From 33e0d5f874dc22c435bff5ed39b59be7f66b2e15 Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Tue, 29 Jun 2021 13:22:00 -0300 Subject: [PATCH] pahole: Introduce --prettify option MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The use of isatty(0) to switch into pretty printing is problematic as reported by Bernd Buschinski, that ran into problems with his scripts: ======================================================================== I am using pahole 1.21 and I recently noticed that I no longer have any pahole output in several scripts. Using (on the command line): $ pahole -V -E -C my_struct /path/to/my/debug.o works fine and gives the expected output. But: $ parallel -j 1 pahole -V -E -C my_struct ::: /path/to/my/debug.o gives nothing, no stderr, no stdout and ret code 0. After testing some versions, it works fine in 1.17 and no longer works in 1.18. ======================================================================== Since the pretty printer broke existing scripts, and its a relatively new feature, lets switch to using a explicit command line option to activate the pretty printer, i.e. where we used: $ pahole --header elf64_hdr < /bin/bash We now use one of: ⬢[acme@toolbox pahole]$ pahole --header elf64_hdr --prettify=/bin/bash { .e_ident = { 127, 69, 76, 70, 2, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0 }, .e_type = 3, .e_machine = 62, .e_version = 1, .e_entry = 204016, .e_phoff = 64, .e_shoff = 1388096, .e_flags = 0, .e_ehsize = 64, .e_phentsize = 56, .e_phnum = 13, .e_shentsize = 64, .e_shnum = 31, .e_shstrndx = 30, }, ⬢[acme@toolbox pahole]$ pahole --header elf64_hdr --prettify /bin/bash { .e_ident = { 127, 69, 76, 70, 2, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0 }, .e_type = 3, .e_machine = 62, .e_version = 1, .e_entry = 204016, .e_phoff = 64, .e_shoff = 1388096, .e_flags = 0, .e_ehsize = 64, .e_phentsize = 56, .e_phnum = 13, .e_shentsize = 64, .e_shnum = 31, .e_shstrndx = 30, }, ⬢[acme@toolbox pahole]$ pahole --header elf64_hdr --prettify - < /bin/bash { .e_ident = { 127, 69, 76, 70, 2, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0 }, .e_type = 3, .e_machine = 62, .e_version = 1, .e_entry = 204016, .e_phoff = 64, .e_shoff = 1388096, .e_flags = 0, .e_ehsize = 64, .e_phentsize = 56, .e_phnum = 13, .e_shentsize = 64, .e_shnum = 31, .e_shstrndx = 30, }, ⬢[acme@toolbox pahole]$ pahole --header elf64_hdr --prettify=- < /bin/bash { .e_ident = { 127, 69, 76, 70, 2, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0 }, .e_type = 3, .e_machine = 62, .e_version = 1, .e_entry = 204016, .e_phoff = 64, .e_shoff = 1388096, .e_flags = 0, .e_ehsize = 64, .e_phentsize = 56, .e_phnum = 13, .e_shentsize = 64, .e_shnum = 31, .e_shstrndx = 30, }, ⬢[acme@toolbox pahole]$ Reported-by: Bernd Buschinski Report-Link: https://lore.kernel.org/dwarves/CACN-hLVoz2tWrtgDLabOv6S1-H_8RD2fh8SV6EnADF1ikMxrmw@mail.gmail.com/ Tested-by-by: Bernd Buschinski Test-Link: https://lore.kernel.org/dwarves/CACN-hLXgHWdBkyMz+w58qX8DaV+WJ1mj1qheGBHbPv4fqozi5w@mail.gmail.com/ Signed-off-by: Arnaldo Carvalho de Melo --- man-pages/pahole.1 | 30 +++++++++++++++--------------- pahole.c | 40 +++++++++++++++++++++++++++++++++------- 2 files changed, 48 insertions(+), 22 deletions(-) diff --git a/man-pages/pahole.1 b/man-pages/pahole.1 index 5cb356b..a2bb920 100644 --- a/man-pages/pahole.1 +++ b/man-pages/pahole.1 @@ -21,7 +21,7 @@ It