This appears to be the relevant output, but I'm not as familiar with strace as I'd like to be:
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, + 0) = 0xb7b8a000 read(0, "load(\'jslint.js\');\nfoo=0;\nEND\n", 1024) = 30 read(0, "", 1024) = 0 read(0, "", 1024) = 0 close(0) = 0 munmap(0xb7b8a000, 4096) = 0 brk(0x8092000) = 0x8092000 open("jslint.js", O_RDONLY) = 0 fstat64(0, {st_mode=S_IFREG|0644, st_size=147870, ...}) = 0 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, + 0) = 0xb7b8a000 read(0, "// (C)2002 Douglas Crockford\n// "..., 4096) = 4096 read(0, " \"lawngreen\": true,\n "..., 4096) = 4096 read(0, "iframe: {},\n img: {\n "..., 4096) = 4096 read(0, " convertPathToHFS: true,\n "..., 4096) = 4096 brk(0x80b3000) = 0x80b3000 read(0, "ption.safe) {\n if (op"..., 4096) = 4096 read(0, " errorAt(\"Expected \'{a}\' and in"..., 4096) = 4096 read(0, ", character + j);\n "..., 4096) = 4096 read(0, " }\n "..., 4096) = 4096 read(0, " line: line,\n "..., 4096) = 4096 read(0, " q += "..., 4096) = 4096 brk(0x80d4000) = 0x80d4000 read(0, " }\n "..., 4096) = 4096 read(0, " l += 1;\n "..., 4096) = 4096 read(0, " break;\n case \'/*jsl"..., 4096) = 4096 read(0, "efault:\n warning("..., 4096) = 4096 read(0, " x.nud = (typeof f === \'funct"..., 4096) = 4096 read(0, "n);\n nonadjacent(toke"..., 4096) = 4096 brk(0x80f5000) = 0x80f5000 read(0, "SAFE.go.\', nexttoken);\n "..., 4096) = 4096 read(0, " warning(\"Expec"..., 4096) = 4096 read(0, " warning(\"Expected a "..., 4096) = 4096 read(0, "rder-top-style\': cssBorderStyle,"..., 4096) = 4096 read(0, "\', \'hidden\', \'collapse\'],\n "..., 4096) = 4096 brk(0x8116000) = 0x8116000 read(0, "== \'important\') {\n "..., 4096) = 4096 read(0, " while (nexttoken.id !== \'</\'"..., 4096) = 4096 read(0, " if (option.adsafe && stack."..., 4096) = 4096 read(0, "f (nexttoken.id && nexttoken.id."..., 4096) = 4096 read(0, " if (t.name !== n) {\n "..., 4096) = 4096 read(0, " case \'label\':\n "..., 4096) = 4096 brk(0x8137000) = 0x8137000 read(0, "\');\n syntax[\'--\'].exps = true"..., 4096) = 4096 read(0, " advance(\'.\');\n "..., 4096) = 4096 read(0, "tation();\n }\n "..., 4096) = 4096 read(0, " }\n for (;;) {\n "..., 4096) = 4096 brk(0x8158000) = 0x8158000 read(0, "ance(\')\', t);\n nospace(pr"..., 4096) = 4096 read(0, "exttoken.id === \'var\') {\n "..., 4096) = 4096 read(0, "eserve(\'let\');\n reserve(\'supe"..., 4096) = 4096 read(0, " approved[option.approved["..., 4096) = 4096 read(0, " + (isFinite(c.line) ? \' at line"..., 4096) = 4096 brk(0x8179000) = 0x8179000 read(0, "ength; i += 1) {\n var"..., 4096) = 414 read(0, "", 4096) = 0 close(0) = 0 munmap(0xb7b8a000, 4096) = 0
And if stops here until killed with ctrl-c, at which point it says "Process X detached", and I have to hunt down and kill the js process.
I can see where it is receiving the output from the perl script:
read(0, "load(\'jslint.js\');\nfoo=0;\nEND\n", 1024) = 30
And the series of reads that begin with:
read(0, "// (C)2002 Douglas Crockford\n// "..., 4096) = 4096
Appears to be where it loads jslint.js from the disk in blocks, but then nothing else appears to happen, which is interesting. If I execute it from the command-line, this is the output (starting from the last read() from the source file:
read(3, "ength; i += 1) {\n var"..., 4096) = 414 read(3, "", 4096) = 0 close(3) = 0 munmap(0xb7af6000, 4096) = 0 fstat64(0, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 0), ...}) = 0 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, + 0) = 0xb7af6000 read(0, foo=bar; "foo=bar;\n", 1024) = 9 read(0, END "END\n", 1024) = 4 write(1, "jslint: No problems found.\n", 27jslint: No problems found. ) = 27 write(1, "\n", 1 ) = 1 exit_group(3) = ?
So, it displays "read(0" from the terminal. What is that telling me, precisely? Does this mean that, once it enters into the "input=readline();" loop, it sends the read signal when in a terminal, but not otherwise? If so, I guess that's my answer.
In reply to Calling strace -f
by Socrates
in thread Diagnosing blocking io (or: finding the WHY of my Open2 woes).
by Socrates
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