从 AVR ihex 文件中提取字符串

Question

我正在使用 avr-gcc 来生成 elf 文件以及稍后

avr-objcopy -O ihex -R .eeprom main.elf main.hex

创建用于编程的十六进制文件。如何从生成的十六进制文件中提取所有字符串？我试过了

avr-objdump -j .sec1 -D -m avr5 main.hex

但是这并没有显示任何字符串。

背景：.hex 文件存储在没有 .elf 的单独介质上，我想在使用 avrdude 编程之前检查版本字符串

Answer 1

假设日期是像“Sep 10 2020”这样的字符串，您可以通过将数据字节解释为字符流，选择该流中的可打印字符串（由 NUL 字节分隔）并将它们与您选择的日期格式。下面是 awk 可执行脚本，如果使用 -vout=date 选项调用，则执行此操作，否则执行其他有用的操作

#!/bin/awk -f
# dump Intel hex format https://en.wikipedia.org/wiki/Intel_HEX
# several output formats are possible
#  normal       is the default hexdump style
#  date         attempts to extract a single date encoded in the binary
#  string/ascii display nonempty strings of printable/ascii characters
#  size         returns the total number of DAT bytes (code)
BEGIN {
    types[0]="DAT"     # Data
    types[1]="EOF"     # End Of File
    types[2]="ESA"     # Extended Segment Address
    types[3]="SSA"     # Start Segment Address
    types[4]="ELA"     # Extended Linear Address
    types[5]="SLA"     # Start Linear Address
    if(!length(out))
    out="normal";  # output format (string,ascii,normal,date,size)
    if(!length(dateform))
    dateform="(Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec) [0-9]+ [0-9]+"
    maxbytes=255       # avoid long strings
    pcnt=nl=0;
    size=0;
}
{
    sub(/^.*:/,"");    # remove the start code byte(s) of the record
    sub(/\r$/,"");     # remove the CR at the end (if terminated by CR+LF)
    patsplit($0,s,"[[:xdigit:]]{2}");
    bytes=s[1];        # byte count
    if(length(s)-5 != strtonum("0x" bytes))
    printf("BYTE COUNT ERROR %i for record " NR " with %s %s bytes and full length of %i bytes\n",
           length(s)-5,strtonum("0x" bytes),type,length(s)) > "/dev/stderr";
    address=s[2] s[3]; # memory location
    type=types[strtonum("0x" s[4])];  # meaning of the data field
    csum=s[length(s)]; # checksum byte at the end
    c=0;               # check record validity
    for (i = 1; i <= length(s); i++) {
    # printf("%02x+%s=", c,s[i]);
    c+=strtonum("0x" s[i]);
    c=and(c,0xFF);
    }
    if(c)
    printf("CHECKSUM ERROR %02x for record " NR " with %s %s bytes and checksum %s\n",
           c,strtonum("0x" bytes),type,csum) > "/dev/stderr";
    sub(/^[[:xdigit:]]{8}/,"");  # remove byte count, address, and type bytes
    sub(/[[:xdigit:]]{2}$/,"");  # remove the checksum endbyte
    if(length(s)-5 != length($0)/2)
    printf("LENGTH ERROR %i for record " NR " with %s %s bytes and full length of %i bytes\n",
           length(s)-5,strtonum("0x" bytes),type,length($0)) > "/dev/stderr";
    switch (out) {
    case "date":
    if(NR==1) d="";
    for (i = 5; i < length(s); i++) {
        if(length(p)>=maxbytes) p=""; # truncate long strings
        p=sprintf("%c",strtonum("0x" s[i]));
        if(p~/[\x00-\x7F]/ && p~/[[:print:]]/) d=d p;
        if(p=="\0") {
        # /(Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec) [0-9]+ [0-9]+/
        if(length(d) && match(d,dateform)) {
            printf("%s\n",d);
            exit; # assuming there's only one date ...
        }
        d="";
        }
    }
    break;
    case "ascii":
    for (i = 5; i < length(s); i++) {
        p=sprintf("%c",strtonum("0x" s[i]));
        if(p~/[\x00-\x7F]/ && p~/[[:print:]]/) {printf("%s",p); pcnt++};
        if(p=="\0") {
        if(pcnt) printf("\n"); nl++; pcnt=0;
        }
    }
    break;
    case "string":
    for (i = 5; i < length(s); i++) {
        p=sprintf("%c",strtonum("0x" s[i]));
        if(p~/[[:print:]]/) {printf("%s",p); pcnt++};
        if(p=="\0") {
        if(pcnt) printf("\n"); nl++; pcnt=0;
        }
    }
    break;
    case "normal":
    default:
    printf("%s %s %s %s %s ", address, bytes, type, $0, csum);
    for (i = 5; i < length(s); i++) {
        p=sprintf("%c",strtonum("0x" s[i]));
        printf("%s",p~/[[:print:]]/?p:".");
    }
    printf("\n");
    case "size":
    if(type==types[0]) size+=bytes;
    }
}

END{
    switch (out) {
    case "size":
    printf("%i\n",size);
    break;
    case "normal":
    printf("%i data bytes\n",size);
    default:
    }
}