also uses these structure layouts to pretty print data feed to its standard input, e.g.: .PP .nf -$ pahole --header elf64_hdr < /lib/modules/5.8.0-rc6+/build/vmlinux +$ pahole --header elf64_hdr --prettify /lib/modules/5.8.0-rc6+/build/vmlinux { .e_ident = { 127, 69, 76, 70, 2, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0 }, .e_type = 2, @@ -566,8 +566,8 @@ $ .SH PRETTY PRINTING .P -pahole can also use the data structure types to pretty print raw data coming -from its standard input. +pahole can also use the data structure types to pretty print raw data specified via --prettify. +To consume raw data from the standard input, just use '--prettify -' .P It can also pretty print raw data from stdin according to the type specified: .PP @@ -585,7 +585,7 @@ $ $ ls -la versions -rw-rw-r--. 1 acme acme 7616 Jun 25 11:33 versions $ -$ pahole --count 3 -C modversion_info drivers/scsi/sg.ko < versions +$ pahole --count 3 -C modversion_info drivers/scsi/sg.ko --prettify versions { .crc = 0x8dabd84, .name = "module_layout", @@ -599,7 +599,7 @@ $ pahole --count 3 -C modversion_info drivers/scsi/sg.ko < versions .name = "param_ops_int", }, $ -$ pahole --skip 1 --count 2 -C modversion_info drivers/scsi/sg.ko < versions +$ pahole --skip 1 --count 2 -C modversion_info drivers/scsi/sg.ko --prettify - < versions { .crc = 0x45e4617b, .name = "no_llseek", @@ -611,7 +611,7 @@ $ pahole --skip 1 --count 2 -C modversion_info drivers/scsi/sg.ko < versions $ This is equivalent to: -$ pahole --seek_bytes 64 --count 1 -C modversion_info drivers/scsi/sg.ko < versions +$ pahole --seek_bytes 64 --count 1 -C modversion_info drivers/scsi/sg.ko --prettify versions { .crc = 0x45e4617b, .name = "no_llseek", @@ -662,7 +662,7 @@ $ Now we can use this to show the first record from offset zero: .PP .nf -$ pahole -C elf64_hdr --count 1 < /lib/modules/5.8.0-rc3+/build/vmlinux +$ pahole -C elf64_hdr --count 1 --prettify /lib/modules/5.8.0-rc3+/build/vmlinux { .e_ident = { 127, 69, 76, 70, 2, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0 }, .e_type = 2, @@ -685,7 +685,7 @@ $ This is equivalent to: .PP .nf -$ pahole --header elf64_hdr < /lib/modules/5.8.0-rc3+/build/vmlinux +$ pahole --header elf64_hdr --prettify /lib/modules/5.8.0-rc3+/build/vmlinux .fi .P The --header option also allows reference in other command line options to fields in the header. @@ -693,7 +693,7 @@ This is useful when one wants to show multiple records in a file and the range w are located is specified in header fields, such as for perf.data files: .PP .nf -$ pahole --hex ~/bin/perf --header perf_file_header < perf.data +$ pahole --hex ~/bin/perf --header perf_file_header --prettify perf.data { .magic = 0x32454c4946524550, .size = 0x68, @@ -718,7 +718,7 @@ $ So to display the cgroups records in the perf_file_header.data section we can use: .PP .nf -$ pahole ~/bin/perf --header=perf_file_header --seek_bytes '$header.data.offset' --size_bytes='$header.data.size' -C 'perf_event_header(sizeof,type,type_enum=perf_event_type,filter=type==PERF_RECORD_CGROUP)' < perf.data +$ pahole ~/bin/perf --header=perf_file_header --seek_bytes '$header.data.offset' --size_bytes='$header.data.size' -C 'perf_event_header(sizeof,type,type_enum=perf_event_type,filter=type==PERF_RECORD_CGROUP)' --prettify perf.data { .header = { .type = PERF_RECORD_CGROUP, @@ -770,7 +770,7 @@ $ For the common case of the header having a