces */
+ while (k > r && isspace(k[-1])) {
+ k--;
+ left++;
+ }
+ }
+
+ strncpy(k, "...", left-1);
+ k[left] = 0;
- r = strjoin("[", t, "]", NULL);
+ if (max_length == 0)
+ r = strjoin("[", t, "]", NULL);
+ else {
+ size_t l;
+
+ l = strlen(t);
+
+ if (l + 3 <= max_length)
+ r = strjoin("[", t, "]", NULL);
+ else if (max_length <= 6) {
+
+ r = new(char, max_length);
+ if (!r)
+ return -ENOMEM;
+
+ memcpy(r, "[...]", max_length-1);
+ r[max_length-1] = 0;
+ } else {
+ char *e;
+
+ t[max_length - 6] = 0;
+
+ /* Chop off final spaces */
+ e = strchr(t, 0);
+ while (e > t && isspace(e[-1]))
+ e--;
+ *e = 0;
+
+ r = strjoin("[", t, "...]", NULL);
+ }
+ }
if (!r)
return -ENOMEM;
}
if (!r)
return -ENOMEM;
}