diff options
| -rw-r--r-- | procps/nmeter.c | 45 |
1 files changed, 30 insertions, 15 deletions
diff --git a/procps/nmeter.c b/procps/nmeter.c index cded67e56..068c739fb 100644 --- a/procps/nmeter.c +++ b/procps/nmeter.c @@ -22,11 +22,14 @@ typedef unsigned long long ullong; -enum { PROC_FILE_SIZE = 4096 }; +enum { /* Preferably use powers of 2 */ + PROC_MIN_FILE_SIZE = 256, + PROC_MAX_FILE_SIZE = 16 * 1024, +}; typedef struct proc_file { char *file; - //const char *name; + int file_sz; smallint last_gen; } proc_file; @@ -124,30 +127,42 @@ static void put_question_marks(int count) put_c('?'); } -static void readfile_z(char *buf, int sz, const char* fname) +static void readfile_z(proc_file *pf, const char* fname) { // open_read_close() will do two reads in order to be sure we are at EOF, // and we don't need/want that. -// sz = open_read_close(fname, buf, sz-1); - - int fd = xopen(fname, O_RDONLY); + int fd; + int sz, rdsz; + char *buf; + + sz = pf->file_sz; + buf = pf->file; + if (!buf) { + buf = xmalloc(PROC_MIN_FILE_SIZE); + sz = PROC_MIN_FILE_SIZE; + } + again: + fd = xopen(fname, O_RDONLY); buf[0] = '\0'; - sz = read(fd, buf, sz - 1); - if (sz > 0) - buf[sz] = '\0'; + rdsz = read(fd, buf, sz-1); close(fd); + if (rdsz > 0) { + if (rdsz == sz-1 && sz < PROC_MAX_FILE_SIZE) { + sz *= 2; + buf = xrealloc(buf, sz); + goto again; + } + buf[rdsz] = '\0'; + } + pf->file_sz = sz; + pf->file = buf; } static const char* get_file(proc_file *pf) { if (pf->last_gen != gen) { pf->last_gen = gen; - // We allocate PROC_FILE_SIZE bytes. This wastes memory, - // but allows us to allocate only once (at first sample) - // per proc file, and reuse buffer for each sample - if (!pf->file) - pf->file = xmalloc(PROC_FILE_SIZE); - readfile_z(pf->file, PROC_FILE_SIZE, proc_name[pf - &first_proc_file]); + readfile_z(pf, proc_name[pf - &first_proc_file]); } return pf->file; } |