member that has the 'offset' and 'size' members, it is possible to use this more compact form: .PP .nf -$ pahole ~/bin/perf --header=perf_file_header --range=data -C 'perf_event_header(sizeof,type,type_enum=perf_event_type,filter=type==PERF_RECORD_CGROUP)' < perf.data +$ pahole ~/bin/perf --header=perf_file_header --range=data -C 'perf_event_header(sizeof,type,type_enum=perf_event_type,filter=type==PERF_RECORD_CGROUP)' --prettify perf.data .fi .P This uses ~/bin/perf to get the type definitions, the defines 'struct perf_file_header' as the header, @@ -844,7 +844,7 @@ If we remove that type_enum=perf_event_type, we will lose the conversion of 'str more descriptive 'struct perf_record_cgroup', and also the beautification of the header.type field: .PP .nf -$ pahole ~/bin/perf --header=perf_file_header --seek_bytes '$header.data.offset' --size_bytes='$header.data.size' -C 'perf_event_header(sizeof,type,filter=type==19)' < perf.data +$ pahole ~/bin/perf --header=perf_file_header --seek_bytes '$header.data.offset' --size_bytes='$header.data.size' -C 'perf_event_header(sizeof,type,filter=type==19)' --prettify perf.data { .type = 19, .misc = 0, @@ -876,7 +876,7 @@ $ Some of the records are not found in 'type_enum=perf_event_type' so some of the records don't get converted to a type that fully shows its contents. For perf we know that those are in another enumeration, 'enum perf_user_event_type', so, for these cases, we can create a 'virtual enum', i.e. the sum of two enums and then get all those entries decoded and properly casted, first few records with just 'enum perf_event_type': .PP .nf -$ pahole ~/bin/perf --header=perf_file_header --seek_bytes '$header.data.offset' --size_bytes='$header.data.size' -C 'perf_event_header(sizeof,type,type_enum=perf_event_type)' --count 4 < perf.data +$ pahole ~/bin/perf --header=perf_file_header --seek_bytes '$header.data.offset' --size_bytes='$header.data.size' -C 'perf_event_header(sizeof,type,type_enum=perf_event_type)' --count 4 --prettify perf.data { .type = 79, .misc = 0, @@ -907,7 +907,7 @@ $ Now with both enumerations, i.e. with 'type_enum=perf_event_type+perf_user_event_type': .PP .nf -$ pahole ~/bin/perf --header=perf_file_header --seek_bytes '$header.data.offset' --size_bytes='$header.data.size' -C 'perf_event_header(sizeof,type,type_enum=perf_event_type+perf_user_event_type)' --count 5 < perf.data +$ pahole ~/bin/perf --header=perf_file_header --seek_bytes '$header.data.offset' --size_bytes='$header.data.size' -C 'perf_event_header(sizeof,type,type_enum=perf_event_type+perf_user_event_type)' --count 5 --prettify perf.data { .header = { .type = PERF_RECORD_TIME_CONV, @@ -966,7 +966,7 @@ data range with the following command: .PP .nf pahole ~/bin/perf --header=perf_file_header \ - -C 'perf_file_attr(range=attrs),perf_event_header(range=data,sizeof,type,type_enum=perf_event_type+perf_user_event_type)' < perf.data + -C 'perf_file_attr(range=attrs),perf_event_header(range=data,sizeof,type,type_enum=perf_event_type+perf_user_event_type)' --prettify perf.data .fi .SH SEE ALSO diff --git a/pahole.c b/pahole.c index 06c4025..520ddef 100644 --- a/pahole.c +++ b/pahole.c @@ -35,6 +35,9 @@ static bool skip_encoding_btf_vars; static bool btf_encode_force; static const char *base_btf_file; +static const char *prettify_input_filename; +static FILE *prettify_input; + static uint8_t class__include_anonymous; static