Linux修改进程名称(setproctitle())
1.2 验证argv和environ执行连续内存的测试程序* To change the process title in Linux andSolaris we have to set argv[1] * to NULL and to copy the title to the sameplace where the argv[0] points to. * However, argv[0] may be too small to hold anew title. Fortunately, Linux * and Solaris store argv[] and environ[] oneafter another. So we should * ensure that is the continuous memory andthen we allocate the new memory * for environ[] and copy it. After this we could use the memory starting * from argv[0] for our process title. * * The Solaris's standard /bin/ps does not showthe changed process title. * You have to use "/usr/ucb/ps -w"instead. Besides, the UCB ps does not * show a new title if its length less than theorigin command line length. * To avoid it we append to a new title theorigin command line in the * parenthesis. */ extern char **environ; static char *ngx_os_argv_last; ngx_int_tngx_init_setproctitle(ngx_log_t *log){ u_char *p; size_t size; ngx_uint_t i; size = 0; for (i = 0; environ[i]; i++) { size+= ngx_strlen(environ[i]) + 1; } p = ngx_alloc(size, log); if (p == NULL) { return NGX_ERROR; } /* 这是为了找出argv和environ指向连续内存空间结尾的位置，为了能处理argv[i]被修改后，指向非进程启动时所分配的连续内存，而采用了下面的算法。但是实际上，这样还是处理不了这种情况。仅仅是个人愚见！！！ */ ngx_os_argv_last= ngx_os_argv[0]; for (i = 0; ngx_os_argv[i]; i++) { if (ngx_os_argv_last == ngx_os_argv[i]) { ngx_os_argv_last= ngx_os_argv[i]+ ngx_strlen(ngx_os_argv[i]) + 1; } } for (i = 0; environ[i]; i++) { if (ngx_os_argv_last == environ[i]) { size= ngx_strlen(environ[i]) + 1; ngx_os_argv_last= environ[i]+ size; ngx_cpystrn(p, (u_char *) environ[i], size); environ[i] = (char *) p; p+= size; } } ngx_os_argv_last--; return NGX_OK;} voidngx_setproctitle(char *title){ u_char *p; #if (NGX_SOLARIS) ngx_int_t i; size_t size; #endif ngx_os_argv[1]= NULL; p = ngx_cpystrn((u_char*) ngx_os_argv[0], (u_char*) "nginx: ", ngx_os_argv_last- ngx_os_argv[0]); p = ngx_cpystrn(p, (u_char *) title, ngx_os_argv_last - (char*) p); #if (NGX_SOLARIS) size = 0; for (i = 0; i < ngx_argc; i++) { size+= ngx_strlen(ngx_argv[i]) + 1; } if (size > (size_t)((char *) p - ngx_os_argv[0])) { /* * ngx_setproctitle() is too rareoperation so we use * the non-optimized copies */ p = ngx_cpystrn(p, (u_char *) " (",ngx_os_argv_last - (char*) p); for (i = 0; i < ngx_argc; i++) { p= ngx_cpystrn(p,(u_char *) ngx_argv[i], ngx_os_argv_last - (char*) p); p= ngx_cpystrn(p,(u_char *) "", ngx_os_argv_last - (char *) p); } if (*(p - 1) == ' ') { *(p- 1) = ')'; } } #endif if (ngx_os_argv_last - (char*) p) { ngx_memset(p, NGX_SETPROCTITLE_PAD,ngx_os_argv_last - (char*) p); } ngx_log_debug1(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0, "setproctitle:\"%s\"", ngx_os_argv[0]);}
