make find_pid_by_name look at /proc/PID/exe too

function                                             old     new   delta
procps_scan                                         1642    1709     +67
find_pid_by_name                                     193     223     +30
free_procps_scan                                      29      37      +8

Signed-off-by: Alexander Shishkin <virtuoso@slind.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/include/libbb.h b/include/libbb.h
index c7b4de1..51ac69e 100644 (file)
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -1280,6 +1280,7 @@ typedef struct procps_status_t {
 /* Fields are set to 0/NULL if failed to determine (or not requested) */
        uint16_t argv_len;
        char *argv0;
+       char *exe;
        IF_SELINUX(char *context;)
        /* Everything below must contain no ptrs to malloc'ed data:
         * it is memset(0) for each process in procps_scan() */
@@ -1327,7 +1328,7 @@ enum {
        PSSCAN_COMM     = 1 << 5,
        /* PSSCAN_CMD      = 1 << 6, - use read_cmdline instead */
        PSSCAN_ARGV0    = 1 << 7,
-       /* PSSCAN_EXE      = 1 << 8, - not implemented */
+       PSSCAN_EXE      = 1 << 8,
        PSSCAN_STATE    = 1 << 9,
        PSSCAN_VSZ      = 1 << 10,
        PSSCAN_RSS      = 1 << 11,

diff --git a/libbb/find_pid_by_name.c b/libbb/find_pid_by_name.c
index 600d4e1..52a0c6d 100644 (file)
--- a/libbb/find_pid_by_name.c
+++ b/libbb/find_pid_by_name.c
@@ -41,18 +41,20 @@ and therefore comm field contains "exe".
 static int comm_match(procps_status_t *p, const char *procName)
 {
        int argv1idx;
+       const char *argv1;
 
-       /* comm does not match */
        if (strncmp(p->comm, procName, 15) != 0)
-               return 0;
+               return 0; /* comm does not match */
 
-       /* in Linux, if comm is 15 chars, it may be a truncated */
-       if (p->comm[14] == '\0') /* comm is not truncated - match */
-               return 1;
+       /* In Linux, if comm is 15 chars, it is truncated.
+        * (or maybe the name was exactly 15 chars, but there is
+        * no way to know that) */
+       if (p->comm[14] == '\0')
+               return 1; /* comm is not truncated - matches */
 
        /* comm is truncated, but first 15 chars match.
         * This can be crazily_long_script_name.sh!
-        * The telltale sign is basename(argv[1]) == procName. */
+        * The telltale sign is basename(argv[1]) == procName */
 
        if (!p->argv0)
                return 0;
@@ -60,8 +62,9 @@ static int comm_match(procps_status_t *p, const char *procName)
        argv1idx = strlen(p->argv0) + 1;
        if (argv1idx >= p->argv_len)
                return 0;
+       argv1 = p->argv0 + argv1idx;
 
-       if (strcmp(bb_basename(p->argv0 + argv1idx), procName) != 0)
+       if (strcmp(bb_basename(argv1), procName) != 0)
                return 0;
 
        return 1;
@@ -83,11 +86,12 @@ pid_t* FAST_FUNC find_pid_by_name(const char *procName)
        procps_status_t* p = NULL;
 
        pidList = xzalloc(sizeof(*pidList));
-       while ((p = procps_scan(p, PSSCAN_PID|PSSCAN_COMM|PSSCAN_ARGVN))) {
+       while ((p = procps_scan(p, PSSCAN_PID|PSSCAN_COMM|PSSCAN_ARGVN|PSSCAN_EXE))) {
                if (comm_match(p, procName)
                /* or we require argv0 to match (essential for matching reexeced /proc/self/exe)*/
                 || (p->argv0 && strcmp(bb_basename(p->argv0), procName) == 0)
-               /* TODO: we can also try /proc/NUM/exe link, do we want that? */
+               /* or we require /proc/PID/exe link to match */
+                || (p->exe && strcmp(bb_basename(p->exe), procName) == 0)
                ) {
                        pidList = xrealloc_vector(pidList, 2, i);
                        pidList[i++] = p->pid;

diff --git a/libbb/procps.c b/libbb/procps.c
index 6e122c4..307d8d6 100644 (file)
--- a/libbb/procps.c
+++ b/libbb/procps.c
@@ -111,6 +111,7 @@ void FAST_FUNC free_procps_scan(procps_status_t* sp)
 {
        closedir(sp->dir);
        free(sp->argv0);
+       free(sp->exe);
        IF_SELINUX(free(sp->context);)
        free(sp);
 }
@@ -213,7 +214,7 @@ procps_status_t* FAST_FUNC procps_scan(procps_status_t* sp, int flags)
                }
 #endif
 
-               filename_tail = filename + sprintf(filename, "/proc/%d", pid);
+               filename_tail = filename + sprintf(filename, "/proc/%u/", pid);
 
                if (flags & PSSCAN_UIDGID) {
                        if (stat(filename, &sb))
@@ -230,7 +231,7 @@ procps_status_t* FAST_FUNC procps_scan(procps_status_t* sp, int flags)
                        unsigned long vsz, rss;
 #endif
                        /* see proc(5) for some details on this */
-                       strcpy(filename_tail, "/stat");
+                       strcpy(filename_tail, "stat");
                        n = read_to_buf(filename, buf);
                        if (n < 0)
                                break;
@@ -340,7 +341,7 @@ procps_status_t* FAST_FUNC procps_scan(procps_status_t* sp, int flags)
                if (flags & (PSSCAN_SMAPS)) {
                        FILE *file;
 
-                       strcpy(filename_tail, "/smaps");
+                       strcpy(filename_tail, "smaps");
                        file = fopen_for_read(filename);
                        if (!file)
                                break;
@@ -390,7 +391,7 @@ procps_status_t* FAST_FUNC procps_scan(procps_status_t* sp, int flags)
                if (flags & PSSCAN_RUIDGID) {
                        FILE *file;
 
-                       strcpy(filename_tail, "/status");
+                       strcpy(filename_tail, "status");
                        file = fopen_for_read(filename);
                        if (!file)
                                break;
@@ -415,7 +416,7 @@ procps_status_t* FAST_FUNC procps_scan(procps_status_t* sp, int flags)
                        sp->argv0 = NULL;
                        free(sp->cmd);
                        sp->cmd = NULL;
-                       strcpy(filename_tail, "/cmdline");
+                       strcpy(filename_tail, "cmdline");
                        /* TODO: to get rid of size limits, read into malloc buf,
                         * then realloc it down to real size. */
                        n = read_to_buf(filename, buf);
@@ -436,7 +437,7 @@ procps_status_t* FAST_FUNC procps_scan(procps_status_t* sp, int flags)
                if (flags & (PSSCAN_ARGV0|PSSCAN_ARGVN)) {
                        free(sp->argv0);
                        sp->argv0 = NULL;
-                       strcpy(filename_tail, "/cmdline");
+                       strcpy(filename_tail, "cmdline");
                        n = read_to_buf(filename, buf);
                        if (n <= 0)
                                break;
@@ -451,6 +452,11 @@ procps_status_t* FAST_FUNC procps_scan(procps_status_t* sp, int flags)
                        }
                }
 #endif
+               if (flags & PSSCAN_EXE) {
+                       strcpy(filename_tail, "exe");
+                       free(sp->exe);
+                       sp->exe = xmalloc_readlink(filename);
+               }
                break;
        }
        return sp;