uint8_t class__include_nested_anonymous; static uint8_t word_size, original_word_size; @@ -854,6 +857,7 @@ ARGP_PROGRAM_VERSION_HOOK_DEF = dwarves_print_version; #define ARGP_with_flexible_array 324 #define ARGP_kabi_prefix 325 #define ARGP_btf_encode_detached 326 +#define ARGP_prettify_input_filename 327 static const struct argp_option pahole__options[] = { { @@ -1202,6 +1206,12 @@ static const struct argp_option pahole__options[] = { .key = ARGP_numeric_version, .doc = "Print a numeric version, i.e. 119 instead of v1.19" }, + { + .name = "prettify", + .key = ARGP_prettify_input_filename, + .arg = "PATH", + .doc = "Path to the raw data to pretty print", + }, { .name = NULL, } @@ -1332,6 +1342,8 @@ static error_t pahole__options_parser(int key, char *arg, btf_gen_floats = true; break; case ARGP_with_flexible_array: show_with_flexible_array = true; break; + case ARGP_prettify_input_filename: + prettify_input_filename = arg; break; default: return ARGP_ERR_UNKNOWN; } @@ -2586,7 +2598,7 @@ static enum load_steal_kind pahole_stealer(struct cu *cu, class_id = 0; } - if (!isatty(0)) { + if (prettify_input) { prototype->class = class; prototype->cu = cu; continue; @@ -2624,7 +2636,7 @@ static enum load_steal_kind pahole_stealer(struct cu *cu, // If we got here with pretty printing is because we have everything solved except for type_enum or --header - if (!isatty(0)) { + if (prettify_input) { // Check if we need to continue loading CUs to get those type_enum= and --header resolved if (header == NULL && conf.header_type) return LSK__KEEPIT; @@ -2637,7 +2649,7 @@ static enum load_steal_kind pahole_stealer(struct cu *cu, // All set, pretty print it! list_for_each_entry_safe(prototype, n, &class_names, node) { list_del_init(&prototype->node); - if (prototype__stdio_fprintf_value(prototype, header, stdin, stdout) < 0) + if (prototype__stdio_fprintf_value(prototype, header, prettify_input, stdout) < 0) break; } @@ -2783,9 +2795,6 @@ int main(int argc, char *argv[]) { int err, remaining, rc = EXIT_FAILURE; - if (!isatty(0)) - conf.hex_fmt = 0; - if (argp_parse(&pahole__argp, argc, argv, 0, &remaining, NULL)) { argp_help(&pahole__argp, stderr, ARGP_HELP_SEE, argv[0]); goto out; @@ -2801,6 +2810,19 @@ int main(int argc, char *argv[]) goto out; } + if (prettify_input_filename) { + if (strcmp(prettify_input_filename, "-") == 0) { + prettify_input = stdin; + } else { + prettify_input = fopen(prettify_input_filename, "r"); + if (prettify_input == NULL) { + fprintf(stderr, "Failed to read input '%s': %s\n", + prettify_input_filename, strerror(errno)); + goto out_dwarves_exit; + } + } + } + if (base_btf_file) { conf_load.base_btf = btf__parse(base_btf_file, NULL); if (libbpf_get_error(conf_load.base_btf)) { @@ -2825,7 +2847,7 @@ int main(int argc, char *argv[]) conf_load.steal = pahole_stealer; // Make 'pahole --header type < file' a shorter form of 'pahole -C type --count 1 < file' - if (conf.header_type && !class_name && !isatty(0)) { + if (conf.header_type && !class_name && prettify_input) { conf.count = 1; class_name = conf.header_type; conf.header_type = 0; // so that we don't read it and then try to read the -C type @@ -2923,6 +2945,10 @@ out_cus_delete: conf_load.base_btf = NULL; #endif out_dwarves_exit: + if (prettify_input && prettify_input != stdin) { + fclose(prettify_input); + prettify_input = NULL; + } #ifdef DEBUG_CHECK_LEAKS dwarves__exit(); #endif